CONTENTS Project team i Executive Summary ii List of tables xiii List of figures xvi Common abbreviations xx 1 INTRODUCTION 1 1.1 Background 1 1.2 Objectives 2 1.3 Scope of study 2 1.3.1 Physical processes 2 1.3.2 Water quality 3 1.3.3 Sediment quality 3 1.3.4 Biological characteristics 3 1.3.5 Assessment 4 1.4 Approach strategy

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2 PROJECT DOMAIN 6 2.1 The company-RSPL 6 2.2 Project Location 6 2.3 Project description 7 2.3.1 Soda ash process 8 2.3.2 Captive power plant 13 2.3.3 DG set 15 2.4 Proposed marine activities 15 2.4.1 Seawater intake 15 2.4.2 Effluent disposal 16 2.4.3 Field and model studies 17 3 EARLIER STUDIES IN SURROUNDING REGION AND AVAILABLE

INFORMATION 18

3.1 Saurashtra coast/Arabian sea 18 3.1.1 Land environment 19 3.1.2 Geomorphology 20 3.1.3 Meteorological conditions 21 3.1.4 Marine environment 22 3.2 Adjacent area 25 3.2.1 Land environment 26 3.2.2 Marine environment 26 4 STUDIES CONDUCTED 30 4.1 Period of study 30 4.2 Sampling locations 30 4.3 Sampling frequency 31 4.4 Physical processes 32 4.5 Water quality 32 4.6 Sediment quality 34 4.7 Flora and fauna 35 4.8 Model studies 38

5 PREVAILING MARINE ENVIRONMENT 39 5.1 Physical processes 39 5.1.1 Bathymetry 40 5.1.2 Tides 40 5.1.3 Currents 41

5.1.4 Tidal excursion 42 5.2 Water quality 43 5.2.1 Temperature 44 5.2.2 pH 45 5.2.3 Suspended Solids (SS) 46 5.2.4 Salinity 47 5.2.5 DO and BOD 48 5.2.6 Phosphorous and nitrogen compounds 50 5.2.7 PHc and phenols 55 5.2.8 Temporal variations 57 5.3 Sediment quality 57 5.3.1 Texture 58 5.3.2 Heavy metals 58 5.3.3 Corg and phosphorus 60 5.3.4 PHc 61 5.4 Flora and fauna 62 5.4.1 Bacteria 64 5.4.2 Phytoplankton 65 5.4.3 Zooplankton 71 5.4.4 Macrobenthos 80 5.4.5 Corals and associated biota 87 5.4.6 Seaweeds 89 5.4.7 Fishery 90 5.4.8 Sand dunes 91 5.4.9 Mangroves 92 6 MODELING STUDIES FOR MARINE FACILITIES 93 6.1 Marine facilities 93 6.1.1 Seawater intake 93 6.1.2 Release of effluent 95 6.1.3 Modeling 96 6.2 Hydrodynamic model 96 6.2.1 Basic governing equations 97 6.2.2 Continuity equation 97 6.2.3 Momentum equations 97 6.2.4 Boundary Fitted Coordinate (BFC) System 97 6.2.5 Diffusion coefficients 98 6.2.6 Numerical solution algorithm 99 6.3 Model setup and calibration 99 6.3.1 Boundary conditions 99 6.3.2 Bed roughness 100 6.3.3 Initial and boundary conditions 100 6.3.4 Model calibration 101 6.4 Modeling for tides and currents 101 6.4.1 Tides and currents during Low Water (LW) 102 6.4.2 Tides and currents during Peak Flood (PF) 102 6.4.3 Tides and currents during Highest High Water (HHW) 102 6.4.4 Tides and currents during Peak Ebb (PE) 103 6.5 Modeling for flow of intake 103 6.5.1 Model description 103 6.5.2 Model setup, calibration and validation 103 6.5.3 Modeling for tides and currents at intake point: IT1 104 6.5.4 Modeling for tides and currents at intake point:IT2 107 6.5.5 Impact on flow regime and flow circulation at the intake point location: IT2 109 6.6 Outfall modeling study 110

6.6.1 Effluent discharge at location: OF1 111 6.6.2 Effluent discharge at location: OF2 116 6.6.3 Summary of results 120 6.7 SS transport modeling 121 6.7.1 Numerical approach to SS (cohesive and non-cohesive) transport modeling

studies 121

6.7.2 Available data pertaining to the morphological assessment 121 6.7.3 SS transport simulation 122 6.7.4 Morphological changes 124 6.8 Particle trajectory modeling 125 6.9 Mode of discharge 125 6.9.1 Near-field dilution due to a forced bottom release 126 6.9.2 Thickness of the polluted layer 128 6.10 Configuration of the diffuser 129 7 POTENTIAL MARINE ENVIRONMENTAL IMPACTS 130 7.1 Seawater intake 130 7.1.1 Scheme 130 7.1.2 Potential marine environmental impacts 130 7.2 Effluent disposal 137 7.2.1 Scheme 137 7.2.2 Potential marine environmental impacts 137 8 MITIGATION MEASURES 145 8.1 Construction phase 145 8.2 Operational phase 146 8.2.1 Seawater intake 146 8.2.2 Effluent disposal 147 9 MANAGEMENT OF MARINE ENVIRONMENT 148 9.1 Pre-project monitoring for baseline quality 148 9.2 Post-project monitoring for assessment 149 10 SUMMARY AND RECOMMENDATIONS 150 10.1 Introduction 150 10.2 Project domain 150 10.2.1 Location 150 10.2.2 Process 151 10.2.3 Marine facilities 151 10.3 Study area 152 10.4 Studies conducted 152 10.4.1 Field investigations 152 10.4.2 Model studies 153 10.5 Prevailing marine environment 153 10.5.1 Physical processes 153 10.5.2 Water quality 153 10.5.3 Sediment quality 154 10.5.4 Flora and fauna 155 10.6 Modeling studies for marine facilities 156 10.6.1 Hydrodynamic modeling 156 10.6.2 Seawater intake 157 10.6.3 Effluent release 157 10.7 Potential marine environmental impacts 159 10.7.1 Seawater intake 159

10.7.2 Effluent disposal 162 10.8 Mitigation Measures 165 10.8.1 Construction phase 165 10.8.2 Operational phase 166 10.9 Management of marine environment 167

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PROJECT TEAM S. N. Gajbhiye V. S. Naidu Anirudh Ram Jaiswar Soniya Sukumaran Rakesh P.S. M.A. Rokade G. K. Chauhan D.S. Bagde Mohammed Ilyas Jairam G. Oza Dipali Bandodkar Gauri Shenoy Amit Patil Prachi Hatkar Ayushi Maloo Sunil Belvekar Shubhangi Kachave Ajay Yadav Divya Majithia Mahesh Chavan Shailesh Salvi Vaibhav Joshilkar Swati Sonavane Suman Ghadigaonkar Nilesh Ghuikar Vaishali Varpe Anurag Killedar Swapnil Dalvi Reshma Kadam CONSULTANTS R. V. Sarma Jiyalal Ram M. Jaiswar EXTERNAL EXPERT A. N. Kadam M. I. Patel

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EXECUTIVE SUMMARY

M/s RSPL Limited (RSPL) proposes to set-up a green field soda ash plant (1500

TPD Light Soda Ash /770 TPD Dense Soda Ash – Dense Soda Ash is conversion of

Light Soda Ash) with a captive power plant (50 MW) near Village Kuranga in Devbhumi

Dwarka District (earlier Jamnagar district) of Gujarat State. RSPL has planned to

establish marine facilities namely (a) seawater intake of about 6 × 105 m3/d for process,

cooling DM plant utilities and process plant effluent dilution etc. and (b) effluent disposal

of 6 × 105 m3/d from process, brine purification rejects, DM plant rejects etc. after

treatment / dilution with once through return cooling water / fresh seawater to meet

GPCB / CPCB norms in the coastal waters off Kuranga in Arabian Sea.

CSIR-NIO on behalf of RSPL therefore conducted detailed oceanographic

investigations of the coastal waters off Kuranga during April-May 2012 (premonsoon),

September 2012 (monsoon) and December 2012 (postmonsoon) with the objectives of

a) establishing prevailing ecological status of the study area,

b) suggesting suitable sites and modes for seawater intake and effluent disposal,

c) assessing impact on the coastal ecology and

d) suggesting adequate Marine Environmental Plan (MEMP) including mitigation

measures.

Project Information Soda Ash process: Soda ash (Na2CO3) is manufactured by the reaction between

sodium chloride and limestone with ammonia as an intermediate carrier. The major

steps involved in the process are as follows: (a) Brine purification in which the saturated

brine is treated with soda ash and milk of lime to remove residual impurities. (b) Limestone calcination whereby limestone is mixed with coke and charged to lime kilns

to produce CO2 and CaO. Part of CaO is hydrated with sweet water to make milk of lime

for treatment of brine. Major part of lime is grind and fed to Prelimer for release of

ammonia. (c) Ammonia is absorbed in purified brine in absorber and thereafter CO2

from compressors is fed in carbonation columns to obtain crude sodium bicarbonate as

a solid phase which is filtered and decomposed to Soda Ash (Na2CO3) in calliper.

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The filtrate containing NH4Cl is reacted with Ca(OH)2 in prelimer stills to recover NH3 in

ammonia still which is recycled. Ammonia still discharge is the major effluent from soda

ash industry. This effluent contains high concentration of inorganic non-toxic solids and

liquid is rich in salts with traces of NH3. About 300 to 500 kg of solids are produced per

tonne of soda ash manufactured. The effluent after removal of NH3 is diluted with return

cooling seawater to meet disposal norms.

Power plant: The captive power plant of 50 MW (20 MW × 2 nos. + 10 MW x 1 no.)

capacity multi-extraction turbo-attunator and 150 TPH × 3 nos. Light/ Coal based

boilers. The steam generator units will be compact semi-outdoor, returned/assisted

circulation, balanced draft, single drum, water tube type provided with circulating

fluidized bed combustion system.

Marine facilities: Seawater intake (6 × 105 m3/d) and effluent release (6 × 105 m3/d) will

be established in the coastal waters off Kuranga in Arabian Sea on the basis of field

investigation and model studies.

Study area

The coastal waters off Kuranga form a part of the coastal stretch between

Dwarka and Porbandar of Saurashtra coast. The area sustains sparse and scattered

vegetation with barely 11 % of the land irrigated. Except few pockets of Porbandar,

Dwarka, Mithapur etc the coastal belt is sparsely populated. With low and variable rains

the climate is hot and humid, and winter is brief.

Prevailing Marine Environment

The coastal waters off Kuranga covering 280 km2 areas was investigated for its

environmental characteristics.

Physical processes:

The tides with 1.2 to 3.5 m rise were mixed semi diurnal. The currents parallel to shore

were 0.3 m/s (max). The tidal excursion was variable depending upon tidal phase,

location and period.

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Water quality:

The average water temperature (21.6 – 29.6 oC) varied in accordance with

the air temperature and was generally below 30oC. The lateral variations

were small and the vertical gradient in temperature was also marginal

indicating well mixed waters.

The average pH (8.0 - 8.3) was in the range expected for the coastal area

and spatial or temporal changes were minor. The surface to the bottom

variation was not marked.

Average SS was in the wide range of 16 to 274 mg/l during the present

study. The vertical variation was insignificant in the study area. The content

was higher with marked spatial variations during pre-monsoon. It was lower

during monsoon and post-monsoon indicating significant seasonal

variations.

The average salinity ranged from 35.2 to 37.0 ppt and was fairly stable.

Narrow ranges of variation between the surface and the bottom as well as

laterally indicated that the waters were well mixed and stratification was

largely absent.

Coastal waters shows the average DO of in excess 4 mg/l, the coastal

waters were well oxygenated indicating healthy environment for biological

growth. The seasonal as well as spatial variations were largely absent

indicating absence of any influxes of biodegradable organic matter.

BOD of the study area was < 0.1 to 6.7 mg/l which is low and common to

such highly productive coastal ecosystems. The low BOD indicated that

degradable organic matter entering the coastal waters was efficiently

oxidised by high available DO in the waters to maintain very good oxidative

conditions in the study area.

Phosphorus as phosphate (PO43--P) one of the major nutrients was present

in low range of ND to 2.3 mol/l and spatial variations were evident only

during pre-monsoon when the levels were higher. Low levels of NH4+-N (av

v

ND – 2.2 mol/l) and NO2--N (av < 2.2 mol/l) indicated good oxidizing

conditions in water.

The average concentrations of PHc (0.2 – 32.8 g/l) and phenols (69 - 146

g/l) were low and in the range commonly encountered in uncontaminated

coastal waters.

Sediment quality:

Sediment exhibited low and variable metal contents while Corg, P and PHc

were low indicating lowly contaminated sediment.

Texture of the sediment in the region was influenced by hard rocky

substratum. The sediment texture was mostly sand (> 91%, dry wt) except

that for the subtidal sediment during December 2012 (postmonsoon) when

sediment was mostly silt(> 83 %). The sediment possessed clay in meagre

percentage.

The subtidal as well as the intertidal sediments off Kuranga sustained

variable concentrations of trace metals such as chromium, cobalt, nickel,

copper, zinc and mercury primarily because of the heterogeneous

character of sediments. The Corg (<1.9 %; dry wt) and phosphorus (< 818 -

1514 g/g; dry wt) contents in sediments were low. The concentrations of

PHc (0.1 - 1.4 g/g; wet wt) in the sediment were also low and revealed

uncontaminated status of the sediment with respect to PHc.

Flora and fauna:

Bacterial count like TVC in water and sediment was low and without any

specific trend. Pathogens were rarely noticed suggesting clean and natural

coastal system off Kuranga.

The concentration of chlorophyll a in the coastal water (0.7 - 30.6 mg/m3)

indicated variable and patchy phytoplankton biomass. The concentration of

phaeophytin (0.2 - 5.8 mg/m3) was low. The phytoplankton population was

variable in accordance with the trend in phytopigments. Overall, 19 genera

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were recorded in the region with the common occurrence of Nitzschia,

Navicula, Chaetoceros, Thalassiosira etc.

Mangroves were absent along the Kuranga coast. The intertidal rocky

region (150-300m) however sustained marine algae. Species such as

Caulerpa racemosa, Ulva lactuca, Andorea indica etc. and floating algae

like sargassum polycastrum. The sand dunes, particularly narrow foreshore

and burm regions of 20 to 40 m width supported sand dune vegetation,

mostly in patches. The sand dune flora was dominated by babul and grass

vegetation.

The zooplankton standing stock in terms of biomass (0.04 - 1.4 ml/100m3)

and population (0.3 - 19.6 × 103 no/100m3) was indicative of an overall

moderate secondary production and varied widely. The composition of

zooplankton was fairly diverse and consisted mainly of copepods,

decapods larvae, lamellibranchs, gastropods and cladocera, foraminiferans

which together contributed about 97 % to the total population. Overall 18

faunal groups were identified. The most dominant groups were crab zoea

and pagurids.

The intertidal macrobenthic standing stock in terms of population and

biomass varied from 0 to 7125 no/m2 and from 0 to 61.0 g/m2; wet wt

respectively. The fauna was mainly constituted by crustaceans,

polychaetes and mollusks. The faunal group diversity varied between 0

and 6 groups. The subtidal benthic macrofaunal standing stock in terms of

population and biomass varied from 0 to 7100 no/m2 and from 0 to 21.5

g/m2; wet wt with poor faunal group diversity (2 - 8 no). The faunal

composition indicated overall dominance of polychaetes followed by

crustaceans.

Three transects IV, V and VI in the intertidal area were investigated for the

presence of corals. The intake corridor is free from corals. Transect IV

sustained isolated corals namely Porites compressa, Favia Favus and

Zoanthus sp. Transect V with predominant sandy intertidal stretch

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sustained low coral density of Porites compressa and Zoanthus. Some

signs of turtle nesting grounds were seen on the sandy beaches. However

live turtles and eggs were not sighted during the visit. Transect VI was free

from corals. No planulae larvae was seen during visit at this transect.

Assessment by remote sensing imagery did not reveal presence of corals

in the 5 km radius of the pipeline corridors including the subtidal area.

The Gulf contributes about 22 % to the fish production of the state. The

share of the Jamnagar District is between 5 and 14 % to the state’s total

marine fish landings. The nearby fish landing centers are Gojines,

Navadra, Bhogat, Harshad etc. Some fishermen were seen operating bag

netting and gill netting in the coastal waters off Kuranga. The fishes

obtained from this local fishermen of Gojiness were John’s snapper

(Lutjanus johnii), Dussumeir’s croaker (Johnius dussumerri), Long

toungsole (Cynoglossus lingua), White fish (Lactarius lactarius), Blackspot

threadfin (Polydactylus sextarius), Paplet/ pomfret (Pampus argenticus),

Black pomfret (Parastomateus niger), Yellowfin jack (Caranx para), Giant

captainfish (Johnius elongatus), Silver black porgy (Sparidentex hasta),

Speigler's mullet (Valamugil speigleri), Mandeli (Coilia dussumieri), Tiger

shrimp (Penaus monodon), White shrimp (Fenneropenaeus indicus) and

Spiny lobster (Panulirus sp).

Adjacent Marine Environment of Gojiness: The present results were comparable

with that of the adjacent coastal areas of Gojiness.

Modeling Studies for Marine Facilities:

Hydrodynamic modeling: Numerical modeling was done using Hydrodyn-FlOSOFT,

Hydrodyn-POLSOFT and Hydrodyn-SEDSOFT software for prediction of tides and

currents, dilution and dispersion processes in marine areas; and sediment transport in

tidally diversion zones.

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Seawater Intake:

Two options IT1: 210 59' 49.70" N; 690 10' 24.60" (depth 4.5 m below CD) and IT2: 210

59' 46.02" N; 690 10' 20.04" (depth 7.0 m below CD) were studied. In both the cases the

impact on currents and water levels was similar in trough of 40 to 50 m radius and not

significant.

The location IT1 is recommended on the basis of minimal area and volume of

excavation and consequent lower macrobenthic losses due to shorter length. The

corridor is devoid of mangroves, corals and sand dunes. The land based sump and

intake point (IT1) will be connected through buried pipelines of suitable diameter. The

seawater will flow under gravity.

Effluent Release:

Two options OF1: 220 01' 25.62" N; 690 08' 06.27"E (depth 13-14 m below CD) and

OF2: 220 00' 39.51" N; 690 09' 07.01"E (depth 12 m below CD) were studied for effluent

release location. In both the cases the critical parameters namely temperature 5 ºC

above ambient, SS: 1000 mg/l and ammonia: 5 mg/l would similarly and would attain

the ambient values within 300 m from the outfalls. The deposition of SS (0.04 m, max)

in the vicinity of the outfall would be advected northwest-southeast.

Both the options OF1 and OF2 have been recommended since the effluent released at

both the locations would behave similarly and both the pipeline corridor are free from

mangroves, corals and sand dunes. The effluent will be transported through suitable

diameter buried pipeline through intertidal and subtidal segments upto the location (OF1

and OF2) where it will join to a 68 m long diffuser with 10 ports.

Based on the results of the Buoyant/Forced-Jet model, the effluent released at 1 m

above bed with a jet velocity of 3 m/s by creating suitable pumping system, will get the

initial plume dilution of 22.3 times. Hence, their destruction due to the development is

unlikely.

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Potential Marine Environmental Impacts Construction phase: Excavation of trawlers would be a small scale operation. Hence it

would not affect the hydrodynamic characteristics of the area. SS generated due to

disturbance of bed sediment would be localized and temporary. Since sediment

entering the water column is unpolluted, it would not influence the water quality. The

small corridors of the activity getting disturbed would not cause any change in the

sediment texture of the area. Impact due to misuse of the intertidal area by the work

force though would increase BOD and pathogenic populations; it would be localized and

temporary.

Hectic construction activities would affect seaweeds and macrobenthos. However the

losses would be small compared with potential of the area. The suspension of

unpolluted sediment would not restrict DO availability though it may increase turbidity

which would be local and temporary, and would not alter phytoplankton. Since the

corridors are devoid of mangroves, corals and sand dunes, their losses are unlikely.

The time overruns or improper planning would increase the period of construction.

Birds, marine reptiles, mammals etc around the project site are not expected to be

impacted adversely. Since there is no commercial fishing operations close to the shore,

the impact on fisheries would be minimal.

Operational phase: During the operational phase of the intake the gravity flow of

seawater would not change current speeds and water levels. Hence sediment

movement at the intake location would be insignificant. Since the seawater would not

flow back to sea, water quality of the area would not be affected. Consequently the

sediment quality also would not be influenced. The marginal changes in the current

velocities would not affect erosion-deposition process of sediment. The biological

characteristics would not be influenced. The biota entering the intake system will not be

lost completely but live in somewhat changed social system.

The predicted maximum water temperature in a small area around the diffuser would be

sufficiently lower than the threshold of 35 oC, hence, unlikely to cause thermal shock to

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the flora and fauna even in the vicinity of the diffuser. There may be minor increase in

salinity in a small area around the diffuser which is unlikely to negatively influence the

biota even in the vicinity of the diffuser.

The model predicts an increase of about 100 folds in the concentration of ammonia over

the baseline in the vicinity of the diffuser. However, at the pH of 8.0 to 8.3 off Kuranga,

only about 3 to 5 % of the total ammonia (NH3+NH+4) would occur as unionized

ammonia – the form in which it is toxic to marine organisms. Hence, no significant

impact of release of ammonia through the effluent is expected.

A major fraction of the SS would settle but fine particles would remain in suspension for

a longer duration. This would impart a milky hue to the water around the diffuser. The

SS in the effluent is inorganic in nature and largely composed of constituents commonly

occurring in the marine environment. The settlement of the effluent associated SS is

therefore unlikely to grossly modify sediment character of the region.

As the critical parameters in the effluent would attain the ambient values within 300 m

(max), the general water quality of the coastal area would not be affected; hence, the

biological characteristics of the region would not be affected adversely except for some

negative impact on macrobenthos in the vicinity of the diffuser, due to the settlement of

SS.

Cross-contamination with Seawater Intake: Cross-contamination of the effluent

release at OF1 or OF2 with the seawater intake which is more than 2 km away from

these locations is ruled out.

Mitigation Measures

Adequate precautions are required to prevent deterioration in the marine environmental

quality beyond the pipeline corridor and the area where the treated effluent is released.

Construction phase: The construction period should be optimized to minimize adverse

impacts on marine ecology and spillage of activities beyond the specified geographical

area which should be kept to a minimum, must be avoided.

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Workers’ colony should be established sufficiently away from the HTL on the landward

side and proper sanitation should be provided to them to prevent abuse of the intertidal

region.

The noise level during transport and construction of marine facilities should be kept to a

minimum.

The intertidal and nearshore subtidal areas should be restored to their original contours

once the construction activities are completed.

Operational phase: The intake pipe should be fitted with bars and screens to avoid

entry for fishes and other organisms. Cleaning and clearing of biofoulers should be on

regular basis to maintain efficiency of the intake system. It should be ensured that the effluent released to the sea meets the prescribed

GPCB/CPCB norms at all times. The actual dilution attained after the scheme is

commissioned should be verified through tracer studies. The effluent release scheme

can then be adequately modified to ascertain necessary dilution, if required. The

efficiency of the diffuser must be checked periodically.

As a navigational safeguard the effluent release and seawater intake locations should

be adequately protected and identified with a marker buoy.

Management of Marine Environment

Based on studies, it can be concluded that there will not be significant impact

due to intake facilities and will be limited to small well defined area around intake.

Further, due to outfall facilities water quality of the coastal area off Kuranga would not

deteriorate w.r.t. temperature, salinity and ammonia except in the immediate vicinity of

the outfall where, the temperature, salinity and ammonia would be relatively higher but

in the range considered tolerable to marine biodata.

It is necessary to verify the predicted environmental changes from the pre-

project baseline apart from ascertaining and periodically checking the efficiency of the

diffuser through periodic monitoring. For this purpose the baseline environmental status

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should be established through intensive monitoring. The results of each monitoring

should be carefully evaluated to identify significant changes, if any, from the baseline.

Gross deviation from the baseline may require a thorough review of the effluent disposal

scheme to identify the causative factors leading to these deviations and accordingly,

corrective measures to reverse the trend would be necessary. Further, the mitigation

measures and recommendations suggested are to be implemented in line with detailed

Marine EIA/EMP report.

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LIST OF TABLES

3.1.1 Details of cyclonic storms along North Gujarat coast (1893-2004) 5.2.1 Water quality at station 1 (coastal waters off Kuranga) during April-May 2012 5.2.2 Water quality at station 2 (coastal waters off Kuranga) during April-May 2012 5.2.3 Water quality at station 3 (coastal waters off Kuranga) during April-May 2012 5.2.4 Water quality at station 4 (coastal waters off Kuranga) during April-May 2012 5.2.5 Water quality at station 5 (coastal waters off Kuranga) during April-May 2012 5.2.6 Water quality at station 7 (coastal waters off Kuranga) during April-May 2012 5.2.7 Water quality at station 8 (coastal waters off Kuranga) during April-May 20122 5.2.8 Water quality at station 9 (coastal waters off Kuranga) during April-May 2012 5.2.9 Water quality at station 1 (coastal waters off Kuranga) during September 2012 5.2.10 Water quality at station 4 : flood (coastal waters off Kuranga) during September 2012 5.2.11 Water quality at station 4 : ebb (coastal waters off Kuranga) during September 2012 5.2.12 Water quality at station 7 (coastal waters off Kuranga) during September 2012 5.2.13 Water quality at station 1 (coastal waters off Kuranga) during December 2012 5.2.14 Water quality at station 2 (coastal waters off Kuranga) during December 2012 5.2.15 Water quality at station 3 (coastal waters off Kuranga) during December 2012 5.2.16 Water quality at station 4 (coastal waters off Kuranga) during December 2012 5.2.17 Water quality at station 5 (coastal waters off Kuranga) during December 2012 5.2.18 Water quality at station 6 (coastal waters off Kuranga) during December 2012 5.2.19 Water quality at station 7 (coastal waters off Kuranga) during December 2012 5.2.20 Water quality at station 8 (coastal waters off Kuranga) during December 2012 5.2.21 Water quality at station 9 (coastal waters off Kuranga) during December 2012 5.3.1 Sediment quality of coastal environment off Kuranga during April-May 2012 5.3.2 Sediment quality of coastal environment off Kuranga during September 2012 5.3.3 Sediment quality of coastal environment off Kuranga during December 2012 5.4.1 Microbial counts in waters (CFU/ml) and sediment (CFU/g) at station 4 in coastal waters off

Kuranga during December 2012 5.4.2 Range and average (parenthesis) of phytopigments at different stations in coastal waters off

Kuranga during April-May 2012 5.4.3 Range and average (parenthesis) of phytopigments in coastal waters off Kuranga during

September 2012 5.4.4 Range and average (parenthesis) of phytopigments at different stations in coastal waters off

Kuranga during December 2012 5.4.5 Range and average (parenthesis) of phytoplankton population at different stations in coastal

waters off Kuranga during April-May 2012 5.4.6 Range and average (parenthesis) of phytoplankton population at different stations in coastal

waters off Kuranga during September 2012 5.4.7 Range and average (parenthesis) of phytoplankton population at different stations in coastal

waters off Kuranga during December 2012 5.4.8 Percentage composition of phytoplankton population at different stations in coastal waters off

Kuranga during April-May 2012 5.4.9 Percentage composition of phytoplankton population at different stations in coastal waters off

Kuranga during September 2012

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5.4.10 Percentage composition of phytoplankton population at different stations in coastal waters off Kuranga during December 2012

5.4.11 Range and average (parenthesis) of zooplankton standing stock at different stations in coastal waters off Kuranga during April-May 2012

5.4.12 Range and average (parenthesis) of zooplankton standing stock at different stations in coastal waters off Kuranga during September 2012

5.4.13 Range and average (parenthesis) of zooplankton standing stock at different stations in coastal waters off Kuranga during December 2012

5.4.14 Composition (%) of zooplankton population in coastal waters off Kuranga during April- May 2012 5.4.15 Composition (%) of zooplankton population in coastal waters off Kuranga during

September 2012 5.4.16 Composition (%) of zooplankton population in coastal waters off Kuranga during December 2012 5.4.17 Total counts and incidence of decapod larvae, Acetes and Lucifer sp and fish larvae in coastal

waters off Kuranga during April- May 2012 5.4.18 Total counts and incidence of decapod larvae, Acetes and Lucifer sp and fish larvae in coastal

waters off Kuranga during September 2012 5.4.19 Total counts and incidence of decapod larvae, Acetes and Lucifer sp and fish larvae in coastal

waters off Kuranga during December 2012 5.4.20 Total counts and incidence of fish eggs and fish larvae in coastal waters off Kuranga during

April- May 2012 5.4.21 Total counts and incidences of fish eggs and fish larvae in coastal waters off Kuranga during

September 2012 5.4.22 Total counts and incidences of fish eggs and fish larvae in coastal waters off Kuranga during

December 2012 5.4.23 Range and average (parenthesis) of intertidal macrobenthic fauna at different transects in

coastal waters off Kuranga during April-May 2012 5.4.24 Range and average (parenthesis) of intertidal macrobenthic fauna at different transects in

coastal waters off Kuranga during September 2012 5.4.25 Range and average (parenthesis) of intertidal macrobenthic fauna at different transects in

coastal waters off Kuranga during December 2012 5.4.26 Composition (%) of Intertidal macrobenthos in coastal waters off Kuranga during April-May 2012 5.4.27 Composition (%) of Intertidal macrobenthos in coastal waters off Kuranga during

September 2012 5.4.28 Composition (%) of Intertidal macrobenthos in coastal waters off Kuranga during

December 2012 5.4.29 Range and average (parenthesis) of subtidal macrobenthic fauna at different stations in coastal

waters off Kuranga during September 2012 5.4.30 Range and average (parenthesis) of subtidal macrobenthic fauna at different stations in coastal

waters off Kuranga during December 2012 5.4.31 Composition (%) of subtidal macrobenthos in coastal waters off Kuranga during September 2012 5.4.32 Composition (%) of subtidal macrobenthos in coastal waters off Kuranga during December 2012 5.4.33 Depth at different stations and Secchi disk reading in coastal waters off Kuranga during April-

May and December 2012 5.4.34 The status of coral along transect IV (seawater intake corridor) 5.4.35 The status of coral along transect V (effluent disposal corridor)

xv

5.4.36 The status of corals along transect VI(effluent disposal corridor) 5.4.37 Marine fish landings (t) for Gujarat State and Jamnagar District. During 1991-2012 5.4.38 Species-wise and yearly-wise marine fish production (kg) of Jamnagar District during 2006-12 5.4.39 Species-wise monthly fish landing (kg) of Jamnagar District during 2011-2012 5.4.40 Species-wise monthly fish landing (kg) of Harshad during 2011-12 5.4.41 Species-wise monthly fish landing (kg) of Navadra during 2011-12 5.4.42 Species-wise monthly fish landing (kg) of Dwarka during 2011-12 5.4.43 Group-wise marine fish production (kg) at 3 major fish landing centers bordering the coastal

waters of Gojiness-Kuranga of Jamnagar District during 2008-09 5.4.44 Data on fishing crafts and fishermen population of Jamnagar District during 2006-07 5.4.45 Scientific and common names of fish, crustacean and molluscan species at Gojiness Creek near

Bhogat village during March 2010 5.4.46 Fishes, crustaceans and gastropods obtained from catch of local fishermen in coastal waters off

Kuranga / Gojiness during April-May 2012 5.4.47 Fishes obtained from catch of local fishermen in coastal waters off Kuranga/ Gojiness during

December 2012 5.4.48 Sand dune vegetation along the coastal waters off Kuranga 5.4.49 Macro algae along the coastal water off Kuranga 5.4.50 Corals along the coastal water off Kuranga 5.4.51 Fauna at the intertidal area of Kuranga 6.6.1 Variation in temperature, ammonia and SS at various observation points around

outfall location OF1 6.6.2 Variation in temperature, ammonia and SS at various observation points around

outfall location OF2 6.7.1 Instantaneous erosion and deposition rates and bed level increase at various observation points

around outfall location OF1 during the run period 6.7.2 Instantaneous erosion and deposition rates and bed level increase at various observation points

outfall location OF2 during the run period 6.9.1 The plume characteristics for the bottom release of RSPL effluent in the coastal waters off

Kuranga

xvi

LIST OF FIGURES

1.1.1 Map showing project area for RSPL in Jamnagar District 1.1.2 Map showing the coast along Kuranga-Gojinesss region 1.4.1 Map showing sampling locations in coastal waters off Kuranga 5.1.1 Map showing bathymetry of marine environment of coastal waters off Kuranga 5.1.2 Soft sediments estimated from the dual frequency echo sounder in the survey area of

coastal waters off Kuranga 5.1.3 Predicted tides at Dwarka and Miyani during 24 April - 11 May 2012 (premonsoon) 5.1.4 Predicted tides at Dwarka and Miyani during 7-27 December 2012 (postmonsoon) 5.1.5 Current speed (a) and direction (b) at station 4 (coastal waters off Kuranga) during

29 April- 6 May 2012 5.1.6 Current speed (a) and direction (b) at station 7 (coastal waters off Kuranga) during 15-21

December 2012 5.1.7 Current (a) speed and (b) components at Dwarka during October 2009 5.1.8 Current speed and direction near Dwarka during 21-29 March 2010 5.1.9 Current component near Dwarka during March 2010 5.1.10 Drogue study conducted at station 4 (coastal waters off Kuranga) during flood-ebb on

2 nd May 2012 5.1.11 Drogue trajectory near Dwarka on 23 October 2002 5.1.12 Drogue trajectory near Dwarka on 24 October 2002 5.1.13 Drogue trajectory near Dwarka on 28 October 2002 5.1.14 Drogue trajectory near Dwarka on 1 April 1999 5.1.15 Drogue trajectory at Rupen Bandar during ebb on 29 March 2010 5.2.1 Temporal variations in water quality (S o ) (B ● ) at station 1 (coastal waters off Kuranga)

on 3rd May 2012 5.2.2 Temporal variations in water quality (S o ) (B ● ) at station 4 (coastal waters off Kuranga)

on 5 May 2012 5.2.3 Temporal variations in water quality (S o ) at station 1 (coastal waters off Kuranga) on

11th September 2012 5.2.4 Temporal variations in water quality (S o ) at station 7 (coastal waters off Kuranga) on

12th September 2012 5.2.5 Temporal variations in water quality (S o ) (B ● ) at station 1 (coastal waters off Kuranga)

on 28th December 2012 5.2.6 Temporal variations in water quality (S o ) (B ● ) at station 4 (coastal waters off Kuranga)

on 16th December 2012 5.4.1 Temporal variations in phytopigments at station 1 in coastal waters off Kuranga on

3rd May 2012 5.4.2 Temporal variations in phytopigments at station 4 in coastal waters off Kuranga on

30th April 2012 5.4.3 Temporal variations in phytopigments at station 1 in coastal waters off Kuranga on

11 September 2012

xvii

5.4.4 Temporal variations in phytopigments at station 7 in coastal waters off Kuranga on 12 September 2012

5.4.5 Temporal variations in phytopigments at station 1 in coastal waters off Kuranga on 28 December 2012

5.4.6 Temporal variations in phytopigments at station 4 in coastal waters off Kuranga on 16 December 2012

5.4.7 Temporal variations in zooplankton at station 1 in coastal waters off Kuranga on 3 May 2012

5.4.8 Temporal variations in zooplankton at station 4 in coastal waters off Kuranga on 30 April 2012

5.4.9 Temporal variations in zooplankton at station 1 in coastal waters off Kuranga on 11 September 2012

5.4.10 Temporal variations in zooplankton at station 7 in coastal waters off Kuranga on 12 September 2012

5.4.11 Temporal variations in zooplankton at station 1 in coastal waters off Kuranga on 12 December 2012

5.4.12 Temporal variations in zooplankton at station 4 in coastal waters off Kuranga on 16 December 2012

5.4.13 Intertidal transects (IV-VI) for investigation of corals along Kuranga coast 6.2.1 Study domain for the hydrodynamic modeling studies showing with the intake locations

(IT1 and IT2) and outfall point locations (OF1 and OF2) 6.3.1 Terrain features of study region in coastal waters off Kurunga 6.3.2 Computational BFC grid 6.3.3 Contours of computed bathy depths (m) 6.3.4 Contours of Chezy’s coefficient (m ½ /s) 6.3.5 Boundary input tides 6.3.5 (a) Comparison of computed and calculated tides at outfall location (OF1) 6.3.5 (b) Comparison of computed and calculated currents at calibration point

(22° 01’ 14.2” N, 69° 07’ 16.3” E) 6.4.1 Simulated tides during a typical spring tide (LLW) 6.4.2 Simulated currents during a typical spring tide (LLW) 6.4.3 Simulated tides during a typical spring peak flood 6.4.4 Simulated currents during a typical spring peak flood 6.4.5 Simulated tides during a typical spring (HW) 6.4.6 Simulated currents during a typical spring (HW) 6.4.7 Simulated tides during a typical spring peak ebb 6.4.8 Simulated currents during a typical spring peak ebb 6.5.1 Terrain features of study region 6.5.2 Computational BFC grid 6.5.3 Simulated tides during a typical spring (LW) with intake at IT1 6.5.4 Simulated currents during a typical spring (LW) with intake at IT1 6.5.5 Simulated tides during a typical spring (HW) with intake at IT1 6.5.6 Simulated currents during a typical spring (HW) with intake at IT1

xviii

6.5.7 Observation points around the Intake point IT1 6.5.8 (a) Variation of elevation / tides at different observation points around intake IT1 6.5.8 (b) Variation of elevation / tides at different observation points around intake IT1 6.5.9 (a) Variation of currents at different observation points around intake IT1 6.5.9 (b) Variation of currents at different observation points around intake IT1 6.5.10 Simulated tides during a typical spring (LW) with intake at IT2 6.5.11 Simulated currents during a typical spring (LW) with intake at IT2 6.5.12 Simulated tides during a typical spring (HW) with intake at IT2 6.5.13 Simulated currents during a typical spring (HW) with intake at IT2 6.5.14 Observation points around the intake point IT2 6.5.15 (a) Variation of elevations/ tides at different observation points around intake IT2 6.5.15 (b) Variation of elevations / tides at different observation points around intake IT2 6.5.16 (a) Variation of currents at different observation points around intake IT2 6.5.16 (b) Variation of currents at different observation points around intake IT2 6.6.1 Temperature dispersion during a typical spring LW with release at OF1 6.6.2 Temperature dispersion during a typical spring peak flood with release at OF1 6.6.3 Observation points around the outfall point OF1 6.6.4 (a) Variation of excess temperature at different locations around OF1 6.6.4 (b) Variation of excess temperature at different locations around OF1 6.6.5 Ammonia dispersion during a typical spring (LW) with release of OF1 6.6.6 Ammonia dispersion during a typical spring peak flood with release at OF1 6.6.7 (a) Variation of ammonia (above ambient) at different location around OF1 6.6.7 (b) Variation of ammonia (above ambient) at different location around OF1 6.6.8 SS dispersion during a typical spring (LW) with Outfall at OF1 6.6.9 SS dispersion during a typical spring peak flood with outfall at OF1 6.6.10 (a) Variation of SS (above ambient) at different locations around OF1 6.6.10 (b) Variation of SS (above ambient) at different locations around OF1 6.6.11 Temperature dispersion during a typical spring (LW) with outfall at OF2 6.6.12 Temperature dispersion during a typical spring peak flood with outfall at OF2 6.6.13 Observation points around the outfall point OF2 6.6.14 (a) Variation of temperature (above ambient) at different locations around OF2 6.6.14 (b) Variation of temperature (above ambient) at different locations around OF2 6.6.15 Ammonia dispersion during a typical spring LW with outfall at OF2 6.6.16 Ammonia dispersion during a typical spring peak flood with outfall at OF2 6.6.17 (a) Variation of ammonia (above ambient) at different locations around OF2 6.6.17 (b) Variation of ammonia (above ambient) at different locations around OF2 6.6.18 SS dispersion during a typical spring (LW) with outfall at OF2 6.6.19 SS dispersion during a typical spring peak flood with outfall at OF2 6.6.20 (a) Variation of SS (above ambient) at different locations around OF2 6.6.20 (b) Variation of excess SS (above ambient) at different locations around OF2 6.7.1 Instantaneous rates of erosion during a typical spring peak flood due to release at OF1 6.7.2 Instantaneous rates of erosion during a typical spring peak ebb due to release at OF1 6.7.3 Instantaneous deposition rates during a typical spring (LW) due to release at OF1 6.7.4 Instantaneous deposition rates during a typical spring (HW) due to release at OF1 6.7.5 Bed level changes after 15 days due to release at OF1

xix

6.7.6 Different observation point locations around outfall location OF1 6.7.7 (a) Instantaneous rate of erosion at different observations points due to release at OF1 6.7.7 (b) Instantaneous rate of erosion at different observations points due to release at OF1 6.7.8 (a) Instantaneous rate of deposition at different observations points due to release at OF1 6.7.8 (b) Instantaneous rate of deposition at different observations points due to release at OF1 6.7.9 (a) Bed level changes at different observations points around OF1 6.7.9 (b) Bed level changes at different observations points due to release at OF1 6.7.10 Instantaneous erosion rates during a typical spring peak flood due to release at OF2 6.7.11 Instantaneous erosion rates during a typical spring peak ebb due to release at OF2 6.7.12 Instantaneous deposition rates during a typical spring (LW) due to release at OF2 6.7.13 Instantaneous deposition rates during a typical spring (HW) due to release at OF2 6.7.14 Bed level changes after 15 days due to release at OF2 6.7.15 Different observation point locations around outfall around OF2 6.7.16 (a) Instantaneous rate of deposition at different observations points due to release at OF2 6.7.16 (b) Instantaneous rate of deposition at different observations points due to release at OF2 6.7.17 (a) Bed level changes at different observations points due to release at OF2 6.7.17(b) Bed level changes at different observations points due to release at OF2 6.8.1 Trajectory of a particle discharged at OF1 6.8.1 Trajectory of a particle discharged at OF2 7.1.1 Map showing alignments of effluent disposal pipeline (LFP1-DP-OF1/OF2) and seawater

intake pipeline (LFP2-IT1)

xx

COMMON ABBREVIATIONS General Av - Average

B - Bottom

BOD - Biochemical Oxygen Demand (mg/l)

Corg - Organic carbon (%)

DO - Dissolved Oxygen (mg/l)

Eb - Ebb tide

FI - Flood tide

Max - Maximum

Min - Minimum

NH4+-N - Ammonium nitrogen (µmol/l)

NO2--N - Nitrite nitrogen (µmol/l)

NO3--N - Nitrate nitrogen (µmol/l)

PHc - Petroleum Hydrocarbons (µg/l)

Phenols - Total phenols (µg/l)

PO43—P - Reactive phosphate phosphorus (µmol/l)

S - Surface

SS - Suspended Solids (mg/l)

Microbiology CFU - Colony Forming Unit

ECLO - Escherichia coli like Organisms counted on

MacConkey medium

M-FC-ECLO - ECLO counted on M-FC media for coliforms

MF - Membrane Filter

PALO - Pseudomonas aeruginosa like organisms

PKLO - Proteus klebsiella like organisms

SFLO - Streptococcus faecalis like organisms

SHLO - Shigella like organisms

SLO - Salmonella like organisms

TC - Total Coliforms

TVC - Total viable counts

xxi

VCLO - Vibrio cholera like organisms

VLO - Vibrio like organisms

VPLO - Vibrio parahemolyticus like organisms

1 INTRODUCTION

1.1 Background

M/s. RSPL Limited (RSPL) a North India based well reputed company

is in the business of detergents, soaps, leather products and dairy products.

The company’s products are well accepted and appreciated by market

because of consistent quality and timely delivery. It has 27 detergent

manufacturing units in various states of India with a turnover of around

Rs. 3000 crores. RSPL is the largest producer of detergent powder and

detergent cake (marketed under brand name of ‘GHARI’) and as Soda Ash

being the raw material for detergent, a conscious strategic decision has been

taken to diversify in the field of heavy chemicals i.e. Soda Ash with the sole

objective of achieving backward integration and of controlling the quality and

cost of raw materials of detergent. Soda Ash contributes about one third of

cost for the detergent.

RSPL therefore proposes to set-up a greenfield soda ash plant

(1500 TPD Light Soda Ash / 770 TPD Dense Soda Ash – Dense Soda Ash is

conversion of Light Soda Ash) including a Captive Power Plant (50 MW)

near Village Kuranga, Taluka Dwarka, District Jamnagar in Gujarat State

(Figure 1.1.1). The water requirement of about 6 x105 m3/d for process,

cooling, RO/DM plant , utilities and process plant effluent dilution etc would

be met by drawing seawater from the adjoining coastal waters off Kuranga.

The diluted combined effluent of about 6 x105 m3/d generated from process,

brine preparation/purification rejects, RO/DM plant rejects, utility rejects etc

after treated/ dilution with return cooling water /fresh seawater would be

released at an appropriate location in the coastal waters to meet Gujarat

Pollution Control Board (GPCB)/ Central Pollution Control Board (CPCB)

(Figure 1.1.2).

RSPL therefore engaged Council of Scientific and Industrial

Research-National Institute of Oceanography (CSIR-NIO) to (a) suggest

suitable seawater intake, and effluent disposal locations in the coastal waters

off Kuranga as well as (b) conduct comprehensive Marine Environmental

2

Impact Assessment (MEIA) of the facilities and (c) recommend adequate

marine Environmental Management Plan (EMP) on the basis of 3 season

field studies conducted.

Accordingly CSIR-NIO conducted field studies in respect of physical

processes, water quality, sediment quality and flora and fauna during April-

May 2012 (premonsoon), September 2012 (monsoon) and December 2012

(postmonsoon) as well as model studies to evaluate the prevailing marine

environment, to suggest seawater intake and effluent disposal locations and

EIA for the proposed activities in the marine environment. This report is

based on the data generated from these studies as well as the data of earlier

period available with CSIR-NIO.

1.2 Objectives

a) To assess the prevailing marine ecological status of the coastal water off

Kuranga and surrounding areas.

b) To suggest suitable locations for seawater intake and release of effluent in

Arabian Sea including the method of disposal of the effluent.

c) To assess the impact on the coastal ecology due to proposed facilities.

d) To suggest mitigation measures for maintaining a healthy marine

environment.

e) To suggest suitable marine environmental management plan to minimize

adverse impacts, if any.

1.3 Scope of studies

The scope of studies to undertake marine EIA/EMP studies will be as

follows:

1.3.1 Physical processes

The oceanographic investigations will be conducted in a suitable grid

which includes the proposed project site, intake and outfall locations and the

coastal environment.

3

a) Tides: The tides will be assessed based on available information.

b) Circulation: Circulation pattern in the study area would be evolved based

on drogue trajectories.

c) Model: A predictive 2D model studies, will be carried out for identifying

the intake and outfall locations.

1.3.2 Water quality

Water quality will be assessed at about 12 stations in the nearshore

water off Kuranga and surrounding region. The samples collected at the

surface and the bottom (wherever the water depth exceeds 3 m) will be

analysed for salinity, suspended solids, pH, Dissolved Oxygen (DO),

Biochemical Oxygen Demand (BOD), phosphate, nitrate, nitrite, ammonia,

Petroleum Hydrocarbons (PHc) and phenols. Two critical locations will be

sampled temporally to assess tidal variability of selected water quality

parameters.

1.3.3 Sediment quality

Subtidal and intertidal sediments of pre-decided sites at 3 transects

would be studied for texture, selected metals (chromium, iron, cobalt, nickel,

copper, zinc, lead, cadmium and mercury), organic carbon, phosphorus and

PHc.

1.3.4 Biological characteristics

The status of flora and fauna of the project area will be established

based on phytoplankton pigments, population and generic diversity,

zooplankton biomass, population and group diversity, macrobenthic biomass,

population and group diversity, corals, fisheries and mangroves.

4

1.3.5 Assessment

The data would be analysed to meet the objectives as stated above.

Based on the results of studies, the potential environmental impacts due to

proposed activities would be assessed. This will include modeling studies for

seawater intake and effluent disposal locations in the Arabian Sea. Suitable

mitigation measures and environmental management plan would be

suggested to minimize the adverse impact, if any identified.

1.4 Approach strategy

Severity of negative impacts of developments in the coastal zone on

associated marine ecology vary widely depending on many factors such as

the extent, period and type of disturbance, anthropogenic perturbations,

availability of adequate seawater quantity at the intake point, effluent quality

and quantity and its available dilution, and extent of ecological sensitivity.

Hence, the primary requirements for assessing adverse impacts on

withdrawal of seawater from the Arabian Sea and disposal of the effluent are

the baseline information for the coastal area in general and intensive site

specific data for the nearshore waters off Kuranga, in particular.

CSIR-NIO has been conducting general and site-specific studies along

the North Saurashtra coast since 1981 with more frequent investigations in

recent years due to several proposed and ongoing developments bordering

the region. These data are adequate to describe general environmental

settings of the study region and intensive field data acquisition in the coastal

waters off Kuranga in the present study is considered sufficient to meet the

objectives.

The published scientific literature and available technical reports

indicate that the site specific information related to the ecology of the coastal

waters off Kuranga is rather scanty. CSIR-NIO, however, monitors the

coastal waters off Okha at a few locations once every year since 1990 that

5

has generated long-term database for water quality, sediment quality and

biological characteristics. The information available for the coastal waters off

Okha-Kachchigadh (approach 13 km from Dwarka) has been assessed to

plan field data acquisition for the present study. Accordingly, 9 subtidal

stations covering an area of about 280 km2 of the open shore segment were

sampled. Intertidal area has been also considered for the study and samples

at 3 intertidal transects were collected. The sampling locations are illustrated

in Figure 1.4.1.

Coastal waters often reveal significant seasonal changes in ecology.

These variations should be clearly understood for assessing the prevailing

status of a water body. The study region experiences three distinct seasons:

premonsoon, monsoon and postmonsoon. However, field observations are

hampered during monsoon due to rough sea conditions. Moreover, monsoon

season is not considered critical with respect to EIA study since the prevailing

high turbulence minimises the impacts of contaminants on ecology. Hence

the data acquisition during monsoon was restricted to few observations. This

report is based on the field studies conducted during April-May 2012

(premonsoon), September 2012 (monsoon) and December 2012

(postmonsoon) as well as the model studies.

6

2 PROJECT DOMAIN

This section is based on the information provided by RSPL.

2.1 The company – RSPL

M/s. RSPL Limited (RSPL) a North India based well reputed company

is in the business of detergents, soaps, leather products and dairy products.

The company’s products are well accepted and appreciated by market

because of consistent quality and timely delivery. It has 27 detergent

manufacturing units in various states of India with a turnover of around Rs.

3000 Crores. RSPL is the largest producer of detergent powder and

detergent cake (marketed under brand name of ‘GHARI’) and Soda Ash

being the raw material for detergent, a conscious strategic decision has been

taken to diversify in the field of heavy chemicals i.e. Soda Ash with the sole

objective of achieving backward integration and of controlling the quality and

cost of raw materials of detergent. Soda Ash contributes about one third of

cost for the detergent.

2.2 Project location

Proposed project location is about 34 km from the Dwarka, District

Jamnagar and located within the Survey of India Topo-sheet No 41/F4

(Restricted). It is geographically located between Latitudes 22° 0'N to 22° 3’N

and between Longitudes 69° 9'E to 69° 12'E with an elevation of

5.0 to 15.0 m above MSL (Figure 1.1.1).

The site is flanked by villages Kuranga in the northwest, Bhatvadia in

northeast, Gojiness in southeast. The approximate effective area for soda

ash plant and captive power plant will be around 1000 acres after considering

the Environmental siting guidelines for setting up of Industries. Arabian

seashore is located at the distance of approx. 1 km. The plant site is beyond

500m from HTL. The Coastal National Highway No. NH-8E (Porbandar-

Dwarka) is passing nearby the project site, which is well connected by road

for efficient transport of raw materials and finished products. The nearest

7

broad gauge railway station is Kuranga at a distance of 2.0 km (aerial). The

nearest airport is Porbandar at a distance of approx. 65 km (aerial) and

Jamnagar at a distance of approx 100 km (aerial).

2.3 Project description

RSPL proposes to set-up a Soda Ash plant (1500 t/d light soda ash

and 770 t/d dense soda ash) and captive power plant (50 MW) as follows:

Proposed plant

Capacity Technology

Soda Ash

Plant

Light Soda Ash 1500 t/d

Dense Soda Ash 770 t/d

Note: Dense Soda Ash

is conversion of Light

Soda Ash

Standard Solvay process with dry

liming technology

Captive

Power Plant

Steam: 3 nosx150 tph

Power : 50 MW

Boilers based on CFBC technology

and back pressure-double extraction

cum condensing turbo-alternator

Emergency

DG set

6 MVA (total no. of sets

can be 2/3)

-

Soda ash process is based on dry liming technology having salient

features as follows:

Adopts dry liming technology instead of milk of lime. Dry lime is fed for

Ammonia Recovery which results in lesser volume of effluents and lesser

requirement of sweet water.

Heat of hydration of lime and of chemical reaction themselves are

sufficient to raise the temperature of liquor to the boiling temperature. Hence

the quantity of steam required is less i.e. only to drive out ammonia.

8

Already proven in India using limestone available in

Saurashtra/Gujarat, coke with high ash content available in India and solar

salt produced in Saurashtra/Gujarat.

Most energy efficient technology.

2.3.1 Soda ash process

The dry lime process consists of the following steps:

a) Brine purification

b) Burning of limestone

c) Ammoniation of brine,

d) Carbonation of ammoniated brine,

e) Filtration of sodium bicarbonate,

f) Calcination of sodium bicarbonate,

g) Recovery of ammonia .

The details are as follows:

a) Brine purification: The main impurities in crude solar salt are calcium

and magnesium in the form of chloride and sulphates and insolubles.

Most of the solid impurities are separated from the salt crystals by

washing. The washed salt is dissolved with treated water to form crude brine

which is then treated with milk of lime followed by soda ash solution to

minimise calcium and magnesium.

b) Burning of limestone: A soda ash plant requires lime for recovery of

ammonia and CO2 for carbonation of ammoniated brine. These are obtained

from limestone.

Limestone is burnt in coke fired vertical shaft kilns where the following

reaction takes place:

CaCO3 + Heat = CaO + CO2

9

Kiln gas containing CO2 (39-40%) leaves the top of the kiln and burnt

lime is discharged from the bottom. Lime gas is cooled, cleaned and

compressed before its use for carbonation of ammoniated brine.

c) Ammoniation of brine: The ammonia and brine are passed through

packed towers along with ammonia that is supplied from the distillation plant

to obtain ammoniated brine.

d) Carbonation of ammoniated brine: The ammoniated brine is carbonated

by passing through the carbonating tower along with compressed CO2 .The

temperature of the tower is controlled by circulating seawater and chilled

water. The exothermic reaction taking place in the carbonating tower is as

follows:

NH3 + NaCl + H2O + CO2 = NaHCO3 + NH4Cl

e) Filtration of sodium bicarbonate: NaHCO3 cake is separated in filters

while NH4Cl and other salts remain in mother liquor in the dissolved state.

The crude bicarbonate is filtered and washed with sweet water to remove

traces of impurities.

f) Calcination of sodium bicarbonate: The crude bicarbonate is fed to a

calciner where it is decomposed into sodium carbonate, carbon dioxide,

ammonia and water according to endothermal reactions

2NaHCO3 = Na2CO3 + CO2 + H2O

NH4HCO3 = NH3 + CO2 + H2O

Soda ash from calciner is further cooled, routed through Soda Ash

cooler and transported to the light ash storage silos for bagging. The Dense

Soda Ash is conversion of Light Soda Ash.

g) Recovery of ammonia: The economical operation of ammonia in soda

ash process depends upon the efficiency of recovery of ammonia because

ammonia is an expensive chemical.

10

The preheated mother liquor is fed to the free-ammonia still where

practically all remaining CO2 in the liquor is stripped out with hot

gases/ammonia vapour. The bottom liquor from the free-ammonia still is

pumped in the prelimer where burnt lime powder is added. The reaction

mixture flows to a solid separation system where the major part of the solid

settles out and the remaining liquor flows to the fixed ammonia still.

h) Raw materials and fuels: The major raw materials for production of soda

ash are salt, limestone and coke. Besides coal / lignite is required for the

boiler for generation of steam. The approximate requirements of raw

materials for production of 1500 t/d soda ash is as follows:

Raw salt : 1.72*1500=2580 t/d

Lime stone : 1.8*1500=2700 t//d

Coke : 180 t/d

Coal / lignite: 1800 t/d/2700 t/d - fuel for the boilers (depending upon the

calorific value)

In addition to the above mentioned raw materials, ammonia about 2 –

2.5 kg /ton of LSA and sodium sulphide 1.49 kg /ton of LSA are also required.

Solar salt produced by evaporation of seawater will be used in soda

ash process. Such salt contains impurities of calcium and magnesium which

have to be removed prior to its use in the process. Consumption of salt is

estimated at 1.7 to 1.8 t/t of Light Soda Ash produced. Salt shall be sourced

primarily from self owned salt works. Salt may also be procured from open

market based on the requirements.

The second major raw material required for the manufacture of soda

ash is limestone. Limestone required for soda ash industries has to be

essentially a chemical grade limestone with silica content preferably not more

than 5%. Essentially it is the carbonate part of the limestone, which is

important. Therefore, higher the content of carbonate in the limestone, lower

the consumption of limestone per ton of soda ash. Higher silica containing

limestone gives considerable trouble in limekiln operation due to formation of

11

lumps and clinker. Consumption of limestone is estimated at 1.8 t/t of soda

ash produced.

Limestone shall be sourced from the captive mines / open market and

transported to plant site by trucks. In recent times, imported limestone is

utilised in the lime kilns for soda ash production which is proven to be more

efficient. Hence imported limestone is also considered for the plant.

In standard Solvay process, major quantity of ammonia is recovered

from ammonium chloride (Mother Liquor) and recycled back to the process.

Fresh ammonia is required only for accounting the process and other losses,

and is generally around 2 – 2.5 kg/t of soda ash produced.

Sodium sulphide is used in the process as a passivating agent against

carbonic acid corrosion attack. The requirement of sodium sulphide is about

1.49 kg/t of soda ash produced.

The fuel for calcining limestone in the lime kilns shall be coke. This

shall be sourced from reputed suppliers like NRE, Agrawal and others who

has plants in the Jamnagar and Kutch regions of Gujarat and transported to

plant site by trucks.

The fuel for boilers of the captive power plant shall be lignite/coal.

Lignite shall be sourced from the lignite mines of GMDC and transported to

plant site by trucks. Coal, for quality and prevailing economic reasons, shall

be sourced from outside India by sea route and transported to plant site by

surface transport.

i) Water requirement: Manufacture of soda ash is water intensive. Water is

required in chemical process for removing low level heat generated at different

stages in the process and for generating steam.

Approximate requirement of treated/process water, for various

purposes is around 15000 m3/d for a 1500 t/d soda ash plant and associated

facilities.

12

Besides above requirement, additional water for washing of crude

bicarbonate cake etc. can be met by recycling the process condensate from

other process sections.

Some of the requirement for washing of dust etc. can be met by

seawater.

Cooling water required to remove low level heat from the process / hot

fluids will vary between 150 m3 and 250 m3 per tonne of soda ash depending

upon the type of system adopted for refrigeration of water required for

carbonation and system adopted for partial recovery of water from process

stream. The main process plant operations which require cooling water in

large quantities are carbonation, refrigeration, calciner, gas cooling,

ammoniated Brine cooling, Distiller gas cooling etc.

Since seawater is considered for cooling water requirement, the ‘once-

through’ seawater is utilized in dilution of the effluent prior to discharge in the

sea.

J) Miscellaneous: Dust emission control: All sources of dust generation in

the plant will be well designed for producing minimum dust and will be

provided with high efficient dust control systems. For collecting the particulate

matter from CFBC boiler and de-dusting of vent air, a suitable sized ESP will

be considered with emission level < 50 mg/Nm3.

For controlling fugitive dust from silos and bunker, bag filter/ spray

systems have been considered. In the stack emission from boiler the CO

content shall be negligible, NOx content will be minimized by properly

designed fuel firing system, SO2 concentration shall be minimised by

limestone dozing, 122 m height stack will be provided for release of

emissions as per GPCB / CPCB norms.

13

Noise pollution: Noise pollution from soda ash plant systems, turbine, fans,

centrifugal pumps, electric motor etc will be kept below the permissible level

of 90 dB(A), in line with the recommendation.

Fire protection system: The entire fire protection system will be designed to

meet the requirements of early detection, alarm and suppression of fire

effectively and quickly.

2.3.2 Captive power plant

Initial start up power will be by setting up of 66 KV sub-station with

Gujarat Electricity Board grid connection. Later power will be generated from

the turbines of captive power plant by using the differential pressure between

the generated steam pressure and the required pressure for use in different

unit processes.

Captive power plant capacity will be of 50 MW having 20 MW x 2 nos.

+ 10 MW x 1 no. multi extraction turbo-alternator and 150 TPH x 3 nos.

Lignite/coal based CFBC boilers, necessary machineries/systems will be

installed in order to meet internal steam and power requirement for the

proposed soda ash complex. As far as possible proper steam power

balancing is done to avoid extra use of steam. The required extra power load

will be met from state electricity.

The steam generator units proposed for the plant will be compact,

semi-outdoor, natural/assisted circulation, balanced draft, single drum, water

tube type provided with circulating fluidized bed combustion system. In a

typical circulating fluidized bed furnace, the lignite/coal fed on a bed of

suitable inert material with addition of a sorbent material (such as limestone)

is burnt in suspension through the action of primary air distributed below the

combustor floor. In addition, secondary air is introduced at suitable points in

the combustion zone to ensure controlled and complete combustion of the

fuel. Suitable lignite/coal feeding and limestone feeding arrangements will be

provided in the typical circulating fluidized bed combustion system.

14

The steam generators will be designed for satisfactory continuous

operation with the range of lignite/coal expected for this plant without any

need for auxiliary fuel oil for fire stabilization etc.

The furnace would be conservatively designed to allow adequate

residence time for fuel to burn completely. The furnace design would also

consider adequate reaction time for removal of sulphur in fuel (max. 6.0 %)

by addition of grounded limestone in the furnace. The air and flue gas

velocities would be carefully selected to minimize erosion of pressure parts

and other vital components on account of ash. Renewable ceramic lining will

be provided in critical areas to prevent high degree of erosion. The steam

generators would be designed in accordance with the latest provisions of the

Indian Boiler Regulations.

Super heater section would be divided in convection and radiant

zones and designed so as to maintain rated steam temperature of around

535 °C with ± 5 °C margin at outlet over the control range of 50 to 100 % of

BMCR load. The boiler furnace and flue gas passages would be designed for

low gas velocities in order to minimize erosion and slagging effect.

Lignite/coal and limestone would be fed into the lower furnace where

combustion and sulphur capture reactions would occur in the furnace. The

solid particles entrained in the flue gases, leaving the furnace would be

mostly separated in the electrostatic precipitator. The feed control for

lignite/coal and limestone would be done through selector switch by manually

or automatically and controlled as per plant load and sulphur content in the

fuel. The steam generating units will be provided with arrangement for initial

start-up by HSD/ furnace Oil.

The power plant consists of

Coal/lignite handling system including stack,

Limestone handling system,

Fly ash handling system,

Boiler (steam generator),

Turbo generator,

15

Condensate tank,

Flash tank,

Ejector condenser,

Gland Vent Condenser (GVC),

Low Pressure Heater (LPH),

High Pressure Heater (HPH),

Deaerator,

Boiler Feed Pump (BFP) and

Condensate Extraction Pump (CEP)

2.3.3 DG set

In order to meet emergency power requirement diesel generators of

total 6 MVA capacity are essential. The emergency loads are for process

requirements, turbine lube oil system, emergency lights and boiler start-up.

The emergency DG set can be used to meet power requirement of the

plant during outage of any boiler/ TG. Synchronizing facilities will also be

provided.

2.4 Proposed marine facilities

Following marine facilities in the coastal waters off Kuranga have been

proposed by RSPL.

2.4.1 Seawater intake

The total seawater requirement of RSPL will be around 6x105 m3/d for

i) Soda ash plant: Process, cooling, desalination (RO/DM) etc.

ii) Power plant: Cooling and desalination (RO/DM)

iii) Miscellaneous: Domestic use

iv) Seawater for dilution of process effluent.

For the purpose of establishment of a pipeline between the seawater

intake point and the intake well with a pump house have been planned in the

16

construction phase while drawing of seawater is envisaged in the operational

phase during which phase seawater will be brought to the intake well/sump

by a pipeline from where it will be pumped to the plant.

The details are given in Section 6.

2.4.2 Effluent disposal

The combined/diluted final effluent of about 6x105 m3/d will be

generated by RSPL from following sources:

i) Soda ash plant: Process diluted distiller Waste effluent, brine preparation/

purification reject once through return, cooling water, washing, RO/ DM plant

rejects.

ii) Power plant: Once through return cooling water, boiler blowdown, RO/DM

plant rejects

iii) Domestic use: Sewage

Sewage will be treated in septic tank and soak pit system / STP as per

GPCB norms and will be used for green belt development/dust suppression.

For releasing the effluent a submarine pipeline from LFP to the

effluent Disposal Point (DP) with diffusers will be established in the

construction phase. The treatment and release of the effluent will be done

routinely in the operational phase.

The soda ash effluent streams, brine preparation/ purification rejects,

boiler blowdown from captive power plant and RO/DM plant rejects will be

mixed with once through return cooling seawater/ fresh seawater to meet the

criteria laid down by GPCB/CPCB for releasing the treated effluent into

nearby coastal waters. The effluent will be transported in an open channel

within the plant premises and thereafter in closed above / underground

pipelines upto LFP. From there it will be released through a submarine

pipeline having a diffuser system at a designated point in the coastal waters

off kuranga.

The details of the system are given in Section 6.

17

2.4.3 Field and model studies

The seawater intake (IT) and effluent disposal (DP) locations, pipeline

alignments and diffuser design will be suggested by CSIR-NIO on the basis

of field investigations conducted and model studies.

18

3 EARLIER STUDIES IN SURROUNDING REGION AND AVAILABLE INFORMATION

The study area of the coastal waters off Kuranga which comes under

the northern portion of the Saurashtra coast which is described below (Figure

1.1.2).

3.1 Saurashtra coast / Arabian sea

The continental shelf which is about 100 km wide off Saurashtra,

increases to 300 km off Mumbai. The cohesive (recent mud) and non-

cohesive (relict calcareous sand) sediment boundary occurs at about 60 km

on the shelf.

The coastal configuration is very irregular with numerous islands,

creeks and bays. Besides, there are a number of eroded shallow banks

along the shore, some of which harbour living corals. The intertidal region is

sandy and muddy or rocky.

As expected for tropical waters, the temperature varies in a narrow

range and in shallow waters (<50 m) there is no vertical stratification.

However in deeper waters, the decrease that is gradual in the surface mixed

layer (50 - 250 m), falls steeply in the thermocline zone followed by a gradual

fall. The DO concentrations in the shallow coastal area and the surface

mixed layer of the deeper regions are generally uniform and close to the

saturation value. A sharp fall in DO occurs within the thermocline with severe

depletion of DO even at 100 m water depth. The occurrence of a permanent

thermocline and high primary production in the euphotic zone results in the

depletion of nutrients above the thermocline. The concentration of nutrients

in the coastal water is relatively high and uniformly distributed in the water

column. Vertical profiles of phosphate and nitrate indicate increase in their

concentrations below the surface mixed layer due to their regeneration from

the sinking organic matter.

19

The marine sediments of the Saurashtra coast are characterised by

low CaCO3 content (<25 %) and is contributed by skeletal components. The

content of organic carbon (Corg) is generally <2 % and the concentrations of

trace metals such as chromium, cobalt, nickel, copper, zinc, mercury and

arsenic indicate their lithogenic origin.

The Saurashtra coast sustains high biological productivity especially in

terms of fishery, macrobenthos, zooplankton and phytoplankton. The water

upto 100 m depth contour along Saurashtra has very high fishery potential as

revealed by the exploratory fishery expeditions by the Fishery Survey of

India. The estimated stock of demersal fishery alone is of the order of 2x105 t.

Veraval, Mangrol, Diu and Jafrabad are the major fish landing centres of the

Saurashtra coast from where thousands of fishing vessels conduct their

operations. The fishing season starts from September and lasts upto April

with October-November often yielding high catch.

3.1.1 Land environment

The coastal area falls under Jamnagar District (14125 km2). The land

use pattern (km2) within 10 km radius from the shoreline in the district is

given below.

Land use / Land Cover Classes Area

(km2) (%)

Arabian Sea 108.17 34.44

Water body 19.22 6.12

Vegetation 25.29 8.00

crop Land 13.02 4.14

Fallow Land 111.12 35.38

Salt pan 2.36 0.75

Waste land 24.09 7.67

Sand 3.10 0.98

Built – up Land 7.60 2.42

Total 314 100

20

This indicates that barely 4.14% land under crops and 8.05%

vegetation. Oil seeds is the dominant crop in the Jamnagar District. Bajra,

pulses, wheat, sugarcane etc are the other common crops in the region. The

general vegetation in the area is sparse and scattered, and of tropical dry

mixed deciduous scrub and desert thorn type belonging to the xerophytic

group. The coastal belt is sparsely populated except few pockets like

Porbandar, Dwarka, Mithapur, Bhogat etc.

Due to extreme unreliability of rainfall in the Jamnagar District, ground

water is a more reliable source of water for domestic as well as agricultural

needs. However, uncontrolled and indiscriminate withdrawal of ground water

has resulted in a sharp decline in the water table in the coastal belt causing

ingress of salinity.

The coastal region is industrially less developed and the majority of

large-scale industries including the refineries, marine oil terminals coal based

thermal power plant and cement industry are located in the Sikka-Salaya

segment of the Jamnagar District. Tata Chemicals Limited (TCL) is located at

Mithapur near Okha Port. Okha and Bedi are the two important intermediate

ports in the Jamnagar District.

3.1.2 Geomorphology

The Saurashtra coast is a unique strip of land displaying varied

geomorphic features all along and is characterised by numerous cliffs - a few

of which rising upto 20 to 25 m, small islands, extensive tidal flats, deposits of

littoral concrete in rocky beaches, sandy beaches, bars, dunes and coral

formations. The peninsular Saurashtra is extensively covered by the Deccan

Traps mainly of basalts and dolomites. The topography of the region is

gently sloping towards the sea, excepting small hillocks of Milliolitic

limestone. These hillocks reach the elevation of 1117 m in the Girnar hill

ranges. Quaternary formations consisting of Milliotic limestone and alluvium

are exposed along the coastline. The solubility of limestone in water is

responsible for creating a krast topography where the limestone is exposed.

21

3.1.3 Meteorological conditions

The region forms a part of the semi-arid coastal belt and receives low

rainfall. The rainfall pattern however is irregular and erratic resulting in

considerable fluctuations in agricultural produce which is dependent on the

rain. Moreover, the fertility of the coastal belt is affected by salinity ingress

due to excess withdrawal of ground water not compensated by the recharge

of aquifers. As a result of combination of these factors, the farming which

has been the major occupation of the local inhabitants, is gradually declining

with people shifting over to other occupations such as service, construction

work, etc. Bajra, jowar, wheat, oil seed, ground nut, mustard, castor etc are

the major crops grown in the region. The region sustains sparse and

scattered vegetation of tropical dry mixed deciduous scrub and desert thorn

type belonging to the xerophytic group.

With a few rain days, the climate is hot and humid from April till

October and pleasant during brief winter from December to February.

Meteorological parameters for the year 2010-11 recorded at Mithapur are

summarised in the table below.

Period Temperature

(oC)

Relative humidity

(%)

Evaporation rate (av) (mm/d)

Rainfall (mm)

April-10 20-34.2 57-92 - 0

May-10 24-35 59-81 6.5 0

June-10 23-36.8 68.2-70 7.1 55

July-10 22-35 66-92 7 787

August-10 20.2-34.6 67-90 3.8 366

September-10 21-36.4 70-92 3.9 239

October-10 21.6-38.2 59-89 3.9 0

November-10 17.6-34.6 50-84 4.2 18

December-10 14-30.6 36-84 4.6 0

January-11 13-29.8 33-78 4.7 0

February-11 15.6-32.6 40-82 4.7 0

March-11 18-39.6 40-88 5.2 0

22

Although the highest temperature recorded during the year was

39.6oC in March 2011, historical data indicate that on a few occasions

temperatures reaching 40oC have occurred. The rainfall received (1465 mm)

during the year was well above average with maximum precipitation in June-

September (98.7% of annual precipitation) and in the remaining part of the

year the climate was hot and humid. No rainfall was observed after

September till March except with a few rainfall days in November. The wind

records of Okha indicate that (a) wind speed varies between 0 and 30 km/h

during November-February; the predominant direction being NW-NE, (b)

wind speed marginally increases during March-April with change in direction

to NW-SW, (c) maximum speeds of 40 to 50 km/h occur during May; the

predominant direction being SW-W, and (d) maximum speeds can reach upto

70 km/h with predominant direction of SW-W during June-September.

Cyclonic disturbances strike North Gujarat, particularly the Kachchh

and Saurashtra regions, periodically. These disturbances generally originate

over the Arabian Sea and sometimes the Bay of Bengal. The details of

number of cyclonic storms which struck the North Gujarat region during last

100 yrs are given in Table 3.1.1. Generally during June, the storms are

confined to the area N of 15oN and E of 65oE. In August, in the initial stages,

they move along the NW course and show a large latitudinal scatter. W of

80oE, the tracks tend to curve towards N. During October the direction of

movement of a storm is to the W in the Arabian Sea. However, E of 70oE

some of the storms move N-NW and later recurve NE to strike Gujarat-North

Mekran coast.

3.1.4 Marine environment

The coastal waters off Kuranga forms part of the coastal belt from

Porbandar to Okha of the Saurashtra coast. The general marine

environmental quality of the region in respect of physical processes, water

quality, sediment quality and flora and fauna is described below.

a) Physical processes: The tides along the coast of Okha-Porbandar are

mixed semi-diurnal with the mean high water spring and neap rise of about

23

3.0 and 1.9 m respectively. The high tide at Okha lags by roughly 1 h 40 min

to 2 h 10 min with respect to the tide at Porbandar.

Off Mithapur-Kachchigadh, the currents are mainly tide-induced

though wind also contributes to some extent. The currents have maximum

speeds of 0.4 to 0.7 m/s with net onshore and alongshore components

varying spatially. The tidal excursion estimated based on drogue trajectories

varies between 5.5 and 28 km depending on the tidal phase, location and

period.

b) Water quality: The average water temperature varies in accordance with

the air temperature and is generally below 28oC. The average pH (7.7 – 8.0)

is in the range expected for the coastal area and spatial or temporal changes

are minor. The average SS is low (21-65 mg/l) as the seafloor is rocky or

sandy. In the absence of freshwater discharges, the salinity is high (>36 ppt)

as compared to that of the typical seawater (35.5 ppt). The water is well-

mixed vertically as well as laterally.

DO content, a vital water quality parameter influencing the health of

aquatic biota, is fairly high (av 4.2 – 6.3 ml/l) and is saturated to the extent of

93 to 120 %. Consequently, the BOD of the coastal water is low. The

average concentrations of PO43--P (0.4 – 1.5 mol/l) and NO3

--N (1.8 – 8.1

mol/l) are in the range expected for the coastal area off Okha. Low levels of

NH4+-N (av 0.2 – 0.5 mol/l) and NO2

--N (av 0.1 – 0.6 mol/l) indicate good

oxidizing conditions in water.

The average concentrations of PHc (2.7 – 6.6 g/l) and phenols (34-

75 g/l) are low and in the range commonly encountered in uncontaminated

coastal waters.

c) Sediment quality: The surface sediment has variable texture but

generally dominated by varying grades of sand. The carbonate (CO32-)

content of surface sediment varies between 11.6 and 89.6 %; dry wt.

24

The subtidal as well as the intertidal sediments off Mithapur-

Kachchigadh sustain variable concentrations of trace metals such as

chromium, cobalt, nickel, copper, zinc and mercury primarily because of the

heterogeneous character of sediments and in the absence of any known

anthropogenic source, they represent a baseline.

The Corg (<1.1 %; dry wt) and phosphorus (<972 g/g; dry wt)

contents in sediments are low and represent the baseline. The

concentrations of PHc (0.2 – 2.2 g/g; wet wt) in the sediment are also low

and reveal uncontaminated status of the sediment with respect to PHc.

d) Flora and fauna: Bacterial count like TVC in water and sediment vary

widely without any specific trend. Pathogens are rarely detected suggesting

clean and natural coastal system off Okha-Kachchigadh.

The concentration of chlorophyll a in the coastal water (0.5–7.6

mg/m3) indicates variable and patchy phytoplankton biomass. The

concentration of phaeophytin (0.1–4.5 mg/m3) is low. The phytoplankton

population is variable in accordance with the trend in phytopigments. Overall,

72 genera are recorded in the region with the common occurrence of

Nitzschia, Guinardia, Navicula, Leptocylindrus, Chaetocerus, Pleurosigma,

Coscinodiscus, Thalassiosira and cyclotella.

Mangroves are generally low or absent at Mithapur-Kachchigadh. The

intertidal rocky region (150-300 m) however sustains marine algae. The

seaweed flora is represented by 17 species of Chlorophyceae, 18 spp of

Phaeophyceae and 28 spp. of Rhodophyceae. The sand dunes, particularly

narrow foreshore and burm regions of 50 to 100 m width, support sand dune

vegetation- mostly in patches. The sand dune flora is represented by 15

species with the common occurrence of Atriplex stocksii, Cressa cretica and

Cyperus arenarius.

The zooplankton standing stock in terms of biomass (0.1-26.9

ml/100m3) and population (1.5×103 – 284×103 no/100m3) varies widely. The

composition of zooplankton is fairly diverse and consists mainly of copepods,

25

decapods larvae, lamellibranchs, gastropods and chaetognaths which

together contribute about 97% to the total population. Overall 22 to 26 faunal

groups are identified. Good number of fish eggs and fish larvae though at a

low percentage, occur in majority of the zooplankton collections. Decapod

larvae occur in all zooplankton samples and contribute about 2.6 % to the

zooplankton population. The most dominant groups are crab zoea and

pagurids.

The intertidal macrobenthic standing stock in terms of population and

biomass vary from 0 to 17900 no/m2 and from 0 to 52.6 g/m2; wet wt

respectively. The fauna is mainly constituted by crustaceans, polychaetes

and molluscs. The faunal group diversity varies between 0 and 11 groups.

The subtidal benthic macrofaunal standing stock in terms of population and

biomass vary from 0 to 1500 no/m2 and from 0 to 17 g/m2 (wet wt) with poor

faunal group diversity (av 2-3 no). The faunal composition indicates overall

dominance of polychaetes followed by crustaceans and molluscs.

The Jamnagar District contributes about 10% of the Gujarat State’s

fish landings. Major fish landings are from Okhamandal zone (76 %) for the

Jamnagar District and within Okhamandal major landings are from Okha.

The experimental trawling reveals a catch rate of 6.6 to 11.0 kg/h consisting

of 13 to 20 species.

The intertidal transect north of Kachchigadh (density: 0.01-0.58/m2)

and corresponding subtidal corridor (density: 0.2-0.5/m2) sustain low coral

density with their absence beyond 7 m depth (CD). Intertidal transect south

of Kachchigadh with predominant sandy intertidal stretch sustains low coral

density, however, the corresponding subtidal corridor harbours good corals

(5-30% coverage). Major genera of corals in the region are Porites, Favia,

Favites, Goniastrea, Cyphastrea, Montipora, Goniopora and Acanthastrea.

Corals however, are absent at most of the other locations.

3.2 Adjacent area

The adjacent area investigated earlier is Gojiness (Figure 1.1.2) which

is described below.

26

3.2.1 Land environment

The Gojiness is located near Bhogat village, about 60 km NW of

Porbandar and 37 km SE of Dwarka in Jamnagar District. The land

environment is mainly barren, largely flat, and the water front available is

about 2.5 km long, bounded by a small creek called the Ghughadwa /

Gojiness Creek to the south and a wind farm to the north extending about 1.5

km inland from the shoreline and separates the villages of Gojiness and

Bhogat. The vegetation in the coastal strip mainly comprises of sand dune

grasses, thorn scrub and cactus etc.

Gojiness village is located just off National Highway NH – 8E, which

extends to Jamnagar to the north and Porbandar to the SE. The shoreline at

Gojiness runs parallel to NH-8E and the nearest railway station is at Kuranga,

which is a broad gauge and non-electrified single line railway route lying 5 km

NW of Gojiness.

The area of Gojiness has appropriate water front with deeper draft for

bringing large vessels near to the shore. The fishermen mostly operate from

Gojiness Creek near Bhogat village. They have temporary sheds on shore.

Some fishing boats operate just off the creek also.

3.2.2 Marine environment

The general marine environmental quality in respect of physical

processes, water quality, sediment quality, and flora and fauna of the coastal

waters off Gojiness (as assessed during March 2010) which is located

towards south of the present study area off Kuranga is described below

(Figure 3.2.1).

a) Physical processes: The coastal waters off Gojiness is a typical marine

environment along the Saurashtra coast where tidal movements highly

influence the flow regime of the area.

Currents which are maximum upto 0.35 m/s are parallel to the shore.

They reverse with tide changing from NW during high tide to SE during low

27

tide. Waves vary between 6.5 to 7.1 m brought in between 157 and 293o.

Circulation off Kuranga is parallel to the coast and is governed by tide.

b) Water quality: The coastal waters off Gojiness sustain very good water

quality due to high oxygen content and low influence of anthropogenic

releases. It is described below.

Temperature of the waters is generally below 27.5oC which varies

according to prevailing air temperatures. The pH remains above 8 indicating

negligible impact of freshwater as well as anthropogenic discharges, if any.

SS is mostly low (< 29 mg/l) revealing low turbidity of the waters.

Salinity is above 35.5 ppt suggesting that influence of the land run-off

of non-saline water is negligible on the coastal environment. It reaches upto

40 ppt during summer when evaporation rates exceed precipitation rates.

This phenomenon is commonly observed as the region is arid. Absence of

surface to bottom gradient in salinity indicates that the waters are well mixed

vertically. DO remains above 5.5 mg/l revealing highly oxidising conditions

prevailing in the area.

The selective nutrients are generally low in the coastal waters. For

instance phosphate and nitrate vary in 0.7 to 1.7 and 0.5 to 4.4 mol/l ranges

respectively. The oxygen deficient species namely nitrite and ammonia are

low (0.2 to 0.5 and 0.2 to 5.5 mol/l respectively) indicating well oxygenated

waters.

Phenols and PHc remain low of 5.4 to 42.5 and 0.7 to 7.8 g/l

respectively indicating that adverse impact of anthropogenic fluxes, if any, is

negligible.

c) Sediment quality: The area possesses rocky bottom with sediment in few

pockets. The organic content in sediment is as low as 1%, dry wt and build-

up of selective toxic metals namely Cd, Pb and Hg are very low representing

lithogenic background of the area.

28

d) Flora and fauna: The coastal waters off Gojiness possess high

biopotential with diverse population as follows:

Phytoplankton: Chlorophyll a and phaeophytin in the coastal waters vary

from 0.63 to 2.2 and 0 to 1.15 mg/l respectively with marginally higher levels

at the surface. They possibly indicate well mixed waters. The ratios of

chlorophyll a to phaeophytin are mostly above 1 revealing favourable

conditions for biological growth. The phytoplankton population is high upto

163 x 102 no/l with total 37 genera identified.

Zooplankton: The standing stock of zooplankton is highly variable with

biomass and population in the ranges of 1.1 to 7.8 ml/100 m3 and 1880 to

24539 no/100 m3 respectively. The population comprises faunal groups

dominated by copepods (35%). Other dominant groups are amphipods,

chaetognaths, Lucifer, fish eggs etc. The economically important groups

namely fish eggs/larvae and decapod larvae account for 5% of the total

zooplankton population.

Macrobenthos: The macrobenthic standing stock in terms of biomass and

population range from 12 to 121 g/m2 and 0 to 4550 no/m2 respectively. The

groups vary from 0 to 9 nos. with gastropods as the dominant group followed

by polychaetes and isopods.

Corals and associated flora: The Gojiness area possesses some locations

having rocks with coralline structure which sustains moderately scattered

patches of reef building corals in the intertidal area. Porites is the dominant

species found there. Fossilized coral boulders are also sighted in the study

area.

Several species are associated with corals in the intertidal area off

Gojiness. They are coelenterates, sponges, gastropods, polychaetes, flat

worms, pelecypods, nudibranchs, cephalopods, echinoderms etc. Few

colourful species of reef fishes are also present in rocky pools.

29

Algae and associated flora: The flora of the area is represented by 17

species of Chlorophyceae, 18 species of Phaeophyceae and 28 species of

Rhodophyceae. Lynghya is the most common species of cyanophyceae.

The lower rocky intertidal zone mainly harbour sargassum, gracilaria,

helimenia species. The upper rocky intertidal zone is dominated by Hypnea

musiformis, Ulva lactuca while pools in rocky and sandy areas in the upper

zone harbour. Padina gymnosphora, Hyphea and Cytoseira. Among

Rhodophyceae; Gracilaria corticata, Champia, Laurencia papillosa and

Acanthopora are common.

Sand dune vegetation: The narrow sand beach is almost devoid of sand

dune vegetation. The backshore dunes are dominated by Prosopis juliflora.

The flora is represented by 15 species with commonly occurring species of

Atriphea stocksii, Cressa cretoca, Cyperus arenarius etc.

Birds: Coral reefs, reef vegetation, sand beach, rocky shore and tidal creeks

provide ideal conditions for avifauna in the region mainly migratory birds such

as white Pelicon, Grey Heron, smaller Egret, Painted stock, Ibis, Red wattled

Lapwing, Kingfisher etc.

Fishery: The coastal area between Dwarka and Bhogat is a traditional

fishing zone. Gill netting is fairly active during the fishing season from

September to May. The fish species commonly occur off Gojiness are white

fish, mackerel, cat fish, croaker etc. Other species are crab, lobster, shrimp

etc.

30

4 STUDIES CONDUCTED

The field studies were conducted in the coastal waters off kuranga are

described below.

4.1 Period of study

The study was conducted in 3 phases for 3 seasons namely

premonsoon, monsoon and postmonsoon as given below.

Season Period shade

Premonsoon April-May 2012

Monsoon September 2012

Postmonsoon December 2012

4.2 Sampling locations

Subtidal sampling stations were selected based on the proposed sites

of seawater intake and effluent release, bathymetry as given in the National

Hydrographic Office (NHO) Chart No. 2055 to obtain intensive information for

the coastal segment likely to be impacted by the seawater intake and the

release of the effluent. These locations are illustrated in Figure 1.4.1.

Stations 1 to 3 fall in the northern segment and stations 7 to 9 in the southern

segment while stations 4 to 6 lie in the middle segment of the study area.

Stations 1, 4 and 7 were sampled over a tidal cycle. These stations were

categorised as nearshore (1, 4, 7), towards offshore (2, 5, 8) and offshore (3,

6, 9). The station positions are given below.

The intertidal area was sampled at 3 transects (I - III) for assessing the

quality of intertidal zone including flora and fauna as well as other biotic

features. These transects are illustrated in Figure 1.4.1.

31

The positions of sampling locations (Figure 1.4.1) were as follows:

Area Station/transect Position shade

Subtidal

1 22o 04’24.0’’N

69o 03’00.0’’E

2 22o 02’30.0’’N

69o 01’00.0’’E

3 22o 01’00.0’’N

68o 59’00.0’’E

4 22o 00’24.8’’N

69o 06’51.2’’E

5 21o 58’30.0’’N

69o 04’24.0’’E

6 21o 56’48.0’’N

69o 02’00.0’’E

7 21o 56’12.0’’N

69o 10’00.0’’E

8 21o 54’24.0’’N

69o 08’00.0’’E

9 21o 53.00.0’’N

69o 06’00.0’’E

Intertidal I 21o 57’48.0’’N; 69o 12.0.0’’E

II 22o 01’48.0’’N; 69o 08.36.0’’E

III 22o 06’12.0’’N; 69o 04’48.0’’E

4.3 Sampling frequency

Spot sampling was done at all stations/ transects in duplicate for water

quality and biological characteristics. Temporal measurements over a tidal

cycle were conducted at stations 1, 4 and 7 with 1 h frequency. Station 6

could not sampled during April – May 2012 (premonsoon).

Intertidal stations were sampled once at each transect in the area

between the Low Tide Line (LTL) and the High Tide Line (HTL).

32

4.4 Physical processes

a) Tide: Available information on tides for Okha and Porbandar was

assessed.

b) Currents: Currents were measured by deploying an Aanderaa (RCM 7)

current meter at station 4 during 29 April to 6 May 2012 and station 7 during

15-20 December 2012.

c) Circulation: Circulation was assessed by deploying a neutrally buoyant

biplane drogue at a pre-decided location and tracking it over the desired

period. The position of the drogue was periodically fixed with a GPS

(Garmin). These positions were then plotted to obtain the trajectory.

4.5 Water quality

a) Sampling procedure: Surface water samples were collected using a

clean polyethylene bucket while an adequately weighed Niskin sampler with

a closing mechanism was used for obtaining subsurface water samples at a

desired depth. Sampling at the surface and the bottom (1 m above the bed)

was done when the station depth exceeded 3 m. For shallow regions, only

surface samples were collected. A glass bottle sampler (2.5 l) was used for

obtaining samples at depth of 1 m below the surface, for the estimation of

PHc. For shallow areas only surface water was collected.

b) Methods of analyses: Majority of the water quality parameters were

analysed within 24 h of collection in the field laboratory. Colorimetric

measurements were made on a Shimadzu (Model 1201) spectrophotometer.

Shimadzu (Model 5301) fluorescence spectrophotometer was used for

estimating PHc. The analytical methods for the measurements were as

follows:

i) pH: pH was measured on a Cyber Scan (pH 510) pH Meter. The

instrument was calibrated with standard buffers just before use.

33

ii) SS: A known volume of water was filtered through a pre-weighed 0.45 m

membrane filter paper (Millipore), dried and weighed again.

iii) Salinity: A suitable volume of the sample was titrated against silver

nitrate (20 g/l) with potassium chromate as an indicator. IASPO standard

seawater (DSIL; UK) was used to standardise silver nitrate.

iv) DO and BOD: DO was determined by Winkler method. For the

determination of BOD, direct unseeded method was employed. The sample

was filled in a BOD bottle in the field and incubated in the laboratory for 3 d

after which DO was again determined. v) Phosphate: Acidified molybdate reagent was added to the sample to

yield a phosphomolybdate complex which was then reduced with ascorbic

acid to a highly coloured blue compound which was measured at 882 nm.

vi) Total phosphorus: Phosphorus compounds in the sample were oxidized

to phosphate with alkaline potassium persulphate at high temperature and

pressure. The resulting phosphate was analyzed as described under (v).

vii) Nitrite: Nitrite in the sample was allowed to react with

sulphanilamide in acid solution. The resulting diazo compound was

reacted with N-1-Naphthyl-ethylenediamine dihydrochloride to form a highly

coloured azo-dye. The light absorbance was measured at 543 nm.

viii) Nitrate: Nitrate was determined as nitrite in (vi) above after its reduction

by passing the sample through a column packed with amalgamated

cadmium.

ix) Ammonia: Ammonium compounds (NH3 + NH4+) in water were reacted

with phenol in presence of hypochlorite to give a blue colour of indophenol.

The absorbance was measured at 630 nm.

34

x) Total nitrogen: Nitrogen compounds in the sample were oxidized to

nitrate by autoclaving with alkaline persulphate. The solution was neutralized

and nitrate was estimated as described under (viii).

xi) PHc: Water sample (1 l) was extracted with hexane and the organic layer

was separated, dried over anhydrous sodium sulphate and reduced to 10 ml

at 30o C under low pressure. Fluorescence of the extract was measured at

360 nm (excitation at 310 nm) with Saudi Arabian crude residue as a

standard. The residue was obtained by evaporating lighter fractions of the

crude oil at 100oC for 30 min.

xii) Phenols: Phenols in water (500 ml) were converted to an orange

coloured antipyrine complex by adding 4-aminoantipyrine. The complex was

extracted in chloroform (25 ml) and the absorbance was measured at 460 nm

using phenol as a standard.

4.6 Sediment quality

a) Sampling procedure: Subtidal surfacial bed sediment from all locations

was obtained by a van Veen grab of 0.04 m2 area. The sample after retrieval

was transferred to a polyethylene bag and preserved for further analysis.

Intertidal sediment was sampled using a hand shovel.

b) Methods of analyses: (i) Texture: Dried sediment (25 g) mixed with

deionised water and 10 ml sodium hexameta phosphate (6.2 g/l) was sieved

through 63 m sieve to retain sand and the passed material was dispersed in

deionised water (1 l). The fraction (20 ml) picked up at 20 and 10 cm depth

immediately and after 2 h 30 min, respectively were considered as silt and

clay after drying and weighing.

ii) Metals: Sediment was brought into solution by treatment with conc HF-

HClO4-HNO3-HCl and the metals were estimated on a Perkin Elmer

(Analyst 300) Atomic Absorption Spectrophotometer (AAS) by flame.

35

Mercury was estimated by flameless AAS technique after digesting the

sediment with aquaregia.

iii) Corg: Percentage of Corg in the dry sediment was determined by oxidising

organic matter in the sample by chromic acid and estimating excess chromic

acid by titrating against ferrous ammonium sulphate with ferroin as an

indicator.

iv) Phosphorus: Dried and powdered sediment (20.5 g) was digested using

HF, HC104, HNO3 and HCl. It was used for estimating total phosphorus as

described under Section 1.5.3(b)(v).

v) PHc: Sediment after refluxing with KOH-methanol mixture was extracted

with hexane. The residue was subjected to clean-up procedure by silica gel

column chromatography. PHc content was then estimated by measuring the

fluorescence as described under Section 1.5.3 (b) (xi).

4.7 Flora and fauna

a) Sampling procedure: For microbial analysis, surface water was collected

directly in a sterilised glass bottle. Sediment sample was obtained using van

Veen grab and transferred directly into sterilised polyethylene bag.

Polyethylene bucket and Niskin sampler respectively, were used for

sampling surface and bottom waters for the estimation of phytoplankton

pigments and population. Samples for phytoplankton cell count were fixed in

Lugol's solution.

Zooplankton samples were collected by oblique hauls using a Heron

Tranter net (mesh size 0.3 mm, mouth area 0.25 m2) with an attached

calibrated TSK flow meter. All collections were of 6 min duration. Samples

were preserved in 5% buffered formaldehyde.

Sediment samples for subtidal macrobenthos were collected using a

van-Veen grab of 0.04 m2 area. Intertidal collections between the HTL and

36

the LTL were done with a hand shovel for muddy and silty substratum while

quadrants of different sizes were employed for sampling rocky, sandy and

areas of compact sediment. All samples were preserved in 5% buffered

formaldehyde - Rose Bengal.

Experimental bottom trawling and gill netting were undertaken

wherever feasible using a high opening bottom net of 20.7 m (637 meshes of

50 mm) length and locally procured gill net.

b) Methods of analyses:

i) Microbes: Samples were analysed by plating and 0.22 m membrane

Millipore filtration techniques for Total viable counts (TVC), Total coliforms

(RC), Escherichia coli like organisms (ECLO), Faecal coliforms like

organisms (FCLO), Shigella like organisms (SHLO), Salmonella like

organisms (SLO), Proteus klebsiella like organisms (PKLO), Vibrio like

organisms (VLO), Vibrio parahaemolyticus like organisms (VPLO), Vibrio

cholerae like organisms (VCLO), Pseudomonas aerugenosa like organisms

(PALO) and Streptococcus faecalis like organisms (SFLO). Colonies of TC,

ECLO, VLO, VPLO and VCLO were counted separately. The bacterial

counts in water (CFU/ml) and sediment (CFU/g; dry wt) are reported. The

media employed for growth of colonies were as follows:

Nutrient agar for TVC, Mac Conkey agar for TC and ECLO, M-Fc agar

for faecal coliforms, Xylose-lysine deoxycholate agar for SHLO, SLO and

PKLO, thiosulphate citrate bile salts medium for VLO, VPLO and VCLO,

centrimide agar for PALO and M.enterococcus agar for SFLO.

ii) Phytoplankton: Pigments: A known volume of water was filtered through

a 0.45 m membrane filter paper (Millipore) and SS retained on the filter

paper were extracted in 90% acetone. For the estimation of chlorophyll a and

phaeophytin the extinction of the acetone extract was measured at 665 nm

after treatment with dilute 0.1 N-HCl of 750 nm. The concentrations of

phytopigments were expressed as mg/m3.

37

Population: The cells in the sample preserved with Lugol’s solution were

allowed to settle and transferred into a Sedgwick-Rafter slide. Enumeration

and identification of phytoplankton were done under a microscope. The cell

counts are expressed as no/l.

iii) Algae, seaweeds, mangrove and sand-dune ecosystem: Algae,

seaweed and mangrove flora were assessed from upper to lower intertidal

region along predecided transect.

iv) Zooplankton: Volume (biomass) was obtained by displacement method.

A portion of the sample (25-50%) was analysed under a microscope for

faunal composition and population count. Biomass and population are

expressed as ml/100 m3 and no.x103/100 m3 respectively.

v) Fish eggs, fish larvae and decapod larvae: These groups were sorted

out from zooplankton samples and counted. Frequency of occurrence and

their percentage composition were then determined.

vi) Benthos: The sediment samples were sieved through a 0.5 mm mesh

sieve and animals retained were preserved in 5% buffered formaldehyde-

Rose Bengal. Total population was estimated as number of animals in 1 m2

area and biomass on wet weight basis (g/m2).

vii) Corals: Distribution and abundance of live corals were assessed by

physical examination of the intertidal zone during low tide and by mapping

using remote sensing.

viii) Fishery: After trawling fishes were sorted out into different groups,

weighed, and catch rate (kg/h) and composition were determined. A part of

the catch was preserved in 5% formaldehyde for identification at species

level. Fish landing data were obtained from the Department of Fisheries,

Government of Gujarat, for assessing the fishery status of the region.

38

4.8 Model studies

A Hydrodyn-FLOWSOFT model was used for predictions on tides and

currents as well as seawater intake. A Hydrodyn-POLSOFT model was

applied for predictions on critical water quality parameters in the effluent as

release while a Hydrodyn-SEDSOFT model was employed for predictions on

spread of SS in effluent on release.

39

5 PREVAILING MARINE ENVIRONMENT

The prevailing marine environment off Kuranga which is adjacent to

the plant site of RSPL has been proposed for establishment of marine

facilities i.e. seawater intake and effluent disposal (Figure 1.4.1). Hence the

area has assessed in respect of physical processes, water quality, sediment

quality, and flora and fauna to generate the oceanographic data for 3

seasons namely April-May 2012 (premonsoon), September 2012 (monsoon),

and December 2012 (postmonsoon). Total 9 stations in the subtidal

environment were so spaced that the transects i.e. nearshore, towards

offshore and offshore would be about 4 to 5, 9 to 10 and 13 to 14 km from

the shore and in 21 to 25, 30 to 35 and 35 to 40 m depths respectively in 280

km2 area (Figure 1.4.1). The stations were categorised in 3 above mentioned

transects (Figure 1.4.1) as follows:

Transect Station

Nearshore 1,4,7

Towards offshore 2,5,8

Offshore 3,6,9

The status of prevailing marine environment has been described in

detail as follows:

5.1 Physical processes

Bathymetry, tides, currents, circulation and stratification in the water

column are the important factors to be considered while evaluating sites for

seawater intake and release of an effluent in coastal areas devoid of

substantial freshwater runoff.

They are described below.

40

5.1.1 Bathymetry

The bathymetry of the region is even with no large depressions or out

crops and the contours are smooth with 10 to 12 m water depths

encountered within 1.5 km from shore. The bathymetry studies conducted for

the site specific information using a dual frequency echo sounder confirmed

that large scale variations did not occur in the bathymetry (Figure 5.1.1).

The identification of type of sediment deposits on the seafloor was

attempted by assessing the difference in depths recorded during the

bathymetry survey using dual frequencies i.e. 200 and 33 kHz. The lower

frequency (33 kHz) has the ability to penetrate the softer bed compared to

the higher frequency (200 kHz). The sedimentation was computed by

subtracting the depth indicated by lower frequency from that of higher

frequency.

The difference in penetration was estimated as the thickness of the

soft sediments present on the sea floor. The sedimentation map prepared

for intake and outfall regions is shown in Figure 5.1.2 from which it can be

expected that the region has soft sediments of 0.2 m in the south nearer to

shore and about 1 m in the north (deep water area).

5.1.2 Tides

The selected stretch is in the open coast of Dwarka-Miyani. This

segment forms a part of the Okha- Porbandar stretch in the Saurashtra

coast. The following tidal parameters (m) with respect to the Chart Datum

(CD) are established for Okha and Porbandar from the recorded tides:

Level Okha Porbandar

MHWS 3.47 2.66

MHWN 2.96 2.38

MSL 2.04 1.82

MLWN 1.20 1.46

MLWS 0.41 0.77

41

The tides along the coast off Saurashtra were mixed semi-diurnal with

two unequal high and two unequal low waters occurring in each tidal day.

The tidal range decreased considerably from Okha to Porbandar. The high

tide at Okha lagged by roughly 1 h 40 min to 2 h 10 min with respect to the

tide at Porbandar.

The predicted tide at Dwarka during premonsoon and postmonsoon of

2012 along with predicted tide at Miyani for the same period are presented in

Figures 5.1.3 and 5.1.4 respectively. Maximum tidal range was 3.4 m at

Dwarka where as at Miyani it was 1.8 m on the same date.

5.1.3 Currents

In the coastal waters off Okha-Kuranga, the currents are generated

mainly due to tidal movement of the water mass though wind also contributes

to some extent. Currents are responsible for dispersion and advection of the

effluent discharged in the sea and hence plays an important role while

selecting sites for the release of an effluent.

Currents were recorded at station 4 during 29 April-6 May 2012

(premonsoon season). The results are presented in Figure 5.1.5. Maximum

currents of 0.4 m/s were observed in this area. In the postmonsoon season

(15-12 December 2012), the current meter was moored at station 7. The

results showed that the maximum currents in this location varied between 0

and 0.3 m/s (Figure 5.1.6). In both the cases, the currents were parallel to

the coast.

In the earlier studies of the general area, currents were recorded at

Dwarka during October 2009 for a period of 5 days (Figure 5.1.7). The

analysis of the currents indicated that the currents were moderate

(maximum 0.4 m/s during flood and 0.55 m/s during ebb) and due to sudden

undulations in bottom topography and curvature of the shoreline the currents

have a net onshore component(+0.22 m/s) almost equal to the net

alongshore component (-0.27 m/s). The net onshore component was positive

42

indicating a shoreward transport particularly during flood phase of the tides.

The net alongshore components were in ebb direction.

During March 2010 a current meter was deployed for about 8 days at

offshore of Kachchigadh which is more than 30 km away towards north from

station 4. The currents are graphically illustrated in Figures 5.1.8 and 5.1.9. It

can be noted that the maximum current speeds during flood was 0.65 m/s

and during ebb it was 0.58 m/s. The general flood and ebb directions were

NNE and SSW respectively. The currents when resolved into v

(onshore/offshore) and u (alongshore) components indicated very small

onshore component and a net negative v component (-0.07 m/s) suggesting

transport in the offshore direction while the alongshore component indicated

a net northerly transport (+ 0.34 m/s).

5.1.4 Tidal excursion

Tidal excursion which is useful while considering advection of

contaminants when released to marine waters is the average distance a

particle travels from slack water to slack water due to tidal currents. In order

to evaluate the tidal excursion in the study area, drogue study was

conducted on 2 May 2012 and the results are presented in Figure 5.1.10.

The excursion length of the float was 6 km during 5 h.

On 23 October 2002, the drogue released near Dwarka during flood

tide travelled 12 km covering 8.6 km in N and 7.5 km in E directions. The

average speed computed based on the results was 0.64 m/s over a period of

5 h 15 min. During the ebb, the excursion was about 6 km covering 4.3 km in

S and 3.7 km in W directions with an average speed of 0 to 0.5 m/s over a

period of 3 h 30 min. The total displacement of the drogue during the

observation period of 8 h 45 min. was 18 km with an average speed of 0 to

0.58 m/s (Figure 5.1.11).

On 24 October 2002, the drogue released near Dwarka during flood

tide travelled a total of 9.8 km distance covering 7.9 km in N and 4.7 km in E

directions with an average speed of 0.61 m/s over a period of 4 h 30 min.

43

During the ebb, the excursion was about 7.6 km covering 6.3 km in S and 2.4

km in W directions with an average speed of 0.33 m/s over a period of 6 h 30

min. The total drogue displacement over 11 h of observation was 17.8 km

with an average speed of 0.44 m/s (Figure 5.1.12).

On 28 October 2002, the drogue released near Dwarka during ebb

tide travelled 5.5 km covering 1.4 km in N and 1.1 km in E directions with an

average speed of 0.23 m/s over a period of 5 h 30 min. During the flood the

excursion was about 17 km covering 10 km in N and 8 km in E directions

with an average speed of 0.67 m/s over a period of 7 h. The total travel

during the observation period of 12 h 30 min was about 22 km with an

average speed of 0.50 m/s (Figure 5.1.13).

Studies available for drogue in the openshore near Dwarka in the past

(1999), indicated that a particle would predominantly move parallel to the

shore over a distance of 18 km over a period of 6 h 10 min (Figure 5.1.14).

Drogue released off Rupen Bandar on 29 March 2010 at peak flood

(Figure 5.1.15) travelled about 8 km in 2 h 30 min with an average speed of

0.88 m/s.

All the above trajectories indicated sufficient excursions and possibility

of distribution of the pollutants associated with the effluents over a wider

area.

5.2 Water quality

Water quality of the coastal waters off Kuranga investigated at 9

stations during April-May, September and December 2012 is presented in

Tables 5.2.1 to 5.2.21 while temporal variations observed at stations 1, 4 and

7 are illustrated in Figures 5.2.1 to 5.2.6. To facilitate discussion averages

are generally used in the following discussion:

44

5.2.1 Temperature

Water temperature generally regulates species distribution,

abundance and their composition and life cycle associated with an aquatic

environment. Since, most of the aquatic animals are cold blooded, water

temperature regulates their metabolism and ability to survive and reproduce

effectively. Hence, artificially induced changes may alter the equilibrium

status of an indigenous ecosystem.

The average temperature (oC) of the coastal waters off Kuranga

varied in following ranges:

Temperature (oC)

Segment Premonsoon

(April-May12)

Monsoon

(Sept 12)

Postmonsoon

(Dec 12)

Nearshore 24.1-28.6

(26.5)

28.1-29.6

(28.9)

21.6-26.7

(25.1)

Towards offshore 26.5-27.9

(27.2)

- 24.3-25.5

(24.8)

Offshore 25.3-27.1

(26.4)

- 24.2-25.1

(24.78)

Overall 24.1-28.6

(26.7)

28.1-29.6

(28.9)

21.6-26.7

(24.9)

Average in parenthesis

These changes were according to prevailing air temperature (23.0 -

32.5 oC, av). The lateral variations were small and the vertical gradient in

temperature was also marginal indicating well mixed waters. Though pre and

postmonsoon temperatures were similar, they were higher during monsoon

possibly because of the retreating of monsoon and beginning of dry weather.

The earlier studies of March 2010 indicated that temperature was

generally below 27.3 oC in the nearshore area off Gojiness which is adjacent

to the study area.

45

5.2.2 pH

The principal systems that regulate pH of water are the carbonate

systems consisting of CO2, H2CO3, HCO3- and CO3

2-. Because of the

buffering capacity of seawater, generally seawater pH has limited variability

(7.8 to 8.3). In shallow, biologically active tropical waters, large diurnal pH

changes from 7.3 to 9.5, may occur naturally because of photosynthesis. In

nearshore and estuarine systems influx of freshwater particularly during

monsoon can affect the buffering process and the pH often remains below 8.

These areas are also vulnerable to pH changes due to release of

anthropogenic discharges. Though pH range of 5 to 9 is not directly harmful

to the aquatic life, such changes can make many common pollutants more

toxic.

The average pH of the study area varied as follows:

pH

Segment Premonsoon (April-May 12)

Monsoon (Sept 12)

Postmonsoon (Dec 12)

Nearshore 8.0-8.0

(8.0)

8.1-8.3

(8.2)

8.0-8.3

(8.2)

Towards offshore 8.0-8.2

(8.1)

- 8.0-8.1

(8.1)

Offshore 8-8.2

(8.1)

- 8.0-8.1

(8.1)

Overall 8.0-8.2

(8.0)

8.1-8.3

(8.2)

8.0-8.3

(8.1)

Average in parenthesis

Thus as expected the average pH varied in a narrow range of 8.0 to

8.3 during the present study. The surface to the bottom variation was not

marked. The spatial as well as seasonal variations were marginal in this case

with minor spatial and temporal changes.

The pH of 8.0 to 8.2 has been reported for March 2010 for the

nearshore area off Gojiness which is adjoining to the study area.

46

5.2.3 Suspended Solids (SS)

SS of natural origin mostly contains clay, silt and sand of bed

sediments, organic debris and plankton. For nearshore areas clay, organic

debris and vegetative matter form important components of SS.

Anthropogenic discharges add a variety of SS depending upon the source.

Since the major contribution comes from the disturbance of bed and shore

sediments, energy of the region such as tidal currents is the vital influencing

factor for SS and typically leads to high values in the bottom water.

The immediate effect of SS is an increase in turbidity which reduces

light intensity and the depth of photic zone leading to decrease in primary

production and fish food. SS in the water column also adversely affects

certain sensitive populations through mortality, reducing growth rate and

resistance to diseases, preventing proper development of fish eggs and

larvae, modifying natural movement and migration and reducing abundance

of available food. SS settling on the bed can damage the benthic invertebrate

population, block spawning etc. Organic content in SS increases oxygen

demand in the water column and its settlement on the bed can make the

sediment anoxic.

The average SS (mg/l) of the study area during 2012 varied as

follows:

SS (mg/l)

Segment Premonsoon (April-May 12)

Monsoon (Sept 12)

Postmonsoon (Dec 12)

Nearshore 24 - 274

(77)

101 - 121

(112)

16 - 23

(20)

Towards offshore 20 - 170

(70)

- 16 - 21

(18)

Offshore 109 - 200

(153)

- 18 - 22

(19)

Overall 20 - 274

(100)

101 - 121

(112)

16 - 23

(19)

Average in parenthesis

47

Thus average SS was in the wide range of 16 to 274 mg/l during the

present study. The vertical variation was insignificant in the study area. The

content was higher with marked spatial variations during premonsoon. It was

lower during monsoon and postmonsoon indicating significant seasonal

variations.

The average SS was low (< 29 mg/l) for the nearshore area off

Gojiness during March 2010.

5.2.4 Salinity

Salinity is an indicator of freshwater incursion in nearshore coastal

waters as well as excursion of saline water in inland water bodies such as

estuaries, creeks and bays. Normally seawater salinity is 35.5 ppt which may

vary depending on the processes such as evaporation and precipitation, and

freshwater addition. Biota is generally acclimatized to a certain range of

salinity where they thrive. Hence, wide changes in salinity can result in

adoption with modification and dominance of selected species in the lower

order while higher order biota may migrate, thereby bringing alterations in

community structure. Sudden changes in salinity may cause high mortality of

biota including fish due to salinity shock.

The average salinity (ppt) of the Kuranga coastal waters varied as

follows:

Salinity (ppt)

Segment Premonsoon (April-May 12)

Monsoon (Sept 12)

Postmonsoon (Dec 12)

Nearshore 35.2-36.4

(35.6)

35.7-37.0

(36.4)

35.9-36.8

(36.3)

Towards offshore 35.2-35.3

(35.3)

- 36.1-36.3

(36.2)

Offshore 35.2-36.4

(35.4)

- 36.1-36.3

(36.2)

Overall 35.2- 36.4

(35.2)

35.7-37.0

(36.4)

35.9-36.8

(36.3)

Average in parenthesis

48

Thus as expected for coastal area devoid of freshwater inflow during

the dry season, the average salinity ranged from 35.2 to 37.0 ppt and was

fairly stable. Narrow ranges of variation between the surface and the bottom

as well as laterally indicated that the waters were well mixed and stratification

was largely absent. The seasonal variations were also not significant in the

content.

The earlier studies of March 2010 reported salinity of 36.4 to 39.4 ppt

for the nearshore area off Gojiness which is adjacent to the study area.

5.2.5 DO and BOD

DO content of water is a vital water quality parameter influencing the

health of aquatic biota. Although there is considerable dispute on minimum

level of DO required for a healthy tropical marine environment, it is

considered that the DO levels should not fall below 3 ml/l for prolonged

periods in inshore waters. The sources of DO in natural waters are

photosynthesis and dissolution from the atmosphere across the air-water

interface. However, the DO is consumed by biotic respiration and decaying

organic matter. Hence, an increase in oxidisable organic matter in water can

deplete DO to levels which can be detrimental to aquatic life.

The average DO (mg/l) in the study area was given in the following

table:

DO (mg/l)

Segment Premonsoon (April-May 12)

Monsoon (Sept 12)

Postmonsoon (Dec 12)

Nearshore 6.4-8.6

(7.3)

6.4-7.0

(6.6)

6.0-7.0

(6.6)

Towards offshore 4.2-7.6

(6.4)

- 6.3-7.0

(6.6)

Offshore 6.7-8.3

(7.5)

- 6.3-7.0

(6.6)

Overall 4.2-8.6

(7.1)

6.4-7.0

(6.6)

6.0-7.0

(6.6)

Average in parenthesis

49

Hence, with the average DO of in excess 4 mg/l, the coastal waters

were well oxygenated indicating healthy environment for biological growth.

The seasonal as well as spatial variations were largely absent indicating

absence of any influxes of biodegradable organic matter.

DO was fairly high (6.0 - 7.4 mg/l, av) in the nearshore area off

Gojiness during March 2010 with the saturation of 93 to 120 %.

The average BOD (mg/l) of the study area was as follows:

BOD (mg/l)

Segment Premonsoon (April-May 12)

Monsoon (Sept 12)

Postmonsoon (Dec 12)

Nearshore 1.6 - 4.3

(2.8)

0.3-6.7

(3.8)

0.3-2.2

(1.2)

Towards offshore 1.6 – 4.2

(2.9)

- 0.6-1.9

(1.2)

Offshore < 0.1 - 4.2

(3.0)

- 1.0-1.9

(1.5)

Overall < 0.1 – 4.3

(2.9)

0.3-6.7

(3.8)

0.3-2.2

(1.3)

Average in parenthesis

BOD of the study area was < 0.1 to 6.7 mg/l which is low and common

to such highly productive coastal ecosystems. The low BOD indicated that

degradable organic matter entering the coastal waters was efficiently

oxidised by high available DO in the waters to maintain very good oxidative

conditions in the study area. BOD was also low (< 2.4 mg/l) in the nearshore

area off Gojiness during March 2010.

50

5.2.6 Phosphorus and nitrogen compounds

Dissolved nutrients though in low concentrations in natural surface

waters play an important role in controlling production at the primary level

and in turn the biotic potential including fishery of the area. Among several

inorganic constituents such as Phosphorus and nitrogen compounds, silicon,

trace metals etc, the traditional nutrients namely phosphorus and nitrogen

compounds have a major role to play in primary productivity particularly in

coastal waters where silicate and metals generally do not control primary

productivity. However, their occurrence in high levels in areas of restricted

water exchange such as creeks, bays and estuaries can lead to an excessive

growth of algae which in extreme conditions results in eutrophication.

Phosphorus as phosphate (PO43--P) is one of the major nutrients

required for plant growth and essential for life. Sources of phosphate in

coastal marine environment include domestic sewage, detergents, effluents

from agro-based and fertilizer industries, agricultural run-off, organic detritus

such as leaves, cattle waste, remains of dead organisms etc.

Nitrogen cycle involving elementary dissolved nitrogen, its oxides like

NO3-, NO2

- and reduced forms like NH4+, NH3; plays a significant role in

sustaining life in aquatic environment. NO3- is the end product of oxidation

and the most stable form at pH 7. The principal source of nitrogen in marine

environment is nitrogen fixation to N2O and NH3 via atmosphere. NO2- occurs

in seawater as an intermediate product of nitrate in microbial processes i.e.

denitrification at low oxygen levels at which NO2- is further transformed into

NH3 and N2 in anoxic conditions. Unionised ammonia (NH3) is in equilibrium

with ammonium ion (NH4+) in water and its toxicity is largely influenced by

pH, total concentration and water temperature. Ionic strength levels of 0.2 to

2.0 mg/l NH3 are lethal to a variety of fish species.

a) Phosphate: The average reactive phosphate-phosphorus (mol/l) in the

coastal waters of the study area is summarised below.

51

PO43--P (mol/l)

Segment Premonsoon (April-May 12)

Monsoon (Sept 12)

Postmonsoon (Dec 12)

Nearshore 0.1-2.3

(0.8)

0.8-1.7

(1.3)

0.4-1.4

(0.9)

Towards

offshore

ND-1.2

(0.6)

- 0.9-1.8

(1.3)

Offshore 0.2-0.8

(0.5)

- 0.9-1.5

(1.3)

Overall ND-2.3

(0.6)

0.8-1.7

(1.3)

0.4-1.8

(1.1)

Average in parenthesis

Hence, phosphate was present in low range of ND to 2.3 mol/l and

spatial variations were evident only during premonsoon when the levels were

higher. The content of 0.7 to 1.7 mol/l recorded for the nearshore of

Gojiness during March 2010 compared well with the present corresponding

values.

b) Total phosphorus: The average phosphorus content (mol/l) in the

coastal waters off Kuranga is given below.

TP (mol/l)

Segment Premonsoon (April-May 12)

Monsoon (Sept 2012)

Postmonsoon (Dec 2012)

Nearshore 1.7 – 2.3

(2.0)

2.0 – 2.1

(2.1)

1.4 – 2.6

(1.9)

Towards offshore 0.3 – 1.7

(1.2)

- 1.8 – 2.5

(2.2)

Offshore 0.6 – 1.6

(1.1)

- 1.8 – 2.6

(2.1)

Overall 0.3 – 2.3

(1.4)

2.0 – 2.1

(2.1)

1.4 – 2.6

(2.1)

Average in parenthesis

52

Hence the average content was low of 0.3 to 2.6 mol/l which was

uniformly distributed in the waters. Spatial as well as seasonal variations

were not noticed in the content. The total Phosphorus content was mostly

contributed by phosphate present in the waters.

The content was similarly low of 0.5 to 1.6 mol/l in the nearshore

area off Gojiness which is located adjacent to the study area during March

2010.

c) Nitrate: The average concentration of nitrate-nitrogen (mol/l) in different

zones of the study area is given below.

NO3--N (mol/l)

Segment Premonsoon (April-May 12)

Monsoon (Sept 12)

Postmonsoon (Dec 12)

Nearshore 1.0-8.3

(4.3)

1.9-5.5

(3.7)

2.6-9.4

(6.8)

Towards offshore 0.8-8.0

(4.5)

- 5.9-9.2

(8.0)

Offshore 1.0-4.8

(3.2)

- 4.3-11.7

(8.7)

Overall 0.8-8.3

(4.0)

1.9-5.5

(3.7)

2.6-11.7

(7.8)

Average in parenthesis

Thus nitrate content varied in 0.8 to 11.7 mol/l range. Significant

seasonal variations were evident but spatial variations were random.

The earlier data for the nearshore (March 2010) indicated the content

of 0.4 to 4.4 mol/l.

d) Nitrite: The average nitrite-nitrogen concentration (mol/l) in the study

area is given below.

53

NO2--N (mol/l)

Segment Premonsoon (April-May 12)

Monsoon (Sept 12)

Postmonsoon (Dec 12)

Nearshore 0.1-1.6

(0.6)

0.2-0.6

(0.3)

0.2-2.2

(0.9)

Towards offshore 0.1-1.5

(0.7)

- 1.2-1.9

(1.6)

Offshore ND-0.2

(0.1)

- 0.5-1.9

(1.1)

Overall 0.1-1.6

(0.5)

0.2-0.6

(0.3)

0.2-2.2

(1.2)

Average in parenthesis

Hence the content was uniformly low (< 2.2 mol/l) as expected for

well-oxygenated natural waters. The spatial as well as seasonal variations

were not exhibited for the content.

The low content (0.2 - 0.5 mol/l) was also reported for the nearshore

area off Gojiness which is adjacent to the study area during March 2010.

e) Ammonium: The study area sustained the following average

concentrations (mol/l) of ammonium-nitrogen:

NH4+-N (mol/l)

Segment Premonsoon (April-May 12)

Monsoon (Sept 12)

Postmonsoon (Dec 12)

Nearshore ND-1.0

(0.1)

0.4-2.2

(1.4)

0.3-1.6

(0.9)

Towards offshore 0.1-1.0

(0.5)

- 0.8-1.5

(1.2)

Offshore 0.2-0.8

(0.5)

- 0.7-1.4

(1.0)

Overall ND-1.0

(0.4)

0.4-2.2

(1.4)

0.3-1.6

(1.0)

Average in parenthesis

54

As expected for uncontaminated natural coastal waters the

ammonium-nitrogen levels in the waters were low (ND – 2.2 mol/l). As in

the case of nitrite, the low content of ammonium was indicative of absence of

any anthropogenic stress and presence of good oxidative conditions in the

study area. The seasonal and spatial variations were not descrinable.

The earlier studies of March 2010 also recorded the low content of 0.2

to 5.5 mol/l for the nearshore.

f) Total nitrogen: The coastal waters off Kuranga sustained very high levels

of total nitrogen (mol/l) as follows:

TN (mol/l)

Segment Premonsoon (April-May 12)

Monsoon (Sept 12)

Postmonsoon (Dec 12)

Nearshore 5.0 – 58.4

(20.9)

42.2 – 57.2

(50.1)

74.1 – 182.5

(118.7)

Towards offshore 12.0 – 85.5

(56.1)

- 119.1 – 159.4

(137.5)

Offshore 12.2 – 85.8

(47.8)

- 95.6 – 195.0

(149.2)

Overall 5.0 – 85.8

(41.6)

42.2 – 57.2

(50.1)

74.1 – 195.0

(135.1)

Average in parenthesis

Hence the average content was in the range of 5.0 to 195.0 mol/l in

the study area. The higher levels clearly indicated the seasonal variations.

The spatial variations were also significant with the higher content away from

the shore. However the total contribution by the above studied species

namely nitrate, nitrite and ammonia in the content appeared less as these

species levels were low (16.1 mol/l, max).

The content was comparable (7.5 – 32.7 mol/l) in the nearshore area

off Gojiness during March 2010.

55

5.2.7 PHc and phenols

a) PHc: Oil enters the marine environment by a number of different routes

as a result of both human activities and natural processes. By far, the biggest

contribution comes from terrestrial source, mainly in the form of domestic and

industrial wastes. The rate and extent to which oil dissolves/disperses,

depend upon its composition, extent of spreading, water temperature,

turbulence and rate of dispersal. The heavy components of crude oil are

virtually insoluble in seawater whereas lighter compounds particularly

aromatic hydrocarbons such as benzene and toluene, are lowly soluble.

However, these components are also the most volatile and so are lost very

rapidly by evaporation, typically 10 to 1000 times faster than by dissolution.

Concentrations of dissolved hydrocarbons thus rarely exceed 1 mg/l even in

areas receiving their fluxes.

Average PHc concentrations (g/l) in the study area were as given in

the following table:

PHc (g/l)

Segment Premonsoon (April-May 12)

Monsoon (Sept 12)

Postmonsoon (Dec 12)

Nearshore 16.1-28.9

(21.0)

0.2-3.2

(2.9)

5.2-19.4

(14.9)

Towards offshore 6.8-27.4

(16.2)

- 7.3-15.2

(11.5)

Offshore 6.6-32.8

(19.7)

- 7.8-10.7

(9.4)

Overall 6.6-32.8

(19.0)

0.2-3.2

(2.9)

5.2-19.4

(11.9)

Average in parenthesis

The concentrations of PHc of upto 32.8 g/l in the coastal waters

indicated some of influence of anthropogenic activities. The contamination by

56

fishing boats operating in the area could be the possible source. These

contents represented the baseline values for the coastal marine waters.

PHc concentration was low (0.7 to 7.8 g/l) for the nearshore off

Gojiness during March 2010.

b) Phenols: Phenols are generally present at levels of a few micrograms

per litre as biologically produced polyphenols in natural waters. Effluents

originating from industries such as pesticide, dye and pigment, coal, refinery

and petrochemical as well as port can raise the levels in an aquatic system.

The average levels of phenols (g/l) in the coastal waters are

summarised below.

Phenols (g/l)

Segment Premonsoon (April-May 12)

Monsoon (Sept 12)

Postmonsoon (Dec 12)

Nearshore 86.2 - 145.9

(111.8)

72.0 - 126.0

(107.1)

91.4 - 137.0

(106.4)

Towards offshore 124.3 - 139.2

(129.4)

- 103 - 126.7

(118.2)

Offshore 68.6 - 111.4

(90.0)

- 84.2 - 95.5

(88.8)

Overall 68.6 - 145.9

(110.4)

72.0 - 126.0

(107.1)

84.2 - 137.0

(104.5)

Average in parenthesis

Thus phenols which varied from 69 to 146 g/l were low and in

absence of any known anthropogenic releases in the area, the content

appeared to have originated from natural sources.

In comparison phenols were 5 to 43 g/l for the nearshore off

Gojiness during March 2010.

57

5.2.8 Temporal variations

The temporal variations (Figures 5.2.1 to 5.2.6) showed that pH,

salinity, DO and ammonia generally varied randomly. Phosphate and nitrite

were higher during ebbing while nitrate increased during flooding.

5.3 Sediment quality

Determination of trace pollutants such as heavy metals and organic

compounds in water often reveals fluctuations in the concentrations

depending on the location and time of sampling, nature of pollutant and

chemical characteristics of water. Moreover, several pollutants get rapidly

fixed to particulate suspended matter and are thus removed from the water

column. In several instances, it is observed that even close to a location of

effluent release, the metal content in the receiving water often decreases to a

normal value making assessment of the contamination through analysis of

water, a difficult task.

The pollutants adsorbed by the particulate matter are ultimately

transferred to bed sediment on settling. Evidently, concentrations of

pollutants in sediment increase over a period of time in regions receiving

their fluxes. Hence, sediment can serve as a useful indicator of certain trace

pollutants such as heavy metals and PHc.

The content of anthropogenic metals, phosphorus, organic carbon,

PHc etc transported to the receiving water through the effluent would be low

since the soda ash manufacturing process does not generate these

contaminants except those inherited from the raw materials namely

limestone, salt and seawater. However, oils originating through spillages and

leakages from compressors, pumps, cranes etc and residual fuel from

vehicles which form part of the floor washing have the potential to enhance

PHc concentrations in the receiving water and ultimately the bed sediment

when the residue gets associated with suspended particulate matter and

sinks.

The results of subtidal and intertidal sediments in the coastal

sediments off Kuranga region are presented in Tables 5.3.1 to 5.3.3.

58

5.3.1 Texture

Texture of the sediment in the region was influenced by hard rocky

substratum. The sediment texture was mostly sand (> 91%, dry wt) except

that for the subtidal sediment during December 2012 (postmonsoon) when

sediment was mostly slit (> 83 %). The sediment possessed clay in meagre

percentage. Hence though the seasonal variations were noticed, the spatial

variations were not observed within the typical segments namely subtidal or

intertidal except during postmonsoon when the subtidal sediment was mostly

silt while the intertidal sediment was mostly sand.

5.3.2 Heavy metals

Natural sediments always contain heavy metals to a varying degree

depending on the source rock from which they are derived as well as the

environment of deposition. This lithogenic contribution should be known fairly

accurately to estimate probable increase due to anthropogenic fluxes. The

situation however is often complicated due to significant variations in

concentration of metals in different areas of the given region primarily

because of the grain-size effect with sediment having higher clay content

often exhibiting higher levels of lithogenic metals. The grain size effect can

be compensated to a certain extent by normalizing the metal value with

aluminium which can be considered as a measure of clay content.

59

The metal content (dry wt) in the subtidal and intertidal sediments was

as follows:

Metal

Period

April-May 2012 September 2012 December 2012

Subtidal

Al (%) - 0.1-0.2 6.0-7.2

Mn (µg/g) - 89-90 449-517

Fe (%) - 0.2-0.3 4.9-5.3

Co (µg/g) - 1 19-22

Ni (µg/g) - 3 42-51

Cu (µg/g) - ND 41-49

Zn (µg/g) - 6-8 62-76

Hg (µg/g) - ND 0.01-0.04

Intertidal

Al (%) 0.2 0.2 0.2-0.3

Mn (µg/g) 91-134 81-94 110-171

Fe (%) 0.1 0.3 0.2-0.3

Co (µg/g) 1 1 1

Ni (µg/g) 5 3 1

Cu (µg/g) 5-6 ND 1

Zn (µg/g) 4-5 7-10 1-2

Hg (µg/g) 0.01-0.02 ND ND-0.01

Thus the data revealed that the metal content in the subtidal sediment

varied in the wide ranges. This is expected in view of wide variations in

texture as well as levels of aluminium, iron and manganese. The levels were

low during premonsoon and monsoon when the sediment texture was sandy

while they were comparatively higher in the subtidal sediment during

postmonsoon when sediment was mostly silt.

As in the case of subtidal sediment, the metal content of the intertidal

sediment also varied considerably, as expected. In view of the absence of

any anthropogenic releases in the study area these concentrations could be

considered as the baseline.

60

The earlier studies conducted during March 2010 in the nearshore

area off Gojiness reported the levels (dry wt) of 0.113 µg/g, 0.48 µg/g and

118 µg/g for Hg, Cd and Pb respectively.

5.3.3 Corg and phosphorus

Generally, organic carbon (Corg), and phosphorus (P) in marine

sediments largely result from decaying organic matter as well as through

anthropogenic releases. Phosphorus also occurs in some mineral phases.

Hence, sediment of areas receiving organic wastes invariably has high

concentrations of these constituents.

The concentrations of Corg (%, dry wt) in the sediments of the region

are given in the following table:

Period (Season)

Type

Subtidal Intertidal

April-May 2012

(Premonsoon) - 0.1-0.2

September 2012

(Monsoon) 0.2-0.3 0.2-0.3

December 2012

(Postmonsoon) 1.5-1.9 0.1-0.2

The above results revealed uniformly low content (< 1.9 %, dry wt) of

Corg in the sediment of the study area during 2012 indicating that the area

was free from anthropogenic organic releases.

The adjacent nearshore area off Gojiness recorded the content of 1

%, dry wt during March 2010.

61

Phosphorus content (g/g, dry wt) in the sediments is as follows:

Period (Season)

Type

Subtidal Intertidal

April-May 2012

(Premonsoon) - 818-1035

September 2012

(Monsoon) 872-1210 993-1514

December 2012

(Postmonsoon) 893-942 967-1250

Hence P content in the region was low suggesting that adverse impact

of domestic releases, if any were negligible.

5.3.4 PHc

Natural concentrations of biogenic hydrocarbons in marine sediments

are low and observed levels invariably result due to anthropogenic releases.

PHc entering marine water is partially weathered and also adsorbed onto SS

and carried to the bed, thereby enhancing their levels in the sediment. In

areas subject to releases of oil wastes, the sediment levels of PHc can be

high and concentrations in excess of 10 g/g, wet wt invariably occur around

oil terminals and ports.

The concentrations of PHc (g/g, wet wt) in the sediments of the

region varied as follows:

Period (Season)

Type Shade

Subtidal Intertidal

April-May 2012

(Premonsoon) - 0.2-0.6

September 2012

(Monsoon) 0.1 0.1-0.2

December 2012

(Postmonsoon) 0.2-1.4 0.1-0.2

62

These levels were low indicating that the study area was generally

free from significant contamination by petroleum hydrocarbons. The levels

did not suggest any trend in seasonal as well as spatial variations.

The comparable low values (0.2-2.2 g/g, wet wt) were also reported

for the nearshore area off Gojiness during March 2010.

5.4 Flora and fauna

Establishment of biological status of a marine ecosystem is an

essential pre-requisite to assess the impacts of existing as well as proposed

developments in the coastal zone. While considering assessment of aquatic

pollution and its implications, it must be realized that, despite many changes it

may cause in the physico-chemical properties of the water body and bed

sediment, the ultimate consequences are inevitably of a biological nature.

Hence, the investigations of an ecosystem and particularly of its communities

constitute an important part of any ecological assessment study. This can be

achieved by selecting a few reliable parameters from a complex community

structure.

The living community of an ecosystem comprises of consumers,

producers and decomposers and related non-living constituents interacting

together and interchanging material as a whole system. The basic process in

an aquatic ecosystem is its primary productivity. The transfer of energy from

the primary sources through a series of organisms is defined as the food

chains, which are of two basic types; the grazing food chain and the detritus

food chain. The stress may cause the communities to exhibit low biomass and

high metabolism. In addition, due to depressed functions of less tolerant

predators, there may be also a significant increase of dead organic matter

deposited in sediments of ecosystems modified under stress. Depending

upon the type, strength and extent of a stress factor, the ecosystem will react

to either re-establish the previous equilibrium or establish a new one, or it may

remain under prolonged inequilibrium.

The coastal segment of Saurashtra harbours a variety of ecosystems

and habitats, in areas such as creeks, mangroves, intertidal foreshore–rocky,

63

sandy, muddy zones; coastal lagoons, coral reefs and seagrass beds. The

biological parameters considered for the present study at Kuranga coastal

system are phytoplankton pigments and cell count, zooplankton standing

stock and population, macrobenthic biomass and population, fishery and coral

status. The first two reflect the productivity of water column at the primary and

secondary levels. Benthic organisms being sedentary animals associated with

the bed, provide information regarding the integrated effects of stress, if any,

and hence are good indicators of early warning of potential damage while

ultimate commercial interest being fisheries. The local fisherman operating

hand net and bag net were seen and the fishes caught by them at Kuranga

were obtained to identify species for understanding the quality of fishes in

association with the landing statistics obtained from the Department of

Fisheries, Government of Gujarat. Information of larval stages of fishes and

decapods is used to evaluate probable occurrence of spawning and breeding

grounds of economically important species. Data on microbiological counts in

water and sediment are used to assess the extent of contamination by

pathogens. Assessment of seaweeds, mangroves, corals and other

macrobenthic fauna of the intertidal area were carried out to understand the

biodiversity of study area. The aggregate data presented in Tables 5.4.1 to

5.4.51 and Figures 5.4.1 to 5.4.13 are used to evaluate the status of flora and

fauna of the coastal waters off Kuranga.

64

5.4.1 Bacteria

Bacterial counts including TVC, TC, FC, ECLO, and SFLO in the

surface water and sediment at station 4 during postmonsoon period

(December 2012) were considered to assess the health status of the coastal

system.

a) Seawater: The total counts of microbes were very low and most of the

pathogens are not detectable in the surface water. The bacterial counts in

surface water are summarised in the table below.

Type of

bacteria

Station 4

Count (CFU/ml)

E Fl

TVC

(X102) 2500 1600

TC 30 ND

FC ND ND

ECLO ND ND

SFLO ND ND

As evident from above data, the TVC count was higher during ebb than

that of flood suggesting the human contamination at the nearshore area.

However, the overall values of TVC and TC indicated the poor bacterial

population and suggested the study area to be free from anthropogenic

contamination.

b) Sediment: The TVC count in subtidal sediments off Kuranga were

significantly poor and the other pathogens like TC, FC, ECLO and SFLO were

not detectable in the sediment of subtidal region indicating the area to be free

from human contamination which is evident in the following table:

Type of

bacteria Station 4

Count (CFU / g)

TVC (X104) 300

TC ND

FC ND

ECLO ND

SFLO ND

65

5.4.2 Phytoplankton

Phytoplanktons are vast array of microscopic plants passively drifting in

natural waters and mostly confined to the illuminated zone. Phytoplankton

being a basic component of food chain, play a major role in transfer of energy

from primary level to secondary level and their assessment in any water body

facilitates and understanding of primary production potential. Phytoplankton

long has been used as indicators of water quality too. Some species flourish

in highly eutrophic waters while others are very sensitive to organic and/or

chemical wastes. Some species develop noxious blooms, sometimes creating

offensive tastes and odours or anoxic or toxic conditions resulting in animal

death or human illness. Because of their short life cycles, plankton responds

quickly to environmental changes. Hence their standing crop in terms of

biomass, cell counts and species composition are more likely to indicate the

quality of the watermass in which they are found. Generally, phytoplankton

standing crop is studied in terms of biomass by estimating chlorophyll a and

primary productivity. The community structure of phytoplankton by means of

population and species composition are more specific to give an idea of status

of marine ecosystem. When under anthropogenic stress or at the end of their

life cycle, chlorophyll a in phytoplankton decomposes to phaeophytin as one

of the major products. The estimation of ratios of chlorophyll a / phaeophytin

gives an idea of phytoplankton cells health.

a) Phytopigments: Phytoplankton pigments in terms of chlorophyll a and

phaeophytin were studied at different locations in the coastal waters off

Kuranga during three seasons and results are shown in tables 5.4.2 to 5.4.4.

The coastal waters off Kuranga revealed a significant variation in the

concentration of chlorophyll a (0.7 - 30.6 mg/m3, av 5.5 mg/m3) suggesting a

good primary production in the region with relatively higher during

premonsoon period. A conspicuous seasonal variation with noticeable

decrease in concentration of chlorophyll a (0.1 - 1.2 mg/m3, av 0.5 mg/m3)

during monsoon in comparison with premonsoon was evident. A slight

improvement in chlorophyll a (0.1 - 7.6 mg/m3, av 0.9 mg/m3) during

postmonsoon as compared to monsoon was clear indication of seasonal

influence on variation of phytoplankton pigments.

66

The status of chlorophyll a is evaluated in the different segments of the

coastal waters off Kuranga and the results are summarised below.

Zone

Chlorophyll a (mg/m3)

Premonsoon (April-May 2012)

Monsoon (September 2012)

Postmonsoon (December 2012)

S B S B S B

Nearshore 1.9-8.9

(4.2)

1.6-7.9

(4.6)

0.1-1.2

(0.5) -

0.2-7.6

(2.3)

0.2-6.6

(1.8)

Towards

offshore

0.9-2.8

(1.9)

3.2-7.4

(5.5) - -

0.1-0.6

(0.3)

0.1-0.6

(0.3)

Offshore 0.7-1.4

(1.1)

1.3-30.6

(15.6) - -

0.1-0.4

(0.3)

0.1-0.2

(0.1)

Overall

0.7-8.9

(2.4)

1.3-30.6

(8.6)

0.1-1.2

(0.5) -

0.1-7.6

(1.0)

0.1-6.6

(0.7)

Average in parenthesis

The nearshore water off Kuranga exhibited higher level of chlorophyll a

than that of the offshore water except one occasion during premonsoon at the

bottom when abnormally high chlorophyll a was recorded. This trend of

variation is common which could be attributed with an enhanced level of

nutrients towards shore. An augmented level of chlorophyll a (30.6 mg/m3) at

the bottom in the offshore water off Kuranga could be a result of high

proliferation of Nitzschia with the presence of optimal irradiance available

there. However, overall level of chlorophyll a suggested a good primary

production in the coastal waters off Kuranga.

The concentration of phaeophytin was also seen to be enhanced which

varied in the range of 0.2 -5.8 mg/m3, av 2.5 mg/m3 during premonsoon. A

decline in phaeophytin ranging between 0.2 and 1.1 mg/m3 (av 0.4 mg/m3)

during monsoon could be attributed with seasonal impact on pigments.

Similar to that of chlorophyll a the concentration of phaeophytin was also

noticed an increased level of 0.04 - 5.5 mg/m3, av 0.6 mg/m3 during

67

postmonsoon as compared to monsoon indicating the seasonal influence on

phytopigments distribution.

The distribution pattern of phaeophytin in the different segments of

coastal waters off Kuranga is shown in the following table:

Zone

Phaeophytin (mg/m3)

Premonsoon (April-May

2012)

Monsoon (September

2012)

Postmonsoon (December

2012)

S B S B S B

Nearshore 1.1-3.9

(2.4)

1.7-5.2

(3.7)

0.2-1.1

(0.4) -

0.2-5.5

(1.6)

0.1-5.3

(1.3)

Towards

offshore

0.3-2.2

(1.0)

2.0-5.8

(4.4) - -

0.1-0.4

(0.2)

0.1-0.4

(0.2)

Offshore 0.2-0.8

(0.5)

0.6-4.7

(2.7) - -

0.1-0.2

(0.1)

0.04-0.1

(0.1)

Overall

0.2-3.9

(1.3)

0.6-5.8

(3.6)

0.2-1.1

(0.4) -

0.1-5.5

(0.6)

0.04-5.3

(0.5)

Average in Parenthesis

In general, the concentrations of phaeophytin were higher in the

nearshore water than that in the offshore water which could be attributed with

increased level of SS towards the shore area. The ratios of chlorophyll

a/phaeophytin were higher than 1 suggesting a healthy condition of

phytoplankton cells in the coastal waters off Kuranga.

Temporal variation in pigments studied at stations 1 and 4 during

premonsoon as depicted in Figure 5.4.1 to 5.4.2 indicated a small variation

which could be due to tidal variability. In general, the concentrations of

pigment were marginally higher during ebbing than that of flooding periods

indicating an increased primary production towards shore region. The results

of temporal variation during postmonsoon again revealed the similar trend of

distribution of pigments as premonsoon (Figures 5.4.5 and 5.4.6). At all the

occasions of observation the surface and the bottom both waters sustained

68

higher concentrations of chlorophyll a than phaeophytin suggesting a healthy

condition of phytoplankton cells and good phytoplankton production in the

region.

b) Phytoplankton: The distribution pattern of phytoplankton population

followed the similar trend of variation as pigments (Tables 5.4.5 - 5.4.7). The

premonsoon period sustained a significant variation in cell counts (71.0 × 103

- 2812.0 × 103 no/l, av 495.7 × 103 no/l) and total genera (11-19 no, av 15 no.)

of phytoplankton. Similar to that of chlorophyll a the phytoplankton population

also showed a decreased level of cell counts (8.8 × 103 to 100.0 × 103 no/l, av

50.5 × 103/l) and total genera (7 - 13, av 10) during monsoon. The gradual

improvement in cell counts (6.0 × 103 to 846.4 × 103 no/l, av 87.9 × 103/l) and

total genera (7 - 15, av 11) during postmonsoon was discernible from the

results (Tables 5.4.5 - 5.4.7).

The distribution of phytoplankton population in terms of cell counts in

the different segments of coastal water is shown below.

Zone

Cell Count (no x 103/l)

Premonsoon (April-May 2012)

Monsoon (September

2012)

Postmonsoon (December 2012)

S B S B S B

Nearshore 210-415.2

(305.1)

201-497.1

(372.4)

8.8-100.0

(50.5) -

42.4-

846.4

(257.7)

6.0-

686.4

(151.6)

Towards

offshore

85.6-

261.3

(183.1)

344.0-687.0

(534.3) -

13.6-57.6

(32.5)

16.0-

66.4

(38.4)

Offshore

71.0-

140.0

(105.5)

135.0-

2812.0

(1473.5)

- 20.8-32.0

(25.8)

15.2-

27.2

(21.3)

Overall

71.0-

415.2

(197.9)

135.0-

2812.0

(793.4)

8.8-100.0

(50.5) -

13.6-

846.4

(105.3)

6.0-

686.4

(70.4)

Average in Parenthesis

69

Vertical variability in phytoplankton cell counts was distinctly seen

during premonsoon with higher values at the bottom than the surface which

could be due to optimal irradiance available at particular depth resulting a

bloom (2812 x 103/l) of Nitzschia. The high irradiance at the bottom was

confirmed with significantly high secchi disc reading in the coastal waters off

Kuranga (Table 5.4.33). This was indicative of significantly high

photosynthetic activities resulting into good primary production in the coastal

waters off Kuranga. During the period of monsoon the scenario of vertical

distribution of phytoplankton was opposite with an enhanced phytoplankton

production at the surface as compared to that of the bottom in the nearshore

and the offshore waters which could be due to an additional input of nutrients

through land drainage during monsoon allowing the fast growth at the surface

and later at the bottom. This phenomenon is common in the water which is

free from anthropogenic input and sustains low level of SS as the case of

Kuranga. The coastal waters off Kuranga was conducive for the growth of

phytoplankton as a result of which generic diversity was seen to be rich as

shown in the following table:

Zone

Total genera

(no.)

Premonsoon (April-May 2012)

Monsoon (September 2012)

Postmonsoon (December 2012)

S B S B S B

Nearshore 14 - 18

(16)

13 - 16

(14)

7 - 13

(10) -

12 - 15

(14)

7 - 14

(10)

Towards

offshore

12 - 14

(13)

17 - 19

(18) - -

9 - 15

(11)

9 - 12

(10)

Offshore 11 - 15

(13)

11 - 16

(14) - -

9 - 12

(10)

8 - 12

(10)

Overall 11 – 18

(14)

11 - 19

(15)

7 - 13

(10) -

9 - 15

(12)

7 - 14

(10)

Average in Parenthesis

The above results indicated that the phytoplankton generic diversity

was significantly high throughout the water column off Kuranga suggesting an

optimal availability of nutrients and irradiance for phytoplankton growth.

70

Overall, the average generic diversity of 15 during premonsoon, 10

during monsoon and 11 during postmonsoon clearly supported the diversity of

good phytoplankton production in the region (Tables 5.4.8 - 5.4.10).

The major phytoplankton genera observed during different seasons are

summarised in the following table:

Premonsoon (April-May 2012)

Monsoon (September 2012)

Postmonsoon (December 2012)

Nitzschia (77) Navicula (25.8) Chaetoceros (76)

Chaetoceros(5.4) Thalassiosira (21.0) Nitzschia (7.9)

Skeletonema(3.6) Melosira (10.5) Navicula (4)

Protoperidinium (2.1) Nitzschia (7.3) Thalassiosira (1.7)

Guinardia(1.6) Surirella (6.0) Thalassionema (1.4)

Navicula (1.3) Licmphora (5.6) Peidinium (1.3)

Thalassiosira (1.3) Coscinodiscus (4.6) Prorocentrum (1.3)

Miscellaneous (7.7) Gramatophora (4.5) Miscellaneous (6.4)

- Pleurosigma (4.2) -

- Miscellaneous (10.5) -

The community structure of phytoplankton revealed a prominent

alteration due to seasonal change which is clearly discernible from the above

table. The predominance of Nitzschia (av 77%) with very high percentage

composition followed by Cheatoceros (av 5.4%) during premonsoon was

replaced by Navicula (av 25.8%) and Thalassiosira (av 21 %) during

monsoon. The succession of species during postmonsoon is apparent in the

above table with the predominance of Cheatoceros (av 76%) and Nitzschia

(av 7.9%) which could be due to transparent water allowing optimal

penetration of light and ample nutrient availability. Thus the overall scenario

of phytoplankton indicated a good primary production in the coastal waters

off Kuranga.

The comparison of phytoplankton standing crop and population

observed during present study are compared with the earlier results (March

2010) of adjacent area off Gojiness are shown in the following table:

71

Parameter

Adjacent area

(March 2010)

Study area

(April-May 2012)

S B S B

Chlorophyll a

(mg/m3)

0.6-2.2

(1.2)

0.5-1.4

(0.8)

0.7-8.9

(2.4)

1.3-30.6

(8.6)

Phaeophytin

(mg/m3)

0.3-1.6

(0.8)

0-1.65

(0.6)

0.2-3.9

(1.3)

0.6-5.8

(3.6)

Cell count

(no x 103/l)

2.9-16.2

(8.7)

1.9-99.7

(5.4)

71.0-415.2

(197.9)

135-2812

(793.4)

Major genera

Coscinodiscus

Thalassiothrix

Navicula

Rhizosolenia

Pyrophacus

Navicula

Thalassiothrix

Coscinodiscus

Nitzschia

Chaetoceros

Skeletonema

Rhizosolenia

Nitzschia

Chaetoceros

Skeletonema

Guinardia

As evident in the above table, there was a noticeable increase in

phytoplankton pigments and population during the present study as compared to

that of earlier records of the nearshore. A conspicuous alteration in community

structure of phytoplankton during both the periods of study is discernible in the

above table. The changes in predominance of species could be inherent to

alteration of season.

5.4.3 Zooplankton

Zooplankton includes arrays of organisms, varying in size from the

microscopic protozoans of a few microns to some jelly organisms with tentacles

of several meters long. By virtue of sheer abundance and intermediate role

between phytoplankton and fish, zooplankton are considered as the chief index

of utilization of aquatic biotope at the secondary tropic level.

The zooplankton biomass (0.04 - 1.4 ml/100 m3, av 0.9 ml/100 m3)

indicated a low secondary productivity in the coastal waters off Kuranga during

premonsoon (Table 5.4.11). A slight increase in biomass (< 0.1 - 3.7 ml/100 m3,

av 1.0 ml/100 m3) during monsoon suggested the seasonal influence on the

distribution of zooplankton standing stock. There was an increase in zooplankton

biomass (0.1 - 19.2 ml/100 m3, av 2.9 ml/100 m3) during postmonsoon season.

72

Thus the gradual increase in zooplankton biomass from premonsoon to

postmonsoon was an indicative of a systematic secondary production following

the reverse distribution trend of primary producers inherent to seasonal changes

in an environment free from anthropogenic stress.

The zone-wise distribution of zooplankton biomass is shown in the

following table:

Zone

Biomass (ml/100m3)

Premonsoon (April-May 2012)

Monsoon (September 2012)

Postmonsoon (December 2012)

Nearshore 0.04 - 1.3

(0.5)

< 0.1 - 3.7

(1.0)

0.1 -19.2

(4.6)

Towards

offshore

0.8-1.4

(1.0) -

0.6 - 7.9

(2.8)

Offshore 1.1 - 1.4

(1.2) -

1.0 - 5.1

(1.8)

Overall 0.04 - 1.4

(0.9)

< 0.1 - 3.7

(1.0)

0.1 - 19.2

(2.9)

Average in Parenthesis

The lower values during premonsoon and gradual increase during

postmonsoon revealed a reverse distribution trend with phytoplankton pigments

suggesting active grazing in the region.

The zooplankton population (0.3 - 19.6 x 103 no/100 m3, av 8.7 x 103 no

/100 m3) during premonsoon and (0.01 - 0.5 x 103 no /100 m3, av 0.2 x 103 no

/100 m3) during monsoon revealed a moderate secondary production. The

influence of season was evident on zooplankton resulting a significant increase

in population (0.001 - 133.8 x 103 no/100 m3, av 23.8 x 103 no/100 m3) during

postmonsoon (Table 5.4.13). The zone-wise distribution of zooplankton

population is presented in the following table:

73

Zone

Population (no x103/100 m3)

Premonsoon

(April-May 2012)

Monsoon (September 2012)

Postmonsoon (December 2012)

Nearshore 0.3 - 16.3

(5.3)

0.01 - 0.5

(0.2)

0.001 - 133.8

(39)

Towards

offshore

8.0 – 14.1

(6.9) -

2.6 - 80.3

(21.5)

Offshore 6.6 - 19.6

(12.1) -

2.6 - 37.4

(11.1)

Overall 0.3 - 19.6

(8.7)

0.01 - 0.5

(0.2)

0.001 - 133.8

(23.8)

Average in Parenthesis

The distribution pattern of zooplankton population was in the opposite

trend of phytoplankton with the lower values in the nearshore water than that in

the offshore water suggesting again active grazing in the study area.

The group diversity of zooplankton was comparable between premonsoon

(4 - 16 no, av 9 no) and postmonsoon (1 - 18 no., av 11 no). The results showed

a slight decline in the group diversity (1 - 10 no, av 4 no.) during monsoon period

which could be due to a limited sampling carried out during this period.

74

The overall scenario of total groups of zooplankton recorded during all the

seasons is shown below.

Zone

Total groups (no.)

Premonsoon

(April-May 2012)

Monsoon

(September 2012)

Postmonsoon

(December 2012)

Nearshore 4 - 16

(8)

1 - 10

(4)

1 - 18

(12)

Towards

offshore

6-11

(9) -

10 - 14

(12)

Offshore 4 - 14

(9) -

7 - 12

(9)

Overall 4 - 16

(9)

1 - 10

(4)

1 - 18

(11)

Average in Parenthesis

The above data revealed a slight increase in the group diversity of

zooplankton in the nearshore water in comparison of the offshore water

which could be due to natural variability in the region.

The results of temporal variations conducted at stations 1 and 4 during

premonsoon and postmonsoon are depicted in Figures 5.4.7, 5.4.8, 5.4.11

and 5.4.12. The results did not indicate any definite trend of distribution

associated with the tide. This could be due to patchiness in the distribution of

zooplankton associated with strong currents playing a role on their existence.

The temporal variation studies also suggested a moderate zooplankton

production in the coastal waters off Kuranga associated with good primary

production as commonly noticed along the northwest coast of India.

As high as 16 groups of zooplankton during premonsoon and 18

groups during postmonsoon as discernible in Tables 5.4.14 to 5.4.16 were

indicative of a conducive environment for zooplankton community. However,

during the period of monsoon the total groups of zooplankton recorded were

10 which could be due to only shore sampling at few stations. The most

common faunal groups were copepods, decapod larvae, cladocerans,

75

lamellibranchs, gastropods, chaetognaths, Lucifer sp, fish eggs and larvae.

In addition to above, the groups like foraminiferans, siphonophores,

medusae, ctenophores, polychaetes, ostracods, amphipods, stomotopods,

pteropods, appendicularians and isopods were also frequently noticed but in

less numbers during the periods of studies.

The percentage compositions of major groups of zooplankton

community for the different seasons recorded during the present study are

shown below.

Premonsoon (%)

Major groups Nearshore Towards offshore Offshore

Copepods 77.8 37.0 34.1

Cladocera 22.4 60.2 62.8

Decapod larvae 2.7 0.2 0.3

Appendiculariae 2.2 0.9 1.4

Fish eggs 1.2 1.4 0.3

Monsoon(%)

Major groups Nearshore Towards offshore Offshore

Foraminiferans 71.3 - -

Gastropods 10.2 - -

Lamellibranchs 9.7 - -

Postmonsoon(%)

Major groups Nearshore Towards offshore Offshore

Copepods 86.4 91.0 94.2

Foraminiferans 3.2 0.8 1.8

Decapod larvae 4.8 0.7 0.9

Lucifer sp 7.6 1.4 0.7

Fish eggs 0.02 0.6 1.4

The alteration in community structure of zooplankton was associated with

changes of season. The copepods which were predominant in the nearshore

water during premonsoon was replaced by forameniferans during monsoon.

76

However, the postmonsoon season again revealed the predominance of

copepods. The community structure of zooplankton in the offshore water

revealed a slight change in the dominance as evident in the above table. During

the period of premonsoon the predominant group of zooplankton was cladocera

whereas postmonsoon sustained copepod as a predominant group.

The results of zooplankton standing stock observed during the present

study are compared with the earlier records and shown below.

Parameter Adjacent area (March 2010)

Study area (April-May 2012)

Biomass (ml/100m3) 1.1-7.8

(3.2)

0.04-1.4

(0.9)

Population (no x 103/1003) 1.7-24.5

(8.8)

0.3-19.6

(8.7)

Major genera Copepods,

Amphipods,

Decapods,

Crustacean larvae

Fish egg and larvae

Copepods

Cladocera

Decapods larvae

Fish egg

Average in Parenthesis

The present results show a decrease in the zooplankton biomass as

compared to earlier data of adjacent area which could be associated with

alteration in the community structure. However, the population density of

zooplankton remains almost similar during the present study as compared to the

results of earlier studies.

a) Breeding and spawning: To identify breeding grounds of fishes and

crustaceans, extensive field observations over a long duration are required. This

approach was not possible during the present short-term investigation. Hence,

alternatively, decapod larvae, fish eggs and fish larvae were studied from

zooplankton collections and taken as indices of probable existence of spawning

grounds. The adults caught while trawling were considered for comparison. The

77

available information on the breeding habits of the species found in the area

were also included as a supportive literature.

i) Decapods: This group forms the major constituent of zooplankton and

includes the larval stages of commercially important shrimps. Decapod larvae

occur in all zooplankton samples and contribute about 2.6 % to the zooplankton

population (Tables 5.4.17 to 5.4.19).

The incidence (%) and abundance of decapod larvae and Lucifer sp in the

study are given below.

Faunal groups

Period

Premonsoon (April-May

2012)

Monsoon (September 2012)

Postmonsoon (December 2012)

a) Decapod larvae

(i) Population

(no /100m3)

(ii) Incidence

(%)

0 - 718

(73)

40 - 100

(93)

0 - 18

(6)

0 - 30

(10)

0 - 6367

(1042)

0 - 100

(96)

b) Lucifer sp

(i) Population

(no/100m3)

(ii) Incidence

(%)

0 - 4

(3)

0 - 50

(42)

-

0 - 1873

(261)

50 - 100

(94)

Average in Parenthesis

As evident from the above table, the abundance of decapod larvae and

Lucifer sp varied widely in the study area. The percentage incidence of decapod

larvae was 93, 10 and 96% during premonsoon, monsoon and postmonsoon

respectively. The Lucifer sp revealed noticeably low incidence associated with

low abundance during premonsoon in the comparison to postmonsoon, however

it was completely absent during monsoon.

78

Generally, the spawning grounds of penaeid prawns are away from the

coast. The spawning ground of M. dobsoni is reported to be at 20 to 30 m while

that of M. affinis is at still deeper waters. Spawning ground of M. monoceros is

reported to be at 50 to 65 m and that of P. stylifera at 18 to 25 m. M. affinis and

P. stylifera prefer areas of salt mud and zones of rich plankton for mating and

spawning.

Acetes indicus is another common economically important species of

shrimps. During January-April they form conspicuous aggregations in nearshore

and are fished on a large scale along the west coast. Fishing grounds of these

shrimps are mostly located in calm muddy intertidal zones or waters shallower

than 5 m. The life span of Acetes is 3 to 10 months and the adults die soon after

spawning. Breeding is continuous and surface water currents stimulate Acetes

to swarm in shallow inshore waters when the wind blows moderately towards the

coast. Acetes is not recorded in the coastal system of Kuranga during the

present study.

ii) Fish eggs and larvae: Fish eggs and larvae though less in number are fairly

common among zooplankton (Tables 5.4.20 - 5.4.22). The relative occurrence

and abundance of fish larvae are less than fish eggs.

The incidence (%) and abundance (no./100m3) of fish eggs and larvae in

the study area during April-May and December 2012 are given below.

79

Faunal

Groups

Period

Premonsoon

(April-May 2012)

Monsoon (September 2012)

Postmonsoon (December 2012)

a) Fish eggs

(i) Population

(no/100m3)

(ii) Incidence

(%)

0-305

(76)

75-100

(97)

-

0-375

(89)

85-100

(98)

b) Fish larvae

(i) Population

(no/100m3)

(ii) Incidence

(%)

0-8

(6)

0-100

(64)

-

0-50

(10)

0-100

(84)

Average in Parenthesis

As evident from above data that the incidence and abundance of fish

eggs and larvae widely vary in the study area.

Generally, along the west coast of India, fishes spawn during monsoon

and postmonsoon periods. The number of eggs shed by different species may

vary considerably. Even individuals of the same species produce varying

number of eggs depending on their age, weight and condition of gonad.

During the present study, Gobiidae an economically unimportant group

dominated the area. Harpadon nehereus is a continuous breeder with intense

activity from October to April and slack from May to September. Breeding of

these species is reported in deeper waters (>75 m) and the number of ova

produced vary from 1.5 x 104 to 1.5 x 105 no as generally known.

80

5.4.4 Macrobenthos

The organisms inhabiting the sediment are referred as benthos.

Depending upon their size, benthic animals are divided into three categories; viz,

microfauna, meiofauna and macrofauna. Macrobenthos being sedentary

organisms, responses to environmental perturbations directly which are useful in

assessing the anthropogenic impacts on environmental quality. Macrobenthic

organisms which are considered for the present study are animals with body size

larger than 0.5 mm. The presence of benthic species in a given assemblage

and its population density depend on numerous factors, both biotic and abiotic.

a) Intertidal macrobenthos: The intertidal macrobenthic standing stock was

studied in terms of biomass, population and total groups during three seasons

(Tables 5.4.23 - 5.4.25).

The macrofaunal biomass recorded at different transects is summarised

in the following table:

Transect

Biomass (g/m2 ;wet wt)

Premonsoon (April-May 2012)

Monsoon (September 2012)

Postmonsoon (December 2012)

I 0 - 9.2

(1.2)

0 - 36.3

(6.0)

0.1 - 9.1

(2.2)

II 0 - 61.0

(23.3)

0 - 5.7

(1.5)

0 - 48.8

(12.0)

III 0 - 3.5

(0.9)

0 - 2.0

(0.5)

0.4 - 9.1

(1.9)

Overall 0 – 61.0

(8.6)

0 - 36.3

(2.8)

0 - 48.8

(5.3)

Average in Parenthesis

The distribution of macrobenthic biomass was associated with seasonal

changes revealing decline (0 - 36.3 g/m2, av 2.8 g/m2; wet wt) during monsoon

than that (0 - 61 g/m2, av 8.6 g/m2, wet wt) observed during premonsoon. The

period of postmonsoon season recorded enhancement in intertidal macrobenthic

production with the biomass of 0 - 48.8 g/m2, av 5.3 g/m2; wet wt suggesting a

seasonal variability on macrobenthos.

81

The summary of intertidal macrobenthic population studied during

different seasons at Kuranga is presented in the table given below.

Transect

Population (no / m2,)

Premonsoon (April-May

2012)

Monsoon (September 2012)

Postmonsoon (December 2012)

I 0 - 525

(125)

0 - 375

(94)

50 - 7125

(1413)

II 0 - 750

(226)

0 - 450

(163)

0 - 350

(144)

III 0 - 1000

(359)

0 - 450

(113)

700 - 4475

(1475)

Overall 0 - 1000

(237)

0 - 450

(123)

0 - 7125

(1011)

Average in Parenthesis

The distribution pattern of intertidal macrobenthic population followed the

similar trend as biomass with the decreased values of 0 to 450 no/m2, av 123

no/m2 during monsoon than that of population (0 - 1000 no/m2, av 237 no/m2)

recorded during premonsoon. There was a significant increase in the population

(0 - 7125 no/m2, av 1011 no/m2) of intertidal macrobenthic fauna during

postmonsoon. However, the overall values of the present study revealed

moderate to good macrobenthic standing stock in the region.

82

The results of total groups of intertidal macrobenthic fauna is shown in the

following table:

Transect

Total groups (no.)

Premonsoon

(April- May 2012)

Monsoon

(September 2012)

Postmonsoon

(December 2012)

I 0 - 3

(1)

0 - 4

(1)

1 - 4

(2)

II 0 - 6

(3)

0 - 3

(2)

0 - 4

(2)

III 0 - 4

(2)

0 – 2

(1)

1 - 5

(2)

Overall 0 – 6

(2)

0 - 4

(1)

0 - 5

(2)

Average in Parenthesis

Since the intertidal macrobenthic faunal group diversity in a single

transect was low similar to other neighbouring area consisting sandy and rocky

shore, the variation with relation to season and space was not significant. Overall

intertidal area represented by intertidal fauna like polychaetes, isopods,

amphipods, gastropods, nematodes, amphimurans, oligochaetes, anomurans,

brachyurans recorded at different occasions and locations which suggested a

good diversity at Kuranga.

The total faunal groups were 6 during premonsoon which decreased to as

low as 4 during monsoon. The postmonsoon period revealed the presence of

overall 5 groups during the period of the study.

83

The composition of the major groups recorded during different seasons is

shown in the following table:

Faunal groups Period

Premonsoon Monsoon Postmonsoon

Polychaetes (%) 38.4 22.6 20.7

Crustaceans (%) 35.1 74.6 77

Molluscs (%) 15.3 2.2 2.3

Others (%) 11.2 0.6 -

Total group (no) 11 7 9

It is evident from the above data that the intertidal zone represented the

dominance of crustaceans followed by polychaetes as compared to molluscs

and other groups.

The present results of intertidal macrobenthic standing stock is compared

with earlier data of adjacent area and shown below.

Parameter Adjacent area

(March 2010)

Study area

(April-May 2012)

Biomass (g/m2;wet

wt)

0.05-178.6

(51.76)

0-61

(8.5)

Population

(no/m2;wet wt)

25-10422

(4390)

0-1000

(237)

Major genera

Gastropods,

Polychaetes,

Amphipods,

Isopods.

Polychaetes,

Isopods,

Gastropods,

Nematodes.

Average in Parenthesis

A decrease in biomass of macrofauna during the present study as

compared to earlier data could be due to variation in faunal composition.

84

However, the population density of macrofauna of the present study was

comparable to earlier records of March 2010

b) Subtidal macrobenthos: The results of macrobenthic standing stock in

terms of biomass, population and total groups are presented in Tables 5.4.29 to

5.4.31 are given in following table:

Transect

Biomass (g/m2;wet wt)

Monsoon

(September 2012)

Postmonsoon

(December 2012)

Nearshore 0 - 21.5

(1.8)

3.3 - 11.5

(6.2)

Towards

offshore -

1.6 - 18.3

(6.6)

Offshore - 3.1 - 19.8

(9.5)

Overall 0 - 21.5

(1.8)

1.6 - 19.8

(7.4)

Average in Parenthesis

The subtidal macrobenthic standing stock in terms of biomass (0 - 21.5

g/m2, av 1.8 g/m2) indicated low benthic productivity during monsoon as evident

in above table. The seasonal impact on the distribution of subtidal macrobenthos

was evident as the biomass increased significantly (1.6 - 19.8 g/m2, av 7.4 g/m2)

during postmonsoon indicating a good standing stock in the region. A gradual

increase in biomass from the nearshore water to the offshore water suggested a

conductive environment for macrobenthic production.

The subtidal macrobenthic population recorded during the present study is

summarized in the following table:

85

Zone

Population (no/m2)

Monsoon (September 2012)

Postmonsoon (December 2012)

Nearshore 0 - 600

(105)

1650 - 1975

(1825)

Towards

offshore -

650 - 2425

(1365)

Offshore - 2200 - 7100

(3582)

Overall 0 - 600

(105)

650 - 7100

(2257)

Average in Parenthesis

The distribution of population recorded during the present study followed

the similar trend as biomass with a low population during monsoon and

substantial increase during postmonsoon as evident in the above table. The

population of macrofauna recorded during postmonsoon suggested again a

good standing stock in the coastal waters off Kuranga. The offshore revealed a

higher macrofaunal population than that of the nearshore suggesting a natural

variation inherent to the environment free from any anthropogenic pressure.

The details of average of subtidal macrobenthic faunal groups are

presented in the table below:

Zone

Total groups (no)

Monsoon (September 2012)

Postmonsoon (December 2012)

Nearshore 0 - 2

(1)

3 - 5

(4)

Towards

offshore -

3 - 5

(4)

Offshore - 2 - 8

(4)

Overall 0 - 2

(1)

2 - 8

(4)

Average in Parenthesis

86

The poor group diversity of macrobenthic fauna in the subtidal region of

Kuranga during monsoon as evident in the above table could be due to limited

sampling conducted during monsoon. However, during the period of

postmonsoon the faunal group diversity increased significantly suggesting the

environment conducive for benthic production.

These results suggested that the subtidal macrobenthic standing stock in

terms of biomass and population varied on a narrow range with moderate values

suggesting moderate benthic production in the study area. This could be

attributed to presence of coarse sandy bottom with rock boulders. In general, the

faunal diversity of macrobenthos varied on a narrow range (0 - 9 groups)

averaging at 4 groups. The different zones of the study area revealed almost

comparable faunal diversity.

The faunal composition of subtidal benthos of the present study is given

below.

Faunal group Period

Monsoon Postmonsoon

Polychaetes (%) 77.2 48.8

Crustaceans (%) 8.9 05.2

Molluscs (%) 0.4 -

Others (%) 13.5 -

Total group (no) 13 2

The above data revealed overall dominance of polychaetes followed by

crustaceans in the study area. Seasonal variation in the community structure is

evident in the above table.

87

5.4.5 Corals and associated biota

The shoreline is clean without any debris of dry seaweeds and dead

corals washed ashore as other coasts of Gujarat. Marine avian fauna is

absent in intertidal area. Further, as per the Coral Atlas of Gujarat State

published by Gujarat Ecology Commission and BISAG, Gandhinagar year

2011, the proposed coastal area off Kuranga coast has not reported

distribution of corals (page 36-39 of Atlas).

There are a few creeklets like shallow intertidal depression running to

the sea. They are covered with sand devoid of any life. The intertidal area is

narrow, rocky and patchy continuously running parallel to the sandy shore. At

a few places, rocky formations are seen on the slope of the sandy shore.

Rocky areas do not support the smooth movements of fascinating reptiles-

the turtles. The intertidal area is connected with intermediate steep fall of

subtidal area with high depth.

a) Seawater intake corridor: An extensive micro level field study was

carried out along a transect IV (Figure 5.4.13) to assess the status of corals

and delineate a suitable intake corridor for the pipeline to minimise the losses

of corals and associated biota on 26 May 2013. The results are given in

Table 5.4.34.

The intertidal area was seen with patchy grass clumps, stolon,

vegetative propagation, rocky formation and coral rock formation with holes

of mudskipper and gobids on upper terrain. The intake corridor is more or

less free from corals. However, there were several locations which were free

from corals as evident in above table.

b) Effluent release corridor: The transect (V, Figure 5.4.13) in the corridor

of LFP for proposed DP was surveyed for the assessment of corals and other

biota on 27 May 2013. The results are summarised in Table 5.4.35.

88

The above table indicates that the intertidal region of proposed LFP

corridor sustained corals viz. Porites compressa and Zoanthus. The coral

colonies were seen in patches on encrusting the rocks. However, there were

many sandy stretcher admeasuring 20 to 110 m on the intertidal region which

were coral free. At the uppermost intertidal area across the limit of tidal

water, old turtle nesting as cited above were seen which were at the

lowermost part of sand dune region (Serial no. 15-17). Thereafter a small

creeklet originating from landward and opening into sea was seen at serial

no. 18. The locations of serial no. 19 to 21 were also seen with some old pits

similar to turtle nesting grounds. A few abandoned old turtle nesting pits were

noticed on almost flat top of sandy shore with closely set clumps of grasses

at different positions described above. Near the north let creek (small check

dam type structure upstream), the funnel shaped 3 to 4 pits were dug out

closely at one point by a female turtle, including false pits. The bursting of

egg shells is irregular. Forest Department, Government of Gujarat collects

live turtle eggs from the different nesting (in situ conditions) and brings to

nearby turtle hatcheries located at Okha Madhi (Ex situ conditions).

However, the live turtles and eggs were not seen during the period of

field visit. Thus the location at 22o 01’ 04.70” N and 69o 09’ 38.93” E may be

considered as an option for LFP to lay the pipeline to dispose the effluent into

sea.

Another transect (VI, Figure 5.4.13) in the continuation of above

transect was assessed for the status of corals on 28 May 2013 and the

results are given in Table 5.4.36.

The results indicated that this transect from serial no 6 to 32 was

almost free of corals. The location of serial no 19 was seen with a small creek

opening into sea and connected with check dam. The location at 22o 01’ 05.6”

N and 69o 09’ 37.0” E was completely sandy area. Adjacent to this location

both north and south sides were also coral free areas. This location is 370 m

away towards south from the end point of old turtle pits. Thus, this location at

22o 01’ 05.6” N and 69o 09’ 37.0” E may be considered as an another option

towards south direction for LFP to lay the pipeline for the effluent release.

89

The corals like Porites, Favites (1 colony), Montipora (1 colony) and

Goniopora, showing very low generic diversity were seen. They were

sedimentary, sedentary and encrusting in nature of seabed. The corals

present here were having pore shape minute polyps. so they were surviving

in sedimentation. The large sized polyps corals were generally not seen here

due to sedimentation. Scattered coral distribution gives rise to intertidal coral

free area. No planulae larvae (coral larvae) were seen in the settling stages

in the area at the time of the visit.

Intertidal area holds stray and scattered distribution, low coverage and

density of Scleractinian hermatypic coral. Creation of intertidal structures in

coralline coral free area may not further impact on the surrounding

Scleractinian corals because the surrounding corals are subjected to high

tide and low tide/water circulation which supply nutrients (largely

zooplankton) and oxygen to corals and remove sediments from the coralline

areas.

c) Mapping by remote sensing: A remote sensing based study related to

coral mapping has been carried by Geosoft Systems, Hyderabad. The

assessment of an area of 5 km radius along the corridors of seawater intake

and effluent release using high resolution images did not reveal presence of

corals in the area.

5.4.6 Seaweeds

Marine flora like algae play a significant role in enriching coastal waters

by adding dissolved organic matter, nutrients and detritus besides serving as

nursery areas for larvae and juveniles of several marine organisms.

The substratum of the intertidal expanse off Kuranga is a combination of

sand and rock. Three intertidal transects (I - III) from HWL to LWL of the study

site were chosen for evaluating marine vegetation, sea grasses, sea anemones

etc. The rocky and sandy intertidal regions were studied for marine algae to

assess their species composition and abundance based on frequency of

occurrence (sparse and dense) of different species.

90

The portion of intertidal area of Kuranga with rocky substratum was seen

with the existence of several algal species such as Caulerpa racemosa,

Caulerpa sps., Ulva lactuca, Ulva fasciata Halimeda tuna, Udotea indica,

Bryopsis plumosa, Chaetomorpha sp, Cladophora facicaularis, Porphyra

vietnamensis ,calcareous algae and floating algae like Sargassum polysystum

which suggested a good biodiversity of seaweeds at Kuranga.

5.4.7 Fishery

The coastal waters off Kuranga were seen with some local small boats

conducting gill netting in the area. However, the commercial fishing operation by

trawling was not seen in the area. Absence of rocky boulders on the intertidal

area results the absence of traditional ‘’Wada” fisheries and “Pagadia” fisheries.

The prevailing fishery status of the region was evaluated on the basis of data

from the Department of Fisheries, Government of Gujarat and fishes obtained

from local fishermen and identified.

Depending on the topography of the coast and type of fishing, necessary

modifications are made to economize fishing operations by local operators.

Small, plant build canoes and traditional crafts like the sail boat locally known as

“Machuwa” were seen to be deployed for fishing in surrounding area. The gears

commonly used by these traditional crafts are drift nets, gill nets, and large bag

nets.

Gujarat State ranks number one in marine fish production in India. The

Gulf contributes about 22 % to the fish production of the state. The share of the

Jamnagar District is between 5 and 14 % to the state’s total marine fish landings

(Table 5.4.37).

The total active fishermen of Jamnagar District were 9330 (Table 5.4.44).

The Jamnagar District had 1637 and 326 mechanised and non-mechanised

fishing boats.

The species in landings of Jamnagar District revealed considerable

fluctuations between the period of 2006 and 2012 (Table 5.4.38). The common

91

species in the landing of Jamnagar were White pomfret, Black pomfret, Bombay

duck, Thread fin, Jew fish, Hilsa, Other clupeids, Coilia, Shark, Mullet, Cat fish,

Eel, Leather jacket, Seer fish, Indian salmon, Ribbon fish, Silver bar, Perches,

Small scienides, Shrimps, Prawns (Medium), Prawns (Jumbo), Lobster, Crabs,

Levta, Cuttle/Squid fish, Tuna, Carangies/Macarel, Ranifish and Sole. The

landing of Jamnagar also revealed a high catch of the important fishes like

lobster (68.5 - 222.3 t), Tuna (7.2 - 683.8 t), Hilsa (0 - 23.7 t) and Shark (876 -

2380 t). The data for white pomfret revealed a marked decrease in the landings

(773) during 2011 - 12 in comparison of landing (4412 t) obtained during 2006-

07. The open shoreline is provided with several fish landing centres from Okha

to Jafarabad. The nearby fish landing centers are Gojines, Navadra, Bhogat,

Harshad etc. Due to fish landing centers there is continuous vessel movement

parallel to the shore. The fish landing during February 2012 was Harshad:

293625kg (small Sciaenides), Navadra: 217500kg (seer fish, small Sciaenides)

and Dwarka: 606100kg (eel, other clupeids)

Some fishermen were seen operating bag netting and gill netting in the

coastal waters off Kuranga. The fishes obtained from this local fishermen of

Gojiness were John’s snapper (Lutjanus johnii), Dussumeir’s croaker (Johnius

dussumerri), Long toungsole (Cynoglossus lingua), White fish (Lactarius

lactarius), Blackspot threadfin (Polydactylus sextarius), Paplet/ pomfret (Pampus

argenticus), Black pomfret (Parastomateus niger), Yellowfin jack (Caranx para),

Giant captainfish (Johnius elongatus), Silver black porgy (Sparidentex hasta),

Speigler's mullet (Valamugil speigleri), Mandeli (Coilia dussumieri), Tiger shrimp

(Penaus monodon), White shrimp (Fenneropenaeus indicus) and Spiny lobster

(Panulirus sp) during April-May and December 2012. This suggested that the

area was conducive for the quality fishes.

5.4.8 Sand dunes

Sand dunes are the innermost portion of the beach. They are subject to

massive erosion by wind and get shifted inland by high monsoon winds and tides

when coastal storms strike the coast. Thus by arresting the storm surges, at

least partially, the dunes act as barriers to the impact of the sea on land thereby

92

reducing the damage to landward developments. The dune area also provides

habitat for shore birds and many species of plants and animals.

The sandy beach of Kuranga had isolated sand dunes dominated by babul

(Prosopis juliflora) and grass (Cynodon dactylon) vegetation. The other

vegetation of sand dunes viz Ipomoea biloba, Cactus, Jancus maritimus,

Euphorbia neriifolia, Ziziphus rotundifolia, Salvadora persica, Suaeda maritima,

Carex condensata, Convolvulus pluricaulis, Sand binding halophyte, and Udotea

indica which were recorded during the period of study.

Few plants (total < 5.nos) of Salvadora persica were seen at 220 01’ 30.9”N

and 69° 09’ 17.5”E which was at the mouth of the creek. The location was away

from LFP corridor.

5.4.9 Mangroves

Mangrove swamps are complex and highly productive ecosystems that

form an important interface between land and sea. In the past, mangrove

habitats were viewed as economically unproductive and, as a consequence,

they were cut to provide timber and fuel wood and create areas for mariculture

and agriculture, which often proved unsustainable. Ecological and economic

values of mangroves are now recognised world-over and several conservation

programmes are in progress to halt their degradation.

During the field visit it was observed that the intertidal area of Kuranga

was devoid of mangrove vegetation. Further the nearest mangrove patches are

located near Dwarka at a distance of approx 25 Km aerially.

93

6 MODELING STUDIES FOR MARINE FACILITIES 6.1 Marine facilities

The water requirement for the project will be met through seawater,

from Arabian Sea, which is close to the plant location (Arabian Sea shore is

located approximately 1 km from plant location).

The total quantity of seawater required for process, coolant for the

Soda Ash Plant as well as Captive power plant, feed water requirement for

the desalination plant will amount to 6 × 105 m3/d. The return once through

cooling water along with the rejects from desalination plant, DM plant and

effluents from the Soda Ash Plant totalling to 6 × 105 m3/d (diluted) will be

discharged to the Arabian Sea at a location selected. The marine facilities

proposed are:

a) seawater intake facility with a sump and pump house on land, and

b) marine outfall with suitable diffuser and a pipeline.

The available options for the above requirements are described below.

6.1.1 Seawater intake

The proposed project will have to depend upon seawater to meet on a

sustained basis both consumptive and cooling water requirements due to

non-availability of sweet water either from surface water sources or

underground sources. The proposed plant is located on the western shore of

Saurashtra coast and hence has to depend on water from the Arabian Sea.

In the planning of the arrangement of the intake system it is necessary to

consider water requirements of soda ash and captive power plant,

desalination etc. Ideally the following criteria should be considered while

selecting the intake system:

i) Existing marine conditions such as water levels, wave heights, currents,

bathymetry, salinity, temperature, suspended solids, littoral sand drift and

marine ecology;

ii) Seawater drawl alternatives such as submerged intake pipe, intake well

and open intake channel;

iii) Increase in temperature, suspended solids and ammonia levels in the

vicinity of intake facility due to the effluents discharged to marine system.

94

a) Water requirement: The water requirement for the once through cooling

system would be substantial and the same can be used partially for

desalination and dilution for the soda ash effluent. Hence, the option is viable

in this case.

The proposed development requires about 6 × 105 m3/d of seawater

for various purposes like soda ash process, cooling water, feed water for

captive power plant, desalination requirements etc.

b) Mode of intake: The intake of 6 × 105 m3/d will require special

arrangements as the quantity is required continuously without any disruption

as the cooling is an integral part of the power production scheme and soda

ash plant operation. Hence, an intake of 6 × 105 m3/d is considered for

modeling purposes.

The options available for intake of the quantity as projected above are

i) caisson and pipeline system ii) pipeline and sump system and iii) open

channel.

i) Caisson well and pipeline system: Seawater can be drawn from an

intake well situated at a depth of 8 to 10 m through pipeline of suitable

diameter with pumping mechanism connected to a water storage/settling

system in the project site. The bathymetry of the adjoining sea shows depths

of 8 to 10 m (with respect to CD) within a distance of 1 to 1.5 km. The system

requires a caisson to be built. This would be the least preferred option as the

requirement of space for storage cum settling area as the forced suction

brings in unwanted sediments into the system and also requires two stages

pumping. Being open sea and subjected to high wave action during SW

monsoon season the safety of the caisson is doubtful.

ii) Pipeline and sump system: Seawater can be drawn from a sufficiently

deep location through a submarine pipeline of suitable diameter connected to

a sump in the project site. The water will flow at a constant rate (evacuation

rate at the land based sump) by gravity.

iii) Open channel: Water can be drawn through an open channel of

sufficient width dug to a depth of below the datum ( the lowest low water

95

level in the vicinity of the channel mouth upto a length so as to meet the a

similar natural depth contour in the sea). This option is not explored as the

channel will require maintenance as the monsoonal waves of the open coast

may develop erosion problem at the mouth area of the channel and

deposition in the channel entailing maintenance dredging and its disposal

apart from the initial dredging quantity generated by the excavation of the soil

to make about 1.2 km long channel which includes both in marine and

terrestrial segments.

The foregoing discussion clearly indicates that the preferred option

would be a subsea pipeline laid at suitable depth and connecting it to a land

based sump so that the seawater flows by gravity into the sump and

evacuation would be in the plant area only as indicated in option ii above.

Such system is working fine at TCL, Mithapur.

Two intake locations have been studied for such setup. These intake

points are

Intake point 1: IT 1:

Latitude 210 59' 49.70" N; Longitude 690 10' 24.60" E (at a depth of 4.5 m

below CD).

Intake point 2: IT 2:

Latitude 210 59' 46.02" N; Longitude 690 10' 20.04" E (at a depth of 7.0 m

below CD)

An intake system with a submarine pipeline has been proposed for

drawing seawater from the sea.

6.1.2 Release of effluent

The effluent from RSPL plant will have SS, ammonia and temperature

load in comparison to that of the ambient seawater.

The total diluted discharge quantity will be around 6 × 105 m3/d.

Two alternative outfall point locations for discharge of effluent studied are:

Outfall point location 1: OF 1:

Latitude 220 01' 25.62" N; Longitude 690 08' 06.27" E

96

Outfall point location 2: OF 2:

Latitude 220 00' 39.51" N; Longitude 690 09' 7.01" E

The effluent is proposed to be discharged through a pipeline and

diffuser system at one of the two selected points, depending on the

suitability, conveying upto the selected discharge location i) OF1 (depth 13-

14 m) or ii) OF2 (depth 12 m). The effluent discharge will be through a

suitably designed diffuser for obtaining optimum initial dilution.

6.1.3 Modeling

The job of carrying out the numerical modeling studies for the flow

regime, dispersion of effluent after discharge and sedimentation processes to

evaluate the suitability of the locations chosen for the intake and outfall was

entrusted to M/s Environ Software (P) Ltd., Bengaluru.

The general area of the project studied is presented in Figure 6.2.1

with the alternative locations for the intake denoted by IT1 and IT2 and

alternative locations for the outfall are marked as OF1 and OF2 therein.

The various physical processes that play a major role in the effluent

release and its dilution and removal from the area of release are tide,

currents and circulation.

a) Tide: Tide data generated by TIDECALC, a program developed by U S

Admiralty for predicting the tides at selected locations all over the world was

used in the study and the tide output generated by the model is compared

with the calculated tide of the above program to calibrate the model.

b) Currents: Current data recorded and supplied by NIO was used in the

study for validating the model.

6.2 Hydrodynamic model

Dedicated software Hydrodyn - FLOSOFT and Hydrodyn - POLSOFT

for prediction of tides and currents and dispersion (pollutant transport)

processes in the seas and estuaries developed at Environ Software (P) Ltd,

Bangalore, based on solving the hydrodynamic equations numerically

97

through coupled way using the present state-of-art of technology are utilized

for the studies.

6.2.1 Basic governing equations

The basic governing equations of flow are solved numerically in

simulation of tides and currents in the coastal environments. These

equations are formulated based on incompressible flow and vertically

integrated hydrostatic distribution since the vertical acceleration of the flow is

much smaller than the pressure gradient. After applying these assumptions,

the basic governing equations of flow momentum can be written in the

conservation form as follows.

6.2.2 Continuity equation

0

yvH

xuH

t

6.2.3 Momentum equations

The two depth-averaged momentum equations can be written as

where, t = time; x, y are Cartesian co-ordinates; u and v are

depth averaged velocity components in the x and y directions,

respectively; f = Coriolis parameter; g = acceleration due to

gravity; Kx, Ky diffusion coefficients in the x and y directions,

respectively; = water elevation with respect to mean sea level,

H = total water depth at any instant.

6.2.4 Boundary Fitted Coordinate (BFC) system

In the Cartesian or rectilinear co-ordinate system, which is generally

used in all global models, it is difficult to represent the complex coastline

accurately, as grid size remains the same at any given location. To better

resolve complex geometries in the horizontal directions, the model makes the

bywyyx

bxwxyx

yvK

yH

xvK

xH

ygHfuH

yHv

xvuH

tvH

yuK

yH

xuK

xH

xgHfvH

yuvH

xHu

tuH

2

2

98

computations on the boundary-fitted Coordinate (BFC) or generalized

curvilinear coordinate system as shown in Figure 6.2.2 This necessitates the

transformation of the governing equations into boundary-fitted coordinates, ),( . However, in the model the (x, y) coordinates are transformed in such a

way that their components are perpendicular to the ),( coordinate lines.

This is accomplished by employing the chain rule transformation.

The momentum equation in the x direction can be written in BFC system as

02

2

222

22

222

22

22

bxwxyyyyyyyyy

xxxxxxxxxxx

yyxx

uuuuuHK

uuuuuHKgH

fvHuvHuvHHuHut

uH

Where, yyxxyyxxyxyx ,,,,,,, grid transformation

parameters

Kx, Ky = diffusion coefficients in x, y directions

H = total water depth at any time

h = water depth up to mean sea level

= water elevation with respect to mean sea level

H = h+

Similarly, the other momentum equation in the y direction and

continuity equation can be written in the BFC coordinate system as described

above. More details about transformation of basic governing equation of flow

can be found in Reddy (1994).

6.2.5 Diffusion coefficients

The horizontal diffusion coefficients Kx and Ky are calculated as

follows:

where x and y are the diffusion factors in x and y directions and C is

the Chezy's coefficient.

222 CvugK yy

222 CvugK xx

99

6.2.6 Numerical solution algorithm

The transformed governing equations of flow have been discretized on

a staggered grid and solved using Leapfrog trapezoidal scheme through a

predictor and corrector step method. The scheme is fully centered in space

and time and can obtain 2nd order accuracy. The scheme consists of two

level computations (predictor and corrector steps) within the time step t.

F(Kn)=(K* - Kn-1)/(2t)

F(Kn)+F(K*)=2(Kn+1 – Kn)/(t)

Where, K* = predicted variable level. The grid transformation

derivatives ),,,( yyxx can be specified at the cell centers

and cell mid-faces.

Since the range of the co-ordinates in the computational plane is

completely arbitrary, the mesh increments are specified as unity for

convenience. Consequently, the geometric variables are defined on a finite

difference mesh with cell increments of 0.5. The computations have been

carried out for the next time step through predictor and corrector schemes

using the above finite difference quotients.

6.3 Model setup and calibration

6.3.1 Boundary conditions

The region of study in the offshore waters near Kuranga is selected

between geographical coordinates: Longitude: 69° 05’ 23.6” E and 69° 11’

33.7” E and Latitude: 21° 57’ 21.0’’ N and 22° 03’ 24.9’’ N for carrying out

sensitivity analysis and further predicting the flow regime of the proposed

facilities in the domain. The terrain features of the domain considered for the model is given in

Figure 6.3.1. In this figure the locations of the intake points and effluent

disposal points are shown as IT1 and IT2 , OF1 and OF2 respectively. The

model domain is divided into 200 and 100 computational grids in x and y

directions respectively. The model domain has an overall size of 10000 m

(width) X 5000 m (height). The grid size is 50 m x 50 m. Figure 6.3.2 shows

the computational grid for the domain. The bathymetry is selected from the

hydrographic chart data incorporating the recent close grid sounding data

100

supplied by the proponents. The interpolated depth contours used for the

model are shown Figure 6.3.3. The maximum depth is 26 m in the domain.

6.3.2 Bed roughness

The bottom roughness in the domain varies according to bed

characteristics. The bed consists of various sizes of clay, sand and silt.

Depending upon bed configuration and sediment sizes, the d50 size varies

from 0.0001 to 0.005 m. In the present study constant Manning’s roughness

coefficient is selected based on the validation and the same is used for

carrying out various computational runs for the prediction of hydrodynamic

parameters in the off Kuranga flow field system. The software has been run

for various sets of Manning roughness coefficient till the deviation is

minimum in the predicted tides.

From the series of computational runs, the Manning coefficient found

to be the best for model calibration is selected. The bed roughness contours

(Chezy’s bed roughness coefficient) has been calculated based on this

Manning roughness and water depth and are shown in Figure 6.3.4. It can be

observed that the roughness coefficient varies from 0 to 36 in the entire

domain. The model has been run for various inputs using the same

roughness coefficient in the prediction of tide and currents in the region off

Kuranga.

6.3.3 Initial and boundary conditions

The initial conditions for the model are selected based on still water

conditions. The vertical density gradients due to salinity variation have been

neglected since the water column is shallow and well mixed by the tidal

currents. The BFC technique has been adopted to take care of shoreline

shape and make fine mesh near the coastline. The grid is a fine mesh.

The open boundary conditions identified are: Western boundary is

taken as free flow; northern boundary and southern boundary are open

(tides) and eastern boundary is closed. The boundary conditions selected are

as follows: (i) January 2013 tide at Dwarka (Figure 6.3.5) and (ii) no flow

across the coastal boundary. In this model, diffusion coefficients for

horizontal exchange of momentum vary with the space.

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6.3.4 Model calibration

Comparison has been made between the calculated tides using

software ‘tidecal” and model computed tides at the outfall location point

(OF1) in the project area and is graphically shown in Figure 6.3.5 (a). From

the figure, it can be inferred that the values match in general and the

variation is small and is within the acceptable limits; (variation is less than

<5% for the parameters compared).

A comparison has been made between the model computed currents

and the measured currents at a calibration point location given by the

coordinates 22° 01' 14.2" N; 69° 07' 16.3" E in the project area and is shown

graphically in Figure 6.3.5 (b). It can be inferred from the figure that the

values match in general.

Thus, the model is validated to produce results of the tides and the

currents in the study domain accurately.

The model runs have been made for a period of 15 days covering

spring and neap tide conditions to obtain an insight into the basic

hydrodynamic behaviour of the study domain.

6.4 Modeling for tides and currents

The model clearly reproduces the tidal variation at various locations in

the off Kuranga region. The typical tidal elevations and velocities pertaining

to Low Water (LLW), High Water (HHW), Peak Flood (PF) and Peak Ebb

(PE) of spring tide are presented in Figures 6.4.1 to 6.4.8. The currents were

bimodal with northwest direction during ebb and south east direction during

flood. The instantaneous tide levels showed a maximum variation of 0.07 m

(during a typical spring high water) and minimum 0.01 m (during a typical

neap low water).

102

6.4.1 Tides and currents during Low Water (LW)

The spatial variation of tides and currents varies between 1.34 and

1.35 m in the total domain during neap low water. The flow velocity observed

is in the range of 0.02 to 0.26 m/s during neap low water.

Figures 6.4.1 and 6.4.2 show the spatial variation of tides and currents

respectively during spring low water condition. The water level varies

between 0.6 and 0.62 m in the domain.

The flow velocity observed is in the range of 0.02 to 0.21 m/s during

spring tide. The general direction of flow is towards southeast. It can be

observed that the intertidal areas near the coast are exposed during the low

water condition.

6.4.2 Tides and currents during Peak Flood (PF)

The water level varies between 2.08 and 2.12 m in the domain. The

flow velocity observed is in the range of 0.2 to 0.42 m/s and the direction of

flow is towards southeast.

Figures 6.4.3 and 6.4.4 show the spatial variation of tides and

currents, respectively during spring peak flood conditions. The water level

varies between 2.01 and 2.07 m in the domain. The flow velocity observed is

in the range of 0.22 to 0.52 m/s with the general direction of flow towards

southeast.

6.4.3 Tides and currents during Highest High Water (HHW)

The spatial variation of tides and currents during neap HW varies

between 2.74 and 2.78 m in the domain indicating that there is little or no

variation in the domain in tidal levels and the flow velocity observed is in the

range of 0.15 to 0.27 m/s in the domain and the flow direction is towards

northwest.

103

Figures 6.4.5 and 6.4.6 show the spatial variation of tides and

currents, respectively during spring tide HHW condition when the water level

varies between 3.25 and 3.32 m in the domain and the flow velocity observed

is in the range of 0.15 to 0.34 m/s. The direction of flow remains towards

northwest in the total domain.

6.4.4 Tides and currents during Peak Ebb (PE)

The spatial variation of tides and currents during neap peak ebb

indicates that the water level varied between 2.42 and 2.44 m in the domain

with flow velocity in the range of 0.23 to 0.51 m/s and the direction of flow

towards northwest.

Figures 6.4.7 and 6.4.8 show the spatial variation of tides and

currents, respectively during spring tide PE condition. The water level varies

between 2.23 and 2.24 m in the domain and the flow velocity observed is in

the range of 0.32 to 0.60 m/s. The direction of flow is northwestwards in the

total domain.

6.5 Modeling for flow of intake 6.5.1 Model description

Dedicated software Hydrodyn - FLOSOFT for prediction of tides and

currents in the seas and estuaries developed at Environ Software (P) Ltd,

Bangalore, based on solving the hydrodynamic equations numerically

through coupled way using the present state-of-art technology is utilized for

the intake modeling studies.

6.5.2 Model setup, calibration and validation

A smaller region of study off Kuranga is selected for flow modeling at

the intake point locations. The study domain is taken between geographical

coordinates: Longitude: 69° 08’ 44.76” E and 69° 11’ 34.7” E and Latitude:

21° 58’ 11.82’’ N and 22° 00’ 59.66’’ N.

The region of study is essentially extracted from the large domain

used for the hydrodynamic modeling studies. The calibrated and validated

model is applied to this smaller domain as well.

104

The terrain features of the domain considered for the model is given in

Figure 6.5.1. The alternate locations of the intake are marked as IT1 and IT2.

The model domain is divided into various computational blocks and

generated the grids in x and y directions respectively. Figure 6.5.2 shows the

computational grid for the domain. The interpolated bathymetric depth

contours for the model are shown Figure 6.3.3.

As this study domain is a part of the calibrated model domain used for

the flow modeling, the same calibration and validation holds good here also

and the validated model is thus run to predict the flow regime around the

intake points IT1 and IT2.

6.5.3 Modeling for tides and currents at intake point: IT1

The validated model was run continuously covering both neap and

spring tides with the withdrawal of 6 × 105 m3/d seawater at a constant rate of

6.944 m3/s imposed in the grid containing the intake point (IT1).

The model clearly reproduces the tidal variation at various locations in

the region off Kuranga. The typical tidal elevations and velocities for Low

Water (LW), High Water (HW), Peak Flood (PF) and Peak Ebb (PE) during

both neap and spring tides are for the domain have been generated and

typical cases of spring low water and spring high water are presented in

Figures 6.5.2, 6.5.3 and 6.5.4, 6.5.5 respectively.

a) Tides and currents during Low Water (LW): The spatial variation of

tides during neap low water varies between 1.004 and 1.04 m in the domain.

However, at the intake point IT1, the tide level is about 0.95 to 0.99 m

surrounded by a region of tide raise of 1.022 m forming a trough of about 7

cm at the center and 1 cm in the periphery with a radius of 50 m. The flow

velocity in the domain is towards southeast direction and is in the range of

0.15 to 0.3 m/s in the overall domain. However, flow at the intake point

location IT1 is like a swirl and of the order of 0.7 to 1.3 m/s within the trough.

The spatial variation of tides during spring low water varies between

0.3 and 0.34 m in the domain. However, at the intake point IT1, the tide level

is about 0.23 to 0.29 m surrounded by a region of tide raise of 0.30 m

forming a trough of about 7 cm at the center and 1 cm in the periphery with a

105

radius of 50 m. The flow velocity in the domain is towards southeast direction

and is in the range of 0.15 to 0.3 m/s in the overall domain. However, flow at

the intake point location IT1 is like a swirl and of the order of 0.6 to 1.35 m/s

within the trough (Figures 6.5.3 and 6.5.4).

b) Tides and currents during Peak Flood (PF): The spatial variation of

tides during neap peak flood varies between 2.15 and 2.20 m in the domain.

However, at the intake point IT1, the tide level is about 2.10 to 2.15 m

surrounded by a region of tide raise of 2.16 m forming a trough of about 6 cm

at the center and 1 cm in the periphery with a radius of 50 m. The flow

velocity in the domain is towards southeast direction and is in the range of

0.25 to 0.5 m/s in the overall domain. However, flow at the intake point

location IT1 is like a swirl and of the order of 0.5 to 0.65 m/s within the

trough.

The spatial variation of tides during spring peak flood varies between

1.97 and 2.08 m in the domain. However, at the intake point IT1, the tide

level is about 1.95 to 2.01 m surrounded by a region of tide raise of 2.02 m

forming a trough of about 7 cm at the center and 1 cm in the periphery with a

radius of 50 m. The flow velocity in the domain is towards southeast direction

and is in the range of 0.4 to 0.78 m/s in the overall domain. However, flow at

the intake point location IT1 is like a swirl and of the order of 0.78 to 0.80 m/s

within the trough.

c) Tides and currents during High Water (HW): The spatial variation of

tides during neap high water varies between 2.98 and 3.01 m in the domain.

However, at the intake point IT1, the tide level is about 2.93 to 2.98 m

surrounded by a region of tide raise of 3.0 m forming a trough of about 7 cm

at the center and 2 cm in the periphery with a radius of 50 m. The flow

velocity in the domain is towards northwest direction and is in the range of

0.08 to 0.17 m/s in the overall domain. However, flow at the intake point

location IT1 is like a swirl and of the order of 0.6 to 1.35 m/s within the

trough.

The spatial variation of tides during spring high water varies between

3.6 and 3.62 m in the domain. However, at the intake point IT1, the tide level

is about 3.56 to 3.61 m surrounded by a region of tide raise of 3.615 m

106

forming a trough of about 5.5 cm at the center and 0.5 cm in the periphery

with a radius of 50 m. The flow velocity in the domain is towards northwest

direction and is in the range of 0.18 to 0.36 m/s in the overall domain.

However, flow at the intake point location IT1 is like a swirl and of the order

of 0.6 m/s within the trough (Figures 6.5.5 and 6.5.6).

d) Tides and currents during Peak Ebb (PE): The spatial variation of tides

during neap peak ebb varies between 2.08 and 2.16 m in the domain.

However, at the intake point IT1, the tide level is about 2.02 to 2.11 m

surrounded by a region of tide raise of 2.12 m forming a trough of about 10

cm at the center and 1 cm in the periphery with a radius of 50 m. The flow

velocity in the domain is towards northwest direction and is in the range of

0.2 to 0.4 m/s in the overall domain. However, flow at the intake point

location IT1 is like a swirl and of the order of 0.6 to 1.35 m/s within the

trough.

The spatial variation of tides during spring peak ebb varies between

2.0 and 2.045 m in the domain. However, at the intake point IT1, the tide

level is about 1.96 to 2.01 m surrounded by a region of tide raise of 2.02 m

forming a trough of about 6 cm at the center and 1 cm in the periphery with a

radius of 50 m. The flow velocity in the domain is towards northwest direction

and is in the range of 0.3 to 0.6 m/s in the overall domain. However, flow at

the intake point location IT1 is like a swirl and of the order of 0.78 to 0.80 m/s

within the trough.

e) Impact on flow regime and flow circulation at the intake point location IT1: The model has been run for 15 days continuously for predicting

the impact on flow regime and circulation for various hydrodynamic tidal

conditions due to the continuous withdrawal of water at the intake point

location IT1.

A number of observation points (1 - 20) have been setup around the

intake location IT1 to observe the variations in the water levels and the

current speeds. The observations points are shown in Figure 6.5.7.

Figures 6.5.8 (a) and 6.5.8 (b) show the variation of water

levels/elevations at different locations around the intake point IT1. It can be

107

seen that the impact on tide regime is not significant and limited to a small

well defined area around the intake.

Figure 6.5.9 (a) and 6.5.9 (b) show the variation of currents at different

locations around the intake point IT1. It can be seen that the impact on

current regime is limited to defined area around the intake and does not

affect the rest of the domain.

The changes in the flow regime are mainly local as discussed at

length in the above sections.

6.5.4 Modeling for tides and currents at intake point: IT2

The model runs are made again to predict the flow regime around the

intake location IT2, a location with 7 m depth below CD. The typical tidal

elevations and velocities for Low Water (LW), High Water (HW), Peak Flood

(PF) and Peak Ebb (PE) during both neap and spring tides for the domain

have been generated and typical cases of spring low water and spring high

water are presented in Figures 6.5.10, 6.5.11 and 6.5.12, 6.5.13 respectively.

a) Tides and currents during Low Water (LW): The spatial variation of

tides during neap low water varies between 1.004 and 1.04 m in the domain.

However, at the intake point IT2, the tide level is about 1.0 to 1.017 m

surrounded by a region of tide raise of 1.022 m forming a trough of about 2.2

cm at the center and 0.5 cm in the periphery with a radius of 40 m. The flow

velocity in the domain is towards southeast direction and is in the range of

0.15 to 0.3 m/s in the overall domain. However, flow at the intake point

location IT2 is like a swirl and of the order of 0.6 to 1.35 m/s within the

trough.

The spatial variation of tides during spring low water varies between

0.3 m and 0.34 m in the domain. However, at the intake point IT2, the tide

level is about 0.27 to 0.32 m surrounded by a region of tide raise of 0.33 m

forming a trough of about 6 cm at the center and 1 cm in the periphery with a

radius of 40 m. The flow velocity in the domain is towards southeast direction

and is in the range of 0.15 to 0.3 m/s in the overall domain. However, flow at

the intake point location IT2 is like a swirl and of the order of 0.7 to 1.26 m/s

within the trough (Figures 6.5.10, 6.5.11).

108

b) Tides and currents during Peak Flood (PF): The spatial variation of

tides during neap peak flood varies between 2.15 and to 2.20 m in the

domain. However, at the intake point IT2, the tide level is about 2.146 to 2.17

m surrounded by a region of tide raise of 2.176 m forming a trough of about 3

cm at the center and 0.6 cm in the periphery with a radius of 40 m. The flow

velocity in the domain is towards southeast direction and is in the range of

0.25 to 0.5 m/s in the overall domain. However, flow at the intake point

location IT2 is like a swirl and of the order of 0.8 to 1.65 m/s within the

trough.

The spatial variation of tides during spring peak flood varies between

1.97 and 2.08 m in the domain. However, at the intake point IT2, the tide

level is about 2.004 to 2.015 m surrounded by a region of tide raise of 2.026

m forming a trough of about 2.2 cm at the center and 1 cm in the periphery

with a radius of 40 m. The flow velocity in the domain is towards southeast

direction and is in the range of 0.4 to 0.78 m/s in the overall domain.

However, flow at the intake point location IT2 is like a swirl and of the order

of 0.8 to 1.3 m/s within the trough.

c) Tides and currents during High Water (HW): The spatial variation of

tides during neap high water varies between 2.98 m and 3.01 m in the

domain. However, at the intake point IT2, the tide level is about 2.96 to 2.98

m surrounded by a region of tide raise of 2.995 m forming a trough of about

3.5 cm at the center and 1.5 cm in the periphery with a radius of 40 m. The

flow velocity in the domain is towards northwest direction and is in the range

of 0.08 to 0.17 m/s in the overall domain. However, flow at the intake point

location IT2 is like a swirl and of the order of 0.8 to 1.68 m/s within the

trough.

The spatial variation of tides during spring high water varies between

3.6 and 3.62 m in the domain. However, at the intake point IT2, the tide level

is about 3.58 to 3.60 m surrounded by a region of tide raise of 3.61 m

forming a trough of about 3 cm at the center and 1 cm in the periphery with a

radius of 40 m. The flow velocity in the domain is towards northwest direction

and is in the range of 0.18 to 0.36 m/s in the overall domain. However, flow

at the intake point location IT2 is like a swirl and of the order of 0.9 to 1.6 m/s

within the trough (Figures 6.5.12, 6.5.13).

109

d) Tides and currents during Peak Ebb (PE): The spatial variation of tides

during neap peak ebb varies between 2.08 and 2.16 m in the domain.

However, at the intake point IT2, the tide level is about 2.05 to 2.106 m

surrounded by a region of tide raise of 2.118 m forming a trough of about 6.8

cm at the center and 1.2 cm in the periphery with a radius of 40 m. The flow

velocity in the domain is towards northwest direction and is in the range of

0.2 to 0.4 m/s in the overall domain. However, flow at the intake point

location IT2 is like a swirl and of the order of 1.0 to 2.0 m/s within the trough.

The spatial variation of tides during spring peak ebb varies between

2.0 to 2.045 m in the domain. However, at the intake point IT2, the tide level

is about 2.007 to 2.019 m surrounded by a region of tide raise of 2.02 m

forming a trough of about 1.3 cm at the center and 0.1 cm in the periphery

with a radius of 40 m. The flow velocity in the domain is towards northwest

direction and is in the range of 0.3 to 0.6 m/s in the overall domain. However,

flow at the intake point location IT2 is like a swirl and of the order of 0.8 to

1.80 m/s within the trough.

6.5.5 Impact on flow regime and flow circulation at the intake point location

IT2: The model has been run for 15 days continuously for predicting the

impact on flow regime and circulation for various hydrodynamic tidal

conditions due to the continuous withdrawal of water at the intake point

location IT2.

The swirl/gyre formed in this case is smaller and not well defined due

to which the currents generated by the withdrawal are of larger magnitude

and restricted to a smaller area.

A number of observation points (1 - 20) have been setup around the

intake location IT2 to observe the variations in the water levels and the

current speeds. The observations points are shown in Figure 6.5.14.

Figure 6.5.15 (a) and 6.5.15 (b) show the variation of water

levels/elevations at different locations around the intake point IT2. It can be

seen that the impact on tide regime is not significant and limited to a small

well-defined area around the intake.

Figure 6.5.16 (a) and 6.5.16 (b) show the variation of currents at

different locations around the intake point IT2. It can be seen that the impact

110

on current regime is limited to a small area around the intake and does not

affect the rest of the domain.

The changes in the flow regime are mainly local as discussed at

length in the above sections.

From the above discussion, it is evident that in both the cases of

intake locations IT1 and IT2 the impact of the continuous withdrawal under

gravity is limited to the Lowest Low Water (LLW) condition only which is also

limited to the immediate surroundings of the intake. However, IT1 is

recommended on the basis minimal area and volume of excavation required

to lay the pipeline and consequent reduction in benthic losses.

It is worthwhile to note that M/s Universal Crescent Power Private Ltd

has planned its intake facility at a location about 500m south and about 1 km

into the sea at a depth of 15-17m CD. The proposed intake point of RSPL is

not expected to have any negative impact on the intake facility of M/s

Universal Crescent Power Private Ltd.

6.6 Outfall modeling study

The RSPL plant will be discharging the effluent to the open sea at the

alternative disposal points OF1 and OF2 through a pipeline and outfall

structure with an increase in SS of 950 mg/l, an increase in ammonia of 5

mg/l and an increase in temperature of 50 C above ambient. The effluent

parameters considered for the present study are SS, ammonia and

temperature at the alternative disposal locations OF1 and OF2, shown in

Figure 6.2.1.

Following is the comparison of critical parameters for the ambient

levels in the coastal waters off Kurunga and levels in the effluent:

Parameter Ambient level Effluent

SS, mg/l 50 1000

Ammonia, mg/l 0 5

Temperature, 0 C 23 28 (50 C above ambient)

The ambient temperature considered pertains to winter period for

which the input tide also pertains.

The study domain is between Longitude of 69° 05’ 23.6” E and 69°

11’ 33.7” E and Latitude of 21° 57’ 21.0’’ N and 22° 03’ 25.9’’ N as shown in

111

Figure 6.2.1 along with terrain features including the intake and the outfall

locations. The hydrodynamic model was coupled to dispersion model.

Two alternative outfall locations for effluent disposal of 6 × 105 m3/d

have been studied and their geographical coordinates are given by

Outfall location 1: OF 1 (Latitude 220 01' 25.62" N; Longitude 690 08' 06.27"

E, depth 13-14 m)

Outfall location 2: OF 2 (Latitude 220 00' 39.51" N; Longitude 690 09' 07.01"

E, depth 12.0 m) This model was run for temperature, ammonia and Suspended Solids

(SS) dispersion in the aqueous medium. The suspended solids were

considered separately in sedimentation model also due to the fact that the

SS particles are not completely miscible but undergo deposition and re-

suspension depending on the local currents and the characteristics of the

particulates.

6.6.1 Effluent discharge at location: OF1

a) Temperature variations: The results pertaining to variation in

temperature at and around the point of disposal OF1 obtained by using the

tide of January 2013 as input are discussed below in detail. The results

pertaining to LW and peak flood of a typical spring tide are shown in Figures

6.6.1 and 6.6.2 (as the worst case and best case scenarios).

The variation of temperature during a typical neap LW condition for

location OF1 produced dispersion around the disposal point more or less

uniformly with a major axis trending towards northwest with the central patch

at the point of discharge having a higher temperature (excess temperature of

3.230 C) near the discharge point but gradually attaining the near ambient

values at the periphery of the patch within a distance of 200 m.

The variation of temperature during a typical neap peak flood

condition produced dispersion elongated towards southeast direction. A very

small central patch around the point of discharge has excess temperature of

2.170 C and within a distance of 250 m the temperature has attained the

ambient conditions. No increase in temperature elsewhere in the domain and

no effect at intake locations predicted.

112

The dispersion of temperature during a typical neap HW indicated that

the temperature is dispersed uniformly around the source with the small

central patch having an excess temperature value of 3.130 C. Temperature

has attained the ambient values within 150 m from the outfall location OF1.

The variation of temperature during a typical neap peak ebb predicted

that the dispersion is trending towards northwest direction with the central

patch having an excess temperature value of 2.480 C. The ambient

conditions are attained within a distance of 250 m from the point of

discharge.

The variation of temperature during a typical spring LW is presented in

Figure 6.6.1. The figure shows that the dispersion is uniform around the

discharge location and is compact with the small central patch having an

excess temperature value of 3.350 C. The ambient conditions prevail within a

distance of 150 m from the point of disposal OF1.

The variation of temperature during a typical spring peak flood

indicated dispersion elongated towards southeast direction with the central

patch having an excess temperature value of 1.50 C above ambient. The

temperature has attained the near ambient values within a distance of 300 m

from the point OF1 (Figure 6.6.2).

The temperature during a typical spring HW dispersed more uniformly

at and around the source. The central patch has an excess temperature

value of 3.060 C above ambient. The temperature has attained at the

ambient conditions within 150 m from the outfall location and dispersed

around the outfall location OF1.

The temperature during a typical spring peak ebb indicated dispersion

trending more towards northwest from the outfall point and the central patch

has an excess temperature value of 1.950 C above ambient. The

temperature values are attained near ambient within a distance of 300 m

from the point OF1.

A number of observation points (1 - 20) have been incorporated

around the discharge point OF1 to record the variation of modeled

parameters around the discharge point. The locations of the observation

points are shown in Figure 6.6.3. The variations of temperature at different

locations during the run period for the proposed discharge at OF1 are shown

in Figures 6.6.4 (a) and 6.6.4 (b). From the figures, it can be seen that the

113

temperature dispersion at all tidal conditions is limited to a small area around

the discharge point and shows no increase at the intake point. The distance

of the points from the disposal points, the maximum and minimum values for

the parameter are presented in Table 6.6.1.

b) Ammonia variations: The results pertaining to variation in ammonia at

and around the point of disposal OF1 for neap and spring tide conditions are

discussed below and typical spreads at LW and peak flood are presented in

Figures 6.6.5 and 6.6.6 ( as the worst case and best case scenarios).

The variation of ammonia during a typical neap LW condition for the

proposed outfall OF1 produced dispersion around the disposal point more or

less uniformly with a major axis trending towards northwest with the central

patch at the point of discharge having a higher ammonia (excess of 2.94

mg/l) near the discharge point but gradually attaining the near ambient

values at the periphery of the patch within a distance of 200 m.

The variation of ammonia during a typical neap peak flood condition

produced dispersion elongated towards southeast direction. A very small

central patch around the point of discharge has excess ammonia of 2.1 mg/l

and within a distance of 250 m ammonia has attained the ambient conditions.

No increase in ammonia elsewhere in the domain and no effect at intake

locations predicted.

The dispersion of ammonia during a typical neap HW indicated that

ammonia is dispersed uniformly around the source with the small central

patch having an excess ammonia value of 2.88 mg/l. Ammonia has attained

the ambient values within 200 m from the outfall location OF1.

The variation of ammonia during a typical neap peak ebb predicted

that the dispersion is trending towards northwest direction with the central

patch having an excess ammonia value of 2.37 mg/l. The ambient conditions

are attained within a distance of 200 m from the point of discharge.

The variation of ammonia during a typical spring LW is presented in

Figure 6.6.5. The figure shows that the dispersion is uniformly around the

discharge location with a small central patch having an excess ammonia

value of 3.04 mg/l. The ambient conditions prevail within a distance of 200 m

from the point of disposal OF1.

The variation of ammonia during a typical spring peak flood indicated

dispersion elongated towards southeast direction with the central patch

114

having an excess ammonia value of 1.55 mg/l above the ambient. Ammonia

has attained the near ambient values within a distance of 300 m from the

point OF1 (Figure 6.6.6).

Ammonia during a typical spring HW dispersed more uniformly at and

around the source. The central patch has an excess ammonia value of 2.82

mg/l above ambient. Ammonia has attained the ambient conditions within

200 m from the outfall location and dispersed around the outfall location OF1.

Ammonia during a typical spring peak ebb indicated dispersion

trending more towards northwest from the outfall point and the central patch

has an excess ammonia value of 1.89 mg/l above the ambient. Ammonia

values are attained the near ambient within a distance of 300 m from the

point OF1.

The variation of ammonia, at different locations (Figure 6.6.3) around

the proposed outfall is shown in Figures 6.6.7 (a) and 6.6.7 (b).

c) SS variations: The results pertaining to variations in SS at and around the

point of disposal OF1 for neap and spring tide conditions are discussed

below and typical spreads at LW and peak flood are presented in Figures

6.6.8 and 6.6.9 (as the worst case and best case scenarios).

The variation of SS during a typical neap LW condition for the

proposed outfall OF1 produced dispersion around the disposal point more or

less uniformly with a major axis trending towards northwest with the central

patch at the point of discharge having a higher SS concentration (557 mg/l

above the ambient) near the discharge point but gradually attaining the near

ambient values at the periphery of the patch within a distance of 200 m.

The variation of SS during a typical neap peak flood condition

produced dispersion elongated towards southeast direction. A very small

central patch around the point of discharge has excess SS of 399 mg/l and

within a distance of 250 m SS has attained the ambient conditions. No

increase in SS elsewhere in the domain and no effect at intake locations

predicted.

The dispersion of SS during a typical neap HW indicated that SS is

dispersed uniformly around the source with the small central patch having an

excess SS value of 543 mg/l. SS has attained the ambient values within 150

m from the outfall location OF1.

115

The variation of SS during a typical neap peak ebb predicted that the

dispersion is trending towards northwest direction with the central patch

having an excess SS value of 448 mg/l. The ambient conditions are attained

within a distance of 300 m from the point of discharge.

The variation of SS during a typical spring LW is presented in Figure

6.6.8. The figure shows that the dispersion is uniformly around the discharge

location with a small central patch having an excess SS value of 573 mg/l.

The ambient conditions prevail within a distance of 200 m from the point of

disposal OF1.

The variation of SS concentration during a typical spring peak flood

indicated dispersion elongated towards southeast direction with the central

patch having an excess SS value of 293 mg/l above the ambient. SS has

attained near ambient values within a distance of 300 m from the point OF1

(Figure 6.6.9).

SS during a typical spring HW dispersed more uniformly at and

around the source. The central patch has an excess SS value of 532 mg/l

above the ambient. SS has attained the ambient conditions within 150 m

from the outfall location and dispersed around the outfall location OF1.

SS during a typical spring peak ebb indicated dispersion trending

more towards northwest from the outfall point and the central patch has an

excess SS value of 358 mg/l above the ambient. SS attained near ambient

level within a distance of 300 m from the point OF1.

The variations of SS at different locations around the proposed

discharge location are shown in Figures 6.6.10 (a) and 6.6.10 (b). From the

figures, it can be seen that the SS dispersion at all tidal conditions is limited

to a small area around the discharge point OF1 and away from the intake

points. Hence, there will not be any re-circulation and no impact on water

quality at the intake as well as at the shore due to the disposal at OF1.

116

6.6.2 Effluent discharge at location: OF2

a) Temperature variations: The results pertaining to variation in

temperature at and around the point of disposal OF2 obtained by using the

tide of January 2013 as input are discussed below in detail. The results

pertaining to LW and peak flood of a typical spring tide are shown in Figures

6.6.11 and 6.1.12 (as the worst case and best case scenarios).

The variation of temperature during a typical neap LW condition for

the proposed outfall OF2 produced dispersion around the disposal point

more or less uniformly with a major axis trending towards northwest with the

central patch at the point of discharge having a higher temperature (excess

temperature of 3.510 C) near the discharge point but gradually attaining the

near ambient values at the periphery of the patch within a distance of 200 m.

The variation of temperature during a typical neap peak flood

condition produced dispersion elongated towards southeast direction. A very

small central patch around the point of discharge has excess temperature of

2.70 C and within a distance of 250 m temperature has attained the ambient

conditions. No increase in temperature elsewhere in the domain and no

effect at intake locations predicted.

The dispersion of temperature during a typical neap HW indicated that

the temperature is dispersed uniformly around the source with the small

central patch having an excess temperature value of 3.270 C. Temperature

has attained the ambient values within 150 m from the outfall location OF2.

The variation of temperature during a typical neap peak ebb predicted

that the dispersion is trending towards northwest direction with the central

patch having an excess temperature value of 2.620 C. The ambient

conditions are attained within a distance of 250 m from the point of

discharge.

The variation of temperature during a typical spring LW is presented in

Figure 6.6.11. The figure shows that the dispersion is uniformly around the

discharge location with a small central patch having an excess temperature

value of 3.470 C. The ambient conditions prevail within a distance of 150 m

from the point of disposal OF2.

The variation of temperature during a typical spring peak flood

indicated dispersion elongated towards southeast direction with the central

117

patch having an excess temperature value of 1.920 C above the ambient.

Temperature has attained the near ambient values within a distance of 300

m from the point OF2 (Figure 6.6.12).

Temperature during a typical spring HW dispersed more uniformly at

and around the source. The central patch has an excess temperature value

of 3.30 C above the ambient. Temperature has attained the ambient

conditions within 150 m from the outfall location and dispersed around the

outfall location OF2.

Temperature during a typical spring peak ebb indicated dispersion

trending more towards northwest from the outfall point and the central patch

has an excess temperature value of 2.370 C above the ambient.

Temperature values are attained the near ambient within a distance of 300 m

from the point OF2.

A number of observation points (1-20) have been incorporated around

the discharge point OF2 to record the variations of modeled parameters

around the discharge point. They are shown in Figure 6.6.13. The variations

of temperature during the run period at different locations are shown in

Figures 6.6.14 (a) and 6.6.14 (b). From the figures, it can be seen that the

temperature dispersion at all tidal conditions is limited to a small area around

the discharge point and in general is found to have no increase at the intake

points. The distances of these points from the disposal point, the maximum

and minimum values for the parameter are presented in Table 6.6.2.

b) Ammonia variations: The results pertaining to variations in ammonia at

and around the point of disposal OF2 for neap and spring tide conditions are

discussed below and typical spreads at LW and peak flood are presented in

Figures 6.6.15 and 6.6.16 ( as the worst case and best case scenarios).

The variation of ammonia during a typical neap LW condition for the

proposed outfall OF2 produced dispersion around the disposal point more or

less uniformly with a major axis trending towards northwest with the central

patch at the point of discharge having a higher ammonia (excess of 3.22

mg/l) near the discharge point but gradually attaining the near ambient

values at the periphery of the patch within a distance of 200 m.

The variation of ammonia during a typical neap peak flood condition

produced dispersion elongated towards southeast direction. A very small

central patch around the point of discharge has excess ammonia of 2.6 mg/l

118

and within a distance of 300 m ammonia has attained the ambient conditions.

No increase in ammonia elsewhere in the domain and no effect at intake

locations predicted.

The dispersion of ammonia during a typical neap HW indicated that

ammonia is dispersed uniformly around the source with the small central

patch having an excess ammonia value of 2.93 mg/l. Ammonia has attained

the ambient values within 200 m from the outfall location OF2.

The variation of ammonia during a typical neap peak ebb predicted

that the dispersion is trending towards northwest direction with the central

patch having an excess ammonia value of 2.5 mg/l. The ambient conditions

are attained within a distance of 200 m from the point of discharge.

The variation of ammonia during a typical spring LW is presented in

Figure 6.6.15. The figure shows that the dispersion is uniformly around the

discharge location and is compact with the small central patch having an

excess ammonia value of 3.12 mg/l. The ambient conditions prevailed within

a distance of 200 m from the point of disposal OF2.

The variation of ammonia during a typical spring peak flood indicated

dispersion elongated towards southeast direction with the central patch

having an excess ammonia value of 1.92 mg/l above the ambient. Ammonia

has attained the near ambient value within a distance of 300 m from the point

OF2 (Figure 6.6.16).

Ammonia during a typical spring HW dispersed more uniformly at and

around the source. The central patch has an excess ammonia value of 3.0

mg/l above the ambient. Ammonia has attained the ambient conditions within

200 m from the outfall location and dispersed around the outfall location OF2.

Ammonia during a typical spring peak ebb indicated dispersion

trending more towards northwest from the outfall point and the central patch

has an excess ammonia value of 2.28 mg/l above ambient. Ammonia

attained the near ambient value within a distance of 300 m from the point

OF2.

The variations of ammonia, at different locations (Figure 6.6.13) for the

proposed outfall discharge at OF2 are shown in Figures 6.6.17 (a) and 6.6.17

(b).

c) SS variations: The results pertaining to variation in SS at and around the

point of disposal OF2 for neap and spring tide conditions are discussed

119

below and typical spreads at LW and peak flood are presented in Figures

6.6.18 and 6.6.19 (as the worst case and best case scenarios).

The variation of SS concentration during a typical neap LW condition

for the proposed outfall OF2 produced dispersion around the disposal point

more or less uniformly and a major axis trending towards northwest with the

central patch at the point of discharge having a higher SS (609 mg/l above

the ambient) near the discharge point but gradually attaining the near

ambient values at the periphery of the patch within a distance of 200 m.

The variation of SS during a typical neap peak flood condition

produced dispersion elongated towards southeast direction. A very small

central patch around the point of discharge has excess SS of 492 mg/l and

within a distance of 300 m SS has attained the ambient conditions. No

increase in SS elsewhere in the domain and no effect at intake locations

predicted.

The dispersion of SS during a typical neap HW indicated that SS is

dispersed uniformly around the source with the small central patch having an

excess SS concentration value of 555 mg/l. SS has attained the ambient

values within 150 m from the outfall location OF2.

The variation of SS during a typical neap peak ebb predicted that the

dispersion is trending towards northwest direction with the central patch

having an excess SS value of 475 mg/l. The ambient conditions are attained

within a distance of 300 m from the point of discharge.

The variation of SS during a typical spring LW is presented in Figure

6.6.18. The figure shows that the dispersion is uniform around the discharge

location and is compact with the small central patch having an excess SS

value of 594 mg/l. The ambient conditions prevailed within a distance of 200

m from the point of disposal OF2.

The variation of SS during a typical spring peak flood indicated

dispersion elongated towards southeast direction with the central patch

having an excess SS value of 364 mg/l above ambient. SS has attained the

near ambient values within a distance of 300 m from the point OF2 (Figure

6.6.19).

SS during a typical spring HW dispersed more uniformly at and

around the source. The central patch has an excess SS value of 566 mg/l

120

above ambient. SS has attained the ambient conditions within 150 m from

the outfall location and dispersed around the outfall location OF2.

SS during a typical spring peak ebb indicated dispersion trending

more towards northwest from the outfall point and the central patch has an

excess SS value of 432 mg/l above ambient. SS values are attained the near

ambient within a distance of 300 m from the point OF2.

The variations of SS, at different locations (Figure 6.6.13) around the

proposed discharge point are shown in Figures 6.6.20 (a) and 6.6.20 (b).

From the figures, it can be seen that the SS dispersion at all tidal conditions

is limited to a small area around OF2 which is away from the intake points.

Hence, there will not be any re-circulation and no impact on water quality at

the intake as well as at the shore due to the disposal at the location OF2.

6.6.3 Summary of results

It can be seen that the dispersion area is compact with higher

temperature, ammonia and SS values prevailing at the central patch at the

points of disposal i.e. OF1 or OF2, during LLW and HHW conditions of both

neap and spring tides. The dispersion is over a larger area with the central

patch showing values lower during the PF and PE conditions compared to

the LW and HW conditions.

From the figures, it can be seen that the temperature, SS and

ammonia dispersion at all tidal conditions is limited to a small area around

the discharge point in both cases of OF1 and OF2. The intake locations are

observed to be free of these contaminants for either of the discharge

locations.

Both the Locations (OF1 and OF2), considered for locating the

discharge point, exhibited 0.9 -1.0 m deep soft sediment cover on the bed

(discussed in Section 5.1) which negates the possibility of presence of

subtidal corals at both the locations.

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6.7 SS transport modeling 6.7.1 Numerical approach to SS (cohesive and non-cohesive) transport

Following the presentation of the hydrodynamic modeling results

pertaining to the proposed intake and outfall locations of RSPL in the waters

off Kuranga and subsequent discussion, it can be inferred that the proposed

intake and outfall locations would be the most suitable in terms of minimal

impact on the flow regime and water quality. This chapter presents the

setting up of SS transport model and simulation of the existing SS transport

conditions for estimating the SS deposition at and around the intake and

outfall locations due to the proposed discharge for various hydrodynamic

conditions.

As with the flow modeling described in the previous section, a critical

step in applying a numerical model of SS transport is the process of model

verification. Whereas data sets against which to calibrate and validate the

flow model are relatively straight forward to obtain, quantitative prediction of

SS transport rates is typically more difficult. The SS transport studies are

aimed at indicating the likely tendency in the bed level change (i.e. erosion or

deposition) as a result of the facility rather than the quantities involved. This

approach is, however, still valid for predicting the SS erosion/deposition at

various locations. The principal aim of these studies was to assess the total (cohesive

and non-cohesive) SS load depositing at around the outfall location due to

continuous discharge of the effluent which carries SS of 1000 mg/l

concentration and accordingly the simulation runs were carried out with a

sand/fine silt/mud transport which was appropriate for the conditions

prevailing in this area.

6.7.2 Available data pertaining to the morphological assessment

Data which was made available in the present study to provide input

to the morphological studies comprised the following:

Bathymetry data

SS concentration in the coastal waters off Kuranga ( 0-50 mg/l)

Bed material properties

The SS of 1000 mg/l present in the effluent

Diluted effluent release quantity amounting to 6 × 105 m3/d

122

This information was used to specify the initial distribution of silt/mud (limiting

it to the subtidal areas) in the numerical modeling simulations.

6.7.3 SS transport simulation

Simulation of SS transport in the study area (Figure 6.2.1) was carried

out with the Hydrodyn-SEDSOFT model for various tide conditions of

January 2013. Hydrodyn-SEDSOFT is a 2D sediment transport model

(cohesive and non-cohesive) and predicts the process of erosion and

deposition of SS transport.

Hydrodyn-SEDSOFT was driven with the neap and spring tide

hydrodynamic flow file generated by the Hydrodyn-FLOSOFT for the entire

model domain and using standard parameters which describe the erodibility

and settling characteristics of the SS. Simulation runs were carried by

specifying SS composition in the shallower (intertidal) zones where the tide

induced bed shear stress was relatively low.

Following simulation of the hydrodynamics in the domain under

existing conditions, the model was adjusted to include the effects of the SS

concentration and particle sizes and the proposed effluent quantity at the

alternate outfall locations OF1 and OF2 (Figure 6.3.2).

a) Discharge at OF1: The predicted results for the instantaneous rate of SS

erosion at LW, peak flood, HW and peak ebb of both neap and spring

conditions in the study domain for a discharge of 6 × 105 m3/d of the effluent

at the location OF1 were used for describing the role of instantaneous

erosion rates in the sedimentation processes. Typical cases of maximum

erosion rates (re-suspension of the settled SS) at peak flood spring and peak

ebb spring are presented in Figures 6.7.1 and 6.7.2 respectively.

Typical cases of maximum deposition rates ( settling of the SS derived

from the effluent as well as the SS brought back to suspension due to

instantaneous erosion in the model domain) at LW spring and HW spring are

presented in Figures 6.7.3 and 6.7.4 respectively.

Figure 6.7.5 shows that the maximum deposition is at the outfall point

location and the bed levels have shown an increase of 0.04 to 0.045 m at the

outfall location over a 15 day period. Due to this gradual change of bed level,

no change in the flow regime is expected.

123

A number of observation points (1 - 20) are incorporated in the model

domain to record the variations in the instantaneous rates of erosion and

deposition at these points in the domain to evaluate the SS transport

processes. The observation points are presented in Figure 6.7.6. Figures

6.7.7 (a) and 6.7.7 (b) show the variation in the instantaneous rate of erosion

at the various observation points in the domain over 15 days. It can be

inferred from these figures that there is no significant variation in the rates of

erosion in the domain except at the outfall location.

Figures 6.7.8 (a) and 6.7.8 (b) show that there is no significant

variation in the rates of deposition in the domain except at the outfall

locations.

Figures 6.7.9 (a) and 6.7.9 (b) show that there is no variation in bed

level at the intake locations and bed level change is around outfall point

location only. The instantaneous erosion and deposition rates along with the

bed level variations at the observation points set up in the model run are

presented in Table 6.7.1.

a) Discharge at OF2: The predicted results for the instantaneous rate of SS

erosion at LW, peak flood, HW and peak ebb of both neap and spring

conditions in the study domain for a discharge of 6 × 105 m3/d at the location

OF2 were used for describing the role of instantaneous erosion rates in the

sedimentation processes. Typical cases of maximum erosion rates (re-

suspension of the settled SS) at peak flood spring and peak ebb spring are

presented in Figures 6.7.10 and 6.7.11 respectively. Typical cases of

maximum deposition rates ( settling of SS derived from the effluent as well as

the SS brought back to suspension due to instantaneous erosion in the

model domain) at LW spring and HW spring are presented in Figures 6.7.12

and 6.7.13 respectively.

Figure 6.7.14 shows that the maximum deposition is at the outfall

point location and the bed levels have shown an increase of 0.018 to 0.045

m at the outfall location over a 15 day period. Due to this gradual change of

bed level, no change in the flow regime is expected.

A number of observation points (1-20) are incorporated in the model

domain to record the variations in the instantaneous rates of erosion and

deposition at these points in the domain to evaluate the SS transport

124

processes. The locations of the observations points are presented in Figure

6.7.15.

The variation in the instantaneous rate of erosion at various

observation points in the domain over 15 days indicated no significant

variation in the rates of erosion in the domain except at the outfall location.

Figures 6.7.16 (a) and 6.7.16 (b) show that there is no significant

variation in the rates of deposition in the domain except at the outfall

locations.

Figures 6.7.17 (a) and 6.7.17 (b) show that there is no variation in bed

level at the intake locations and bed level change is around outfall point

location only. The instantaneous erosion and deposition rates along with the

bed level variations at the observation points set up in the model run are

presented in Table 6.7.2.

The model results are entirely consistent with the analysis based on

the tidal currents and as described in Section 6.4, in which deposition zones

around the outfall point location (Max. 0.018 kg/m2/s for SS in the effluent) is

predicted to occur. From the figures, it can be observed that there is no sign

of erosion around the intake and outfall locations.

6.7.4 Morphological changes

The continuous model runs of 15 days each taking account of neap

and spring tide conditions during January 2013 were compared to delineate

the morphological changes. Results of the variation in the bed level are

shown in Figures 6.7.5 and 6.7.14 for the outfall discharge quantity of 6

x105m3/d (effluent having 1000 mg/l SS) at the two alternate outfall points of

OF1 and OF2 respectively. From the figures, it can be seen that the variation

of bed level due to resultant erosion and deposition over 15 days is found to

be 0.04 and 0.018 m at OF1 and OF2 locations, respectively in the vicinity of

respective outfall locations. This result is consistent with the information that

the seabed is relatively stable. From the model results, it can be concluded

that there is no impact on intake of sea water and the effluent discharge at

any of the outfall locations.

From the above figures in can be said that SS subsequently deposited

in the vicinity of outfall location may not result in significant bed level changes

125

as the fine grained SS erodes and gets advected to settle over a larger area.

These predictions are in response to the change in the tidal currents and

would reduce in time as the seabed gets re-established itself to the new

hydraulic regime. In the short-term, however, it should be noted that there is

a possibility of siltation due to discharge of continuous effluent discharge

around the selected location, in a limited area.

6.8 Particle trajectory modeling

The trajectories of a particle released at outfall locations OF1 and OF2

are plotted graphically. The trajectories are shown in Figures 6.8.1 and 6.8.2,

respectively. From the figures, it can be seen that the trajectory of the particle

is moving in the northwest-southeast axis almost parallel to the coastline and

is not reaching either the proposed intake locations or the shore. Hence, it

can be said that the disposal of the effluent at either of the proposed outfall

locations will not have any impact on the intake or the shore areas.

6.9 Mode of discharge

As evident from the model studies both the locations OF1 and OF2

are well suited for the release of effluent discharge.

The model predictions are based on a point discharge and works like

a single port discharge. The initial dilutions can be enhanced by providing a

suitable mode of discharge for which two options are available.

1) Surface release: This option is suitable if a structure to convey the

pipeline such as a jetty or other offshore structure is available. Since the

effluent is denser than seawater, surface release is advantageous as the

entire water column can be used for dilution. However, in the open coastal

waters of Saurashtra where sheltered shore is not available, it will be difficult

for a trestle bridge to withstand the fury of monsoonal waves.

2) Bottom release: This is a suitable option for the region as the pipeline can

be taken along the seabed to effect a bottom release. This option is explored

as under.

126

6.9.1 Near-field dilution due to a forced bottom release

Near-field dilution was assessed based on the Buoyant Jet Model for

which the governing equations are as follows:

du 2g2 2u

= sin -

ds u o b

db 2 bg2

= - sin

ds u2 o

d 2g2

= - cos

ds u2 o

1 + 2 d 2

d = sin -

ds 2 dy

dx dy

= cos ; = sin

ds ds

where g = acceleration due to gravity

= density of effluent

o = density of seawater

= constant

= entrainment coefficient

x = horizontal distance from jet orifice

y = vertical jet coordinate

u = jet velocity

= angle of jet orifice with horizontal plane

ds = step increment

also co, uo, bo = c, u, b

where c = concentration at given time

127

b = width of jet/plume at given time

co, uo, bo represent concentration/mass density, jet velocity and jet width

respectively at time t = 0.

The model also takes the ambient velocity into account while calculating

initial dilution. The above equations were solved explicitly by Range Kutta

integration scheme by taking the following model inputs:

Input Value

Effluent density(kg/m3) (depending on SS content) 1035

Seawater density (kg/m3) 1025

water depth (m) 12.0

Current velocity (av) (m/s) 0.3

Step increment (m) 0.001

Computations were performed for different options of number of jets, jet

angles and jet velocities. From these computations it is concluded that to make

optimum use of the water column above the diffuser, the effluent should be

released with a minimum initial jet velocity of 3 m/s through a multiport diffuser

discharging at an angle of 60o to the axis of the diffuser. As the effluent is

heavier than the receiving water, it would tend to descend through the water

column after initial rise. Plume characteristics, specification of diffuser, dilution

etc., for the effluent release, are summarized below.

Jet velocity

(m/s)

Ports (no)

Port dia (m)

Plume rise (m)

Dilution (Times)

Plume width (m)

Diffuser length

(m)

DSS

(mg/l) DRHO

(kg/m3) Dtemp

( oC) DAm

(mg/l)

3 10 0.538 8.5 22.3 6.83 68 42.5 0.45 0.22 0.22

When released with the initial jet velocity of 3 m/s through a 10 port

diffuser, the plume would rise through the water column to a height of 8.5 m due

to the initial jet velocity attaining dilution by 13.4 times. When the inertia forces

weaken and become inadequate to overcome the gravity forces, the plume

would sink through the water column attaining additional dilution. By the time the

plume approaches the bed level, the dilution attained would be by 22.3 times.

Theoretically, though a minimum 13.0 m water column is available at the

discharge location, a limited water column only would be used for diluting the

effluent. The far-field dilutions will be augmented by the initial dilutions to render

the effluent harmless to the marine life.

128

In practice, as the plume velocity decreases, the SS particles associated

with the plume would be sorted out depending on their density with the heavier

particles descending faster. The lighter particles in the effluent would rise

through the water column and may even attain more rise as the bulk density

decreases with the separation of heavier particles. The concentration of SS in

the plume would be higher by 45 to 690 mg/l above the ambient.

To avoid overlap of the adjacent plumes, the distance between the

adjacent orifices should be maintained equal to the maximum width of plume that

is 6.83 m. The total diffuser length would therefore be about 68 m for the option

considered. In practice it is not advisable to release the effluent at the bed level

to prevent silt, mud, sand etc getting into the diffuser during the periods of

maintenance or shut-down. However, as the depth of water is 13 m which is

more than the maximum plume rise, the effluent can be released 1 m above the

bed level. The plume characteristics for the selected option are presented in

Table 6.9.1.

6.9.2 Thickness of the polluted layer

It should be established whether the ambient currents are capable of

transporting away the polluted water as the plume descends through the water

column. The approximate thickness H' of seawater layer which would be

affected by the effluent was calculated by using the relation

H' = Dq/V

where H' = thickness of the polluted layer

D = mean dilution in the jet or plume

q = effluent discharge rate

= plume dia at the bottom after sinking

V = mean current velocity across H'

The results are given below.

D (times) (m) H' (m)

14.8 6.83 5.01

This thickness of the polluted layer would be at the bottom around each

diffuser port. As the thickness is far less than the available depth, the diluted

effluent reaching the bottom would be effectively advected by the prevailing

129

currents and a build up is unlikely and the polluted layer is a result of the fresh

discharge emanating from the ports.

6.10 Configuration of the diffuser

In order to minimize the erosion/deposition processes, the pipeline

should be buried in the intertidal stretch. Large vessels do not navigate in this

stretch, however local fishing crafts may use this stretch. Hence it is

suggested that the pipelines may be buried in the areas where water depths

of 6 m or less prevail. The remaining portion of the pipeline can be laid on the

bottom with suitable anchoring provided to keep the pipeline in place.

The 10 port diffuser forms the end of the pipeline. The ports should be

aligned with the directions of the bimodal currents. Alternate ports should be

in flood direction and ebb direction respectively. The angle of the ports to the

horizontal should be 60o upwards. The initial jet velocity of 3 m/s should be

maintained by installing suitable pumping mechanism. The diffuser should be

designed in such a way that all the ports maintain the prescribed velocity so

that the no sediment accumulates in the diffuser pipe. This ensures the

performance of the diffuser consistently.

130

7 POTENTIAL MARINE ENVIRONMENTAL IMPACTS

The potential marine environmental impacts that possibly may occur

on hydrodynamic characteristics, water quality, sediment quality, flora and

fauna etc during construction and operational phases of the marine facilities

namely seawater intake and effluent disposal. They are described as follows:

7.1 Seawater intake 7.1.1 Scheme

Of the 2 options for intake locations (IT1 and IT2), the alignment for

IT1 is selected on the basis of lesser area and volume of excavation required

to lay the pipeline and consequent reduction in benthic losses due to shorter

length. Since the alignment corridor is devoid of mangroves and corals, their

destruction due to the development is unlikely.

From the land based sump in the project site to the intake point (IT1,

21o 59’ 49.70’’N; 69o 10’ 24.60’’E) at 4.5 m (CD) depth , 526 m long pipelines

of suitable diameter will be laid (Figure 7.1.1). Obviously, it will be buried all

along the stretch of 70 m length while that passing through 456 m long

subtidal stretch will also be buried to provide unhindered passage to local

fishing crafts.

The gradient of the pipeline will be so maintained that seawater will

flow into the sump at a constant rate by gravity. The pipeline orifice at the

intake point will be located 0.5 m above seabed to avoid direct entry of bed

sediment into the intake.

7.1.2 Potential marine environment impacts

Major potential negative marine environmental impacts due to the

proposed activity would be largely associated with (a) construction phase

related to laying of the intake pipeline and (b) operational phase because of

increase of current speeds and variation in current directions, spatial variation

of tide, changes in erosion-deposition rates due to variations in currents, if

any, and fate of the biota entering the sump through the intake pipes.

Evidently, potential negative impacts on marine ecology can arise during the

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construction as well as the operational phases of the intake scheme as

described below.

Construction phase: Adverse impacts of the proposed project on the

marine environment during the construction phase could be due to

modifications in the hydrodynamic characteristics of the area, degradation in

water and sediment qualities and consequent impact on biota depending on

the construction methodology selected and duration.

Assuming a corridor width of 5 m in the intertidal area for trenching

and pipe laying and a 20 m corridor in the subtidal area due to requirement of

suitable craft in the pipe laying operation, the total area (Figure 7.1.1) which

would be adversely influenced by the construction activities would be as

follows:

Area Width (m) Length (m) Area (ha) Total area (ha)

Intertidal 5 70 0.035 0.95

Subtidal 20 456 0.9120

Hydrodynamic characteristics: As the trenching and burial of the pipeline

would be across the open coast with a sandy beach, the construction if not

conducted in a stipulated time, there is a likelihood of minor and temporary

erosion both sides of the trench due to non-compacted sand moving into the

channel. However, due to the limited length of the trench (70 m), this would

not be significant. Trenching and Laying of 456 m long pipeline of suitable

diameter in the subtidal area would not hinder the seawater flow in the

subtidal area. Since the water movement in the area during the construction

phase would not be hampered, significant changes in tide levels and currents

to influence local hydrodynamics are unlikely.

Water quality: Suspension of the bed sediment in water during excavation

for laying pipelines has the potential to increase SS in water. Considering the

sandy nature of the sediment, the suspended particles would settle fairly

quickly though some local turbidity may persist in the working area. The rest

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of the coastal segment would be largely free from additional SS and coral

habitats in the study domain would not be influenced. Moreover, the impact

would be localized, temporary and confined only to the construction phase of

trenching, pipe laying and trench back-filling.

If areas where the sediment is polluted there is a fear of release of

pollutants entrapped in sediment to the water column when the bed is

disturbed thereby mixing interstitial water rich in contaminants with the

overlying water. However, as the sediment of the region is mainly beach

sand subjected to continuous wave action, leachable pollutants are not

expected in their interstitial water. Moreover as the sediments of the area are

by and large pristine as discussed under Section 5.3, there would not be

deterioration in water quality on this count.

Sediment quality: Since the intertidal segment (0.035 ha) through which the

pipes would be laid is narrow, the small volume of the excavated sediment is

unlikely to cause change in the sediment texture on a wider area of the

seabed excepting in the close vicinity of the trenching site. Such impact

would be negligible.

Misuse of the intertidal area by the work force employed during the

construction phase can locally degrade the sediment quality by increasing

BOD and population of pathogens. The impact, however, would be minor

and temporary and recovery would occur when the source of this

contamination is eliminated at the end of the construction phase.

Flora and fauna: Hectic construction activities, though confined to a pre-

determined stretch of the marine area, could influence the local biotic

communities, particularly the seaweeds and macrobenthos along the

corridors selected for laying the pipelines. As the sediment is not enriched in

Corg (Section 5.3), its suspension in the water column is unlikely to deplete

DO in this dynamic marine area and DO availability would not constrain the

biotic processes. The danger of biota getting exposed to pollutants released

from the sediment interstitial water when the bed is disturbed is ruled out

since the sediment from the intertidal area is uncontaminated.

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The corridors proposed for laying the pipelines (Figure 7.1.1) are

largely composed of degraded reef sand, devoid of mangrove vegetation

except for the patches of seaweeds with a few species. Their loss would be

minor, temporary and recovery would be fairly quick on termination of

constructions. Hence no significant long-term major loss of flora and fauna is

envisaged.

An increase in turbidity due to enhanced levels of SS can negatively

influence the photosynthesis and hence the primary productivity. However,

the impact, if any, would be insignificant, local and temporary with the

phytoplankton community structure remaining more or less unaltered.

Evidently there would not be any adverse influence on phytoplankton and

zooplankton.

Laying of pipelines would have negative impact on benthic habitats

which would be destroyed in the excavated corridors. An area of about 0.95

ha is likely to be disturbed during the construction phase. However, when the

trenches are filled, the area would be available for re-colonisation of

macrobenthos. Assuming the average production of 4.6 g/m2 (biomass);

1181 no/m2 (population) for the subtidal area and 5.5 g/m2 (biomass); 463

no/m2 (population) for the intertidal areas the probable losses of standing

stock of macrobenthos and affected faunal groups during the construction

phase are estimated as given below.

Environment Biomass (kg)

Population (106 no)

Major groups

Intertidal 1.9 0.2 Polychaetes,

Crustaceans,

Molluscs

Subtidal 42.0 10.7

Total 43.9 10.9

It is evident from the above table that the estimated loss of

macrobenthic standing stock would be 43.9 kg of biomass and 10.9 x 106 no

of population. Considering the benthic potential of the study area, such

losses are unlikely to be reflected on the overall biopotential of the coastal

marine system off Kuranga. Moreover, this loss would be temporary and the

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benthos would re-colonise in due course of time, once the activities are

terminated and contours are restored after construction activities are over.

The corridor selected for the seawater intake pipeline is devoid of

mangroves and corals. Hence, there would not be any loss of mangroves

and corals during the construction phase.

e) Miscellaneous: The aesthetics of the coastal zone off Kuranga would

deteriorate due to the presence of construction machinery and materials.

Left-over solid waste and that generated during construction would be a

source of nuisance if not cleared from the site.

The extent of impact on marine ecology would also depend on the

duration of the construction phase. If the construction is prolonged due to

time-overruns or improper planning, the adverse influence would increase

accordingly.

The birds using the intertidal area around the project site are not

expected to be impacted adversely as the limited excavation does not

warrant the use of heavy machinery and large vessels. However, the

construction work on land for the sump and pump installation would generate

noise during construction phase. Marine reptiles and mammals would not be

affected due to the construction activities since they keep away from such

sites. As there are no major commercial fishing operations close to the shore,

the impact on fisheries would be minor.

b) Operational phase: Marine environmental implications during the

operational phase of the project would be essentially confined to the negative

influence of seawater intake on hydrodynamic characteristics, water quality,

sediment quality, and flora and fauna of the region.

Hydrodynamic characteristics: The seawater intake system consists of ,

526 m long pipelines of suitable diameter passing through the subtidal area

and buried in the intertidal area. Seawater from the intake point (IT1) to the

land based sump will flow under gravity.

135

The 2D numerical model output (Section 6) indicate a few centimetres

reduction in the water level in a small area at the pipe inlet that too around

low waters. The change in the currents speeds when the intake becomes

operational is predicted to be marginal and would not lead to marked

sediment movement. Evidently the hydrodynamics of the area would not be

influenced due to withdrawal of seawater as envisaged.

Water quality: The intake would be by gravity and the level of water in the

sump will be at par or below that of the sea level. Hence, there will not be

back flow of seawater from the sump to the sea. Moreover, there will not be

any chemical additives in the sump. Hence impact on physico-chemical

quality of the adjoining seawater is not expected.

Sediment quality: Since the water quality would not be adversely impacted,

perturbation in sediment quality due to water born particulates is discounted.

Modelling results indicated that the changes in the current velocities

are low to induce additional erosion/deposition in the area due to the intake.

The intake location is away from the wave breaker zone. The chance

of the suspended particulates generated by the breaking waves entering the

sump along with the intake water is rare. Such small sediment movement

would not cause any adverse impacts on sediment quality during the

operational phase.

Flora and fauna: As discussed above, the general water quality as well as

sediment quality of the coastal area would not be affected adversely. Hence,

the biological characteristics of the region would not be influenced to a

significant extent except for some minor negative impact on macrobenthic

community in the vicinity of the intake due to limited disturbance to the

sediment.

General ecological concern during the operational phase of seawater

intake systems is marine life impingement that occurs when organisms such

as fish, crabs and cephalopods are sucked into an intake pipe and pinned

136

against screens by the velocity and force of water flowing through them. The

fate of impinged organisms differs between intake designs and among

marine life species, age, and water conditions. Entrainment occurs when

smaller organisms such as plankton, eggs and larvae of a variety of

organisms including fish and other commercially important species pass

through an intake screen and into the sump. These are killed by pumps or in

the process where the seawater is used.

Impingement occurs when the intake through-screen velocity is so

high that species such as fish or crab cannot swim away. In the present case

the intake being by gravity, the speed generated would be small and in the

horizontal direction. Hence, it is unlikely that fish, crab or other similar

organisms are impinged. It may be noted that fish have receptors along the

length of their bodies that sense horizontal velocity pattern that gives them an

indication for danger and they swim away from the intake sites.

Considering the short life span of plankton and their fast multiplication

rates, the loss due to entrainment is considered to be insignificant to the

productivity of the region. Impact of entrainment of fish eggs and larvae on

future adult populations is also considered minor since fishes during their

breeding cycle lay millions of eggs of which only a very small fraction grows

to adulthood.

e) Cross-contamination with effluent discharge: RSPL has been

considering release of treated/diluted effluent in the Arabian Sea (Section

6.2). Probable landfall point for the effluent pipeline is marked in Figure 7.1.1.

Based on numerical modelling it has been predicted that the impact of the

effluent would not be evident beyond 560 m (max) distance from the outfall

locations OF1 and OF2 (Figure 7.1.1).

The intake location IT1 is at a distance of more than 2 km south of

both the proposed effluent release locations (Figure 7.1.1). Hence, transport

of effluent in the intake area would not occur.

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7.2 Effluent disposal 7.2.1 Scheme

Both the options (OF1 & OF2) have been recommended since

behavior of the effluent on release into sea and consequent impacts are

almost similar at both the discharge points. The pipeline corridors are devoid

of mangroves and corals.

From LFP to the effluent disposal points (OF1, 22o 01’ 25.62’’N; 69o

08’ 06.27’’E or OF2, 22o 00’ 39.51’’N; 69o 09’ 07.01’’E) pipelines with a

suitable diameter to maintain the requisite velocity, will be laid to release the

diluted effluent of 6 x 105 m3/d into sea (Figure 7.1.1). The pipelines will be

buried in the intertidal stretch of 80 m. It will be laid on the bed along the

subtidal segment. However, it will be buried wherever water depth of 6 m or

less prevails for un-hindered navigation of local fishing crafts.

The pipelines will end with a 68 m long diffuser with 10 number of

ports of 0.53 m diameter spaced 6.83 m apart suitably anchored at the

seabed. The ports will be aligned alternatively with the directions of biomodal

currents (ebb and flood). The port angle to the horizontal will be 60o upwards.

The diffuser will be aligned in such a way that all the ports maintain the

prescribed velocity so that no sediment accumulates in the diffuser pipe. This

ensures the performance of the diffuser consistently. As both the options

(OF1 and OF2) are suitable the final selection of disposal point can be guided

by the engineering considerations.

The effluent will be released at 1 m above bed at the jet velocity of 3

m/s, by creating suitable pumping system, to get the plume dilution of 22.3

times. Hence, their destruction due to the development is unlikely.

7.2.2 Potential marine environmental impacts

Major potential negative marine environmental impacts due to the

proposed activity would be largely associated with (a) laying of the effluent

pipeline, (b) installation of the diffuser, and (c) pollutants entering the marine

area through the effluent. Evidently, potential negative impacts on marine

ecology can arise during the construction as well as the operational phases

of the effluent release scheme as described below.

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a) Construction phase: Adverse impacts of the proposed project on the

marine environment during the construction phase could be due to

modifications in the hydrodynamic characteristics of the area, degradation in

water and sediment qualities and consequent impact on biota depending on

the alignment, construction methodology selected and duration.

Assuming the corridor width of 5 m the area which would be adversely

influenced by the construction activities would be as follows:

Discharge point

Environment Width (m)

Length (m)

Area (ha)

Total area

OF1 Intertidal 5 80 0.04

Subtidal 20 2655 5.3 5.35

OF2 Intertidal 5 80 0.04

Subtidal 20 1250 2.5 2.54

Hydrodynamic characteristics: The contour of the intertidal area will be

restored after pipe laying. Hence hydrodynamic characteristics of the

corridors in the intertidal area though would get influenced for a short period

of trenching. Pipe laying in the subtidal area will be over the seabed. Hence,

disturbance of the water column would take place for a short period. Hence,

the negative influence of the pipe laying on the hydrodynamic characteristics

could be localised and short-lived.

Water quality: Suspension of the bed sediment in water has the potential to

increase SS in water. However, trenching in area with hard substratum has

relatively low potential to disperse the bed sediment as compared to an area

having soft substratum such as silt and clay for laying a pipeline in the

intertidal area. Moreover, the contour of the intertidal area will be restored.

The pipe laying and establishment of the diffuser in the subtidal area will be

over the seabed disturbing small corridors. The bed sediment disturbed at the

site would generate SS which may remain in suspension for some period in

the vicinity of the corridor area while the rest of the coastal area would be

139

largely free from additional SS. The impact would be localized, temporary

and confined only to the construction phase of the pipeline.

If areas where the sediment is polluted there is a fear of release of

pollutants entrapped in sediment to the water column when the bed is

disturbed thereby mixing interstitial water rich in contaminants with the

overlying water. However, as the sediment of the region is unpolluted

(Section 5.3), there would not be deterioration in water quality on this

account.

Sediment quality: Since the total area to be influenced during trenching and

pipelaying in the intertidal area and subtidal areas possess hard substratum

/sand; the activity is unlikely to cause change in the sediment texture on a

wider area of the seabed except in the close vicinity along the corridors.

Such impact would be negligible, localised and temporary.

Misuse of the intertidal area by the work force employed during the

construction phase can locally degrade the sediment quality by increasing

BOD and populations of pathogens. The impact, however, would be minor

and temporary and recovery would occur when the source of this

contamination is eliminated at the end of the construction phase.

Flora and fauna: Hectic construction activities in the intertidal and subtidal

areas would influence the local biotic communities, particularly the seaweeds

and macrobenthos along the corridor selected for laying the pipeline and the

diffuser. As the sediment is not enriched in Corg (Section 5.3), its suspension

in the water column is unlikely to deplete DO in this dynamic marine area and

DO availability would not constrain the biotic processes. The danger of biota

getting exposed to pollutants released from the sediment porewater when the

bed is disturbed, is low since the sediment is free from anthropogenic

contaminants.

The intertidal corridors (Figure 7.1.1) are largely composed of

degraded reef and sand devoid of mangrove vegetation except for the

patches of seaweeds with a few species. Hence, no significant loss of flora &

140

fauna is envisaged. Loss of localized seaweeds would be easily recouped by

fresh recruitment once the activities are terminated.

An increase in turbidity due to enhanced levels of SS can negatively

influence the photosynthesis and hence the primary productivity. However,

the impact, if any, would be local and temporary with the phytoplankton

community structure remaining more or less unaltered in this dynamic marine

environment.

A temporary and insignificant reduction in phytoplankton standing

stock, if at all, and increase in turbidity along the corridor is unlikely to

produce any negative impact on zooplankton though a localised and marginal

change in the community structure and population alternations may occur

confined to the project area. Such changes are localized, temporary and

irrelevant to the overall secondary productivity of the area.

The laying of effluent pipelines and diffuser would have negative

impact on benthic habitats which would be destroyed along the corridors.

Based on the average production of 4.6 g/m2 (biomass); 1181 no/m2

(population) for subtidal and 5.5 g/m2 (population) for intertidal areas are

likely to be disturbed, the probable loss of standing stock of macrobenthos

and affected faunal groups during the construction phase are estimated as

given below.

Discharge point Environment Biomass

(kg)

Population

(no×105)

Major

groups

OF1 Intertidal 2.2 1.85 Polychaetes,

Crustaceans,

Molluscs

Subtidal 243.8 625

Total 246 627

OF2 Intertidal 2.2 1.85 Polychaetes,

Crustaceans,

Molluscs

Subtidal 115 295

Total 117.2 297

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It is evident from above results that the estimated loss of macrobenthic

standing stock (biomass and population) would be relatively high at the

subtidal zone. Considering the benthic potential of the study area, such

losses are unlikely to be reflected on the overall biopotential of the coastal

marine system off Kuranga. Moreover, this loss would be temporary and the

benthos would re-colonise in due course after the phase is completed and

construction activities are terminated. Moreover, the structures would provide

additional surface area for the subtidal benthos to colonise on the newly

created substratum.

The corridors selected for the effluent disposal pipeline are devoid of

corals, mangroves as well as sand dunes. Hence, there would not be any

loss of corals, mangroves and sand dunes along the pipeline corridors.

Miscellaneous: The aesthetics of the coastal zone off Kuranga would

deteriorate due to the presence of construction machinery and materials,

make-shift huts of labour force, cabins etc. Left-over solid waste and that

generated during construction would be a source of nuisance if not cleared

from the site.

The extent of impact on marine ecology would also depend on the

duration of the construction phase. If the construction is prolonged due to

time-overruns or improper planning, the adverse influence would increase

accordingly.

The birds using the intertidal area around the project site would be

disturbed particularly if the construction activity is scheduled during their

migratory months. However, this would be limited to only construction phase.

Marine reptiles and mammals would not be affected due to the construction

activities since they keep away from such sites. There are no major

commercial fishing operations close to the shore. Hence, the impact on

fisheries would be minor.

b) Operational phase: Marine environmental implications during the

operational phase of the project would be essentially confined to the adverse

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influence of release of the effluent on hydrodynamic characteristics, water

quality, sediment quality, and flora and fauna of the region. They are

described below.

Hydrodynamic characteristics: The release of 6 x 105 m3/d of the treated

and diluted effluent would not influence the hydrodynamic characteristics at

the disposal point (OF1) at 13-14 m depth. However, accumulation of

sediment along the sides of the pipeline in the subtidal area is expected. It

would strengthen the pipeline and would also provide additional area for

colonising macrobenthos.

Water quality: Probable impact of release of the treated effluent at any of the

the designated sites (OF1 and OF2, Figure 7.1.1) through a suitably designed

diffuser as discussed in Section 6, on water quality is predicted based on

probable dilution the effluent would attain and assuming conservative

behaviour of constituents in the receiving water. It should however be

acknowledged that several pollutants undergo decay and/or physical

transformations on entering water leading to reduction in their concentration,

faster than predicted on the basis of conservative mixing. Hence, the

concentrations of pollutants such as ammonia in the receiving medium would

be lower than predicted on the basis of conservative mixing.

The predicted behaviour of selective parameters namely temperature

(5oC above ambient), SS (1000 mg/l) and ammonia (5 mg/l) in the treated

final effluent on release at OF1 and OF2 (Figure 7.1.1) through a multiport

diffuser has been studied in detail using a numerical model as described in

Section 6. The results show that the ambient conditions namely

temperature: 280C, SS: 50mg/l and Ammonia: ND are attained within 300m

(max). Hence the negative impact of the effluent release is not expected to

be evident beyond 300m distance from the diffuser in case of both the

release points OF1 and OF2.

Available information indicates the water temperatures of 28oC (av) in the

Okha-Dwarka-Kuranga region can occur in summer. Therefore, the predicted

maximum water temperature in a small area around the diffuser would be <31oC

143

which is lower than the threshold of 35 oC considered for tropical marine areas.

Hence the release of the effluent is unlikely to cause thermal shock to the flora

and fauna even in the vicinity of the diffuser.

The SS recorded off Kuranga is 274 mg/l (av). Based on the model

results, it may increase to about 883mg/l (max) in a limited area around the

diffuser subsequent to the effluent release. An incremental increase of this order,

that too in a small area, is unlikely to negatively influence the biota even in the

vicinity of the diffuser.

As discussed under Section 5.2.6, the concentration of ammonia

(NH3+NH+4) in seawater is very low. The maximum concentration of ammonia

(NH3+NH+4) off Kuranga was 0.031 mg/l (av). The model predicts an increase of

about 100 folds (3.04 mg/l) in the vicinity of the diffuser. Ammonia as NH3

(unionized ammonia) is harmful to marine organisms even at low concentrations

and its acute toxicity varies between 0.08 and 1.5 mg/l depending on the

organism. However, the concentration of unionized ammonia in seawater mainly

depends on pH. Available literature indicates that at the pH of 8.0 to 8.3 (av) off

Kuranga (Section 5.2.2), only about 3 to 5 % of the total ammonia (NH3+NH+4)

would occur as unionized ammonia. For the predicted highest concentration of

3.04 mg/l off Kuranga about 0.15 mg/l would occur in the unionized form. This

concentration would be confined to a very small area around the diffuser. Hence,

no significant impact of release of ammonia through the effluent is expected.

The particle trajectory modelling shows that the trajectory of particle

changes with the tide but moves in the northwest-southeast axis almost parallel

to the coastline and does not reach the intake location (IT1, Figure 7.1.1). A

major fraction of the SS with bed level variation of 0.04 m but fine particles would

remain in suspension for a longer duration. This would impart a milky hue to the

water around the diffuser under continuous release of effluent. This however

would not affect the water quality since the SS in the effluent in non-toxic.

Sediment quality: Modeling results (Section 6.7) indicate that the deposition

of SS on the sea floor around the diffuser would raise the bed level by 0.04

144

m/15 d for 1000 mg/l of SS in the effluent. Over the course of time however

the rise in bed levels would be stabilised as the bed gets re-established itself

to the new hydraulic regime. This SS is inorganic in nature and largely

composed of constituents commonly occurring in the marine environment.

Considering the sediment type off Kuranga, the settlement of the effluent

associated SS is unlikely to grossly modify sediment texture of the region.

Flora and fauna: The general water quality of the coastal area would not be

affected adversely, though limited degradation would result in a small area

around the diffuser. Hence, by and large, the biological characteristics of the

region would not be affected adversely except for some negative impact on

macrobenthos in the vicinity of the diffuser, due to the settlement of SS. The

SS though not harmful, it may change the sediment character locally and the

macrobenthos community would have to adjust to this modified habitat.

Cross-contamination with seawater intake: As discussed in Section 6 the

vital parameters in the treated combined effluent would attain near ambient

levels of the water quality within 300 m (max). Hence its cross-contamination

with the seawater intake which is located at a distance of more than 2 km

away towards south would not take place.

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8 MITIGATION MEASURES

The marine segments through which the proposed intake and effluent

disposal pipelines would pass is a typical segment of the Arabian Sea coast

of Kuranga consisting of a sandy pocket beach with an underlying rocky

substratum. The North Saurashtra coast where the project site is located

sustains seaweeds, patches of dead coral reefs with live scattered corals and

good fishery potential. Hence, adequate precautions are required to prevent

deterioration in marine environmental quality beyond the pipeline corridor.

8.1 Construction phase

As discussed under Section 5.4 the proposed corridors are free from

corals and mangroves. However, seaweeds and macrobenthos along the

corridors would be destroyed due to excavation/trenching. Adequate

precaution is necessary to minimize this damage. Therefore, the construction

activities should be confined to the pre-determined corridors taking care to

avoid use of intertidal area beyond the width of the corridors.

The impact on marine and terrestrial ecology during the construction

phase would be largely confined to the duration over which the activities are

spread. Hence, the key factor in minimising the adverse impacts would be

reduction in the construction period at the site and avoidance of spillage of

activities beyond the specified geographical area which should be kept to a

minimum. Sometimes different contractors are engaged for jobs such as

fabrication and supply of pipeline, installation etc. Lack of proper

understanding and coordination among contractors often leads to time-

overruns. This should be avoided by taking up the scheme as a single

integrated project with proper coordination among contractors as well as the

RSPL personnel.

The soil side-cast during trenching should not be left on the intertidal

zone to avoid being washed away and settling on nearby areas. It should be

removed and temporarily stored above the high tide level and used for back-

filling later.

146

There is a distinct advantage of reduction in time of marine

construction operations, by prefabricating the components wherever possible

and transporting them to the site. However, the fabrication yard should be

located sufficiently away from the shore and transport of pipes, machinery etc

to the site should be through a pre-decided corridor.

To prevent the misuse the intertidal and supralitoral areas, the

makeshift facilities for workers should be established beyond the CRZ zone

on the landward side and proper sanitation should be provided to them.

The noise level during transport and construction of marine facilities

should be kept to a minimum.

The intertidal and nearshore areas should be restored to their original

contours once the marine construction activities are completed. General

clean-up along the corridor areas, and intertidal segments etc should be

undertaken and discarded materials including left-over excavated soil should

be removed to restore the aesthetic quality of surroundings on completion of

the construction phase.

Once the alignments of the pipelines for seawater intake and effluent

disposal are finalised it is necessary to conduct a physical survey of the

routes to ensure that the alignments are free from corals, mangroves and

sand dunes. If the need be the alignments can be modified to avoid corals

mangroves and sand dunes.

8.2 Operational phase

8.2.1 Seawater intake

For well-designed and constructed gravity seawater intake systems,

only a few mitigation measures listed below are required.

Appropriate screens and bars should be provided in the intake to avoid

the large marine organisms entering the intake system.

The efficiency of the intake system might decrease over a period of

time due to the settlement of bio-foulers such as barnacles, at and inside the

pipe openings, entry of sediment into the sump etc. Periodic removal of these

147

materials will be required. The cleared material should not be dumped to sea

or intertidal areas.

As a navigational safeguard, the seawater intake locations should be

adequately protected and identified with a marker buoy.

8.2.2 Effluent disposal

Predictions of impacts of release of the effluent on the marine ecology

are made based on the assumption that the effluent meets the GPCB /CPCB

norms. Hence, it should be ensured that the effluent released to the sea

meets the prescribed GPCB /CPCB norms at all times.

It is predicted that the effluent would attain 22.3 times initial dilution

when released through a multiport diffuser (Section 6.9). Such calculations

are based on average environmental conditions and some assumptions

which cannot be easily verified. Hence, the actual dilution attained should be

measured through tracer studies after the outfall becomes operational. The

effluent release scheme can then be adequately modified to ascertain

necessary dilution, if required.

The efficiency of diffuser might decrease over a period time due to the

settlement of biofoulers at the port openings, entry of sediment in the diffuser

etc. Hence, the efficiency of the diffuser must be checked periodically (once

in 2 y or so) and if necessary it should be cleaned to revert back to the

dilution ascertained through initial tracer studies.

As a navigational safeguard, the effluent release location should be

adequately protected and identified with a marker buoy.

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9 MANAGEMENT OF MARINE ENVIRONMENT

The guiding principal of marine environment management is to ensure

that the perturbations due to the proposed coastal activities are within the

assimilative capacity of the marine zone. This is best done by integrating into

the project itself, a plan of actions for mitigating predicted adverse effects as

discussed in Section 8.

It is necessary to verify the predicted environmental changes from the

pre-project baseline apart from ascertaining and periodically checking the

efficiency of the diffuser by post project monitoring as described below. 9.1 Pre-project monitoring for baseline quality

In Sections 5.1 to 5.4 baseline settings of relevant environmental

components with respect to the marine environment of Kuranga are

discussed pertaining to short-term measurements conducted during the field

studies. Like all natural ecosystems, the marine environment also undergoes

seasonal variations. To understand these variations it is necessary to

conduct periodic investigations, at carefully selected monitoring locations.

These should include subtidal as well as intertidal segments. In the present

case, the stations 1 to 9 should be adequate to represent the subtidal

environment, while, the intertidal transects I to VI can be selected for

evaluation of the intertidal ecology including corals. Till a proper baseline is

established, the data presented in this report can be considered for

comparing the results of future monitoring studies. The monitoring however

should be confined to the months in which the data are collected.

Many coastal areas which are under profound tidal influence reveal

diurnal changes particularly when anthropogenic contaminants are

introduced in excess of their assimilative capacity. Hence, selected stations

should be sampled diurnally during monitoring programmes. The parameters

to be monitored are listed below.

a) Water quality: Water samples obtained from 2 levels in the vertical when

the depths exceed 3 m, should be studied for temperature, pH, salinity, DO,

BOD, (or total organic carbon), dissolved phosphate, nitrate, nitrite,

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ammonia, PHc and phenols. For shallower waters, surface samples can be

analysed.

b) Sediment quality: Sediment from subtidal and intertidal regions should

be analysed for texture, Corg, phosphorus, chromium, nickel, copper, zinc,

cadmium, lead, mercury and PHc.

c) Flora and fauna: Biological characteristics should be assessed based on

primary productivity, phytopigments, phytoplankton populations and their

generic diversity; biomass, population and group diversity of zooplankton;

biomass, population and group diversity of benthos; seaweeds, corals and

fish quality.

9.2 Post-project monitoring for assessment

A comprehensive marine quality monitoring programme with periodic

investigations at predetermined locations (These should preferably coincide

with those used for baseline quality) by a specialised agency is a practical

solution to ensure quality data acquisition. This can be a continuation of the

study designed for baseline quality and the some parameters listed above

should be included in the post-project monitoring programme. The post-

project monitoring can be as follows:

a) Just prior to the commencement of operation of marine facilities.

b) After 6 months of commencement of operations.

c) Once a year from the commencement of operation preferably in the

premonsoon period or as recommended by MoEF.

The results of each monitoring should be carefully evaluated to

identify changes if any, beyond the natural variability identified through

baseline studies. Gross deviation from the baseline may require a thorough

review of the effluent disposal scheme to identify the causative factors

leading to these deviations and accordingly, corrective measures to reverse

the trend would be necessary.

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10 SUMMARY AND RECOMMENDETIONS

10.1 Introduction

M/s RSPL Limited (RSPL) proposes to set-up a green field soda ash

plant (1500 TPD Light Soda Ash /770 TPD Dense Soda Ash – Dense Soda

Ash is Conversion of Light Soda Ash) with a captive power plant (50 MW)

near Village Kuranga in Jamnagar District of Gujarat State. For the purpose

RSPL has planned to establish marine facilities namely seawater intake of

about 6 × 105 m3/d for process, cooling DM plant utilities and process plant

effluent dilution etc. and effluent disposal of 6 × 105 m3/d from process, brine

purification rejects, DM plant rejects etc. after treatment / dilution with once

through return cooling water / fresh seawater to meet GPCB / CPCB norms

in the coastal waters off Kuranga.

CSIR-NIO on behalf of RSPL therefore conducted detailed

oceanographic investigations of the coastal waters off Kuranga during 2012-

13 with the objectives of a) establishing prevailing ecological status of the

study area, b) suggesting suitable sites and modes for seawater intake and

effluent disposal, c) assessing impact on the coastal ecology and d)

suggesting adequate Marine Environmental Plan (MEMP) including

mitigation measures. The present report is prepared to meet these

objectives.

10.2 Project domain

RSPL, a North India based well reputed company is in the business of

Detergents, Soaps, leather products and dairy products. RSPL proposes to

produce Soda Ash with a sole objective of achieving backward integration

and of controlling quality and cost of raw materials of detergent.

10.2.1 Location

The RSPL site is flanked by villages Kuranga, Bhatvadia and Gojiness

with the Arabian Sea in the southwest. It is well connected to National

Highway (NH- 8E), Railway and airport.

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10.2.2 Process

Soda Ash: Soda ash (Na2CO3) is manufactured by the reaction between

sodium chloride and limestone with ammonia as an intermediate carrier. The

major steps involved in the process are as follows: (a) Brine purification in

which the saturated brine is treated with soda ash and milk of lime to remove

residual impurities. (b) Limestone calcination whereby limestone is mixed

with coke and charged to lime kilns to produce CO2 and CaO. Part of CaO is

hydrated with sweet water to make milk of lime for treatment of brine. Major

part of lime is grind and fed to Prelimer for release of ammonia. (c) Ammonia

is absorbed in purified brine in absorber and thereafter CO2 from

compressors is fed in carbonation columns to obtain crude sodium

bicarbonate as a solid phase which is filtered and decomposed to Soda Ash

(Na2CO3) in calliper.

The filtrate containing NH4Cl is reacted with Ca(OH)2 in prelimer stills

to recover NH3 in ammonia still which is recycled. Ammonia still discharge is

the major effluent from soda ash industry.This effluent contains high

concentration of inorganic non-toxic solids and liquid is rich in salts with

traces of NH3. About 300 to 500 kg of solids are produced per tonne of soda

ash manufactured. The effluent after removal of NH3 is diluted with return

cooling seawater to meet disposal norms.

Power plant: The captive power plant of 50 MW (20 MW × 2 nos. + 10 MW x

1 no.) capacity multi-extraction turbo-attunator and 150 TPH × 3 nos. Light/

Coal based boilers.The steam generator units will be compact semi-outdoor,

returned/assisted circulation, balanced draft, single drum, water tube type

provided with circulating fluidized bed combustion system.

10.2.3 Marine facilities

(a) Seawater intake: The seawater requirement of 6 × 105 m3/d for process,

cooling, RO/DM plant utilities and process plant dilution etc. will be met by

drawing seawater from the Arabian Sea.

(b) Effluent disposal: The diluted combined effluent from process, brine

preparation/purification rejects, washings, return cooling, RO/DM plant

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rejects, utility rejects etc. will be adequately treated to meet GPCB/ CPCB

norms and proposed to be disposed at a suitable location in the Arabian Sea.

(c) Field study: The seawater intake and effluent disposal location, pipeline

alignments and diffuser design will be suggested by CSIR-NIO on the basis

of field investigations and model studies.

10.3 Study area

The coastal waters off Kuranga forms a part of the coastal stretch

between Dwaraka and Porbandar of the Saurashtra coast of Arabian sea.

The area sustains sparse and scattered vegetation of the tropical dry

mixed deciduous scrub and desert thorn type belonging to the xerophytic

group. The land use pattern within 10 km distance of the project site in

Jamnagar District indicates that 4.14 % land is under crops and 8.05% has

vegetation. The coastal belt is sparsely populated except few pockets like

Porbandar, Dwaraka, Mithapur, Bhogat etc.

With few rain days, and highly variable and low rains, the climate is

hot and humid from April till October and pleasant during brief winter from

December to February. Wind speeds are 0 to 70 km/h.

10.4 Studies conducted 10.4.1 Field investigations

The studies were conducted in respect of physical processes, water

quality, sediment quality, and flora and fauna at 9 subtidal stations and 6

intertidal transects during April-May 2012 (premonsoon), September 2012

(monsoon), and December 2012 (postmonsoon). The analyses were

performed as per recommended oceanographic procedures.

The coral investigations in intertidal regions were carried out during

April - May 2013.

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10.4.2 Model studies

Predictions on dilution and dispersion of pollutants, SS transport and

bed level changes were done on the basis of 2D models.

10.5 Prevailing marine environment

The coastal area off Kuranga in an area of 280 km2 was investigated

for its environmental characteristics such as physical processes, water

quality, sediment quality and biological characteristics. The status was

evolved for 3 seasons namely premonsoon, monsoon and postmonsoon

during 2012.

10.5.1 Physical processes

The tides along the coast were mixed semi-diurnal with the mean high

water spring and neap rise of about 3.5 and 1.2 m respectively. The high tide

at Okha lagged by 1 h 40 min to 2 h 10 min with respect to the tide at

Porbandar. Tide measured at station 7 compared well with the recorded tide

at Okha.

Off Kuranga the currents are mainly tide-induced though wind also

contributes to some extent. The currents which were parallel to the shore

have maximum speeds of 0.0 to 0.3 m/s with net onshore and alongshore

components varying spatially. The tidal excursion estimated based on drogue

trajectories was variable depending on the tidal phase, location and period.

10.5.2 Water quality

The average water temperature varied in accordance with the air

temperature and was generally below 30oC. The average pH (8.0 - 8.3) was

in the range expected for the coastal area and spatial or temporal changes

were minor. The average SS was variable (16 - 274 mg/l) as the seafloor is

rocky or sandy. In the absence of freshwater discharges, the salinity was

high (35.2 - 37.0 ppt) as compared to that of the typical seawater (35.5 ppt).

The water was well-mixed vertically as well as laterally.

DO content, a vital water quality parameter influencing the health of

aquatic biota, was in excess of 4mg/l. Consequently BOD of the coastal

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water was low (av < 0.1 – 6.7 mg/l). The average concentrations of PO43--P

(ND – 2.3 mol/l) and NO3--N (0.8 - 11.7 mol/l) were in the range expected

for the coastal area. Low levels of NH4+-N (av ND – 2.2 mol/l) and NO2

--N

(av < 2.2 mol/l) indicated good oxidizing conditions in water.

The average concentrations of PHc (0.2 – 32.8 g/l) and phenols (69 -

146 g/l) were low and in the range commonly encountered in

uncontaminated coastal waters.

The prevailing water quality of the nearshore for premonsoon

compared well with that of the coastal waters off Gojiness which is adjacent

to the study area recorded during March 2010.

10.5.3 Sediment quality

The surface sediment of the study area had variable texture but

generally dominated by varying grades of sand.

The subtidal as well as the intertidal sediments off Kuranga sustained

variable concentrations of trace metals such as chromium, cobalt, nickel,

copper, zinc and mercury primarily because of the heterogeneous character

of sediments and in absence of any known anthropogenic source, they

represented a baseline.

The Corg (<1.9 %; dry wt) and phosphorus (< 818 - 1514 g/g; dry wt)

contents in sediments were low and represented the baseline. The

concentrations of PHc (0.1 - 1.4 g/g; wet wt) in the sediment were also low

and revealed uncontaminated status of the sediment with respect to PHc.

The prevailing sediment quality of the nearshore for premonsoon was

comparable with that of the coastal waters off Gojiness reported for March

2010. Incidentally Gojiness is located adjacent to Kuranga.

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10.5.4 Flora and fauna

Bacterial count like TVC in water and sediment was low and without

any specific trend. Pathogens were rarely noticed suggesting clean and

natural coastal system off Kuranga.

The concentration of chlorophyll a in the coastal water (0.7 - 30.6

mg/m3) indicated variable and patchy phytoplankton biomass. The

concentration of phaeophytin (0.2 - 5.8 mg/m3) was low. The phytoplankton

population was variable in accordance with the trend in phytopigments.

Overall, 19 genera were recorded in the region with the common occurrence

of Nitzschia, Navicula, Chaetoceros, Thalassiosira etc.

Mangroves were absent along the Kuranga coast. The intertidal rocky

region (150-300m) however sustained marine algae. Species such as

Caulerpa racemosa, Ulva lactuca, Andorea indica etc. and floating algae like

sargassum polycastrum. The sand dunes, particularly narrow foreshore and

burm regions of 20 to 40 m width supported sand dune vegetation, mostly in

patches. The sand dune flora was dominated by babul and grass vegetation.

The zooplankton standing stock in terms of biomass (0.04 - 1.4

ml/100m3) and population (0.3 - 19.6 × 103 no/100m3) was indicative of an

overall moderate secondary production and varied widely. The composition

of zooplankton was fairly diverse and consisted mainly of copepods,

decapods larvae, lamellibranchs, gastropods and cladocera, foraminiferans

which together contributed about 97 % to the total population. Overall 18

faunal groups were identified. Good number of fish eggs and fish larvae

though at a low percentage, occurred in majority of the zooplankton

collections. Decapod larvae occurred in all zooplankton samples and

contributed about 2.6 % to the zooplankton population. The most dominant

groups were crab zoea and pagurids.

The intertidal macrobenthic standing stock in terms of population and

biomass varied from 0 to 7125 no/m2 and from 0 to 61.0 g/m2; wet wt

respectively. The fauna was mainly constituted by crustaceans, polychaetes

and mollusks. The faunal group diversity varied between 0 and 6 groups. The

subtidal benthic macrofaunal standing stock in terms of population and

biomass varied from 0 to 7100 no/m2 and from 0 to 21.5 g/m2; wet wt with

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poor faunal group diversity (2 - 8 no). The faunal composition indicated

overall dominance of polychaetes followed by crustaceans..

Jamnagar District contributed about 5 to 14% of the Gujarat State’s

fish landings. The landings of Jamnagar District revealed a variety of

common species and important fishes such as pomfret, Bombay duck, Hilsa,

prawns, tuna, shark etc. The important fish landing centers are Dwarka,

Harshad, Navadra etc. The data suggested that area was conducive for the

quality fishes.

Three transects IV, V and VI in the intertidal area were investigated for

the presence of live corals. The intake corridor is free from corals. Transect

IV sustained isolated corals namely Porites compressa, Favia Favus and

Zoanthus sp. Transect V with predominant sandy intertidal stretch sustained

low coral density of Porites compressa and Zoanthus. Some signs of turtle

nesting grounds were seen on the sandy beaches. However live turtles and

eggs were not sighted during the visit. Transect VI was free from corals. No

planulae larvae was seen during visit at this transect. Assessment by remote

sensing imagery did not reveal presence of corals in the 5 km radius of the

pipeline corridors including the subtidal area.

10.6 Modeling studies for marine facilities

RSPL proposes to establish marine facilities namely seawater intake

and effluent disposal in the coastal waters off Kuranga. The suitability of

these locations has been studied by using the numerical models. They are

described below.

10.6.1 Hydrodynamic modeling

Numerical modeling was done using Hydrodyn-FLOSOFT, Hydrodyn-

POLSOFT and Hydrodyn-SEDSOFT software for prediction of tides and

currents; dilution and dispersion processes in marine areas; and sediment

transport in tidally driven zones. The model runs were made for a period of

15 d for different seasons. The comparison of the observed and the

computed tides as well as current components indicated good agreement

between the two.

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10.6.2 Seawater intake

It is proposed to withdraw seawater from the Arabian Sea by gravity

through a submarine pipeline.

a) Locations of intake: It is proposed to establish the seawater intake site at

one of the two sites given below.

IT1: 210 59' 49.70" N; 690 10' 24.60" (depth 4.5 m below CD).

IT2: 210 59' 46.02" N; 690 10' 20.04" (depth 7.0 m below CD).

b) Behavior at intake: The study predicts that the seawater withdrawal at

location IT1 forms a trough of 50 m radius with a tide raise of 0.3 m and swirl

velocity of 0.78 to 0.80 m/s at spring peak ebb and peak ebb.

At location IT2 the trough is of 40 m radius with a tide raise of 2.03 m

and swirl velocity of 0.8 to 1.3 m/s at spring flood. At spring ebb the 40 m

radius trough possesses a tide raise of 2.02 m and swirl velocity of 0.8 to 1.8

m/s.

Thus in both the cases the impact of the tide regime is similar, in

significant and limited to small well defined area around the intakes. The

location IT1 is recommended on the basis of minimal area and volume of

excavation required to lay the pipeline and consequent reduction in the

benthic losses.

10.6.3 Effluent release

It is proposed to release the effluent at the bottom in the Arabian Sea

through a submarine pipeline.

a) Locations of release: It is proposed to release the effluent into the sea at

one of the two sites given below.

OF1: 220 01' 25.62" N; 690 08' 06.27"E (depth 13-14 m below CD)

OF2: 220 00' 39.51" N; 690 09' 07.01"E (depth 12 m below CD)

b) Behaviour of effluent: The effluent if released at OF1/OF2, the levels of

critical parameters in the effluent around the location and small central patch

namely temperature: 50 C above ambient, SS: 1000 mg/l and ammonia: 5

mg/l attain the ambient levels of temperature: 23°C, SS: 50mg/l and

ammonia: ND at 300m (max) from the outfall.

Ammonia in free form is toxic to some marine organisms at low

concentrations. The concentrations of ammonia predicted at OF1and OF2

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would be higher than the natural levels. However, at the ambient pH of

seawater much of this ammonia is expected to be converted to NH4+, the

form in which it is not toxic to marine organisms.

Based on the results of numerical modeling it can be concluded that

the water quality of the coastal area off Kuranga would not deteriorate with

respect to temperature, SS and ammonia beyond 300m distance from the

outfall except in the immediate vicinity of the outfall where the temperature,

SS and ammonia would be relatively higher but in the range considered

tolerable to marine biota.

The bed level changes due to release of SS of 1000 mg/l from the

effluent would be 0.018 m (max) at the outfall with no significant variation in

the rate of erosion/deposition for the both the options. The deposited SS in

the vicinity of the outfall would be advected northwest-southeast to settle

over a large area as the fine grained SS erodes. This would reduce in time

as the seabed gets re-establish itself to a new hydraulic regime. In short term

however there is a possibility of siltation due to continuous discharge of the

effluent.

The output clearly shows that behaviour of the effluent released at

OF1 and OF2 was similar. Also the ambient condition would attain within 300

m (max) in both the cases. Presence of soft mud at OF1and OF2 negates

the possibility of presence of subtidal corals. Hence both the location OF1

and OF2 are recommended suitable for the effluent release.

C) Near-field dilution: Based on the results of the Buoyant / Forced-Jet

Model it is suggested that the effluent should be released with a minimum

initial jet velocity of 3 m/s through a 10 port diffuser at 13 m below CD depth

above the bottom. As the effluent plume descends through the water column

it would attain initial dilution by 22.3 times.

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10.7 Potential marine environmental impacts 10.7.1 Seawater intake

a) Scheme: From the two options (IT1 and IT2), the alignment for IT1 was

selected on the basis of lower area and volume of excavation required to lay

the pipeline and consequent reduction in benthic losses due to shorter

length. Since the corridor is devoid of mangroves and corals as well as Sand

dunes. Their losses are unlikely. The land based sump and the intake point

(IT1, 210 59' 49.70"N; 690 10' 24.60"E) will be connected by 70 and 456 m

long intertidal and subtidal pipeline segments respectively. The gradient of

the buried pipeline will be so maintained that the seawater flows at a

constant rate.

b) Potential marine environmental impacts: Major potential negative

marine environmental impacts due to the proposed activities would be largely

associated with (a) construction phase of laying of the intake pipelines and b)

operational phase due to circulation pattern, changes in erosion-deposition

processes, as well as impingement and entrainment of biota.

i) Construction phase: Adverse impacts of the proposed project on the

marine environment during the construction phase could be due to

modifications in the hydrodynamic characteristics of the area, degradation in

water and sediment qualities and consequent impact on biota depending on

the construction methodology selected and duration.

The intertidal and subtidal areas of 0.035 and 0.91 ha totalling 0.95 ha

would be adversely affected by the construction activities.

Hydrodynamic characteristics: As the trenching and burial of the pipeline

would be across the intertidal zone with a sandy beach and subtidal zone

with hard substratum, the construction if not conducted in a stipulated time

and planning there can be minor and local erosion both sides of the trench

due to non-compacted sand moving into the trench. However, due to the

limited length of the trench and shallow excavation, this would not be

significant. Apart from this, the coastal dynamics are unlikely to be influenced

by the construction activities.

Water quality: The bed sediment disturbed at the excavation site would

generate SS which may remain in suspension for some time at the

construction site. However, considering the sandy nature of the sediment it is

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expected to settle fairly quickly. The impact would be localized, temporary

and confined only to the construction phase of trenching, pipelaying and

trench filling.

As the sediment of the region is mainly sand subjected to continuous

wave action and sorting, leachable pollutants are not expected in them.

Moreover the sediments of the area are unpolluted. Hence there would not

be any deterioration in water quality on this account.

Sediment quality: Since the area that would be disturbed is small, the

excavated sediment volume is unlikely to cause change in the sediment

texture on a wider area of the seabed excepting in the close vicinity. Such

impact would be negligible.

Misuse of the intertidal area by the workforce employed can locally

degrade the sediment quality by increasing BOD and populations of

pathogens. If proper arrangement is not made for them. The impact,

however, would be minor and temporary and recovery would occur when the

source of this contamination is eliminated at the end of the construction

phase.

Flora and fauna: Hectic construction activities in the corridor areas would

influence the local biotic communities, particularly the macrobenthos along

the corridors selected for laying the pipelines. As the sediment is not

enriched in Corg, its suspension in the water column is unlikely to deplete DO

in this dynamic marine area and DO availability would not constrain the biotic

processes. The danger of biota getting exposed to pollutants released from

the sediment interstitial water when the bed is disturbed, is low. The corridor

and nearby zone are devoid of mangrove vegetation and corals. Hence,

there would be no impact on these habitats.

The impact of turbidity due to enhanced levels of SS if any, would be

local and temporary with the phytoplankton community structure remaining

more or less unaltered as the enhancement in turbidity during the activity is

expected to be low.

Laying of pipeline would destroy the benthic habitats in the corridor of

0.95 ha. However, when the trench is back-filled, entire area would be

available for their re-colonisation. Probable temporary loss of macrobenthic

biomass and population would be 43.9 kg (av) and 10.9 × 106 no (av)

respectively. Considering the benthic potential of the study area, such losses

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are unlikely to be reflected on the overall biopotential of the coastal marine

system off Kuranga.

Loss of mangroves and corals as well as Sand dunes is not

envisaged, as the pipeline corridor is devoid of mangroves , corals and Sand

dunes.

Miscellaneous: The aesthetics of the coastal zone off Kuranga would

deteriorate due to the presence of construction machinery, materials and left-

over solid waste.

If the construction is prolonged due to time-overruns or improper

planning, the adverse influence would increase accordingly.

The birds using the intertidal area around the project site are not

expected to be impacted adversely as the limited excavation does not

warrant the use of heavy machinery and large vessels. Marine reptiles and

mammals would not be affected due to the construction activities since they

keep away from such sites. Since there are no major commercial fishing

operations close to the shore, the impact on fisheries would be minor.

ii) Operational phase: Marine environmental implications during the

operational phase of the project would be confined to the probable negative

influence of seawater intake on hydrodynamic characteristics, water quality,

sediment quality, and flora and fauna of the region.

Hydrodynamic characteristics: As the flow of seawater in the sump is by

gravity, the change in the current speeds and water levels during operations

of the intake system would be marginal as predicted and the overall

hydrodynamics of the region would remain unaltered.

Water Quality: During the operational phase there would be no activity

leading to release of contaminants to the coastal area. Hence the impact on

physico-chemical quality of the adjoining seawater is not expected to be

influenced.

Sediment quality: Since the water quality would not be impacted, change in

sediment quality due to water borne particulates is discounted. The change

in the current velocities due to withdrawal of seawater would be minor and

would not alter erosion/deposition in the area.

Flora and fauna: General water quality of the coastal area would not be

affected adversely. Hence, the biological characteristics of the region would

not be influenced except for minor negative impact on macrobenthic

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community in the vicinity of the intake due to limited local disturbance to the

sediment.

The current velocities at the pipe orifice are predicted to be low.

Hence, impingement of species such as fish or crab would be insignificant.

Considering the short life span of plankton and their fast multiplication rates,

the loss due to entrainment would not adversely influence the productivity of

the coastal region. Impact of entrainment of fish eggs and larvae on future

adult populations is also considered minor since fishes during their breeding

cycle lay millions of eggs of which only a very small fraction grows to

adulthood.

10.7.2 Effluent disposal a) Scheme: Both the (OF1 and OF2) have been recommended for the

effluent release since behaviour of the effluent is similar in both the cases

and the released effluent would attain the ambient levels within 300m (max).

Since the corridors are devoid of mangroves and corals as well as Sand

dunes their destruction due to the development is unlikely. A pipeline will be

laid between LFP and the disposal sites (OF1: 220 01' 25.62" N; 690 08'

06.27"E or OF2: 22° 00’ 39.51”N; 69°09’ 7.01”E). It will be buried in the

intertidal stretch and wherever depth is below 6 m in the subtidal stretch. It

will be end at a 68 m long, 10 port diffuser. The diluted effluent (6 × 105 m3/d)

will be released at a jet velocity of 3 m/s to get the plume dilution of 22.3

times.

b) Potential marine environmental impacts: Potential negative impacts on

marine ecology can arise during the construction as well as the operational

phases of the effluent release scheme.

I) Construction phase: Adverse impacts of the proposed effluent release

scheme on the marine environment during the construction phase could be

due to modifications in the hydrodynamic characteristics, degradation in

water and sediment qualities and impact on biota.

Hydrodynamic characteristics: The hydrodynamics of the area would get

influenced during a short period of trenching and pipelaying only. Hence the

impact on the characteristics would be localised and temporary.

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Water quality: Trenching/pipelaying in the area having hard

substratum/sand has relatively low potential to disperse the bed sediment.

The impact would be localized, temporary and confined only to the

construction phase. The sediment of the region is unpolluted; hence, there

would not be deterioration in the water quality on this account.

Sediment quality: Since the area possesses hard substratum/sand and the

excavated sediment is a small volume, it is unlikely to cause change in the

sediment texture on a wider area.

Misuse of the intertidal area by the work force can locally degrade the

sediment quality by increasing BOD and populations of pathogens. The

impact, however, would be minor and temporary.

Flora and fauna: The intertidal corridor is largely composed of degraded

reef and sand with isolated patches of seaweeds with a few species. Hence,

no significant loss of flora and fauna is envisaged. Loss of localized weeds

would be easily recouped by fresh recruitment once the activities are

terminated.

The impact of increase in turbidity due to enhanced levels of SS, if

any, would be local and temporary with the phytoplankton community

structure remaining more or less unaltered. Zooplankton are unlikely to be

affected.

The project would have negative impact on benthic habitats which

would be destroyed during pipelaying. However, this loss would be minor and

temporary and the benthos would re-colonise in due course after the

construction activities are terminated. Moreover, structures would provide

additional surface area for benthos to colonise on the newly created

substratum.

Since the corridor selected is devoid of corals and mangroves, their

destruction during the construction is unlikely.

Miscellaneous: The aesthetics of the coastal zone would deteriorate due to

the presence of construction machinery and materials, make-shift huts of

labour force etc. Left-over solid waste and that generated during

construction would be a source of nuisance if not cleared from the site. If

the construction is prolonged due to time-overruns or improper planning, the

adverse influence would increase accordingly.

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The birds using the intertidal area around the project site would be

disturbed particularly if the construction activity is scheduled during their

migratory months. However, this would be limited to only construction phase.

Since there are no major commercial fishing operations close to the shore,

the impact on fisheries would be minor.

ii) Operational phase: Marine environmental implications during the

operational phase could be due to the release of the effluent on water quality,

sediment quality, and flora and fauna of the region as follows:

Hydrodynamic characteristics: The release of the effluent at 13 - 14 m

depth (CD) would not influence the hydrodynamic characteristics. Though,

accumulation of the sand along the sides of the pipeline is expected, that

would provide additional area for benthos to re-colonise.

Water quality: The predicted maximum water temperature in a small area

around the diffuser would be lower than the threshold of 35 oC considered for

tropical marine areas. Hence the release of the effluent is unlikely to cause

thermal shock to the flora and fauna even in the vicinity of the diffuser.

An incremental increase of SS in a small area is unlikely to negatively

influence the biota even in the vicinity of the diffuser.

The model predicts an increase of about 100 folds in the concentration

of ammonia over the baseline in the vicinity of the diffuser. Ammonia as NH3

(unionized ammonia) is harmful to marine organisms even at low

concentrations. However, the concentration of unionized ammonia in

seawater mainly depends on pH. At the pH of 8.0 to 8.3 (av) off Kuranga,

only about 3 to 5 % of the total ammonia (NH3+NH+4) would occur as

unionized ammonia. For the predicted highest concentration of 3.04 mg/l off

Kuranga, about 0.15 mg/l would occur in the unionized form. This

concentration would be confined to a very small area around the diffuser.

Hence, no significant impact of release of ammonia through the effluent is

expected.

The field of influence of increase in temperature, SS and ammonia

would vary between 150 to 300 m length along the advected plume. The

ambient condition would be attained within 300 m distance from the outfall

location.

A major fraction of the SS would settle but fine particles would remain

in suspension for a longer duration. This would impart a milky hue to the

165

water around the diffuser under continuous release of effluent. This however

would not affect the flora and fauna since the SS in the effluent in non-toxic.

Sediment quality: The SS in the effluent is inorganic in nature and largely

composed of constituents commonly occurring in the marine environment.

Considering the sediment type off Kuranga, the settlement of the effluent

associated SS is unlikely to grossly modify sediment character of the region.

Flora and fauna: The general water quality of the coastal area would not be

affected negatively. Hence, by and large, the biological characteristics of the

region would not be affected adversely except for some negative impact on

macrobenthos in the vicinity of the diffuser, due to the settlement of SS. The

SS though not harmful, it may change the sediment character locally and the

macrobenthos community would have to adjust to this modified habitat.

c) Cross-contamination with seawater intake

The vital parameters in the treated combined effluent would attain

near ambient levels of the water quality at a distance of about 300 m (max)

from the effluent disposal points OF1 and OF2. Hence its cross-

contamination with the seawater intake which is more than 2 km away is

ruled out.

10.8 Mitigation Measures

The marine segment off kuranga sustains seaweeds, live corals in

isolated patches and good fishery potential. Hence, adequate precautions

are required to prevent deterioration in marine environmental quality beyond

the pipeline corridor as described below.

10.8.1 Construction phase:

The key factor in minimize negative impacts on marine ecology would

be reduction in the construction period at the site and avoidance of spillage

of activities beyond the specified geographical area. Hence, the project must

be properly planned and project site adequately demarcated. Lack of proper

understanding among contractors often leads to time-overruns. This should

be avoided by taking up the scheme as a single integrated project with

proper coordination among contractors as well as the RSPL personnel.

Both terrestrial and marine components of the project should be

coordinated with planning that takes the tidal conditions into account since

166

the work also involves intertidal stretch. The excavated sediment should not

be kept in the intertidal zone. It should be properly stored on land and used

for back-filling the trenches. Fabrication yard should be located sufficiently

away from the shore and transport of pipes, machinery etc. to the site should

be through a pre-decided corridor.

Work force misusing the intertidal and supratidal areas should be

avoided by establishing the makeshift facilities for workers sufficiently away

from the HTL on the landward side and proper sanitation should be provided

to them to prevent abuse of the intertidal region.

The noise level during transport and construction of marine facilities

should be kept to a minimum.

The intertidal and nearshore areas should be restored to their original

contours once the marine construction activities are completed. General

clean-up along the corridor areas, and intertidal segment etc. should be

undertaken and discarded materials including left-over soil should be

removed from the intertidal site. The aesthetic quality of surroundings should

be restored on completion of the construction phase.

It is necessary to ensure that the pipeline corridors selected are free

from mangroves, corals and Sand dunes by physical survey. If the need be

the alignments can be modified.

10.8.2 Operational phase:

a) Seawater intake: Since the pipes are large, large fishes may enter the

pipe along with the intake water. To mitigate this each pipe end should be

fitted with bars (either vertical or horizontal) to avoid chocking. Screen should be provided in the intake design to avoid the fish and

other organisms entering the intake system passing the bars.

Cleaning and clearing of bio-fouler such as barnacles on and inside

the pipe openings and sediment in the sump etc. should be done on regular

basis to maintain efficiency of the intake system. The cleared material should

not be dumped in the sea or on the intertidal areas. It should be washed

thoroughly with freshwater to remove its salt content and disposed off in

landfills.

As a navigational safeguard, the effluent release location should be

adequately protected and identified with a marker buoy.

167

b) Effluent disposal: It should be ensured that the effluent released to the

sea meets the prescribed GPCB/ CPCB norms at all times.

It is predicted that the effluent would attain 22.3 times initial dilution.

This should be verified through tracer studies after the outfall becomes

operational. The effluent release scheme can then be adequately modified to

ascertain necessary dilution, if required. The efficiency of the diffuser must

be checked periodically (once in 2 y or so) and if necessary it should be

cleaned to revert back to the dilution ascertained through initial tracer

studies.

As a navigational safeguard, the effluent release location should be

adequately protected and identified with a marker buoy.

10.9 Management of marine environment

It is necessary to verify the predicted environmental changes from the

pre-project baseline apart from ascertaining and periodically checking the

efficiency of the diffuser through periodic monitoring. For this purpose the

baseline environmental status should be established through intensive

monitoring. The post-project monitoring can be just prior to the

commencement of effluent release, after 6 months of commencement of

operations and once a year from the commencement of operation, or as

recommended by MoEF.

The results of each monitoring should be carefully evaluated to

identify significant changes, if any, from the baseline. Gross deviation from

the baseline may require a thorough review of the effluent disposal scheme

to identify the causative factors leading to these deviations and accordingly,

corrective measures to reverse the trend would be necessary.

Table 3.1.1: Details of cyclonic storms along North Gujarat coast (1893-2004)

Year Month Intensity Point of origin Track followed

1893 Nov Str-SStr Arabian Sea Veraval-Bhavnagar

1894 Oct SStr Arabian Sea Jafarabad-S.Gujarat

1896 Nov SStr Indian Ocean Off Jafarabad-Bhopal-Allahabad

1897 Jul Depr Arabian Sea Off Jafarabad-Veraval-Gulf of Kachchh

1897 Sep Depr Off Diu Veraval-Off Dwaraka-NW

1903 Jul Str Arabian Sea Off Jafarabad-Veraval-North

1909 Sep Depr Bay of Bengal Surat-Jafarabad-Kandla-NW

1920 Jun SStr Arabian Sea Veraval-Ahmedabad

1925 Jun Depr Arabian Sea Off Veraval-Kandla-Bhopal-Allahabad

1925 Jun Depr Arabian Sea Bharuch-Bhavnagar-Okha

1926 Sep Depr Off Veraval Veraval-N-W-N

1933 May Depr Arabian Sea Veraval-N

1934 Oct Depr Arabian Sea Dissipated Off Jafarabad

1935 Jun Depr Bay of Bengal Gulf of Khambhat

1944 Aug Str Bihar Ahmedabad-Kandla-Off Jafarabad-W

1944 Oct Depr Bay of Bengal Pune-Mumbai-Off Jafarabad-

Ahmedabad

1947 Apr SStr Off Cochin Arabian Sea-Bharuch-along the West

coast

1948 Sep SStr Bay of Bengal Mumbai-Off Diu-Porbandar

1954 Jul Depr Off Jafarabad Vadinar-Karachi

1959 Oct Depr-Str Arabian Sea Jafarabad-Veraval-across the Arabian

Sea-Oman

1960 Jul Depr Off Veraval Off Dwarka-Mandwa

1962 Sep Depr Bay of Bengal Surat-Jafarabad-Dwarka-Mandwa

Table 3.1.1 (Contd 2)

Year Month Intensity Point of origin Track followed

1964 Aug Str Arabian Sea Jafarabad

1969 Jun Depr Arabian Sea Jafarabad-Bhavnagar

1973 Jul Depr Off Diu Veraval-Porbandar-Vadinar-N

1975 Jun Depr Off Jafarabad Okha-W

1976 May-Jun SStr Arabian Sea Jafarabad-Ahmedabad

1982 Nov Depr Arabian Sea Veraval-Ahmedabad-NE

1983 Jun Depr Off Veraval Veraval-Rajkot

1985 Oct Depr Off Mumbai Jafarabad-W of Bhavnagar Jafarabad-

Surat-NE

1989 Jun Depr Off Veraval Junagadh-Rajkot-Navlakhi-Vadinar-NW

1996 Jun SStr Kandla Kandla-Rajkot

1996 Oct SStr Arabian Sea Kandla-Veraval-Jafarabad

1998 June SStr Arabian Sea Porbandar-Jamnagar-Kandla

1999 June SStr Arabian Sea Porbandar-Dwaraka-Jakhau

2001 May Depr Arabian Sea Porbandar-Dwarka

2001 Sep Depr-

Strm-Dep Arabian Sea Porbandar

2004 May

Depr-Str-

Sstr-Str-

Depr

Arabian Sea Porbandar

2004 Sep Depr-Sstr Arabian Sea Bhuj

Intensity (Wind speed) Depression (Depr): Upto 61 km/h. Storm (Str): 62-87 km/h. Severe Storm (SStr): 89-117 km/h.  

Table 5.2.1: Water quality at station 1 (coastal waters off Kuranga) during April - May 2012.

Parameter Level Min Max Av

Temperature (oC) S 28.1 28.6 28.4 B 25.2 25.7 25.4 (27.8) (28.9) (28.4)

pH S 8.0 8.1 8.1 B 8.0 8.1 8.1

SS(mg/l) S - - 24* B - - 29*

Salinity(ppt) S 36.3 36.4 36.3 B 36.3 36.4 36.4

DO (mg/l) S 6.7 8.0 7.6 B 6.4 7.7 7.3

BOD (mg/l) S - - 3.4* B - - 4.3*

PO43--P(µmol/l)

S 0.1 0.3 0.2 B 0.1 0.5 0.1

TP (µmol/l) S - - 1.7* B - - 2.3*

NO3--N (µmol/l)

S 1.0 3.8 2.1 B 2.5 4.0 3.4

NO2--N(µmol/l)

S 0.1 0.5 0.1 B 0.3 0.7 0.5

NH4+-N(µmol/l)

S 0.3 1.0 0.5 B 0.3 0.9 0.5

TN (µmol/l) S - - 5.8* B - - 5.0*

PHc(µg/l) 1m - - 18.1* Phenols(µg/l) S - - 145.9*

Air temperature in parenthesis * Single value  

Table 5.2.2: Water quality at station 2 (coastal waters off Kuranga) during April - May 2012.

Parameter Level Min Max Av

Temperature (oC) S 27.9 27.9 27.9 B 26.5 26.5 26.5 (26.1) (26.1) (26.1)

pH S 8.1 8.1 8.1 B 8.0 8.0 8.0

SS(mg/l) S - - 142* B - - 170*

Salinity(ppt) S 35.3 35.3 35.3 B 35.2 35.3 35.3

DO (mg/l) S 7.4 7.4 7.4 B 4.2 4.5 4.3

BOD (mg/l) S - - 4.2* B - - 1.6*

PO43--P(µmol/l)

S 0.5 0.5 0.5 B 1.1 1.1 1.1

TP (µmol/l) S - - 0.9* B - - 1.7*

NO3--N (µmol/l)

S 5.2 5.4 5.3 B 7.1 8.0 7.6

NO2--N(µmol/l)

S 0.2 0.2 0.2 B 0.9 0.9 0.9

NH4+-N(µmol/l)

S 0.4 0.5 0.5 B 0.7 1.0 0.8

TN (µmol/l) S - - 58.1* B - - 84.8*

PHc(µg/l) 1m - - 14.3* Phenols (µg/l) S - - 124.3*

Air temperature in parenthesis * Single value

Table 5.2.3: Water quality at station 3 (coastal waters off Kuranga) during April -May 2012.

Parameter Level Min Max Av

Temperature (oC) S 27.1 27.1 27.1 B 26.3 26.3 26.3 (25.9) (25.9) (25.9)

pH S 8.0 8.0 8.0 B 8.1 8.1 8.1

SS(mg/l) S - - 140* B - - 109*

Salinity(ppt) S 35.2 35.3 35.3 B 35.2 35.3 35.3

DO (mg/l) S 8.0 8.3 8.2 B 7.4 7.4 7.4

BOD (mg/l) S - - 4.2* B - - <0.1*

PO43--P(µmol/l)

S 0.3 0.4 0.4 B 0.4 0.4 0.4

TP (µmol/l) S - - 0.8* B - - 1.6*

NO3--N (µmol/l)

S 4.1 4.8 4.4 B 4.4 4.5 4.4

NO2--N(µmol/l)

S 0.1 0.2 0.2 B 0.1 0.1 0.1

NH4+-N(µmol/l)

S 0.3 0.4 0.4 B 0.2 0.4 0.3

TN (µmol/l) S - - 62.0* B - - 85.8*

PHc(µg/l) 1m - - 6.6* Phenols (µg/l) S - - 68.6*

Air temperature in parenthesis * Single value

Table 5.2.4: Water quality at station 4 (coastal waters off Kuranga) during April- May 2012.

Parameter Level Min Max Av

Temperature (oC) S 26.1 26.9 26.4 B 24.1 25.6 25.2 (26.8) (28.0) (27.5)

pH S 8.0 8.1 8.0 B 8.0 8.1 8.0

SS(mg/l) S - - 274* B - - -

Salinity(ppt) S 35.2 35.3 35.2 B 35.2 35.3 35.2

DO (mg/l) S 8.0 8.6 8.2 B 6.7 7.4 7.0

BOD (mg/l) S - - 2.2* B - - 1.9*

PO43--P(µmol/l)

S 0.9 1.6 1.1 B 1.0 2.3 1.7

TP (µmol/l) S - - - B - - -

NO3--N (µmol/l)

S 3.9 6.9 4.9 B 3.2 4.5 3.9

NO2--N(µmol/l)

S 0.2 0.6 0.3 B 0.4 0.8 0.6

NH4+-N(µmol/l)

S 0.2 0.7 0.4 B 0.0 0.2 0.1

TN (µmol/l) S - - 16.4* B - - 37.9*

PHc(µg/l) 1m - - 16.1* Phenols (µg/l) S - - 86.2*

Air temperature in parenthesis * Single value 

Table 5.2.5: Water quality at station 5 (coastal waters off Kuranga) during April- May 2012.

Parameter Level Min Max Av

Temperature (oC) S 27.3 27.3 27.3 B 26.7 26.7 26.7 (26.4) (26.4) (26.4)

pH S 8.2 8.2 8.2 B 8.2 8.2 8.2

SS(mg/l) S - - 19.6* B - - 20.8*

Salinity(ppt) S 35.2 35.2 35.2 B 35.2 35.2 35.2

DO (mg/l) S 7.3 7.6 7.4 B 7.0 7.3 7.1

BOD (mg/l) S - - 3.8* B - - 3.8*

PO43--P(µmol/l)

S ND ND ND B 0.6 0.7 0.6

TP (µmol/l) S - - 1.1* B - - 1.7*

NO3--N (µmol/l)

S 0.8 1.0 0.9 B 1.4 1.5 1.4

NO2--N(µmol/l)

S 0.1 0.1 0.1 B 0.9 0.9 0.9

NH4+-N(µmol/l)

S 0.4 0.5 0.5 B 0.4 0.5 0.4

TN (µmol/l) S - - 62.0* B - - 85.5*

PHc(µg/l) 1m - - 27.4* Phenols (µg/l) S - - 124.8*

Air temperature in parenthesis * Single value  

Table 5.2.6: Water quality at station 7 (coastal waters off Kuranga) during April-May 2012.

Air temperature in parenthesis * Single value

Parameter Level Min Max Av

Temperature ( oC ) S 26.7 26.7 26.7 B 26.8 26.8 26.8 (30.1) (30.1) (30.1)

pH S 8.0 8.0 8.0 B 8.0 8.1 8.1

SS(mg/l) S - - 27* B - - 30*

Salinity(ppt) S 35.3 35.5 35.4 B 35.3 35.3 35.3

DO (mg/l) S 7.0 7.0 7.0 B 6.7 6.7 6.7

BOD (mg/l) S - - 3.5* B - - 1.6*

PO43--P(µmol/l)

S 0.6 0.6 0.6 B 1.2 1.2 1.2

TP (µmol/l) S - - - B - - -

NO3--N (µmol/l)

S 3.6 3.9 3.8 B 6.5 8.3 7.4

NO2--N(µmol/l)

S 0.4 0.4 0.4 B 1.4 1.6 1.5

NH4+-N(µmol/l)

S 0.4 0.4 0.4 B ND 0.1 0.1

TN (µmol/l) S - - 51.0* B - - 58.4*

PHc(µg/l) 1m - - 28.9* Phenols (µg/l) S - - 103.2*

Table 5.2.7: Water quality at station 8 (coastal waters off Kuranga) during April-May 2012.

Parameter Level Min Max Av

Temperature (oC) S 27.2 27.2 27.2 B 27.4 27.4 27.4 (30.5) (30.5) (30.5)

pH S 8.0 8.1 8.1 B 8.0 8.1 8.1

SS(mg/l) S - - 25* B - - 29*

Salinity(ppt) S 35.3 35.7 35.5 B 35.3 35.5 35.4

DO (mg/l) S 6.7 7.0 6.9 B 5.1 5.4 5.3

BOD (mg/l) S - - 1.0 B - - -

PO43--P(µmol/l)

S 0.2 0.2 0.2 B 1.2 1.2 1.2

TP (µmol/l) S - - 0.3* B - - 1.4*

NO3--N (µmol/l)

S 5.3 6.0 5.7 B 5.5 6.4 6.0

NO2--N(µmol/l)

S 0.4 0.4 0.4 B 1.4 1.5 1.5

NH4+-N(µmol/l)

S 0.5 0.5 0.5 B 0.1 0.2 0.1

TN (µmol/l) S - - 12.0* B - - 34.4*

PHc(µg/l) 1m - - 6.8* Phenols (µg/l) S - - 139.2*

Air temperature in parenthesis * Single value

Table 5.2.8: Water quality at station 9 (coastal waters off Kuranga) during April-May 2012.

Air temperature in parenthesis * Single value    

Parameter Level Min Max Av

Temperature ( oC ) S 26.9 26.9 26.9 B 25.3 25.3 25.3 (28.4) (28.4) (28.4)

pH S 8.1 8.2 8.2 B 8.2 8.2 8.2

SS(mg/l) S - - 165* B - - 200*

Salinity(ppt) S 35.2 35.3 35.3 B 35.2 35.3 35.3

DO (mg/l) S 7.4 7.4 7.4 B 6.7 7.0 6.9

BOD (mg/l) S - - 3.8* B - - 3.8*

PO43--P(µmol/l)

S 0.2 0.2 0.2 B 0.8 0.8 0.8

TP (µmol/l) S - - 0.6* B - - 1.5*

NO3--N (µmol/l)

S 1.0 1.2 1.1 B 2.7 2.7 2.7

NO2--N(µmol/l)

S ND ND ND B 0.2 0.2 0.2

NH4+-N(µmol/l)

S 0.2 0.8 0.5 B 0.8 0.8 0.8

TN (µmol/l) S - - 31.1* B - - 12.2*

PHc(µg/l) 1m - - 32.8* Phenols (µg/l) S - - 111.4*

Table 5.2.9: Water quality at station 1 (coastal waters off Kuranga) during September 2012.

Parameter Level Min Max Av

Temperature (oC)

S 28.4 29.5 28.9 (29.0) (31.0) (30.1)

pH S 8.1 8.2 8.2 SS (mg/l) S 108 121 114

Salinity (ppt) S 36.5 36.6 36.5 DO (mg/l) S 6.4 6.7 6.6

BOD (mg/l) S - - 2.1* PO4

3--P (µmol/l)- S 0.8 1.4 1.1 TP (µmol/l) S - - 2.0*

NO3--N (µmol/l) S 3.1 5.5 4.0

NO2--N (µmol/l) S 0.2 0.3 0.2

NH4+-N (µmol/l) S 0.4 0.6 0.5

TN (µmol/l) S - - 57.2* PHc (µg/l) 1m - - 3.0*

Phenols (µg/l) S - - 98.3* Air temperature in parenthesis * Single value

Table 5.2.10: Water quality at station 4: flood (coastal waters off Kuranga) during September 2012.

Parameter Level Min Max Av

Temperature (oC) S 28.8 28.8 28.8 (29.0) (29.0) (29.0)

pH S 8.1 8.2 8.2 SS(mg/l) S - - 104*

Salinity(ppt) S 36.1 36.3 36.2 DO (mg/l) S 6.4 6.4 6.4

BOD (mg/l) S - - 0.6* PO4

3--P (µmol/l)- S 1.0 1.4 1.2 TP (µmol/l) S - - -

NO3--N (µmol/l) S 1.9 2.2 2.0

NO2--N(µmol/l) S 0.3 0.3 0.3

NH4+-N(µmol/l) S 1.4 1.6 1.5

TN (µmol/l) S - - 42.2* PHc(µg/l) 1m - - 5.3*

Phenols (µg/l) S - - 125.0* Air temperature in parenthesis * Single value

Table 5.2.11: Water quality at station 4: ebb (coastal waters off Kuranga) during September 2012.

Parameter Level Min Max Av

Temperature (oC) S 29.6 29.6 29.6

(32.5) (32.5) (32.5) pH S 8.2 8.2 8.2

SS(mg/l) S - - 123* Salinity(ppt) S 36.3 36.3 36.3 DO (mg/l) S 6.7 7.0 6.9

BOD (mg/l) S - - 4.5* PO4

3--P (µmol/l)- S 1.5 1.6 1.5 TP (µmol/l) S - - 1.7*

NO3--N (µmol/l) S 4.6 5.2 4.9

NO2--N (µmol/l) S 0.2 0.3 0.2

NH4+-N(µmol/l) S 2.0 2.2 2.1

TN (µmol/l) S - - 59.8* PHc(µg/l) 1m - - 1.4*

Phenols (µg/l) S - - 106.1* Air temperature in parenthesis * Single value

Table 5.2.12: Water quality at station 7 (coastal waters off Kuranga) during September 2012.

Parameter Level Min Max Av

Temperature (oC) S 28.1 28.3 28.2 (28.0) (28.5) (28.3)

pH S 8.1 8.3 8.2 SS(mg/l) S 101 112 107

Salinity(ppt) S 35.7 37.0 36.5 DO (mg/l) S 6.4 6.7 6.5

BOD (mg/l) S 0.3 6.7 4.8 PO4

3--P (µmol/l)- S 1.2 1.7 1.5 TP (µmol/l) S 1.9 2.2 2.1

NO3--N (µmol/l) S 2.8 4.7 4.0

NO2--N (µmol/l) S 0.4 0.6 0.5

NH4+-N(µmol/l) S 1.0 1.5 1.3

TN (µmol/l) S 44.7 57.4 51.0 PHc(µg/l) 1m 0.2 3.2 1.7

Phenols (µg/l) S 72.0 126.0 99.0 Air temperature in parenthesis * Single value

Table 5.2.13: Water quality at station 1(coastal waters off Kuranga) during December 2012.

Parameter Level Min Max Av

Temperature (oC) S 22.0 25.2 24.1 B 21.6 24.9 24.0 (20.5) (26.0) (24.4)

pH

S 8.0 8.1 8.0 B 8.0 8.1 8.0

SS (mg/l) S 17 19 18 B 16 18 17

Salinity (ppt) S 35.9 36.3 36.0 B 35.9 36.1 36.1

DO (mg/l) S 6.7 7.0 6.8 B 6.7 7.0 6.9

BOD (mg/l) S 1.9 2.2 2.1 B 0.6 1.9 1.3

PO43—P (µmol/l)

S 0.8 1.4 1.0 B 0.8 1.4 1.2

TP (µmol/l) S 1.8 2.5 2.1 B 2.2 2.6 2.4

NO3--N (µmol/l)

S 4.8 8.4 7.1 B 5.2 7.0 6.0

NO2—N (µmol/l)

S 1.9 2.2 2.0 B 1.5 1.9 1.7

NH4+-N (µmol/l)

S 0.3 0.9 0.7 B 0.4 0.8 0.7

TN (µmol/l) S 166.0 178.5 172.3 B 157.3 182.5 169.9

PHc (µg/l) 1m 5.2 13.4 9.3 Phenols (µg/l) S 107.3 115.0 111.1

Air temperature in parenthesis * Single value

Table 5.2.14: Water quality at station 2 (coastal waters off Kuranga) during December 2012.

Air temperature in parenthesis * Single value 

Parameter Level Min Max Av

Temperature ( oC ) S 25.3 25.3 25.3 B 24.3 24.3 24.3 (26.0) (26.0) (26.0)

pH

S 8.0 8.0 8.0 B 8.1 8.1 8.1

SS(mg/l) S - - 21* B - - 18*

Salinity(ppt) S 36.1 36.1 36.1 B 36.1 36.3 36.2

DO (mg/l) S 6.3 6.3 6.3 B 6.7 6.7 6.7

BOD (mg/l) S - - 1.6* B - - 0.6*

PO43--P(µmol/l)

S 1.7 1.8 1.8 B 1.4 1.4 1.4

TP (µmol/l) S - - 2.4* B - - 2.4*

NO3--N (µmol/l)

S 5.9 6.1 6.0 B 6.8 7.1 7.0

NO2--N(µmol/l)

S 1.5 1.6 1.6 B 1.4 1.5 1.4

NH4+-N(µmol/l)

S 1.4 1.5 1.5 B 0.9 1.3 1.1

TN (µmol/l) S - - 119.1* B - - 122.1*

PHc(µg/l) 1m - - 12.0* Phenols (µg/l) S - - 103.0*

Table 5.2.15: Water quality at station 3 (coastal waters off Kuranga) during December 2012.

Parameter Level Min Max Av

Temperature (oC) S 24.9 24.9 24.9 B 24.2 24.2 24.2 (25.5) (25.5) (25.5)

pH

S 8.1 8.1 8.1 B 8.1 8.1 8.1

SS(mg/l) S - - 19.0* B - - 19.2*

Salinity(ppt) S 36.1 36.1 36.1 B 36.3 36.3 36.3

DO (mg/l) S 6.3 6.7 6.5 B 6.7 7.0 6.8

BOD (mg/l) S - - 1.9* B - - 1.3*

PO43--P(µmol/l)

S 0.9 0.9 0.9 B 1.3 1.4 1.4

TP (µmol/l) S - - 1.8* B - - 2.2*

NO3--N (µmol/l)

S 5.8 6.4 6.1 B 4.3 6.7 5.5

NO2--N(µmol/l)

S 1.8 1.9 1.9 B 1.9 1.9 1.9

NH4+-N(µmol/l)

S 1.2 1.4 1.3 B 0.7 0.9 0.8

TN (µmol/l) S - - 95.6* B - - 107.9*

PHc(µg/l) 1m - - 10.7* Phenols (µg/l) S - - 95.5*

Air temperature in parenthesis * Single value 

Table 5.2.16: Water quality at station 4 (coastal waters off Kuranga) during December 2012.

Parameter Level Min Max Av

Temperature (oC) S 24.5 26.7 25.7 B 23.9 26.4 25.2 (21.0) (28.5) (25.5)

pH

S 8.2 8.3 8.3 B 8.2 8.3 8.3

SS(mg/l) S 21 23 22 B 17 21 19

Salinity(ppt) S 35.9 36.1 36.1 B 36.3 36.5 36.4

DO (mg/l) S 6.0 6.7 6.3 B 6.3 6.7 6.6

BOD (mg/l) S 0.6 1.3 1.0 B 0.3 0.6 0.5

PO43--P(µmol/l)

S 0.4 0.8 0.7 B 0.4 0.9 0.7

TP (µmol/l) S 1.7 2.0 1.8 B 1.8 1.9 1.8

NO3--N (µmol/l)

S 2.6 6.5 3.9 B 8.4 8.4 8.4

NO2--N(µmol/l)

S 0.2 0.4 0.3 B 0.2 0.4 0.3

NH4+-N(µmol/l)

S 0.5 1.1 0.8 B 0.5 1.1 0.8

TN (µmol/l) S 74.1 82.7 78.4 B 75.6 97.4 86.5

PHc(µg/l) 1m 13.7 18.1 15.9 Phenols (µg/l) S 91.4 137.0 114.2

Air temperature in parenthesis * Single value 

Table 5.2.17: Water quality at station 5 (coastal waters off Kuranga) during December 2012.

Parameter Level Min Max Av

Temperature (oC) S 25.5 25.5 25.5 B 24.9 24.9 24.9 (26.0) (26.0) (26.0)

pH

S 8.0 8.0 8.0 B 8.0 8.1 8.1

SS(mg/l) S - - 18.7* B - - 16.0*

Salinity(ppt) S 36.1 36.1 36.1 B 36.3 36.3 36.3

DO (mg/l) S 6.7 6.7 6.7 B 7.0 7.0 7.0

BOD (mg/l) S - - 1.9* B - - 1.0*

PO43--P(µmol/l)

S 1.4 1.5 1.4 B 1.1 1.3 1.2

TP (µmol/l) S - - 2.5* B - - 2.2*

NO3--N (µmol/l)

S 8.2 8.5 8.4 B 8.4 8.7 8.6

NO2--N(µmol/l)

S 1.2 1.2 1.2 B 1.3 1.3 1.3

NH4+-N(µmol/l)

S 1.3 1.4 1.4 B 0.9 1.1 1.0

TN (µmol/l) S - - 125.9* B - - 146.9*

PHc(µg/l) 1m - - 15.2* Phenols (µg/l) S - - 126.7*

Air temperature in parenthesis * Single value

Table 5.2.18: Water quality at station 6 (coastal waters off Kuranga) during December 2012.

Air temperature in parenthesis * Single value

Parameter Level Min Max Av

Temperature ( oC ) S 24.6 24.6 24.6 B 24.2 24.2 24.2 (25.0) (25.0) (25.0)

pH

S 8.0 8.0 8.0 B 8.1 8.1 8.1

SS(mg/l) S - - 18* B - - 19*

Salinity(ppt) S 36.3 36.3 36.3 B 36.3 36.3 36.3

DO (mg/l) S 6.3 6.3 6.3 B 6.7 6.7 6.7

BOD (mg/l) S - - 1.9* B - - 1.0*

PO43--P(µmol/l)

S 1.1 1.2 1.2 B 1.3 1.4 1.4

TP (µmol/l) S - - 2.2* B - - 2.6*

NO3--N (µmol/l)

S 9.8 10.2 10.0 B 8.0 9.5 8.7

NO2--N(µmol/l)

S 0.5 0.6 0.6 B 0.6 0.6 0.6

NH4+-N(µmol/l)

S 1.1 1.1 1.1 B 0.7 0.9 0.8

TN (µmol/l) S - - 192.7* B - - 195.0*

PHc(µg/l) 1m - - 9.8* Phenols (µg/l) S - - 84.2*

Table 5.2.19: Water quality at station 7 (coastal waters off Kuranga) during December 2012.

Parameter Level Min Max Av

Temperature (oC) S 25.9 25.9 25.9 B 25.7 25.7 25.7 (26.5) (26.5) (26.5)

pH

S 8.1 8.1 8.1 B 8.2 8.2 8.2

SS(mg/l) S - - 23* B - - 19*

Salinity(ppt) S 36.6 36.6 36.6 B 36.8 36.8 36.8

DO (mg/l) S 6.3 6.3 6.3 B 6.7 6.7 6.7

BOD (mg/l) S - - 1.3* B - - 1.0*

PO43--P(µmol/l)

S 0.4 0.8 0.6 B 0.8 0.9 0.9

TP (µmol/l) S - - 1.6* B - - 1.4*

NO3--N (µmol/l)

S 6.3 6.8 6.5 B 8.0 9.4 8.7

NO2--N(µmol/l)

S 0.2 1.3 0.8 B 0.5 0.5 0.5

NH4+-N(µmol/l)

S 1.5 1.6 1.6 B 0.9 1.0 0.9

TN (µmol/l) S - - 100.7* B - - 104.1*

PHc(µg/l) 1m - - 19.4* Phenols (µg/l) S - - 93.8*

Air temperature in parenthesis * Single value 

Table 5.2.20: Water quality at station 8 (coastal waters off Kuranga) during December 2012.

Parameter Level Min Max Av

Temperature (oC) S 24.4 24.4 24.4 B 24.6 24.6 24.6 (24.5) (24.5) (24.5)

pH

S 8.0 8.1 8.1 B 8.1 8.1 8.1

SS(mg/l) S - - 18* B - - 18*

Salinity(ppt) S 36.1 36.1 36.1 B 36.3 36.3 36.3

DO (mg/l) S 6.3 6.3 6.3 B 6.7 6.7 6.7

BOD (mg/l) S - - 1.6* B - - 0.6*

PO43--P(µmol/l)

S 0.9 1.0 0.9 B 1.2 1.3 1.3

TP (µmol/l) S - - 1.8* B - - 2.1*

NO3--N (µmol/l)

S 8.4 8.7 8.6 B 8.9 9.2 9.1

NO2--N(µmol/l)

S 1.9 1.9 1.9 B 1.9 1.9 1.9

NH4+-N(µmol/l)

S 0.8 1.1 0.9 B 1.0 1.2 1.1

TN (µmol/l) S - - 151.6* B - - 159.4*

PHc(µg/l) 1m - - 7.3* Phenols (µg/l) S - - 125.0*

Air temperature in parenthesis * Single value 

Table 5.2.21: Water quality at station 9 (coastal waters off Kuranga) during December 2012.

Parameter Level Min Max Av

Temperature (oC) S 25.1 25.1 25.1 B 25.1 25.1 25.1 (30.0) (30.0) (30.0)

pH

S 8.0 8.0 8.0 B 8.0 8.1 8.1

SS(mg/l) S - - 22* B - - 20*

Salinity(ppt) S 36.1 36.1 36.1 B 36.3 36.3 36.3

DO (mg/l) S 6.3 6.7 6.5 B 6.7 6.7 6.7

BOD (mg/l) S - - 1.9* B - - 1.0*

PO43--P(µmol/l)

S 1.1 1.2 1.1 B 1.5 1.5 1.5

TP (µmol/l) S - - 1.8* B - - 2.0*

NO3--N (µmol/l)

S 11.2 11.7 11.5 B 10.1 10.1 10.1

NO2--N(µmol/l)

S 0.6 0.7 0.7 B 0.6 0.7 0.6

NH4+-N(µmol/l)

S 1.0 1.1 1.0 B 1.1 1.3 1.2

TN (µmol/l) S - - 145.2* B - - 159.0*

PHc(µg/l) 1m - - 7.8* Phenols (µg/l) S - - 86.6*

Air temperature in parenthesis * Single value

Table 5.3.1: Sediment quality of coastal environment off Kuranga during April- May 2012

Dry wt basis except PHc which is wet wt.

Table 5.3.2: Sediment quality of coastal environment off Kuranga during September 2012

Dry wt basis except PHc which is wet wt.

Station/ transect

Sand (%)

Silt (%)

Clay (%)

Al (%)

Cr (μg/g)

Mn (μg/g)

Fe (%)

Co (μg/g)

Ni (μg/g)

Cu (μg/g)

Zn (μg/g)

Hg (μg/g)

Corg (%)

P (μg/g)

PHc (µg/g)

Intertidal I 99.2 0.4 0.4 0.2 16 127 0.1 1 5 6 5 0.01 0.2 1035 0.2 II 98.6 0.6 0.8 0.2 16 134 0.1 1 5 6 4 0.02 0.2 818 0.2 III 99.6 0.2 0.2 0.2 16 91 0.1 1 5 5 5 0.01 0.1 950 0.6

Station/ transect

Sand (%)

Silt (%)

Clay (%)

Al (%)

Cr (μg/g)

Mn (μg/g)

Fe (%)

Co (μg/g)

Ni (μg/g)

Cu (μg/g)

Zn (μg/g)

Hg (μg/g)

Corg (%)

P (μg/g)

PHc (µg/g)

Subtidal 1 97.6 1.0 1.4 0.1 10 89 0.2 1 3 ND 6 ND 0.3 872 0.1 4 96.0 3.4 0.6 0.2 10 89 0.3 1 3 ND 8 ND 0.2 1170 0.1 7 99.2 0.2 0.6 0.2 11 90 0.3 1 3 ND 8 ND 0.3 1210 0.1

Inertidal I 96.0 2.8 1.2 0.2 11 94 0.3 1 3 ND 10 ND 0.2 1514 0.1 II 98.4 1.2 0.4 0.2 9 84 0.2 1 3 ND 7 ND 0.2 1135 0.2 III 98.4 1.0 0.6 0.2 9 81 0.2 1 3 ND 7 ND 0.3 993 0.1

Table 5.3.3: Sediment quality of coastal environment off Kuranga during December 2012 Station/ transect

Sand (%)

Silt (%)

Clay (%)

Al (%)

Cr (μg/g)

Mn (μg/g)

Fe (%)

Co (μg/g)

Ni (μg/g)

Cu (μg/g)

Zn (μg/g)

Hg (μg/g)

Corg (%)

P (μg/g)

PHc (µg/g)

Subtidal 2 1.3 89.1 9.6 6.8 114 507 4.9 20 46 43 73 0.03 1.6 893 0.3 3 10.4 88.8 0.8 6.2 107 454 4.9 20 43 45 64 0.04 1.7 938 0.9 4 1.9 89.7 8.4 7.2 112 517 4.9 19 48 41 76 0.04 1.5 898 1.4 5 0.2 89.0 10.8 7.1 124 515 5.3 21 51 47 74 0.02 1.7 894 0.2 6 1.2 97.4 1.4 6.0 106 449 4.9 19 42 44 62 0.03 1.7 912 0.4 8 4.4 95.0 0.6 6.9 121 512 5.2 21 48 48 75 0.02 1.7 942 0.2 9 13.4 83.2 3.4 6.7 120 485 5.3 22 49 49 72 0.01 1.9 942 0.5

Intertidal I 91.0 8.2 0.8 0.2 10 171 0.2 1 1 1 1 0.01 0.2 967 0.2 II 91.8 5.8 2.4 0.2 11 118 0.2 1 1 1 1 0.01 0.1 1021 0.1 III 98.4 1.0 0.6 0.3 9 110 0.3 1 1 1 2 ND 0.2 1250 0.2

Dry wt basis except PHc which is wet wt.

 

Table 5.4.1: Microbial counts in waters (CFU/ml) and sediment (CFU/g) at station 4 in coastal waters off Kuranga during December 2012.

Type of bacteria

Water Eb Fl

TVC (X102) 2500 1600 TC 30 ND FC ND ND

ECLO ND ND SFLO ND ND

sediment TVC (X104) 300

TC ND FC ND

ECLO ND SFLO ND

Table 5.4.2: Range and average (parenthesis) of phytopigments at different

stations in coastal waters off Kuranga during April-May 2012.

Station Date Chlorophyll a

(mg/m3) Phaeophytin

(mg/m3) Ratio of Chl a

to Phaeo S B S B S B

1 03.05.12 4.2-8.9 (7.1)

4.2-7.9 (6.5)

1.2-3.9 (3.1)

3.7-5.2 (4.2)

2.1-3.6 (2.6)

0.8-2.1 (1.7)

2 05.05.12

1.9-2.0 (2.0)

5.7-6.0 (5.9)

0.7-0.7 (0.7)

4.7-5.8 (5.3)

2.9-2.9 (2.9)

1.0-1.3 (1.2)

3 05.05.12

1.3-1.4 (1.4)

1.3-1.5 (1.5)

0.6-0.8 (0.7)

0.6-0.8 (0.7)

1.7-2.6 (2.2)

2.0-2.2 (2.1)

4 30.04.12

1.9-3.7 (2.5)

1.6-2.6 (2.2)

1.1-3.1 (1.8)

1.7-2.4 (2.0)

1.1-1.9 (1.4)

1.0-1.2 (1.1)

5 06.05.12

0.9-1.0 (1.0)

7.0-7.4 (7.2)

0.3-0.5 (0.4)

5.5-5.7 (5.6)

2.1-3.3 (2.7)

1.3-1.3 (1.3)

7 01.05.12 3.0-3.2 (3.1)

5.0-5.2 (5.1)

2.1-2.6 (2.4)

4.7-5.1 (4.9)

1.2-1.4 (1.3)

1.0-1.1 (1.1)

8 01.05.12 2.8-2.8 (2.8)

3.2-3.6 (3.4)

1.3-2.2 (1.8)

2.0-2.4 (2.2)

1.3-2.1 (1.7)

1.5-1.6 (1.6)

9 06.05.12 0.7-0.7 (0.7)

28.6-30.6 (29.6)

0.2-0.3 (0.3)

4.6-4.7 (4.7)

2.3-3.4 (2.9)

6.2-6.5 (6.4)

Table 5.4.3: Range and average (parenthesis) of phytopigments in coastal

waters off Kuranga during September 2012.

Station Date Chlorophyll a

(mg/m3) Phaeophytin

(mg/m3) Ratio of Chl a

to Phaeo S S S

1 10.09.2012 0.4-1.2 (0.7)

0.3-1.1 (0.6)

1.1-1.2 (1.2)

4 09.09.2012 0.1-0.8 (0.4)

0.2-0.4 (0.2)

0.3-4.2 (1.5)

7 12.09.2012 0.2-0.6 (0.3)

0.2-0.5 (0.3)

0.8-1.2 (1.0)

 

Table 5.4.4: Range and average (parenthesis) of phytopigments at different stations in coastal waters off Kuranga during December 2012.

Station Date Chlorophyll a

(mg/m3) Phaeophytin

(mg/m3) Ratio of Chl a

to Phaeo S B S B S B

1 28.12.12 0.2-0.6 (0.4)

0.2-0.4 (0.3)

0.2-0.4 (0.2)

0.1-0.2 (0.2)

1.4-1.9 (1.6)

1.6-1.9 (1.8)

2 27.12.12 0.6-0.6 (0.6)

0.5-0.6 (0.6)

0.4-0.4 (0.4)

0.3-0.4 (0.3)

1.5-1.6 (1.6)

1.6-1.8 (1.7)

3 27.12.12 0.3-0.4 (0.4)

0.1-0.2 (0.2)

0.2-0.2 (0.2)

0.1-0.1 (0.1)

1.8-1.8 (1.8)

1.8-1.8 (1.8)

4 16.12.12 3.4-7.6 (5.9)

1.9-6.6 (4.6)

2.7-5.5 (4.3)

0.9-5.3 (3.4)

1.1-1.8 (1.4)

1.1-1.9 (1.4)

5 27.12.12 0.2-0.2 (0.2)

0.2-0.4 (0.3)

0.1-0.1 (0.1)

0.1-0.2 (0.2)

1.5-1.8 (1.7)

1.6-1.8 (1.7)

6 27.12.12 0.1-0.2 (0.2)

0.1-0.1 (0.1)

0.1-0.1 (0.1)

0.1-0.1 (0.1)

1.8-1.9 (1.8)

1.7-1.8 (1.8)

7 15.12.12 0.7-0.7 (0.7)

0.6-0.6 (0.6)

0.5-0.5 (0.5)

0.4-0.4 (0.4)

1.5-1.6 (1.5)

1.6-1.6 (1.6)

8 27.12.12 0.1-0.1 (0.1)

0.1-0.1 (0.1)

0.1-0.1 (0.1)

0.1-0.1 (0.1)

1.7-1.8 (1.8)

1.8-2.0 (1.9)

9 27.12.12 0.1-0.2 (0.2)

0.1-0.1 (0.1)

0.1-0.1 (0.1)

0.04-0.1 (0.06)

1.7-1.9 (1.8)

1.5-1.5 (1.5 )

Table 5.4.5: Range and average (parenthesis) of phytoplankton population at

different stations in coastal waters off Kuranga during April-May 2012.

Station Date

Cell count (no x 103/l)

Total genera

(no) Major genera

S B S B S B

1 03.05.12 415.2* 419.2* 18* 16*

Nitzschia Skeletonema Guinardia Rhizosolenia

Nitzschia Skeletonema Biddulphia Chaetoceros

2 05.05.12 202.4* 572.0* 14* 17*

Chaetoceros Nitzschia Thalassiosira Navicula

Nitzschia Chaetoceros Skeletonema Guinardia

3 05.05.12 140.0* 135.0* 11* 11*

Chaetoceros Nitzschia Guinardia Rhizosolenia

Chaetoceros Nitzschia Guinardia Peridinium

4 30.04.12 210.4* 201.0* 16* 14*

Nitzschia Protoperidinium Chaetoceros Peridinium

Nitzschia Navicula Pleurosigma Surirella

5 06.05.12 85.6* 687.0* 12* 19*

Nitzschia Chaetoceros Skeletonema Synedra

Nitzschia Skeletonema Guinardia Rhizosolenia

7 01.05.12 290.0* 497.1* 14* 13*

Nitzschia Protoperidinium Skeletonema Navicula

Nitzschia Biddulphia Navicula Chaetoceros

8 01.05.12 261.3* 344.0* 13* 19*

Nitzschia Protoperidinium Synedra Skeletonema

Nitzschia Chaetoceros Skeletonema Synedra

9 06.05.12 71.0* 2812.0* 15* 16*

Nitzschia Skeletonema Cyclotella Rhizosolenia

Nitzschia Skeletonema Guinardia Rhizosolenia

*single value

Table 5.4.6: Range and average (parenthesis) of phytoplankton population at

different stations in coastal waters off Kuranga during September 2012.

Station Date Cell count (no x 103/ l)

Total genera (no) Major genera

S S S

1 10.09.2012 45.5-100.0

(66.9)

7-9 (8)

Thalassiosira Navicula Melosira Surirella

4 09.09.2012 8.8-73.7 (41.3)

7-10 (9)

Navicula Licmophora Thalassiosira Cyclotella

7 12.09.2012 23.0-37.6 (28.9)

11-13 (12)

Navicula Gramatophora Thalassiosira Melosira

Table 5.4.7: Range and average (parenthesis) of phytoplankton population at

different stations in coastal waters off Kuranga during December 2012.

*single value

Station Date Cell count (no x 103/l)

Total genera(no) Major genera

S B S B S B

1 28.12.12

42.4-56.0

(49.2)

30.4-37.6 (34)

12-13(12)

7-14(11)

Nitzschia Thalassionema Chataeceros Thalassiosira

Nitzschia Thalassiosira Thalassionema Navicula

2 27.12.12 57.6* 66.4* 15* 12*

Chataeceros Prorocentrum Thalassionema Nitzschia

Chataeceros Nitzschia Guinardia Navicula

3 27.12.12 32.0* 27.2* 12* 11*

Chataeceros Nitzschia Protoperidinium Prorocentrum

Chataeceros Nitzschia Peridinium Navicula

4 16.12.12

438.4-846.4

(642.4)

143.2-686.4

(414.8)

12-15(14)

11-11(11)

Chataeceros Navicula Nitzschia Rhizosolenia

Chataeceros Navicula Nitzschia Leptocylindrus

5 27.12.12 26.4* 32.8* 9* 10*

Nitzschia Prorocentrum Chaetoceros Peridinium

Nitzschia Prorocentrum Thalassiosira Peridinium

6 27.12.12 24.0* 21.6* 9* 12*

Nitzschia Prorocentrum Thalassionema Thalassiosira

Thalassionema Thalassiosira Chataeceros Nitzschia

7 15.12.12 81.6* 6.0* 15* 10*

Chataeceros Nitzschia Navicula Leptocylindrus

Chataeceros Nitzchia Navicula Rhizosolenia

8 27.12.12 13.60* 16.0* 9* 9*

Nitzschia Skeletonema Cyclotella Rhizosolenia

Nitzschia Skeletonema Guinardia Rhizosolenia

9 27.12.12 20.8 15.2 10 8

Navicula Thalassiosira Nitzschia Thalassionema

Nitzshia Navicula Thalassiosira Rhizosolenia

Table 5.4.8: Percentage composition of phytoplankton population at different

stations in coastal waters off Kuranga during April-May 2012.

Algal genera Station 1 2 3 4 5 7 8 9

Amphora 0.1 - - - - - - - Amphiprora - 0.1 - - - 0.2 - - Asterionella 0.1 - - - 0.1 - - - Bacteriastrum - 0.1 0.4 0.3 0.4 - - - Biddulphia 1.1 0.1 0.3 1.0 0.6 4.2 3.9 0.1 Ceratium - - - - 0.1 - 0.9 - Chaetoceros 1.3 19.4 54.8 3.3 1.8 0.9 8.3 - Coscinodiscus - 0.1 - 0.3 0.1 0.3 0.3 - Cyclotella - 0.2 - 2.6 - 0.7 5.0 0.2 Diploneis - - - 2.6 - 0.2 0.3 - Distephanus 0.1 - - - 0.1 - 0.7 - Ditylum - 0.1 - 1.3 - 0.8 3.3 - Guinardia 1.6 1.9 5.2 2.3 3.5 - 0.6 1.1 Gyrosigma 0.1 - - - - 0.2 - - Meuniera - 0.2 - - 0.1 - - - Navicula 0.8 0.7 - 6.8 0.5 3.6 2.9 0.2 Neodenticula - - - 0.3 - - - - Nitzschia 83.0 68.7 33.1 53.5 80.6 69.2 39.6 93.9 Noctiluca - - - - - 0.4 0.7 - Oscillatoria - 0.1 - - - - - - Peridinium 0.5 0.1 0.7 3.3 0.2 2.3 3.2 0.3 Pleurosigma 0.2 - - 4.2 0.1 0.2 0.7 - Prorocentrum 0.2 - - 1.6 - 0.3 0.2 - Protoperidinium 0.7 0.2 1.0 6.8 0.5 7.6 7.1 0.3 Pyrophacus 0.1 0.1 0.9 2.3 0.1 0.4 - - Rhizosolenia 1.2 0.4 0.9 0.7 1.4 - - 0.4 Salpingella - - 0.3 - - - - - Skeletonema 5.7 1.8 - 1.3 5.7 3.3 7.4 2.9 Streptotheca 0.1 - 0.4 - 0.5 - - - Surirella - 0.1 - 3.3 0.1 1.0 0.3 0.1 Synedra 1.2 0.1 0.6 0.3 1.1 0.5 7.8 0.1 Thalassionema - 0.6 - - - - 0.9 - Thalassiosira 1.0 3.6 0.7 1.6 1.0 2.9 2.0 0.3 Thalassiothrix 0.8 1.3 0.7 0.3 1.4 0.8 3.9 0.1 Trichodesmium 0.1 - - - - - - - Total 100 100 100 100 100 100 100 100

Table 5.4.9: Percentage composition of phytoplankton population at different stations

in coastal waters off Kuranga during September 2012.

Algal genera Station 1 4 7

Biddulphia - 4.6 4.2 Coscinodiscus 2.5 2.6 3.1 Cyclotella 3.7 2.9 1.7 Diploneis 0.5 1.6 1.6 Dictyocha - - - Fragillaria - - 6.1 Gramatophora - 1.6 18 Guinardia - - 0.9 Gyrosigma 2.2 2.6 3.3 Licmophora - 16.2 4.2 Melosira 14.5 - 8.5 Navicula 22 61.5 20.8 Neodenticula 9.7 1.0 6.1 Nitzschia 9.7 1.0 6.1 Neodenticula - - 0.9 Peridinium - - 0.9 Pleurosigma 6.7 2.6 5.0 Protoperidinium - - Surirella 9.0 1.6 4.3 Thalassiosira 27 4.2 10.4 Thalassiothrix 2.2 - - Total 100 100 100

Table 5.4.10: Percentage composition of phytoplankton population at different

stations in coastal waters off Kuranga during December 2012.    

Algal genera Station 1 2 3 4 5 6 7 8 9

Amphora - - - - - - 0.6 - - Asterionella 0.5 - - - - - - - - Bacteriastrum 1.0 - 1.4 0.2 6.8 1.8 - 8.1 2.2 Biddulphia - - - 0.2 - - 2.8 2.7 2.2 Campyloneis - - - - - 1.8 - - - Ceratium - - 1.4 - - - - - - Chaetoceros 8.2 46.4 37.8 92.1 9.5 8.8 40.7 - - Climacosphaeria - - - - - - 0.6 - - Coscinodiscus 1.4 0.6 - 0.1 1.4 1.8 - - - Diploneis 0.5 - - 0.2 1.4 1.8 0.6 5.4 2.2 Distephanus 1.0 - - 0.1 - - - - - Euglenozoa - - - - 5.4 - - 2.7 - Fragillaria - 3.2 8.1 - 1.4 - - - - Guinardia 1.0 5.5 1.4 0.5 - - 0.6 - - Gyrosigma 1.0 - - - - - - - - Hemiaulus - - - - - - 2.3 - - Leptocylindrus 2.4 3.7 - 0.7 - - 4.0 - - Lithodesmium 0.5 - - - - - - - - Navicula 6.7 5.1 5.4 2.6 6.8 7.0 9.0 21.6 22.2 Nitzschia 42.5 16.0 14.6 1.6 28.0 24.6 26.0 35.1 24.4 Oscillatoria 1.0 0.6 2.7 - - - - - - Peridinium 5.3 2.9 6.8 0.3 12.2 5.3 2.3 2.7 4.4 Pleurosigma - 1.5 - 0.3 - 5.3 2.3 5.4 6.7 Prorocentrum 3.4 7.1 4.1 0.1 16.2 12.3 - 2.7 2.2 Protoperidinium 1.9 0.6 5.4 0.1 1.4 - - 5.4 2.2 Rhizosolenia 0.5 0.8 2.7 0.7 - - 2.8 - 6.7 Salpingella - - - - - 1.8 2.3 - - Stauroneis 0.5 - - - - - - 2.7 - Streptotheca - - - - - 1.4 - - - Stephanodiscus - 0.6 - - - - - - - Surirella - 0.8 - - - - - - - Thalassionema 11.1 7.4 2.7 - - 14.0 0.6 - 6.7 Thalassiosira 9.1 2.1 4.1 0.2 9.5 12.3 2.5 5.5 17.9 Thalassiothrix 0.5 0.6 1.4 - - - - - -

Total 100 100 100 100 100 100 100 100 100

Table 5.4.11: Range and average (parenthesis) of zooplankton standing stock at

different stations in coastal waters off Kuranga during April-May 2012.

Station (Date)

Biomass (ml/100 m3)

Population (no x 103/100

m3)

Total groups

(no) Major groups

(%)

1 (03.05.2012)

0.4-1.3 (0.8)

0.8-16.3 (8.1)

6-10 (7)

Copepods (59.7), cladocera (32.4), appendicularians (4.0), decapod larvae (3.3), lamellibranchs (0.3), fish eggs (0.2), others (0.1).

2 (05.05.2012)

0.8-0.9 (0.9)

11.3-12.1 (11.7)

6-7 (7)

Cladocera (72.5), copepods (25.2), fish eggs (1.9), decapod larvae (0.1), appendicularians (0.1), chaetognaths (0.1), others (0.1).

3 (05.05.2012)

1.2-1.4 (1.3)

10.6-19.6 (15.1)

4-5 (5)

Cladocera (84.2), copepods (15.3), decapod larvae (0.3), fish eggs (0.1), others (0.1).

4 (30.04.2012)

0.04-0.8 (0.3)

0.3-2.0 (0.9)

4-11 (6)

Copepods (95.7), fish eggs (2.2), foraminiferans (0.6), lamellibranchs (0.3), siphonophores (0.2), chaetognaths. (0.2), decapod larvae (0.2), fish larvae (0.2), appendicularians (0.1), polychaetes (0.1), cladocera (0.1), Others (0.1).

5 (06.05.2012)

1.0-1.4 (1.2)

11.2-14.1 (1.26)

9-11 (10)

Cladocera (51.4), copepods (46.9), appendicularians (0.8), fish eggs (0.4), siphanophores (0.1), chaetognaths (0.1), decapod larvae (0.1), fish larvae (0.1), Others (0.1).

Table 5.4.11: (Continue) 

Station (Date)

Biomass (ml/100 m3)

Population (no x 103/100

m3)

Total groups

(no)

Major groups (%)

7 (01.05.2012)

0.5-1.2 (0.9)

5.7-15.5 (10.6)

13-16 (15)

Copepods (80.5), cladocera (17.6), appendicularians (0.9), fish eggs (0.3), lamellibranchs (0.3), decapod larvae (0.1), siphanophores (0.1), gastropods (0.1), others (0.1).

8 (01.05.2012)

0.9-1.1 (1.0)

8.0-8.1 (8.0)

10-11 (11)

Cladocera (56.0), copepods (39.9), fish eggs (1.9), appendicularians (1.6), decapod larvae (0.3), siphanophores (0.2), others (0.1).

9 (06.05.2012)

1.1-1.4 (1.3)

6.6-11.4 (9.0)

14-14 (14)

Copepods (51.8), cladocera (42.1), appendicularians (2.2), siphanophores (2.2), chaetognaths (1.0), fish eggs (0.3), fish larvae (0.1), decapod larvae (0.1), lamellibranches (0.1), others (0.1).

Table 5.4.12: Range and average (parenthesis) of zooplankton standing stock at

different stations in coastal waters off Kuranga during September 2012

Station (Date)

Biomass (ml/100

m3)

Population (no x 103/100

m3)

Total groups

(no)

Major groups (%)

1 (11.09.2012)

0.1-3.7 (1.6)

0.1-0.5 (0.3) 3*

Foraminiferons (81.7), gastropods (9.2), lamellibranchs (9.1), others (0.0).

7 (12.09.2012)

<0.1-0.2 (0.2)

0.01-0.5 (0.2)

1-10 (4)

Foraminiferons (49.9), Lamellibranchs(15.4). copepods (12.8), gastropods (12.8), decapod larvae (3.7), chaetognaths (1.8), siphonophores (0.9), amphipods (0.9), isopods (0.9), marine insects (0.9), others (0.0).

Table 5.4.13: Range and average (parenthesis) of zooplankton standing stock at different stations in coastal waters off Kuranga during December 2012.

Station (Date)

Biomass (ml/100m3)

Population (no ×103/100m3)

Total groups

(no) Major groups (%)

1 (28/12/12)

0.1 – 19.2 (3.7)

0.001 –30.9 (16.5)

1-13 (9)

Copepods (91.6), foraminiferans (2.8), decapods larvae (2.2), siphonophora (1.6), lucifer sp (1.0), chaetognaths (0.6), fish eggs (0.1), others (0.1).

2 (27/12/12)

0.7-1.5 (1.1)

10.7-11.9

(11.3)

10-12 (11)

Copepods (94.8), foraminiferans (1.5), decapods larvae (1.2), fish larvae (1.2), lucifer sp (1.0), amphipods(0.1), chaetognaths (0.1), others (0.1).

3 (27/12/12)

1.8 - 5.1 ( 3.4)

6.5 – 37.4 (21.9)

8 -11 (10)

Copepods (99.3), chaetognaths (0.3), lucifer sp (0.2), others (0.2)

4 (16/12/12)

2.3-6.3 (4.2)

17.1-133.8 (64.9)

11-14 (12)

Copepods (92.5), decapods larvae (3.3), gastropods(1.0), lucifer sp (0.7), appendiculariae (0.7), lamellibranchs (0.6), foraminiferans (0.6), chaetognaths (0.3), fish eggs (0.1), polychaetes(0.1), others (0.1)

5 (27/12/12)

5.3-7.9 (6.6)

18.0-80.3 (49.2)

13 - 14 (14)

Copepods (81.1), chaetognaths (16.5), Lucifer sp (1.3), decapods larvae (0.4), fish eggs (0.3), gastropods (0.2), others (0.2).

Table 5.4.13: (Continue.)  

Station (Date)

Biomass (ml/100m3)

Population (no ×103/100m3)

Total groups

(no) Major groups (%)

6 (27/12/12)

1.0 – 1.0 (1.0)

2.6 - 2.8 (2.7)

7 – 12 (10)

Copepods (88.4), fish eggs (3.3), foraminiferans (2.8), chaetognaths (2.3), Lucifer sp (1.4), decapods larvae (1.3), siphonophora (0.3), amphipods (0.1), others (0.1).

7 (23/04/12)

1.9 – 10.0 (5.9)

16.7 – 54.6 (35.6)

15 – 18 (17)

Copepods (72.8), decapods larvae (12.7), gastropods (6.2), lamellibranchs (5.1), chaetognaths (1.6), fish eggs (0.6), polychaetes (0.3), Lucifer sp (0.2), ostracods(0.2), amphipods(0.2), others (0.1).

8 (27/12/12)

0.6-0.8 (0.7)

2.6-5.6 (4.1)

10-10 (10)

Copepods (92.3), chaetognaths (5.9), Lucifer sp (1.0), foraminiferans (0.4), fish eggs (0.1), decapods larvae (0.1), gastropods (0.1), others (0.1).

9 (27/12/12)

1.0-1.1 (1.1)

7.5-9.7 (8.6)

7-9 (8)

Copepods (95.6), chaetognaths (3.1), foraminiferans (0.5), Lucifer sp (0.4), siphonophora (0.2), fish eggs(0.1), others(0.1)

Table 5.4.14: Composition (%) of zooplankton population in coastal waters off Kuranga during April–May 2012.

Faunal group Station %

compo 1 2 3 4 5 7 8 9 Foraminiferans <0.1 - - 0.6 <0.1 <0.1 <0.1 - <0.1 Siphonophores - <0.1 - 0.3 0.1 0.1 0.2 2.2 0.3 Medusae - - - - <0.1 - <0.1 <0.1 <0.1 Ctenophores - - - - - <0.1 <0.1 <0.1 <0.1 Chaetognaths <0.1 0.1 - 0.2 0.1 - - 1.0 0.1 Polychaetes <0.1 - - 0.1 <0.1 - <0.1 <0.1 <0.1 Cladocera 32.4 72.5 84.2 0.1 51.4 17.7 56.0 42.1 52.8 Copepods 59.7 25.2 15.4 95.7 46.9 80.4 39.9 51.8 44.4 Amphipods - - - - - <0.1 - <0.1 <0.1 Mysids - - - - - - - <0.1 <0.1 Lucifer sp <0.1 - - - - <0.1 - <0.1 <0.1 Decapods 3.3 0.1 0.3 0.2 0.1 0.1 0.3 0.1 0.5 Stomatopods - - - - - - <0.1 - <0.1 Gastropods <0.1 - - <0.1 - 0.1 <0.1 <0.1 <0.1 Lamellibranchs 0.4 - - 0.3 <0.1 0.3 <0.1 0.1 0.1 Appendiculariae 4.0 0.1 <0.1 0.1 0.8 0.9 1.6 2.3 1.1 Doliolum - - - - - - - <0.1 <0.1 Fish Eggs 0.2 1.9 0.1 2.2 0.3 0.4 1.9 0.3 0.7 Fish Larvae <0.1 - - 0.2 0.1 <0.1 <0.1 0.1 <0.1 Isopods - - - - - <0.1 - - <0.1 Total 100 100 100 100 100 100 100 100 100 Table 5.4.15: Composition (%) of zooplankton population in coastal waters off

Kuranga during September 2012.

 

 

 

 

 

 

Faunal group Station % compo 1 7 Foraminiferans 81.7 49.9 64.9 Siphonophores - 0.9 0.3 Chaetognaths - 1.8 0.6

Copepods - 12.8 4.1 Amphipods - 0.9 0.3 Decapods - 3.6 1.2

Gastropods 9.2 12.8 12.5 Lamellibranchs 9.1 15.4 15.5

Isopods - 0.9 0.3 Marine Insects - 0.9 0.3

Total 100 100 100

Table 5.4.16: Composition (%) of zooplankton population in coastal waters off

Kuranga during December 2012.

Faunal group Station % compo1 2 3 4 5 6 7 8 9

Foraminiferans 2.8 1.5 <0.1 0.6 <0.1 2.8 <0.1 0.4 0.7 0.6 Siphonophora 1.6 <0.1 <0.1 <0.1 <0.1 0.3 - <0.1 0.1 0.1 Medusae <0.1 - - - - <0.1 <0.1 <0.1 - <0.1 Ctenophora - - - - - - - <0.1 - <0.1 Chaetognatha 0.6 0.1 0.3 0.3 16.5 2.3 1.6 5.9 3.3 4.5 Polychaetes <0.1 - <0.1 0.1 - <0.1 0.3 <0.1 - 0.1 Cladocera - <0.1 <0.1 <0.1 <0.1 - <0.1 - - <0.1 Ostracods - - - <0.1 - - 0.2 - - <0.1 Copepods 91.6 94.9 99.3 92.6 81.1 88.5 72.8 92.3 95.3 87.4 Cumaceans - - - <0.1 - - <0.1 - - <0.1 Amphipods <0.1 0.1 <0.1 <0.1 <0.1 0.1 0.1 - <0.1 <0.1 Mysids - - - <0.1 - - <0.1 - - <0.1 Lucifer sp 1.0 1.0 0.2 0.8 1.3 1.4 0.2 1.0 0.5 0.8 Decapods 2.2 1.2 <0.1 3.3 0.4 1.3 12.7 0.1 - 3.5 Stomatopods <0.1 - - <0.1 <0.1 <0.1 <0.1 - - <0.1 Heteropods - - - <0.1 - - - - - <0.1 Pteropods - - - - <0.1 - - - - <0.1 Cephalopods - - - - - - <0.1 - - <0.1 Gastropods <0.1 <0.1 - 1.0 0.2 - 6.2 0.1 - 1.4 Lamellibranchs <0.1 <0.1 - 0.6 <0.1 - 5.1 - - 1.0 Appendiculariae <0.1 <0.1 - 0.7 <0.1 <0.1 <0.1 - - 0.2 Fish Eggs 0.1 1.2 <0.1 0.1 0.3 3.3 0.6 0.1 0.1 0.3 Fish Larvae <0.1 <0.1 <0.1 <0.1 <0.1 - <0.1 <0.1 <0.1 <0.1 Isopods <0.1 <0.1 - <0.1 <0.1 - <0.1 - <0.1 <0.1 Total 100 100 100 100 100 100 100 100 100 100

Table 5.4.17: Total counts and incidence of decapod larvae, Acetes and Lucifer sp

and fish larvae in coastal waters off Kuranga during April - May 2012.

Station Decapod larvae Acetes Lucifer sp.

(no/100m3) Incidence (%) (no/100m3) Incidence

(%) (no/100m3) Incidence (%)

1 85-718 (267)

100 0

0 0-4 (1)

25

2 15-18 (16)

100 0 0 0 0

3 47-73 (60)

100 0 0 0 0

4 0-8 (2)

40 0 0 0 0

5 9-22 (16)

100 0 0 0 0

7 9-31 (20)

100 0 0

0-1 (1)

50

8 20-26 (23)

100 0

0 0 0

9 2-10 (6)

100 0 0 0-3 (2)

50

Average in parenthesis.

 

Table 5.4.18: Total counts and incidence of decapod larvae, Acetes and Lucifer sp

and fish larvae in coastal waters off Kuranga during September 2012

Average in parenthesis.  

Station Decapod larvae Acetes Lucifer sp.

(no/100m3) Incidence (%) (no/100m3) (no/100m3) Incidence

(%) (no/100m3)

1 0 0 0 0 0 0 7 0-18

(6) 30 0 0 0 0

Table 5.4.19: Total counts and incidence of decapod larvae, Acetes and Lucifer sp and fish larvae in coastal waters off Kuranga during December 2012.

Station Decapod larvae Acetes Lucifer sp.

(no/100m3) Incidence (%) (no/100m3) (no/100m3) Incidence

(%) (no/100m3)

1 0-1188 (359)

85 0

0 2-576 (168)

100

2 95-182 (139)

100 0 0 83-136 (109)

100

3 9-11 (10)

100 0 0 27-66 (47)

100

4 0-4177 (2153)

85 0 0 51-1873 (493)

100

5 172-235 (203)

100 0 0 646-649 (647)

100

6 32-37 (35)

100 0 0 24-52 (38)

100

7 2077-6367 (4522)

100 0 0

0-148 (74)

50

8 2-6 (4)

100 0 0 36-48 (42)

100

9 0 0 0 0 34-41 (38)

100

Average in parenthesis.   Table 5.4.20: Total counts and incidence of fish eggs and fish larvae in coastal

waters off Kuranga during April - May 2012.

Station Fish eggs Fish larvae

(no/100m3) Incidence (%) (no/100m3) Incidence

(%) 1 0-48

(17) 75 0-5

(1) 25

2 147-305 (226)

100 0 0

3 16-39 (27)

100 0 0

4 1-44 (19)

100 0-3 (1)

60

5 28-59 (44)

100 8-8 (8)

100

7 47-74 (58)

100 0-4 (2)

50

8 79-230 (155)

100 0-1 (1)

50

9 10-36 (23)

100 8-8 (8)

100

Average in parenthesis.  

Table 5.4.21: Total counts and incidence of fish eggs and fish larvae in coastal

waters off Kuranga during September 2012

Station Fish eggs Fish larvae (no/100m3) Incidence (%) (no/100m3) Incidence (%)

1 0 0 0 0 7 0 0 0 0

 

Table 5.4.22: Total counts and incidence of fish eggs and fish larvae in coastal

waters off Kuranga during December 2012

Station Fish eggs Fish larvae (no/100m3) Incidence (%) (no/100m3) Incidence (%)

1

0-74 (21) 85 0-11

(5) 70

2 55-215 (135) 100 0-5

(3) 50

3 6-6 (6) 100 2-5

(4) 100

4 2-119 (40) 100 4-50

(23) 100

5 159-176 (167) 100 5-15

(10) 100

6 15-162 (89) 100 0 0

7 30-375 (202) 100 12-12

(12) 100

8 4-6 (5) 100 0-2

(1) 50

9 5-7 (6) 100 1-2

(2) 100

Average in parenthesis.   

Table 5.4.23: Range and average (parenthesis) of intertidal macrobenthic fauna at different transects in coastal waters off Kuranga during April-May 2012.

Transect Biomass

(g/m2; wet wt.)

Population(no/m2)

Faunal groups (no)

Major group

I 0-9.2 (1.2)

0-525 (125)

0-3 (1)

Nematodes

II 0-61.0 (23.3)

0-750 (226)

0-6 (3)

Gastropods polychaetes

isopods

III 0-3.5 (0.9)

0-1000 (359)

0-4 (2)

Polychaetes isopods

Overall Average

0-61.0 (8.5)

0-1000 (237)

0-6 (2)

Polychaetes isopods

Table 5.4.24: Range and average (parenthesis) of intertidal macrobenthic fauna

at different transects in coastal waters off Kuranga during September 2012.

Transect Biomass

(g/m2; wet wt.)

Population (no/m2)

Faunal groups (no)

Major groups

I 0-36.3 (6.0)

0-375 (94)

0-4 (2)

Isopods

II 0-5.7 (1.5)

0-450 (163)

0-3 (2)

Isopods polychaetes

III 0-2.0 (0.5)

0-450 (113)

0-2 (1)

Isopods

Overall Average

0-36.3 (2.7)

0-450 (123)

0-4 (1)

Isopods

Table 5.4.25: Range and average (parenthesis) of intertidal macrobenthic fauna

at different transects in coastal waters off Kuranga during December 2012.

Transect Biomass (g/m2; wet wt.)

Population(no/m2)

Faunal groups (no) Major groups

I 0.1-9.1 (2.2)

50-7125 (1413)

1-4 (2)

Isopods.

II 0-48.8 (12.0)

0-350 (144)

0-4 (2)

Gastropods, Anomurans.

III 0.4-9.1 (1.9)

700-4475 (1475)

1-5 (2)

Mysids, polychaetes.

Overall Average

0-48.8 (5.4)

0-7125 (1011)

0-5 (2)

Isopods, Polychaetes.

Table 5.4.26: Composition (%) of intertidal macrobenthos in coastal waters off Kuranga during April- May 2012.

Faunal group Transect

Av I II III HW MW LW HW MW LW HW MW LW

Phylum Nematoda Nematodes 92.5 10.3Phylum Mollusca Amphineurans 2 5.1 1.2 Gastropods 87.1 48.8 18.7 14.1Phylum Annelida Oligochaetes 2 3.5 0.9 Polychaetes 2.5 23.5 28.7 81.5 38.4Phylum Arthropoda Amphipods 2.5 6.4 20.3 3.3 1.7 5.6 Anomurans 4.4 1.6 0.9 Brachyurans 4.4 5.1 1.5 Isopods 2.5 12.9 100 100 8.5 17 100 96.7 2.4 21.8Mysids 14.4 5.3

 

Table 5.4.27: Composition (%) of intertidal macrobenthos in coastal waters off Kuranga during September 2012.

Faunal group Transect

Av I II III HW MW LW HW MW LW HW MW LW

Phylum Nematoda Nematodes 100 0.5 Phylum Mollusca Amphineurans 13.6 NIL 0.5 Gastropods 43.3 1.7 Phylum Annelida Polychaetes 5.8 29.8 7.9 2.5 44.9 22.6Phylum Arthropoda Copepods 2.2 0.5 Isopods 100 94.2 13.6 21 87.3 97.8 55.1 71.8Ostracods 10.2 2.3

Table 5.4.28: Composition (%) of intertidal macrobenthos in coastal waters off

Kuranga during December 2012.

Faunal group Transect

Av I II III HW MW LW HW MW LW HW MW LW

Phylum Mollusca Gastropods 34 76.4 1.9 Amphineurans 1.6 0.2 9.1 0.4 Phylum Annelida Polychaetes 2.1 9.6 25.5 12.2 0.6 100 29.5 20.7Phylum Arthropoda Amphipods 1.4 0.6 5.7 0.5 0.4 Anomurans 50 5.7 1.7 Brachyurans 6.9 0.2 0.3 Cumaceans 0.4 0.1 Isopods 98.4 95.5 89.2 74.5 99.4 0.2 53.9Mysids 0.6 69.6 20.6

Table 5.4.29: Range and average (parenthesis) of subtidal macrobenthic fauna at different stations in coastal waters off Kuranga during September 2012.

Table 5.4.30: Range and average (parenthesis) of subtidal macrobenthic fauna

at different stations in coastal waters off Kuranga during December 2012

Station Biomass

(g/m2; wet wt.)

Population(no/m2)

Faunal groups (no) Major groups

1 Rocky Bottom

2 2.5-9.5 (6.8)

925-1400 (1150)

4-5 (5)

Polychaetes, sipunculids

3 7.2-15.6 (10.8)

2200-4375 (3295)

4-6 (5)

Polychaetes

4 3.3-11.5 (6.2)

1650-1975 (1825)

3-5 (4)

Amphipods, sipunculids, polychaetes

5 2.6-18.3 (9.2)

1125-2425 (1563)

3-4 (4)

Polychaetes, sipunculids

6 6.0-10.4 (8.5)

2575-7100 (4107)

4-8 (5)

Polychaetes

7 No collection due to heavy current

8 1.6-7.0 (4.0)

650-2375 (1382)

3-4 (3)

Polychaetes, sipunculids

9 3.1-19.8 (9.3)

2875-3950 (3345)

2-4 (3)

Polychaetes, sipunculids

Overall average

1.6-19.8 (7.8)

650-7100 (2381)

2-8 (4)

Polychaetes, sipunculids

Station Biomass (g/m2; wet wt.)

Population(no/m2)

Faunal groups

(no)

Major groups

1 0-0.2 (0.1)

0-150 (44)

0-2 (1)

Isopods

4 0.7-21.5 (7.0)

150-600 (357)

1-2 (2)

Isopods polychaetes

7 0-0.02 (0.01)

0-75 (19)

0-2 (1)

Isopods

Overall average

0-21.5 (1.8)

0-600 (105)

0-2 (1)

Isopods

Table 5.4.31: Composition (%) of subtidal macrobenthos in coastal waters off

Kuranga during September 2012.

Faunal group Station

1 2 3 4 5 6 7 8 9 Av Phylum Sipuncula

collectionto rocky bottom

no collection

due to heavy current

Sipunculids 20.1 5.3 36 12 7.3 14.5 12.1 12.9

Phylum

Phoronids 0.6 0.4 0.3 0.2

Phylum Mollusca

Pelecypods 0.5 0.8 0.3 0.4 0.6 0.4 0.4

Phylum Annelida Polychaetes 72.9 91.3 16.4 84 81.8 83.3 86.5 77.2Phylum Arthropoda

Amphipods 2.2 46.3 2 0.9 0.6 5.6 Anomurans 0.4 0.5 0.2 Brachyurans 0.5 0.2 0.1 Copepods 1.2 5.9 1.7 Cumaceans 2.7 0.4 0.2 Isopods 0.7 2.9 0.4 0.9 Sergestids 0.6 0.1 Tanaids 0.3 0.1 Phylum Chordata Fish Larvae 1.1 0.2 0.8 0.1 0.9 0.4 0.4 Table 5.4.32: Composition (%) of subtidal macrobenthos in coastal waters off

Kuranga during December 2012.

Faunal group Station

1 4 7 Av

Phylum Annelida

Polychaetes 43.2 45.7 31.6 44.8 Phylum Arthropoda Isopods 56.8 54.3 68.4 55.2

Table 5.4.33: Depth at different stations and Secchi disk reading in coastal

waters off Kuranga during April-May and December 2012.

Station Premonsoon (April-May 2012) Postmonsoon (December 2012)

Depth (m) Secchi disk depth (m) Depth (m) Secchi disk

depth (m)

1 20.0-23.0 (21.2)

2.9-3.4 (3.1)

21.5-25.0 (23.0)

2.0 – 3.0 (2.7)

2 32.0 4.0 40.0 3.0 3 33.0 4.1 47.0 2.5

4 23.8-26.0 (24.6)

3.5-4.2.0 (3.8)

22.26.0 (24.0)

2.8-3.5 (3.1)

5 42.0 3.9 38.0 2.8 6 45.0 2.5 7 24.0 3.7 25.0 - 8 29.0 3.9 35.0 2.5 9 37.0 3.9 40.0 2.7

Average in parenthesis

Table 5.4.35: The status of corals along transect V (effluent disposal corridor)

The transect V was on 27 May 2013. The results were as follows.

Sr. no Latitude Longitude Description

1 22o 01’ 03.2” 69o 09’ 39.1” Starting point

2 22o 01’ 02.8” 69o 09’ 36.9” Nearby the shore Porites compressa - 30 cm, Porites compressa - 23 cm, Porites compressa -15 cm

3 22o 01’ 04.8” 69o 09’ 35.2” Coral free area

4 22o 01’ 05.3” 69o 09’ 34.6” Porites compressa -10 cm, Porites compressa -11 cm, random sampling, 1x1 m, 1 colony

5 22o 01’ 06.2” 69o 09’ 34.2” Porites compressa - 10x22cm, Zoanthus species- 30 cm

6 22o 01’ 06.5” 69o 09’ 34.1” Porites compressa -69 cm, Porites compressa -90 cm random sampling 1x1 m, 1 colony. Favites, Goniopora sp. nearby at 22o 01’ 07.1” Lat and 69o

09’ 33.0”Long.

7 22o 01’ 08.9” 69o 09’ 31.9” Porites compressa

8 22o 01’ 09.3” 69o 09’ 31.5” Coral free area

9 22o 01’ 12.2” 69o 09’ 28.5”

10 22o 01’ 14.5” 69o 09’ 27.0” (A crab, a sea urchin)

11 22o 01’ 14.5” 69o 09’ 27.0” Coral free area

12 22o 01’ 15.0” 69o 09’ 26.5”

13 22o 01’ 15.0” 69o 09’ 26.5” Coral free area

14 22o 01’ 30.9” 69o 09’ 17.5”

15 22o 01’ 25.9” 69o 09’ 22.0” Old remnants of Turtle nesting along with false nesting was found in between HTL and flat top with clumps of grasses on sandy shore. 16 22o 01’ 25.0” 69o 09’ 22.1”

17 22o 01’ 19.8” 69o 09’ 26.3” 17 small dehydrated bleaches with oblong faecal structures from the turtle nesting pit without leathery materials was observed.

18 22o 01’ 18.4” 69o 09’ 27.6” Dry creeklet – shallow one.

19 22o 01’ 16.8” 69o 09’ 28.5” Turtle hatches and egg shells- leathery ones.

20 22o 01’ 16.6” 69o 09’ 28.8”

21 22o 01’ 15.4” 69o 09’ 29.6” End point of old turtle nesting sites.

22 22o 01’ 15.4” 69o 09’ 30.2” A minor dry creeklet towards south

23 22o 01’ 14.7” 69o 09’ 30.4” A minor dry creeklet

24 22o 01’ 04.70” 69o 09’ 38.93” Porites compressa,

25 22o 01’ 25.62” 69o 08’ 06.27”

Table 5.4.36: The status of corals along transect VI (effluent disposal corridor)

Another transect VI was assessed on 28 May 2013 and the results are shown as follows:

Sr. no Latitude Longitude Description

1 22o 01’ 03.2” 69o 09’ 36.2” Starting point

2 22o 01’ 04.6” 69o 09’ 35.2” Porites compressa - 33 cm

3 22o 01’ 06.3” 69o 09’ 34.1” Porites compressa with zoanthus sp

4 22o 01’ 05.8” 69o 09’ 33.4” Porites compressa

5 22o 01’ 07.3” 69o 09’ 32.6” Porites compressa more in number big sizes

6 22o 01’ 09.4” 69o 09’ 31.6” Coral free area with sandy bottom

7 22o 01’ 09.2” 69o 09’ 31.1”

8 22o 01’ 10.3” 69o 09’ 30.4” Coral free area with sandy bottom

9 22o 01’ 12.0” 69o 09’ 28.1” Coral free area

10 22o 01’ 14.0” 69o 09’ 27.2” Coral free area

11 22o 01’ 13.8” 69o 09’ 26.7”

12 22o 01’ 16.9” 69o 09’ 24.6” Towards north only sandy area, coral free

13 22o 01’ 17.0” 69o 09’ 24.9”

14 22o 01’ 21.1” 69o 09’ 22.0” Coral free sandy area

15 22o 01’ 21.3” 69o 09’ 22.2”

16 22o 01’ 22.5” 69o 09’ 20.9” Towards north coral free, sandy area

17 22o 01’ 22.8” 69o 09’ 21.2”

18 22o 01’ 27.7” 69o 09’ 17.5” Sandy shore, coral free area

Creek area near the small temple on the shore

19 22o 01’ 31.8” 69o 09’ 15.8” Creek with small check dam

20 22o 01’ 34.7” 69o 09’ 13.4” Creek without small check dam

21 22o 01’ 35.8” 69o 09’ 12.3”

22 22o 01’ 35.1” 69o 09’ 11.4” End point of second creek area

23 22o 01’ 43.3” 69o 09’ 30.7”

24 22o 01’ 41.6” 69o 09’ 03.0” Rocky formation

25 22o 01’ 39.9” 69o 09’ 05.4” Algal covering rocks

26 22o 01’ 24.0” 69o 09’ 22.8” Old turtle nesting remnants with two tracks.

27 22o 01’ 10.8” 69o 09’ 33.3” Pit was small, No track was there.

28 22o 01’ 06.3” 69o 09’ 36.6” Towards south; the point was 80-100m north from DP.

29 22o 01’ 05.6” 69o 09’ 37.0” Coral free sandy area (120 m), Earlier LFP is 97 m towards south from this point.

30 22o 01’ 05.2” 69o 09’ 36.5” Towards south

31 22o 01’ 04.4” 69o 09’ 35.5” Coral free area

32 22o 01’ 02.1” 69o 09’ 40.9” Scattered rocky and sandy area free of corals.

Table 5.4.37: Marine fish landings (t) for Gujarat State and Jamnagar District. during 1991 - 2012

Year Gujarat State Jamnagar District Percentage to total State landing

1991-92 530017 63452 11.97 1992-93 609836 66202 10.86 1993-94 619836 58887 9.50 1994-95 645261 58912 9.13 1995-96 598351 68088 11.38 1996-97 660068 76157 11.54 1997-98 702355 56043 7.98 1998-99 551660 28592 5.18 1999-00 670951 71683 10.68 2000-01 620474 72551 11.69 2001-02 650829 83398 12.81 2002-03 743638 102843 13.84 2003-04 609136 37957 6.23 2004-05 584951 45935 7.85 2005-06 663884 66489 10.02 2006-07 676762 70685 10.4 2007-08 680848 62512 9.2 2008-09 683855 62618 9.1 2009-10 687445 88293 12.8 2010-11 688930 67530 9.8 2011-12 - 37145 -

Source: Department of Fisheries, Government of Gujarat, Gandhinagr

Table 5.4.38: Species-wise and year-wise marine fish production (kg) of

Jamnagar District during 2006- 12.

Name of fish Year

2006-07 2007-08 2008-09 2009-10 2010-11 2011-12 White pomfret 4412116 3620846 2931396 2296274 2087977 773596 Black pomfret 1028051 836440 804609 1451793 534590 536045 Bombay duck 142060 61510 267224 97860 74550 2361210 Thread fin 1361008 1326499 3181413 3119210 2632755 1700164 Jew fish 3092997 2797830 2996547 1904771 2932682 1694611 Hilsa 930 2604 9900 0 23746 23520 Other clupeids 3658565 2522123 3031440 3254257 2543093 1066770 Coilia 8525 1395 15066 19530 64735 349959 Shark 1427856 1515896 1637096 2380723 1458747 876140 Mullet 1169521 912586 945173 1044008 986899 1769471 Cat fish 4788881 4064906 5431794 6335643 6098217 2448640 Eel 238569 68224 95432 224770 307405 1145662 Leather jacket 2545289 2515569 4167101 4110887 2478665 1088267 Seer fish 4575515 4825309 6033737 7413926 4453915 4579534 Indian salmon 174710 42868 125030 381310 258390 481078 Ribbon fish 3731848 1418259 2587277 3041642 4045644 2163585 Silver bar 1235748 1056559 1236061 1327143 1207950 1131208 Perches 2327192 2425168 3062715 4504580 5219104 2915113 Small sceinides 9235979 8306015 5523265 14884047 5819460 5361025 Shrimps 5662619 8994713 4948860 7791142 5459071 1364209 Prawns (Mediaum) 2345939 2851242 2215816 4712432 3049563 500151 Prawns (Jumbo) 564996 262889 130731 241685 766020 240464 Lobster 119637 92827 111971 68540 222304 95925 Crabs 378081 286898 349023 404086 324214 3938837 Levta 0 6820 1488 0 0 625115 Cuttle/Squid fish 6022693 3993857 4881056 55940801 4402781 2232200 Tuna 29692 7161 54000 682705 683800 477748 Carangies/Macarel 622558 292369 309807 974015 443549 118850 Ranifish 671200 3255 2700 27000 0 58900 Sole 10139 0 31500 665190 121666 1351399 Others 3648885 4111983 5498721 9340037 8828839 8852263 Total 65231799 59224620 62617949 88293256 67530339 37145135

Source: NIO data bank

Table 5.4.39: Species-wise monthly fish landing (kg) of Jamnagar District during 2011-12

Name of fish April 2011

May 2011

June 2011

July 2011

Aug 2011

Sept 2011

Oct 2011

Nov 2011

Dec 2011

Jan 2012

Feb 2012

March 2012 Total

White pomfret 95160 93927 30240

NO

CA

TCH

97448 149640 107722 156126 93028 57564 56612 55456 773596 Black pomfret 104400 102455 2925 4160 55980 162750 59400 32240 49600 130065 41850 536045 Bombay duck 0 0 0 0 20220 18600 0 858390 1116000 348000 0 2361210 Thread fish 330690 330770 59715 104192 101120 403806 141420 181040 342736 257520 168330 1700164 Jew fish 414360 439642 117198 66000 207220 214148 222204 443610 182528 226345 132556 1694611 Hilsa 0 0 0 0 23520 0 0 0 0 0 0 23520 Other clupeids 169680 173848 45474 64262 68790 124844 72354 150061 202902 294506 89051 1066770 Coilia 0 0 0 0 0 163959 0 0 186000 0 0 349959 Shark 111300 122078 31038 43169 186384 99694 139350 148897 76756 97623 84267 876140 Mullet 79920 68355 38745 47007 100500 540927 68040 334382 354173 209654 114788 1769471 Cat fish 574800 588876 184635 249014 115810 0 316380 423167 471797 506360 366112 2448640 Eel 32850 34100 5328 0 16200 39990 25200 563270 79050 309980 111972 1145662 Leather jacket 155100 172670 48420 121504 51680 697810 9600 22475 64108 64670 56420 1088267 Seer fish 323580 333281 95256 156944 1180716 47430 655314 522660 1015808 521681 478981 4579534 Indian salmon 0 0 1800 0 4050 394878 0 10850 0 0 71300 481078 Ribbon fish 609000 668670 180360 236000 100380 159340 319800 1249145 22320 40020 36580 2163585 Silver bar 121770 123349 27018 49584 123440 232190 99006 153859 187581 136996 148552 1131208 Perches 856200 869705 230940 239088 281760 511500 838860 224595 170655 112665 535990 2915113 Small Sciaenids 737100 695020 153540 270400 503160 362655 557400 101750 506385 678165 2381110 5361025 Shrimps 466410 474424 126810 200980 231360 108190 391470 46273 114004 214861 57071 1364209 Prawns (M) 251040 246047 64407 97198 50100 55955 141060 30938 56792 15563 52545 500151 Prawns (Jumbo) 108720 79825 16941 28225 20034 7440 32400 85312 35836 10261 20956 240464 Lobster 22980 29605 3924 3328 17850 48575 21060 0 3720 1392 0 95925 Crabs 38970 33976 16947 20210 71100 0 24870 51937 3688880 39817 42023 3938837 Levta 0 0 0 0 0 625115 0 0 0 0 0 625115 Cuttle/Squid fish 562200 605740 170415 306880 38400 0 560700 0 406100 556800 363320 2232200 Tuna 140400 153140 35640 58080 0 21638 105000 106950 0 133690 52390 477748 Carangids 97200 124775 21870 28800 9450 0 0 0 58280 0 22320 118850 Ranifish 0 0 0 0 0 0 0 31000 0 0 27900 58900 Sole 0 0 5040 0 0 635299 0 0 0 0 716100 1351399 Others 1608510 1651897 468600 751390 169882 5790565 629268 349616 606624 318758 236160 8852263 Total 8013960 8218255 2172750 3240703 3885426 5602482 6251549 6411867 5289656 6463452 37145135

Table 5.4.40: Species-wise monthly fish landing (kg) of Harshad during 2011-12

Name of fish April 2011

May 2011

June 2011

July 2011

Aug 2011

Sept 2011

Oct 2011

Nov 2011

Dec 2011

Jan 2012

Feb 2012

March 2012 Total

White pomfret 0 0 0

NO

CA

TCH

9600 0 0 0 0 0 0 0 9600 Black pomfret 0 0 0 0 0 0 0 0 49600 32625 0 82225 Bombay duck 0 0 0 0 0 0 0 0 0 0 0 - Thread fin 0 0 0 0 0 0 0 0 0 0 0 - Jew fish 0 0 0 0 0 0 0 0 0 0 0 - Hilsa 0 0 0 0 0 0 0 0 0 0 0 - Other clupeids 0 0 0 1280 0 0 0 0 0 0 0 1280 Coilia 0 0 0 0 0 0 0 0 0 0 0 Shark 0 0 0 0 0 55800 0 0 0 0 0 55800 Mullet 0 0 0 0 0 0 0 0 0 0 0 Cat fish 0 0 0 1920 0 0 0 2790 0 0 0 4710 Eel 0 0 0 0 0 0 0 209250 0 130500 0 339750 Leather jacket 0 0 0 5760 24000 0 0 6975 27280 0 0 64015 Seer fish 0 0 14400 8320 312000 209250 0 195300 136400 3915 0 879585 Indian salmon 0 0 1800 0 0 47430 0 0 0 0 24800 74030 Ribbon fish 0 0 12600 0 0 12555 0 18135 11160 26100 18600 99150 Silver bar 0 0 1800 8320 0 16740 0 3348 40920 5220 0 76348 Perches 0 0 1440 7040 240000 0 0 32085 0 0 0 280565 Small Sciaenides 75600 92070 7200 0 0 0 0 58220 0 95265 485150 813505 Shrimps 0 0 0 0 0 0 0 0 0 0 0 0 Prawns (M) 0 0 0 0 0 0 0 0 0 0 0 0 Prawns (Jumbo) 0 0 0 0 0 0 0 0 0 0 0 0 Lobster 6480 9207 0 0 8400 0 16380 0 0 0 0 40467 Crabs 0 0 0 0 0 0 0 0 0 0 0 0 Levta 0 0 0 0 0 0 0 0 0 0 0 0 Cuttle/Squid fish 0 0 0 0 0 57195 46800 0 0 0 0 103995 Tuna 0 0 0 0 0 0 0 0 0 0 0 0 Crangies/Mackrel 61200 75990 7560 7040 0 0 0 0 43400 0 0 195190 Ranifish 0 0 0 0 0 0 0 0 0 0 0 0 Sole 0 0 0 0 0 0 0 0 0 0 0 0 Others 0 0 2520 4480 0 0 0 1953 8680 0 42470 60103 Total 143280 176607 51120 53760 584400 398970 63180 520056 317440 293625 571020 3180318

Table 5.4.41: Species-wise monthly fish landing (kg) of Navadra during 2011-12

Name of fish April 2011

May 2011

June 2011

July 2011

Aug 2011

Sept 2011

Oct 2011

Nov 2011

Dec 2011

Jan 2012

Feb 2012

March 2012 Total

White pomfret 0 0 0

NO

CA

TCH

5400 0 0 0 0 0 5400 Black pomfret 21000 27280 0 0 4050 14880 21600 0 0 8700 97510 Bombay duck 0 0 0 0 0 0 0 0 0 0 0 Thread fin 0 0 0 0 0 0 0 0 0 0 0 Jew fish 0 0 0 0 135000 0 0 0 0 0 135000 Hilsa 0 0 0 0 0 0 0 0 0 0 0 Other clupeids 0 0 0 4000 0 0 0 0 0 0 4000 Coilia 0 0 0 0 0 0 0 0 0 0 0 Shark 0 0 0 0 13500 9920 0 9920 0 0 33340 Mullet 0 0 0 0 0 0 0 0 0 0 0 Cat fish 0 0 0 4000 0 0 0 6200 5580 0 15780 Eel 0 0 1170 0 16200 0 25200 0 41850 0 84420 Leather jacket 0 0 0 8000 5400 0 0 0 3348 0 16748 Seer fish 0 0 0 8800 297000 0 180000 66960 446400 60900 1060060 Indian salmon 0 0 0 0 4050 0 0 0 0 0 4050 Ribbon fish 0 0 2880 4000 13500 0 0 17360 0 0 37740 Silver bar 0 0 2430 4800 13500 12400 0 0 6975 0 40105 Perches 0 0 9000 0 0 3720 0 76880 9765 0 99365 Small Sciaenides 115500 82150 3600 0 0 0 0 21000 59985 147900 430135 Shrimps 0 0 0 0 0 0 0 0 0 0 0 Prawns (M) 0 0 0 0 0 0 0 0 0 0 0 Prawns (Jumbo) 0 0 0 0 0 0 0 0 0 0 0 Lobster 8100 10850 0 0 5400 7440 0 0 0 0 31790 Crabs 0 0 0 0 0 0 0 0 0 0 0 Levta 0 0 0 0 0 0 0 0 0 0 0 Cuttle/Squid fish 0 0 0 0 0 18600 63000 0 0 0 81600 Tuna 0 0 0 0 0 0 0 0 0 0 0 Crangies/Mackrel 27000 34100 4950 12800 9450 9920 0 0 0 0 98220 Ranifish 0 0 0 0 0 0 0 0 0 0 0 Sole 0 0 0 0 0 0 0 0 0 0 0 Others 0 0 0 0 0 0 0 52080 23715 0 75795 Total 171600 154380 28080 55200 522450 76880 289800 250480 597618 217500 2363988

Table 5.4.42: Species-wise monthly fish landing (kg) of Dwarka during 2011-12

Name of fish April 2011

May 2011

June 2011

July 2011

Aug 2011

Sept 2011

Oct 2011

Nov 2011

Dec 2011

Jan 2012

Feb 2012

March 2012 Total

White pomfret 0 0 0

NO

CA

TCH

8320 5400 0 0 0 0 0 0 13720 Black pomfret 75000 59985 0 0 4050 125550 0 0 0 19140 41850 325575 Bombay duck 0 0 0 0 0 0 0 0 0 0 0 0 Thread fin 60000 62775 03600 0 0 139500 0 62000 137640 86130 41850 593495 Jew fish 0 0 0 0 135000 9765 0 155000 0 0 0 299765 Hilsa 0 0 0 0 0 0 0 0 0 0 0 0 Other clupeids 0 0 0 5760 0 0 0 43400 106020 213730 11160 380070 Coilia 0 0 0 0 0 0 0 0 0 0 0 0 Shark 0 0 0 0 135000 0 0 21700 0 0 12555 169255 Mullet 0 0 0 0 0 0 0 0 0 0 0 0 Cat fish 10500 13950 0 4480 0 0 0 46500 0 0 11160 86590 Eel 0 0 0 0 16200 0 0 217000 29760 159500 55800 478260 Leather jacket 0 0 0 5760 5400 0 0 15500 0 0 0 26660 Seer fish 21000 18135 0 10880 297000 195300 336000 15500 81840 127600 39060 1142315 Indian salmon 0 0 0 0 4050 0 0 10850 0 0 0 14900 Ribbon fish 21000 30690 1080 3200 13500 10323 0 4650 0 0 13950 98393 Silver bar 6000 11160 864 4480 0 22320 0 18600 13020 0 11160 87604 Perches 60000 51615 0 0 0 25110 630000 0 0 0 0 766725 Small Sciaenides 0 0 0 0 0 0 0 0 9300 0 19530 28830 Shrimps 0 0 0 0 0 0 0 0 0 0 0 0 Prawns (M) 0 0 0 0 0 0 0 0 0 0 0 0 Prawns (Jumbo) 0 0 0 0 4050 0 0 0 0 0 0 4050 Lobster 0 0 1854 0 0 0 0 0 0 0 0 1854 Crabs 0 0 0 0 0 0 0 0 0 0 0 0 Levta 0 0 0 0 0 0 0 0 0 0 0 0 Cuttle/Squid fish 0 0 0 0 0 106020 69300 0 0 0 0 175320 Tuna 0 0 0 0 0 0 0 0 0 0 0 0 Crangies/Mackrel 9000 34100 9360 8960 0 11718 0 0 14880 0 22320 110338 Ranifish 0 0 0 0 0 0 0 31000 0 0 0 31000 Sole 0 0 5040 0 0 0 0 0 0 0 0 5040 Others 0 0 0 8960 0 0 0 0 11160 0 0 13720 Total 262500 154380 21528 60800 661500 645606 1035300 641700 403620 606100 280395 325575

Table5.4.43: Group-wise marine fish production (kg) at 3 major fish landing centers bordering the coastal waters of Gojiness-Kuranga of Jamnagar District during 2008-09.

Fish groups

Major fish landing centre Jamnagar District Dwarka Harshad Navadra

Production % Production % Production % Production White pomfret 64800 2.21 122410 4.18 33760 1.15 2931396 Black pomfret 40340 5.01 44716 5.56 19456 2.42 804609 Bombay duck 0 0.00 0 0.00 0 0.00 267224 Thread fin 652103 20.50 32402 1.02 123842 3.89 3181413 Jew fish 982103 3.28 13950 0.05 27770 0.09 29965547 Hilsa 9900 100.0 0 0.00 0 0.00 9900 Other clupeids 83318 2.75 26668 0.88 0 0.00 3031440 Coilia 0 0.00 0 0.00 0 0.00 15066 Shark 85436 5.22 32282 1.97 6540 0.40 1637096 Mullet 0 0.00 0 0.00 0 0.00 945173 Cat fish 226811 4.18 53282 0.98 45904 0.85 5431794 Eel 45597 47.78 35740 37.45 0 0.00 95432 Leather jacket 78080 1.87 17904 0.43 78444 1.88 4167101 Seer fish 371398 6.16 95080 1.58 130080 2.16 6033737 Indian salmon 9920 7.93 3600 2.88 0 0.00 125030 Ribbon fish 25235 0.98 325896 12.60 308348 11.92 2587277 Silver bar 60253 4.87 43970 3.56 32854 2.66 1236061 Pearch 687355 22.44 37975 1.24 32300 1.05 3062715 Small Scienids 78062 1.41 174283 3.16 156660 2.84 5523265 Shrimps 8060 0.16 990 0.02 0 0.00 4948860 Prawns (Medium) 0 0.00 0 0.00 0 0.00 2215816 Prawns (Jumbo) 0 0.00 0 0.00 0 0.00 130731 Lobster 61797 55.19 0 0.00 12480 11.15 111971 Crabs 0 0.00 0 0.00 0 0.00 349023 Levta 0 0.00 0 0.00 0 0.00 1488 Cuttlefish/Squids 38760 0.79 16461 0.34 39630 0.81 4881056 Tuna 0 0.00 0 0.00 0 0.00 54000 Carangids/ mackerel 81050 26.16 56367 18.19 150070 48.44 309807

Pink Perch 0 0.00 0 0.00 2700 100.0 2700 Sole fish 0 0.00 0 0.00 0 0.00 31500 Miscellaneous 77348 1.41 78755 1.43 161202 2.93 5498721 Total 2884193 4.61 1213234 1.94 1361040 2.17 62617949

Source: Department of Fisheries, Govt. of Gujarat, Gandhinagar

Table 5.4.44: Data on fishing crafts and fishermen population of Jamnagar District during 2006-07.

Parameter Number

Length of coastline (km) 342

Coastline percentage with that of the State 21.37

Landing centers (no) 23

Fishermen families (no) 5982

Total fishermen population (no) 40904

Active fishermen (no) 9330

Fishing boat: mechanized (no) : non-mechanized (no)

1637

326

Total fishing gears (nets) (no) 2,61,030

a. Dol net (no) 1704

b. Gill net (no) 106273

c. Hook and line, cast net and others (no) 153053

Landing center

Fisherman families

(no)

Total fishermen

(no)

Active fishermen

(no)

Total boats

Mechanized (no)

Non-mechanized

(no) Dwarka 724 5669 1261 919 972

Table 5.4.45: Scientific and common names of fish, crustacean and molluscan

species at Gojiness Creek near Bhogat village during March 2010.

Scientific name Common name Fish species Sphyraena barracuda Great barracuda Polydactylus sextarius Blackspot threadfin Lactarius lactarius White fish Lutjanus johnii John’s snapper Megalaspis cordyla Horse mackerel Cynoglossus lingua Long toungsole Atule mate Yellow tail scad Epinephelus diacanthus Cheek spined grouper Epinephelus sps Common Grouper Leioganthus splendens Splendid ponyfish Muraenesox bagio Common pink conger Plectorhinchus griseus Grey sweetlip Plotosus canius Grey eel catfish Johnius dussumerri Dussumeir’s croaker Johnius saldado Croaker Otolithes ruber Tiger toothed croaker Pennahia anea Truncate tail croaker Pseudorhombus malayanus Malayans flounder Crustaceans species Calappa lophos Box crab Dromia dormia Common sponge crab Portunus pelagicus Blue swimming crab Portunus sanguinolentus Three spotted crab Panulirus spp. Spiny lobster Fenneropenaeus indicus White shrimp Penaeus monodon Tiger shrimp Gastropod species Tibia curta Indian tibia Murex brunneus Adustus murex Murex adustus Eel Turbo coronatus Turban shell Turritella maculata Screw shell Cypraea arabica Arabian cowry

Source: NIO data bank

Table 5.4.46: Fishes, crustaceans and gastropods obtained from catch of local

fishermen in coastal waters off Kuranga /Gojiness during April-May 2012.

Scientific name Common name Fish Lutjanus johnii John’s snapper

Johnius dussumerri Dussumeir’s croaker Johnius elongatus Giant captainfish Sparidentex hasta Silver black porgy Cynoglossus lingua Long toungsole Lactarius lactarius White fish Polydactylus sextarius Blackspot threadfin Crustaceans Penaus monodon Tiger shrimp Fenneropenaeus indicus White shrimp Gastropods Cyprea arabica Arabian cowery Murex adustus Eel Murex brunneus Adustus murex Turbo coronatus Turban shell

Table 5.4.47: Fishes obtained from catch of local fishermen in coastal waters off Kuranga /Gojiness during December 2012.

Scientific name Common name Fish Pampus argenticus Paplet/ pomfret Parastomateus niger Black pomfret Polynemus sexifillis - Caranx para Yellowfin jack Johnius elongatus Giant captainfish Sparidentex hasta Silver black porgy Lactarius lactarius White fish Valamugil speigleri Speigler's mullet Coilia dussumieri Mandeli Lutjanus johnii John’s snapper Johnius dussumerri Dussumeir’s croaker Crustaceans Penaus monodon Tiger shrimp Portunus pelagicus Blue swimming crab Panulirus spp. Spiny lobster Fenneropenaeus indicus White shrimp Gastropods Cyprea arabica Arabian cowery Murex adustus Eel Turbo coronatus Turban shell

Table 5.4.48: Sand dune vegetation along the coastal waters off Kuranga .

Plant Density Cynodon dactylon D Prosopsis juliflora D Ipomoea biloba S Cactus S Jancus maritimus (Halopyrum mucronatum)

S

Euphorbia neriifolia S Ziziphus rotundifolia S Salvadora persica S Suaeda maritima S Carex condensata S Convolvulus pluricaulis S Sand binding halophyte S Udotea indica S

D- Dense; S-Sparse

Table 5.4.49: Macro algae along the coastal water off Kuranga.

Algae Udotea indica Bryopsis plumosa Caulerpa racemosa Chaetomorpha spp Cladophora facicaularis Calcareous algae Gracillaria sp. Halimeda tuna Porphyra vietnamensis Sargassum polycystum Ulva lactuca Ulva fasciata

Table 5.4.50: Corals along the coastal water off Kuranga.

Corals Porites compressa Goniopora minor Polycyanthus verrilli Tubastrea aurea Turbinaria crater Favites

Table 5.4.51: Fauna at the intertidal area of Kuranga.

Total species(no) Common species

F-1 Fishes : Mud. Goby Jelly fish

C-4 Crabs: Portunus pelagicus, Neptunus sp., Charybdis sps., wolf crab, Pilimnus vespertilio

M-3 Mollusc: Sepia sp., Sea hare, Rock oyster

G-10 Gastropods: Conus, Turbo intercostalis, Murex, Chicoreus ramosus, Bursa spinosa, Patella sp, Tibia, Volema, Cowries (Arabica arabica), Limpet

Table 6.6.1: Variation in temperature, ammonia and SS at various observation points

around outfall location OF1.

Observation point

Distance of observation point from

OF1 (m)

Variation of temperature

(above ambient, oC)

Variation of ammonia

(above ambient, mg/l)

Variation of SS (above

ambient, mg/l)

1 0 1.5-3.3 1.5-3.05 300-515 2 100m towards NW 0-1.5 0-1.25 0-220 3 250m towards NW 0-0.5 0-0.8 0-150 4 380m towards NW -- 0-0.015 -- 5 550m towards NW -- 0-0.01 -- 6 130m towards SE 0-1.25 0-1.0 0-180 7 300m towards SE -- 0-0.2 -- 8 430m towards SE -- 0-0.45 0-50 9 560m towards SE -- 0-0.015 --

10 450m towards NNW -- 0-0.018 -- 11 280m towards WNW -- 0-0.005 -- 12 350m towards WNW -- -- -- 13 170m towards W -- -- -- 14 110 m towards NE -- 0.05-0.3 0-45 15 160 m towards S -- 0.05-0.3 0-40 16 190 m towards E -- -- -- 17 260 m towards SSW -- -- -- 18 380 m towards ESE -- 0-0.05 -- 19 415 m towards SSW -- -- -- 20 120 m towards N -- 0-0.25 0-20

Table 6.6.2: Variation in temperature, ammonia and SS at various observation points

around outfall location OF2.

Observation point

Distance of observation point

from OF2 (m)

Variation of temperature

(above ambient, oC)

Variation of ammonia

(above ambient, mg/l)

Variation of SS (above ambient,

mg/l)

1 0 2.0-3.6 1.8-3.6 350-620 2 120 m towards NW 0-1.0 0-1.1 0-200 3 250 m towards NW 0-0.5 0-0.75 0-130 4 400 m towards NW -- 0-0.36 0-50 5 530 m towards NW -- 0-0.36 0-50 6 100 m towards SE 0-1.75 0-1.5 0-260 7 220 m towards SE 0-1.2 0-1.0 0-160 8 360 m towards SE -- 0-0.25 0-30 9 520 m towards SE -- 0-0.25 0-50

10 360 m towards NNW -- -- -- 11 230 m towards NNW -- 0-0.015 -- 12 130 m towards NNE -- 0-0.005 -- 13 350 m towards WNW -- 0-0.005 -- 14 210 m towards WNW -- 0-0.005 -- 15 100 m towards SSW -- 0-0.005 -- 16 160 m towards SSE -- 0-0.15 -- 17 110 m towards E -- 0-0.2 0-40 18 190 m towards ESE -- 0-0.01 -- 19 280 m towards ESE -- 0-0.01 -- 20 440 m towards ESE -- 0-0.01 --

Table 6.7.1: Instantaneous erosion and deposition rates and bed level increase at

various observation points around outfall location OF1 during the run period.

Observation point

Distance of observation point from

OF1 (m)

Variation of instantaneous erosion rates

(kg/m2,s)

Variation of instantaneous

deposition rates(kg/m2,s)

Variation of bed level (m)

1 0 0-0.003 0-0.045 0.1

2 100m towards NW 0-0.002 0-0.011 0.005

3 250m towards NW 0-0.003 0-0.025 0.02

4 380m towards NW 0-0.0025 0-0.02 0.01

5 550m towards NW 0-0.0025 0-0.02 0.009

6 130m towards SE 0-0.002 0-0.0075 0.005

7 300m towards SE 0-0.0006 0-0.0015 0.005

8 430m towards SE 0-0.0038 0-0.0125 0.008

9 560m towards SE 0-0.005 0-0.0025 0.003

10 450m towards NNW 0-0.004 0-0.002 0.002

11 280m towards WNW 0-0.003 0-0.002 0.003

12 350m towards WNW 0-0.002 0-0.0015 0.002

13 170m towards W 0-0.005 0-0.025 0.008

14 110 m towards NE 0-0.005 0-0.002 0.002

15 160 m towards S 0-0.005 0-0.002 0.002

16 190 m towards E 0-0.004 0-0.002 0.002

17 260 m towards SSW 0-0.001 0-0.002 0.003

18 380 m towards ESE 0-0.0001 0-0.002 0.003

19 415 m towards SSW 0-0.0005 0-0.008 0.003

20 120 m towards N 0-0.003 0-0.002 0.002

Table 6.7.2: Instantaneous erosion and deposition rates and bed level increase at

various observation points around outfall location OF2 during the run period.

Observation point

Distance of observation point from

OF2 (m)

Variation of instantaneous erosion rates

(kg/m2,s)

Variation of instantaneous

deposition rates(kg/m2,s)

Variation of bed level

(m)

1 0 0-0.003 0-0.002 0.005

2 120 m towards NW 0-0.0021 0-0.0017 0.022

3 250 m towards NW 0-0.0028 0-0.005 0.006

4 400 m towards NW 0-0.0022 0-0.015 0.014

5 530 m towards NW 0-0.0022 0-0.015 0.014

6 100 m towards SE 0-0.002 0-0.004 0.0075

7 220 m towards SE 0-0.0008 0-0.002 0.007

8 360 m towards SE 0-0.0038 0-0.012 0.0065

9 520 m towards SE 0-0.005 0-0.002 0.005

10 360 m towards NNW 0-0.004 0-0.002 0.005

11 230 m towards NNW 0-0.0028 0-0.002 0.006

12 130 m towards NNE 0-0.002 0-0.002 0.006

13 350 m towards WNW 0-0.005 0-0.002 0.005

14 210 m towards WNW 0-0.005 0-0.002 0.005

15 100 m towards SSW 0-0.0052 0-0.002 0.005

16 160 m towards SSE 0-0.004 0-0.002 0.005

17 110 m towards E 0-0.001 0-0.0075 0.007

18 190 m towards ESE 0-0.0001 0-0.002 0.0075

19 280 m towards ESE 0-0.0002 0-0.007 0.0075

20 440 m towards ESE 0-0.0032 0-0.002 0.005

Table 6.9.1: The plume characteristics for the bottom release of RSPL effluent in the coastal waters off Kurunga.

Paramter Value NO OF PORTS 10 DIAMETER OF THE PORT (m) 0.538 INITIAL JET VELOCITY(m/s) 3 PORT ANGLE (Degrees to horizontal) 60

Plume width (m)

Plume angle (rad)

Distance from port (m)

Plume rise (m)

Dilution

(times) ΔSS ΔDT ΔNH4 Δρ

1.10 1.05 1.7 2.9 1.4 678 3.57 3.57 7.14 1.12 1.05 1.7 3.0 1.4 658 3.47 3.47 6.93 1.24 1.04 1.8 3.2 1.7 572 3.01 3.01 6.02 1.36 1.04 2.0 3.4 1.9 503 2.65 2.65 5.30 1.44 1.04 2.0 3.5 2.0 469 2.47 2.47 4.93 1.61 1.03 2.2 3.8 2.4 401 2.11 2.11 4.22 1.71 1.03 2.3 4.0 2.6 370 1.95 1.95 3.89 2.01 1.01 2.6 4.5 3.2 296 1.56 1.56 3.12 2.32 0.99 3.0 5.0 3.9 244 1.28 1.28 2.57 2.64 0.97 3.3 5.5 4.6 205 1.08 1.08 2.16 2.98 0.94 3.6 6.0 5.4 175 0.92 0.92 1.85 3.38 0.89 4.0 6.5 6.3 150 0.79 0.79 1.58 3.80 0.83 4.5 7.0 7.3 129 0.68 0.68 1.36 4.35 0.73 5.0 7.5 8.6 110 0.58 0.58 1.16 5.01 0.57 5.6 8.0 10.1 94 0.49 0.49 0.99 6.30 -0.20 7.4 8.5 13.4 71 0.37 0.37 0.75 6.32 -0.25 7.5 8.4 13.5 71 0.37 0.37 0.74 6.20 -0.64 8.5 8.0 13.9 68 0.36 0.36 0.72 6.06 -0.82 9.0 7.5 14.1 67 0.35 0.35 0.71 5.98 -0.93 9.4 7.0 14.4 66 0.35 0.35 0.70 5.95 -1.00 9.8 6.5 14.7 65 0.34 0.34 0.68 5.95 -1.06 10.1 6.0 15.1 63 0.33 0.33 0.66 5.97 -1.10 10.4 5.5 15.6 61 0.32 0.32 0.64 6.00 -1.13 10.6 5.0 16.0 59 0.31 0.31 0.62 6.06 -1.16 10.8 4.5 16.6 57 0.30 0.30 0.60 6.12 -1.19 11.0 4.0 17.1 56 0.29 0.29 0.58 6.19 -1.21 11.2 3.5 17.7 54 0.28 0.28 0.56 6.27 -1.23 11.4 3.0 18.3 52 0.27 0.27 0.55 6.35 -1.25 11.6 2.5 18.9 50 0.26 0.26 0.53 6.45 -1.27 11.7 2.0 19.6 48 0.25 0.25 0.51 6.54 -1.28 11.9 1.5 20.3 47 0.25 0.25 0.49 6.63 -1.29 12.0 1.0 20.9 45 0.24 0.24 0.48 6.74 -1.30 12.2 0.5 21.7 44 0.23 0.23 0.46 6.83 -1.31 12.3 0.0 22.3 43 0.22 0.22 0.45

Figure 1.1.1: Map showing project area for RSPL in Jamnagar District.

Figure 1.1.2: Map showing the coast along Kuranga-Gojiness region.

Figure 1.4.1: Map showing sampling locations in coastal waters off Kuranga.

1 - 9: Subtidal stations

TI – TIII: Intertidal transects

NS

EW

SP

HE

RO

ID - W

GS 84

515000 mX

516000 mX

517000 mX

518000 mX

2432000 mY 2433000 mY 2434000 mY 2435000 mY

21°59'30" N 22°00' N 22°01' N21°59'30" N 22°00' N 22°00'30" N 22°01' N

ARABIANSEA

COASTLINE

519000 mX

514000 mX

22°01'30" N

NOTES :

LEGEND:

GeneralBathymetry

GEODETIC DETAILS :

CLIENT :

SCALE:

RSPL LIM

ITED

SURVEYED BY :

DRAWING TITLE :

PROJECT TITLE :

BA

THY

ME

TRY M

AP

FIG. 4.

26 ,5

1

TIDAL INFORMATION:(N.H.Chart No-203)

SC

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MED

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22

1 m

2 m

3 m

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8 m

9 m

10 m

11 m

12 m

13 m

14 m

15 m

16 m

17 m

18 m

19 m

20 m

GU

LF O

F K

AC

HC

HH

ARABIANSEA

525 m

1200 m

875 m

2735 m

Lat: 22°00' 00.62" N ; Long: 69°10'38.70" E

X : 0518313 m

; Y : 2432857 m

LFP - INTAKE

Lat: 21°59' 49.70" N ; Long: 69°10'24.60" E

X : 0517909 m

; Y : 2432520 m

INTA

KE - PRO

POSED

DEP

TH : 4.40 m

DIS

TAN

CE : 525 m

Lat: 22°01' 04.70" N ; Long: 69°09'38.93" E

X : 0516597 m

; Y : 2434825 m

LFP - OUTFALL

Lat: 22°01' 25.62" N ; Long: 69°08'06.27" E

X : 0513940. m

; Y : 2435466 m

OUTFA

LL - PROPO

SED

DEP

TH : 15.4 m

DIS

TAN

CE : 2735 m

Lat: 21°59' 42.35" N ; Long: 69°10'15.48" E

X : 0517638 m

; Y : 2432295 m

INTAKE - SU

GG

ESTED

DEP

TH : 10.0 m

DIS

TAN

CE : 875 m

Lat: 22°00' 39.51" N ; Long: 69°09'07.01" E

X : 0515683 m

; Y : 2434049 m

OUTFA

LL - SUGG

ESTED

DEP

TH : 12.0 m

DIS

TAN

CE : 1200 m

BA

THYM

ETRY SU

RVEY A

ND

TIDE M

EASU

REM

ENTS FO

R SETTIN

G U

P O

F GR

EENFIELD

SOD

A A

SH PR

OJEC

T IN

JAM

NA

GA

R, G

UJA

RA

T

Figure 5.1.1: Map show

ing bathymetry of m

arine environment off coastal w

aters off Kuranga.

NS

EW

SPH

ERO

ID - W

GS 84

515000 mX

516000 mX

517000 mX

518000 mX

2432000 mY 2433000 mY 2434000 mY 2435000 mY

21°59'30" N

69°08'30" E69°09' E

69°09'30" E69°10' E

21°59'30" N 22°00' N 22°00'30" N 22°01' N

69°10'30" E69°08'30" E

69°09' E69°09'30" E

69°10' E

ARABIANSEA

COASTLINE

519000 mX

514000 mX

69°08' E69°11' E

22°01'30" N

COASTLINE

Figure 5.1.2: Soft sedim

ents estimated from

the dual frequency echo sounder in the survey area of

SC

ALE

- 1: 25000

coastal waters off K

uranga.

24-Apr-12 27-Apr-12 30-Apr-12 4-May-12 7-May-12 11-May-12

0.00

1.00

2.00

3.00

4.00

Miyani Tide

Dwaraka Tide

Predicted Tide at Dwaraka and Miyani for the period of Observation during premonsoon

Figure 5.1.3: Predicted tides at Dwarka and Miyani during 24 April - 11 May 2012 (premonsoon).

7-Dec-12 13-Dec-12 20-Dec-12 27-Dec-12

0.00

1.00

2.00

3.00

4.00

Dwaraka Tide

Miyani Tide

Predicted Tides at Dwaraka and Miyani During the period of Postmonsoon observationFigure 5.1.4: Predicted tides at Dwarka and Miyani during 7 - 27 December 2012 (postmonsoon).

0

0.1

0.2

0.3

0.4

0.5

4/29/12 13:20 4/30/12 22:40 5/2/12 8:00 5/3/12 17:20 5/5/12 2:40 5/6/12 12:00

0

100

200

300

400

Spe

ed(m

/s)

Direc

tion(de

g)

Date and Time (mm/dd/yy hh:mm) Figure 5.1.5: Current speed (a) and direction (b) at station 4 (coastal waters off

Kuranga) during 29 April – 6 May 2012.

(a)

(b)

0

0.1

0.2

0.3

12/15/12 20:00 12/17/12 5:20 12/18/12 14:40 12/20/12 0:00 12/21/12 9:20 12/22/12 18:40

0

100

200

300

400

Spe

ed (m

/s)

Dire

ction (deg

)

Date and time (mm/dd/yy hh:mm)

(a)

(b)

Figure 5.1.6: Current speed (a) and direction (b) at station 7 (coastal waters off

Kuranga) during 15 – 21 December 2012.

0

0.2

0.4

0.6

10:30 19:50 5:10 14:30 23:50

-0.8

-0.4

0

0.4

0.8U-componentV-component

Spee

d (m

/s)

Com

pone

nts (m

/s)

(a)

(b)

11.10.09 12.10.09 14.10.09 15.10.09 16.10.09

Figure 5.1.7 Current (a) speed and (b) components at Dwarka during October

2009.

0

50

100

150

200

250

Dire

ction (D

egrees

)

3/21/10 12:20 3/24/10 7:00 3/27/10 1:40 3/29/10 20:20

0

0.2

0.4

0.6

0.8

Spe

ed (m

/s)

Date and Time (mm/dd/yy hh:mm) Figure 5.1.8: Current speed and direction near Dwarka during 21 – 29 March

2010.

3/21/10 12:20 3/24/10 7:00 3/27/10 1:40 3/29/10 20:20

-0.8

-0.4

0

0.4

0.8u-compv-comp

Date and Time(mm/dd/yy hh:mm)

Com

pone

nts(m/s)

Figure 5.1.9: Current component near Dwarka during March 2010.

Figure 5.1.10: Drogue study conducted at station 4 (coastal waters off Kuranga) during flood-ebb on 2 May 2012.

Figure 5.1.11: Drogue trajectory near Dwarka on 23 October 2002.

Figure 5.1.12: Drogue trajectory near Dwarka on 24 October 2002.

Figure 5.1.13: Drogue trajectory near Dwarka on 28 October 2002.

Figure 5.1.14: Drogue trajectory near Dwarka on 1 April 1999.

Figure 5.1.15: Drogue trajectory at Rupen Bandar during ebb on 29 March

2010.

24

26

28

30Temperature (0C)

A.T.

7.9

8.0

8.1

8.2 pH

36

36

36

37

37

37

Salinity (ppt)

6.0

7.0

8.0

9.0

DO (mg/L)

0.0

0.2

0.4

0.6

0.8

PO43--P (µmol/L)

0.0

0.2

0.4

0.6

0.8NO2

--N (µmol/L)

0.0

1.0

2.0

3.0

4.0

5.0

1000 1100 1200 1300 1400 1500

NO3--N (µmol/L)

1000 1100 1200 1300 1400 15000.0

0.4

0.8

1.2NH4

+-N (µmol/L)

h h

EbFl Fl

Eb

Figure 5.2.1: Temporal Variations in Water Quality (S ) (B ) at Station 1 (coastal waters off Karunga ) on 3rd May 2012

22.0

24.0

26.0

28.0

30.0

A.T.

7.9

8.0

8.1

8.2

5.0

6.0

7.0

8.0

9.0

10.0

34.5

35.0

35.5

36.0

0.0

0.5

1.0

1.5

2.0

2.5

0.0

0.2

0.4

0.6

0.8

1.0

900 1100 1300 15003.0

4.0

5.0

6.0

7.0

900 1100 1300 15000.0

0.2

0.4

0.6

0.8

PO43--P (µmol/L)

h h0 0

Eb

Eb

pH

Salinity (ppt)

NO2--N (µmol/L)

DO (mg/L)

Temperature (0C)

NO3--N (µmol/L) NH4

+-N (µmol/L)

Figure 5.2.2: Temporal variations in water quality (S ) (B ) at station 4 (coastal waters off Kuranga) on 5 May 2012.

28

29

30

31Temperature(°C)

8.0

8.1

8.2

8.3 pH

36.0

36.2

36.4

36.6

36.8

37.0Salinity (ppt)

5.0

6.0

7.0

8.0DO (mg/l)

0.4

0.8

1.2

1.6

2.0PO4

3--P (µmol/l)

0.0

2.0

4.0

6.0

8.0NO3

--N (µmol/l)

730 930 1130 13300.0

0.2

0.4

0.6NO2

--N (µmol/l)

730 930 1130 13300.0

0.4

0.8

1.2NH4

+-N (µmol/l)

AT

h h

Figure 5.2.3: Temporal Variations in Water quality (S ) at Station 1(Coastal waters off Karunga) On 11th September, 2012

27

28

29

30Temperature(°C)

8.0

8.1

8.2

8.3

8.4 pH

35.0

36.0

37.0

38.0Salinity (ppt)

5.0

6.0

7.0

8.0DO (mg/l)

0.5

1.0

1.5

2.0PO4

3--P (µmol/l)

0.0

2.0

4.0

6.0

8.0NO3

--N (µmol/l)

800 1000 1200 14000.0

0.3

0.6

0.9NO2

--N (µmol/l)

800 1000 1200 14000.0

0.5

1.0

1.5

2.0NH4

+-N (µmol/l)

AT

h h

Figure 5.2.4: Temporal Variations in Water quality (S ) at Station 7 (coastal waters off Kuranga) on 12th September , 2012.

20

22

24

26

28TEMPERATURE( OC)

7.8

7.9

8.0

8.1

8.2pH

6.5

6.7

6.9

7.1

7.3

7.5DO(mg/l)

35.5

35.7

35.9

36.1

36.3

36.5

SALINITY( ppt )

0.6

0.8

1.0

1.2

1.4

1.6PO43--P(µmol/l)

600 800 1000 1200 1400 1600 18001.4

1.6

1.8

2.0

2.2

2.4

NO2--N(µmol/l)

4.0

5.0

6.0

7.0

8.0

9.0

NO3--N(µmol/l)

600 800 1000 1200 1400 1600 18000.0

0.2

0.4

0.6

0.8

1.0

1.2NH4+-N(µmol/l)

Fd Eb Fd Eb

00 00h h

Figure 5.2.5: Temporal Variations in Water quality Parameters (S ) (B ) at Station 1(coastal waters off Kuranga) on 28th December

2012.

20

22

24

26

28

30TEMPERATURE(OC)

8.1

8.2

8.3

8.4pH

0.0

0.2

0.4

0.6

0.8

1.0PO43--P(µmol/l)

600 800 1000 1200 1400 1600 18000.2

0.3

0.3

0.3

0.4

NO2--N(µmol/l)

0.04

0.08

0.12

0.16

0.20

0.24NO3--N(µmol/l)

600 800 1000 1200 1400 1600 18000.04

0.06

0.08

0.10

0.12NH4

+-N(µmol/l)

5.8

6.2

6.6

7.0DO(mg/l)

35.8

36.0

36.2

36.4

36.6SALINITY(ppt)

Fd Eb Fd Eb

000 0h h

Figure 5.2.6: Temporal Variations in Water quality (S ) (B ) at Station 4 (coastal waters off Kuranga) on 16th December 2012.

0

2

4

6

8

10Chl aPhaeo

S B S B S B S B

Fl1000 1200 1400 1500

Figure 5.4.1:Temporal variations in phytopigments at station 1 in costal water of Kurunga on 3 May, 2012

Con

centratio

n (m

g/m3 )

h

0

1

2

3

4

S B S B S B S B S B900 1100 1300 1500 1600

FlFigure 5.4.2: Temporal variations in phytopigments at station 4 in costal water of Kurunga on 30 April, 2012

h

Figure 5.4.1: Temporal variations in phytopigments at station 1 in coastal waters off Kuranga on 3 May 2012.

Figure 5.4.2: Temporal variations in phytopigments at station 4 in coastal waters off Kuranga on 30 April 2012.

0

0.2

0.4

0.6

0.8

1

1.2

Con

centratio

n (m

g/m

3 )

S S S S730 930 1130 1230F.Eb F.Fl

Figure 5.4.3: Temporal variations in phytopigments at station 1 in costal water of Kuranga on 11 September, 2012

h

0

0.2

0.4

0.6

S S S S800 1000 1200 1300

Con

centratio

n (m

g/m

3 )

F.Eb F.FlFigure 5.4.4: Temporal variations in phytopigments at station 7 in costal water of Kurunga on 12 September, 2012

Figure 5.4.3: Temporal variations in phytopigments at station 1 in coastal waters off Kuranga on 11 September 2012.

Figure 5.4.4: Temporal variations in phytopigments at station 7 in coastal waters off Kuranga on 12 September 2012.

0

0.2

0.4

0.6

0.8

S B S B S B S B S B S B S B700 900 1100 1300 1500 1700 1800

Figure 5.4.5: Temporal variations in phytopigments at station 1 in costal water of Kurunga on 28 December 2012

h

Con

centra

tion(

mg/m

3 )

Fl Eb

0

2

4

6

8Chl aPhaeo

S B S B S B S B S B S B S B700 900 1100 1300 1500 1700 1800h

Eb FlFigure 5.4.6: Temporal variations in phytopigments at station 4 in costal water of Kurungaon 16 December 2012

Figure 5.4.5: Temporal variations in phytopigments at station 1 in coastal waters off Kuranga on 28 December 2012.

Figure 5.4.6: Temporal variations in phytopigments at station 4 in coastal waters off Kuranga on 16 December 2012.

0

4

8

12

16

20

hFl

Figure 5.4.7: Temporal variations in zooplnkton at station 1 in costal water of Kurunga on 3 May, 2012

1000 1200 1400 1500

0

4

8

12BiomassPopulationTotal groups

hEb

Figure 5.4.8: Temporal variations in zooplnkton at station 4 in costal water of Kurunga on 30 April, 2012

900 1100 1300 1500 1600

Figure 5.4.7: Temporal variations in zooplankton at station 1 in coastal waters off Kuranga on 3 May 2012.

Figure 5.4.8: Temporal variations in zooplankton at station 4 in coastal waters off Kuranga on 30 April 2012.

0

1

2

3

4BiomassPopulationTotal group

h 730 930 1130 1230F.Eb F.Fl

Figure 5.4.9: Temporal variations in zooplankton at station 1 in costal water of Kurunga on 11 September, 2012

0

1

2

3

4

5

(10)

h 1000 1200 1300 F.Fl

Figure 5.4.10: Temporal variations in zooplankton at station 7 in costal water of Kurunga on 12 September, 2012

Figure 5.4.9: Temporal variations in zooplankton at station 1 in coastal waters off Kuranga on 11 September 2012.

Figure 5.4.10: Temporal variations in zooplankton at station 7 in coastal waters off Kuranga on 12 September 2012.

0

10

20

30

40

Figure 5.4.11: Temporal vriation in zooplankton at station 1 during 12 December, 2012

700 900 1100 1300 1500 1700 1800

Fl Eb

h

0

40

80

120

160

200

Biomas

s (m

/100

m3 ), P

opulation (n

o x 10

3 /100

3 )

To

tal g

roup

(no)

Figure 5.4.12: Temporal variation in zooplankton at station 4 during 16 December, 2012

h 700 900 1100 1300 1500 1700 1800

Eb Fl

Figure 5.4.11: Temporal variations in zooplankton at station 1 in coastal waters off Kuranga on 12 December 2012.

Figure 5.4.12: Temporal variations in zooplankton at station 4 in coastal waters off Kuranga on 16 December 2012.

Figure 5.4.13: Intertidal transects (IV - VI) for investigation of corals along Kuranga coast.

Figure 6.2.1: Study domain for the hydrodynamic modeling studies showing the intake

locations (IT1 and IT2) and outfall locations (OF1 and OF2).

Figure 6.3.1: Terrain features of study region in coastal waters off Kurunga.

Figure 6.3.2: Computational BFC grid.

Figure 6.3.3: Contours of computed bathy depths (m).

Figure 6.3.4: Contours of Chezy’s coefficient (m1/2 /s).

Figure 6.3.5: Boundary input tides.

Figure 6.3.5 (a): Comparison of computed and calculated tides at outfall location (OF1).

Figure 6.3.5 (b): Comparison of computed and calculated currents at calibration point (22° 01'

14.2" N, 69° 07' 16.3" E).

Figure 6.4.1: Simulated tides during a typical spring tide (LLW).

Figure 6.4.2: Simulated currents during a typical spring tide (LLW).

Figure 6.4.3: Simulated tides during a typical spring peak flood.

Figure 6.4.4: Simulated currents during a typical spring peak flood.

Figure 6.4.5: Simulated tides during a typical spring (HW).

Figure 6.4.6: Simulated currents during a typical spring (HW).

Figure 6.4.7: Simulated tides during a typical spring peak ebb.

Figure 6.4.8: Simulated currents during a typical spring peak ebb.

Figure 6.5.1 Terrain features of study region

Figure 6.5.2 Computational BFC grid

Figure 6.5.3: Simulated tides during a typical spring (LW) with intake at IT1.

Figure 6.5.4: Simulated currents during a typical spring (LW) with intake at IT1.

Figure 6.5.5: Simulated tides during a typical spring (HW) with intake at IT1.

Figure 6.5.6: Simulated currents during a typical spring (HW) with intake at IT1.

Figure 6.5.7: Observation points around the Intake point IT1

Figure 6.5.8 (a): Variation of elevation/tides at different observation points around intake IT1.

Figure 6.5.8 (b): Variation of elevation/tides at different observation points around intake IT1.

Figure 6.5.9 (a): Variation of currents at different observation points around intake IT1.

Figure 6.5.9 (b): Variation of currents at different observation points around intake IT1.

Figure 6.5.10: Simulated tides during a typical spring (LW) with intake at IT2.

Figure 6.5.11: Simulated currents during a typical spring (LW) with intake at IT2.

Figure 6.5.12: Simulated tides during a typical spring (HW) with intake at IT2.

Figure 6.5.13: Simulated currents during a typical spring (HW) with intake at IT2.

Figure 6.5.14: Observation points around the intake point IT2.

Figure 6.5.15 (a): Variation of elevations/tides at different observation points around intake IT2.

Figure 6.5.15 (b): Variation of elevations / tides at different observation points around intake IT2.

Figure 6.5.16 (a): Variation of currents at different observation points around intake IT2.

Figure 6.5.16 (b): Variation of currents at different observation points around intake IT2

Figure 6.6.1: Temperature dispersion during a typical spring (LW) with release at OF1.

Figure 6.6.2: Temperature dispersion during a typical spring peak flood with release at

OF1.

Figure 6.6.3: Observation points around the outfall point OF1

Figure 6.6.4 (a): Variation of excess temperature at different locations around OF1.

Figure 6.6.4 (b): Variation of excess temperature at different locations around OF1.

Figure 6.6.5: Ammonia dispersion during a typical spring LW with release of OF1.

Figure 6.6.6: Ammonia dispersion during a typical spring peak flood with release at OF1.

Figure 6.6.7 (a): Variation of ammonia (above ambient) at different locations around OF1.

Figure 6.6.7 (b): Variation of ammonia (above ambient) at different locations around OF1.

Figure 6.6.8: SS dispersion during a typical spring (LW) with Outfall at OF1.

Figure 6.6.9: SS dispersion during a typical spring peak flood with Outfall at OF1.

Figure 6.6.10 (a): Variation of SS (above ambient) at different locations around OF1.

Figure 6.6.10 (b): Variation of SS (above ambient) at different locations around OF1.

Figure 6.6.11: Temperature dispersion during a typical spring (LW) with outfall at OF2.

Figure 6.6.12: Temperature dispersion during a typical spring peak flood with outfall at OF2.

Figure 6.6.13 : Observation points around the outfall point OF2

Figure 6.6.14 (a): Variation of temperature (above ambient) at different locations around OF2.

Figure 6.6.14 (b): Variation of temperature (above ambient) at different locations around OF2.

Figure 6.6.15: Ammonia dispersion during a typical spring (LW) with outfall at OF2.

Figure 6.6.16: Ammonia dispersion during a typical spring peak flood with outfall at OF2.

Figure 6.6.17 (a): Variation of ammonia (above ambient) at different locations around OF2.

Figure 6.6.17 (b) Variation of ammonia (above ambient) at different locations around OF2.

Figure 6.6.18: SS dispersion during a typical spring (LW) with outfall at OF2.

Figure 6.6.19: SS dispersion during a typical spring peak flood with outfall at OF2.

Figure 6.6.20 (a): Variation of SS (above ambient) at different locations around OF2.

Figure 6.6.20 (b) Variation of excess SS (above ambient) at different locations around OF2.

Figure 6.7.1: Instantaneous rates of erosion during a typical spring peak flood due to release

at OF1.

Figure 6.7.2: Instantaneous rates of erosion during a typical spring peak ebb due to release at

OF1.

Figure 6.7.3: Instantaneous deposition rates during a typical spring (LW) due to release at

OF1.

Figure 6.7.4: Instantaneous deposition rates during a typical spring (HW) due to release at

OF1.

Figure 6.7.5: Bed level changes after 15 days due to release at OF1.

Figure 6.7.6: Different observation point locations around outfall location OF1.

Figure 6.7.7 (a): Instantaneous rate of erosion at different observations points due to release at

OF1.

Figure 6.7.7 (b): Instantaneous rate of erosion at different observations points due to release at

OF1.

Figure 6.7.8 (a): Instantaneous rate of deposition at different observations points due to release

at OF1.

Figure 6.7.8 (b): Instantaneous rate of deposition at different observations points due to release

at OF1.

Figure 6.7.9 (a): Bed level changes at different observations points around OF1.

Figure 6.7.9 (b): Bed level changes at different observations points due to release at OF1.

Figure 6.7.10: Instantaneous erosion rates during a typical spring Peak Flood due to

release at OF2.

Figure 6.7.11: Instantaneous erosion rates during a typical spring peak ebb due to

release at OF2.

Figure 6.7.12: Instantaneous deposition rates during a typical spring (LW) due to release

at OF2.

Figure 6.7.13: Instantaneous deposition rates during a typical spring (HW) due to

release at OF2.

Figure 6.7.14: Bed level changes after 15 days due to release at OF2.

Figure 6.7.15: Different observation point locations around outfall around OF2.

Figure 6.7.16 (a): Instantaneous rate of deposition at different observations points due to

release at OF2.

Figure 6.7.16 (b): Instantaneous rate of deposition at different observations points due to

release at OF2.

Figure 6.7.17 (a): Bed level changes at different observations points due to release at OF2.

Figure 6.7.17 (b): Bed level changes at different observations points due to release at OF2.

Figure 6.8.1: Trajectory of a particle discharged at OF1.

Figure 6.8.2: Trajectory of a particle discharged at OF2.

Figure 7.1.1: Map showing alignments of effluent disposal pipeline (LFP1-DP-OF1/OF2) and seawater intake pipeline (LFP2-IT1).