54

CHAPTER III

STUDY AREA

3.0 INTRODUCTION

The system chosen for the study, namely, the Veeranam Tank

System, and the database employed in the study are described in this

chapter. The Veeranam Tank System is one of the major irrigation tank

systems of Tamil Nadu. It forms a part of the Cauvery basin, the largest of

the river basins of Tamil Nadu. The sub-basin to which it belongs is referred

to as the Udayarpalayam-Cauvery basin, a minor basin of the Coleroon

basin. The Veeranam Tank System is the second largest in terms of tank

capacity (1465 Mcft), next only to the Chembarambakkam Tank(3,645

Mcft), which is near Chennai(Arumugam and Mohan,1997) and is also a

source of drinking water for the city, the capital of Tamil Nadu. The

Veeranam Tank is located at 235 km south of Chennai. It commands the two

taluks of Kattunannarkoil and Chidambaram comprising of a large number

of villages and hamlets, which sums up to 91.It is a system tank, as it

receives water from the Lower Coleroon Anicut System through a feeder

canal and small amount of surplus from other small tanks upstream of it, in

addition to rainfall intercepted by its catchment. The Veeranam Tank is the

largest wetland ecosystem of Tamil Nadu as well as a migratory spot for

several rare species of water birds during winter, from October to March.

55

The purpose of this chapter is to provide a reasonable profile of the

study area, particularly the Veeranam Tank Catchment, and place it amidst

its ‘surround’, which includes the Cauvery and the Coleroon River System,

the Catchment and Command of the Veeranam Tank System. The focus of

discussion is both the physical and the socio-economic systems of the

Veeranam Tank System first and the Chennai city water supply scheme

popularly known as the New Veeranam Project. In effect, the Drinking

Water Supply Scheme of the Veeranam Project draws much of the waters of

the Veeranam Tank System and thus resulting in the conflict of interest

between the farmers of the Veeranam Command and the people of the city

of Chennai.

3.1 THE STUDY AREA AND THE STUDY PERIOD

The study area of the present research is the Veeranam Catchment

and the purpose is to estimate the surface runoff in the catchment using three

estimation models, namely, the Strange Table Method, the NRCS-CN model

and the SWAT model, the results of which are compared with that of the

Indirectly Estimated flow in the catchment. In addition, land use and land

cover changes are also studied using remotely sensed data and the

geographical information systems. The period of estimation and analysis are:

surface runoff estimation 1980-2011 but comparison is made only for 1995

to 2011. Land use / land cover change detection covers 1986, 1996, and

2005.

56

3.2 THE CAUVERY AND COLEROON RIVER SYSTEMS

The Cauvery River is famous for its traditional sanctity, picturesque

scenery and utility of irrigation in the state of Tamil Nadu, being the largest

of the river systems of the state of Tamil Nadu. The Cauvery originates in

the Brahmagiri Hills of Kodagu district of Karnataka. It flows on to the

Deccan Plateau, taking a long course through Karnataka before entering into

the state of Tamil Nadu through Krishnagiri district and through the famous

waterfalls at Hogenekkal. It then slides and glides into the flat plains of the

state where it meanders like a snake with glittering but slowing waters

heavily burdened by the sediments. The tributaries of Palar, Chennar and

Thoppar join the Cauvery on its journey above the Stanley Reservoir at

Mettur. Then the Cauvery traverses through the textile towns of Erode and

Karur via the mango town of Salem.

From Mettur in Salem district, where the Mettur dam is on the river

Cauvery (the reservoir of this dam is known as the Stanley Reservoir) which

is the lifeline for the rice bowl of erstwhile Thanjavur, the river Cauvery

runs for a distance of 115 km to Upper Anicut (Anicut is a Tamil word for a

dam, small or large as the case may be). The river Cauvery branches off into

two arms at the Upper Anicut. The left arm is the Cauvery while the right

arm is the Coleroon. A barrage was constructed on the Coleroon in 1836.

And from this point onwards, the river Coleroon serves as the flood carrier

57

and runs parallel to the Cauvery. About 32 km down the Upper Anicut, the

surplus waters of the Cauvery is let into the river Coleroon. In the irrigation

season of the area, 10 percent of the realization at the Grand Anicut is let

into the Coleroon to irrigate the ayacut in Chidambaram and

Kattumannarkoil taluks of Cuddalore district and Sirkazhi taluk of

Nagapattinam district. Besides, the water drained from the Cauvery ayacut is

also received in the river Coleroon and is utilized in the development of the

ayacut of the Coleroon Anicut system.

Further about 108 km down from the Upper Anicut, a regulator was

constructed across the river Coleroon at Anaikkari in 1836 as well, to serve

as a diversion and a flood regulator for the ayacuts in Cuddalore and

Thanjavur districts. It fact, it was an anicut, originally, but in the year 1901

shutters of about 2 metres in height were provided for the purpose of flood

regulation. Later in 1909 the height of the shutters was increased to about

2.5 metres and again to nearly 3 metres in 1953. Four channels by the names

Vadavar, Coleroon North Rajan, Kanjankollai and Vinayagantheru take off

from the left of the regulator and irrigate an ayacut of 42,470 ha in first crop

and 9,387 ha in the second crop seasons in Cuddalore district. Similary,

four other channels, namely, Coleroon South Rajan, Kummukkimanniar,

Melaraman and Keelaraman take off from the right side and together irrigate

an extent of 12,480 ha in the first crop season and 3,538 ha in the second

crop season in Thanjavur district.

58

The regulator was designed to discharge 0.45 million cusecs of floods

and the maximum discharge observed was about 0.39 million cusecs in

1924, 0.18 million cusecs in 1961, 0.152 million cusecs in 1977, 0.18

million cusecs in 1989 and 0.23 million cusecs in 1993, all of which were

flood years.

Among the Northern branch channels, the discharges from the

Vadavar channel (5 vents) is 2,200 cusecs, North Rajan channel is 675

cusecs and the other two channels together discharge 8 cusecs only. Further,

among the southern branch channels, the South Rajan channel discharges

443 cusecs, Kummukkimanniar channel 32 cusecs and Melaraman channel

25 cusecs.

The total discharge draining into the Veeranam Tank from the Sengal

odai is 10,000 to 15,000 cusecs. But the discharges from the Karvatti odai

happens only when a continuous rainfall of 3-4 days is received and the flow

in varies depending on the intensity and quantity of rainfall flowing as the

runoff. The surplus flow arrangements from the Lalpet weirs lead to a

discharge of 17,845 cusecs and the discharge from the right flank surplus

weir is 3,517 cusecs.

The Veeranam Project for the Chennai city water supply scheme is a

part of this larger system of the river Coleroon. The study area being the

Catchment of the Veeranam Tank System, which is an ungauged system, the

59

study focuses pointedly on the estimation of surface runoff entering into the

Veeranam Tank and also what is lost to the system second and then what is

taken away from the people of the Command as the drinking water for the

city of Chennai.

3.3 LOCATION OF THE VEERANAM TANK SYSTEM

The Veeranam Tank is in the West of Chidambaram town of

Cuddalore district. The Veeranam catchment is between 11o10

’N and 11

o25

’

N latitudes and 79o10’ E and 79

o25’E longitudes. It covers a total catchment

area of 542.94 km2

including the Veeranam Tank. The tank is about 24 km

west of Chidambaram town, is elongated in shape, starting from

Kattumannarkoil in the south to Sethiyathope in the North. Veeranam Tank

system is an irrigation tank of Tamil Nadu and forms part of the Cauvery

basin. The sub-basin to which it belongs is referred as Udayarpalayam minor

basin of lower Coleroon basin. The total capacity of the Veeranam Tank

was 1,465 Mcft as per silt survey conducted during New Veeranam project. .

Figure 1 shows the location of the Veeranam Tank. The study period

considered for the study is 1980-2011 and for comparison with indirectly

estimated flow the period selected is between 1995 and 2011.

3.4 THE VEERANAM TANK SYSTEM

The Veeraman tank system is a part of the Lower Anicut system. The

main source of supply of water to the tank is the Vadavar canal, the feeder

canal taking off from the head sluice of the Lower Anicut, at Anaikkarai.

60

The Vadavar canal branching from the Lower Anicut is running to a distance

of 22 km and finally falls into the Veeranam Tank. Its command area has an

extent of 11,282 acres with 24 branch channels providing for irrigation.

3.4.1 Water Spread Area

The tank has had an original water-spread area of 38.85km2

at FTL

long back, may be in the early 1960s. The water spread area has become

gradually reduced due to deposition of silt on the bed of the tank. The last

known extent according to the silt survey of 1982 was 23.66 km2. The

capacity of the tank at FTL of 14.47 m is 41.46 Mm3. The Radha Canal is

taken as the reference sluice of the Veeranam Tank for hydraulic parameters

as it forms the midpoint of the main bund stretch. Figure 3.1 shows the

location map of the study area.

Figure 3.1 Location of the study area: The Veeranam Tank Catchment

and its Environs

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3.4.2 Chennai Metro Water Supply

The New Veeranam Project was resorted to rescue the thirsty

Chennai, as it was known as the solution of all problems. Under the project,

a pipeline was laid and a total of 180 MLD of water was sent to Chennai

from the Veeranam Tank over a distance of 235 km.

3.4.3 Surplus Water

There are two sets of three surplus weirs known as the Lalpet Weirs,

on the end of the southern flank of the tank, just below the entry of the

Vadavar canal, with manually operated shutters. There are 14 vents, each of

the size of 6.1 m x 1.905 m, with manually operated shutters, over a sill

level of +12.344 m .In addition, there is one nature-paved bye-wash on the

right of Lalpet weirs for a length of 150 m, which has the crest level at 14.1

m. The maximum designed discharge of the two surplus arrangements is

21,362 cusecs. On the Northern tip of the tank, there is a sluice called

Veeranam New Supply Sluice (VNSS) through which water from Veeranam

is supplied to the Vellar River, just upstream of the Sethiyathope Anicut

across the Vellar River. Figure3.2 shows the layout of the Veeranam tank.

62

Figure 3.2: The Layout of the Veeranam Tank System

3.5 Physiographic Features

3.5.1 Geology

The study of geology of the basin helps with the understanding of the

various rock types and soil groups present in the study area. Soil types play

an important role in controlling the infiltration of a place and hence the

surface runoff. In the Veeranam catchment, as shown in Table 3.1 Figure

3.3, 76.36 percent of the area is covered with coarse sand stone with clay,

20.48 percent of the area is covered with clay and sand stone, 3.15 percent

Grand Anicut

Lower Anicut

Veeranam tank

Cauvery River

Mettur Dam

Cauvery River

Upper Anicut

Coleroon

Vadavar Channel

Cauvery

Ullar

Vennar

Cauvery River

Canal

K.M. canal

South Rajan channel

Coleroon

North Rajan channel

Lalpet surplus weir

VNSS

Surplus regulator

VNES

Sethiyathope

anicut

Vellar river

Vellar river

63

of the area is covered with clay and 0.003 percent of the area is covered with

sand and silt.

Table 3.1: Geological Formations of the Study Area

Lithology Area in km2 Area in

percentage

Clay 16.33 3.15

Clay and sand stone 106.15 20.48

Coarse Sand stone with clay 395.77 76.36

Sand and silt 0.017 0.003

Figure 3.3 Geology map of the study area

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3.5.2 Geomorphology

Geomorphology deals with different landforms, which are related to

the occurrence and distribution of groundwater as well as the land use

patterns of the basin. Geomorphology of a place also plays an important role

in controlling infiltration and hence the surface runoff. The Veeranam

catchment has nearly 70 percent of its area under pediplain, 23.17 percent

under upland, 6.83 percent under alluvial plains and 0.27 percent under

floodplains Table 3.2 Figure3.4.

Table 3.2: Geomorphology of the study area

Geomorphic units Area in km2

Area in percentage

Alluvial plain 35.42 6.83

Flood plain 1.408 0.27

Pediplain 361.15 69.71

Upland 120.04 23.17

Figure 3.4 Geomorphology map of the study area

65

3.5.3 Morphometric Analysis

The study of morphometric analysis of the Veeranam catchment

basin has been conducted based on the secondary source of data: the SRTM

(Shuttle Radar Topographic Mission) data. The data were downloaded from

the http://www.srtm.csi.cgiar.org website. Total number of streams in the

catchment is 1,753 of which 1,356 are of the first order, 307 are of the

second order, 75 are of the third order, 12 are of the fourth order and 3 are of

the fifth order streams. The number of streams decreases as the stream order

increases. Basin area is 542.94 km2.Basin length is 40.39 km. Basin

perimeter is 124.5 km. Drainage density is 2.29 per square kilometres

indicates that the subsurface soil is impermeable. Circulatory ratio of 0.44

indicates that the catchment is elongated in shape with high runoff and low

permeable sub-soils. Form factor is 0.33 which shows that the basin is

elongated have lower peak flow of longer duration.

Shape of the basin: Elongated in shape stretching between Kattumannarkoil

and sethiyathope.

Elevation: Minimum elevation is 6m and Maximum elevation is 116 m.

Type of drainage network : The below mentioned patterens are most

commonly available drainage patterens. Figure3.5. Of which the pattern

exists in the study area is Dendritic to sub-dendritic. Looks like branching

pattern tree roots. Since the underlying material is homogenous this was

developed. In this case tributaries join at acute angle.

66

Figure 3.5 Common drainage patterns

3.5 CHARACTERISTICS OF THE VEERANAM CATCHMENT

The characteristics of the Veeranam Catchment are looked at from

various angles but particularly from the physical and the socio-economics of

the area of study. It is important to note that the Veeranam Tank System is

located in the rain shadow of the Western Ghats, depriving the catchment

and the command the rainfall of the southwest monsoon. Based on the

rainfall distribution, irrigation patterns, cropping patterns and other physical,

ecological, social and economic characteristics, the Veeranam Tank System,

and hence the study area, that is, the Veeranam Catchment is in the agro-

climatic zone known as the Cauvery-Delta Zone (Arumugam and Mohan,

1977).

67

However, in the Northeast and retreating monsoon period, the region

receives about 70 per cent of its total rainfall, because the rain shadow has

no effect in this period between October to December. The area of the

system is also within 30 km of the Bay of Bengal, thus falling within the

influence of the sea. Hence, the low pressure troughs formed in the south of

Bay of Bengal during the Northeast monsoon brings heavy rains to the study

area.

The source of supply of water to the Veeranam Tank System is the

Vadavar canal, which is indeed a feeder canal, taking off from the head

sluice of the Lower Anicut, at Anaikarai. The tank also receives its supply

from the runoff caused by the rainfall in its own catchment area. Surpluses

from other tanks upstream flow at times into the tank as well.

3.5.1 Climate and Rainfall

The Veeranam Tank Catchment and Command have a typical tropical

climate. It is indeed a hot summer and a mild winter. Agro-climatically,

however, the area of our concern in the study falls under the semi-arid

region of the State of Tamil Nadu, which is between the coastal and the hilly

or highland regions. The average annual rainfall in the area is about 1022.67

mm, of which 613.7mm is received during October to December; that is, the

Northeast monsoon season. The rest of the rainfall is accounted for by the

three other seasons, namely, the southwest monsoon, the hot weather and the

68

cold weather (Arumugam and Mohan, 1977). The vagaries of the weather

about here are such that, often, the Veeranam Tank has to depend on the

release of the water from the Mettur dam on the Cauvery system, which

traverses also through the Grand Anicut system. There are six raingauge

stations located in and around the basin. Fairly good amount of rainfall is

received from five stations except for a station by the name Senthurai.

3.5.2 Solar Radiation: The solar radiation during the Northeast

monsoon varies from 16 MJ/m2/day to 20 MJ/m

2/day. The solar radiation is

generally high during the months of March, April and May, which is the

summer season.

3.5.3 Temperature: Temperature of the study area averages from

20° C to 38° C in winter and from 26° C to 41° C in summer. In summer,

hot weather prevails in the study area with the maximum temperature

varying from 30o

C to 38o

C, with moderately hot summers and mild

winters.

3.5.4 Relative Humidity: The relative humidity values of the basin

area vary between 65 percent and 70 percent. Generally, however, relative

humidity is quite high during the monsoon seasons (Southwest and

Northeast) compared to the non-monsoon seasons (Winter and Summer).

3.5.5 Wind Velocity: The Northeast monsoon wind velocity varies

between 2.8 m/s and 3.5 m/s. The wind velocity is high during the months of

69

June, July and August, mainly influenced by the southwest monsoon (June –

September) winds.

3.5.6 Evapotranspiration and Potential Evapotranspiration: The

mean monthly evapotranspiration of the Northeast monsoon ranges between

57 mm and 66 mm whereas the average mean monthly Northeast monsoon

potential evapotranspiration ranges between 135 mm and 159 mm.

3.6 SOURCES OF SUPPLY

The Veeranam Tank receives runoff from its own catchment through

five drains, namely, the Karruvattu odai (182.93 km2), Vannanguli odai

(102.41 km2), Papagudi odai (15.53 km

2), Sengal odai(131.96 km

2) and

Palayamkkottai odai (86.18 km2).The water resources potential of the

Cauvery river basin covering a geographical area of 87,900 km2, in 2005,

was assessed at 21.36B CM for the surface water and at 12.30 BCM for the

dynamic (rechargeable) groundwater potential by the National Commission

for Integrated Water Resources Development Plan (NCIWRDP).

The Cauvery, originating and taking a long course through Karnataka

before entering into Tamil Nadu through Krishnagiri district meanders into

the flat plains. Three minor tributaries of the Cauvery join the river above

the Stanley Reservoir at Mettur and traverses through Erode district. Then

the river Cauvery flows in an easterly direction until it splits into two at the

Upper Anicut, about 14 km west of Tiruchirappalli. The Northern fork of the

70

river, the Coleroon, and the southern branch, the Cauvery and flows directly

eastwards into Thanjavur district. The river Cauvery commands the entire

districts of Thanjavur, Thiruvarur and Nagapattinam, by different names,

through its 34 distributaries and their branches.

From the head of the Grand Anicut system, the Coleroon river runs

Northeast and irrigates the ayacut of Sirkazhi taluk of Nagapattinam district

and Chidambaram and Kattunannarkoil taluks of Cuddalore district.

Ultimately, it discharges itself into the sea at Devakottai, a little south of

Parangipettai. The total length of the river from the origin to its outfall into

the sea is 800km,of which 320km is in Karnataka,416km is in Tamil Nadu,

and 64km forms the common border between the states of Karnataka and

Tamil Nadu (CWC, 2005).The Vadavar, as indicated earlier, is one among

the four channels that take off from the left side of the regulator. The

Vadavar canal which is 21.80 km long directly commands an area of 4,740

ha, prior to discharging into the Veeranam Tank. The Cauvery contributes

nearly 75 percent of the Veeranam waters.

The catchment is characterized dominantly by Cuddalore sandstone

of the Tertiary period, underlain and is surrounded by alluvial deposits of

Quaternary age to a major extent, except in the southwest, where the

sedimentary rocks of the Cretaceous age are present. Charnockites, gneisses

of the Archaean age are found further west. All these rock formations,

71

except for alluvium, have a distinct NE-SW (Northeast –Southwest) strike

(Selvaraj and Ramasamy, 1998).The topsoil comprises of black soils or

clay loams.

There are about 135tanks in total (83 significant and 52 insignificant

ones) in the catchment from where the surplus overflows downstream into

the Veeranam Tank, in addition to the rainfall excess of the free catchment

(Ashik, 2008). Sengal odai and Karuvaattu odai are the two major drainage

courses, carrying runoff from its catchment to the tank. The catchment is

more or less fan–shaped and is a triangle. The maximum inflow of water

into the Veeramam tank is during the Northeast monsoon; that is, during

October to December. Inspite of the different sources of supply, the tank

invariably goes dry for a period of nearly six months from February to July,

almost every year.

The tank has had an original water-spread area of 38.85km2

at full

tank level. The water spread area has become gradually reduced due to silt

deposition in the bed of the tank. The tank is bounded on the eastern side by

a main bund, 16 km long in the North-South direction which has a black-

topped motorable road over it, connecting the towns Sethiyathope and

Kattumannarkoil. The foreshore bund lies on the western side of the tank,

for a length of 10.90 km, which was extended to 35.32km recently to avoid

breaches and restrict encroachment of the farmers. There are 34 sluices

72

taking off from Veeranam Tank for its command area with branch canals, 28

sluices in the main bund and 6 sluices on the foreshore bund.

The capacity of the tank at the full tank level of 14.47 m is 41.46

Mm3. Radha canal is taken as the reference sluice of the Veeranam Tank for

all its hydraulic parameters, as it forms the midpoint of the main bund

stretch. It is maintained by the PWD, enabling consistency in measurements

that can be taken as a basis for tank flow parameters. The tank has two

flowing water courses bounded on two sides: the Vellar river course to the

North of it, meeting at Sethiyathope and the tail-end of the Coleroon River,

flowing south of it towards the Bay of Bengal. As they form a boon for

irrigating the agriculturally predominant district so also these flood carriers

cause considerable devastation during floods.

3.7 COMMAND AREA

The present command area under the tank is 44,856 acres or 18,153

hectares. Until three decades ago, double crop was raised in about 50 percent

of the total command area. But over the last thirty years, the area under

double crop had considerably reduced due to non-availability of sufficient

water for raising two crops in a water year (June to May). This was partially

due to socio-economic reasons also. Inquiries with local riots reveal that

originally, one filling of the tank at the beginning of the irrigation season

was quite sufficient to irrigate the entire command area, in the major portion

73

of which only single crop was raised. But now, due to the reduction in the

original capacity of the tank due to silting, more than one filling of the tank

is necessary to maintain supply to its command area till the end of the

irrigation season. There are 34 sluices with canals taking off from the

Veeranam Tank to cater to the needs of its command area. Out of this, 28

sluices are on the main bund and are generally able to serve the command

area throughout the season. To facilitate this, a canal connecting all the

sluices in the main bund has been excavated inside the tank bed, parallel to

the bund. This is referred to as ‘Thottivaikkal’ in Tamil, meaning ‘the canal

in the tank’. This enables the operation of any of the sluices for low water

levels, without leaving dead storage of water in any portion of the tank bed.

The remaining 6 sluices are located along the foreshore bund and are thus

high level sluices. The supply for these sluices is assured only when the tank

contains water more than two-thirds full.

Major canals are governed and financed by the Water Resources

Organization Wing of the Public works Department whereas several sluices

are revenue canals, which are supported by the revenue from the farming

community in the respective command. Table 3.3 shows the salient features

of Veeranam tank.

74

3.8 SALIENT FEATURES OF THE VEERANAM TANK

Table 3.3 Salient Features of the Veeranam Tank

Climate : Sub-tropical, semi-arid

Average rainfall : More than 1022.67 mm

Main bund : 16 km (North-South direction), 28 sluices

Foreshore bund : 35.32 km, 6 sluices

System : Lower ColeroonAnicut, Coleroon river

Basin : Udayarpalayam Cauvery Basin

Sources of supply :(i) Vadavar feeder canal from Lower Anicut

(ii) Rainfall from own catchment

Water spread area : 38.85 km2.

Command area : 44,856 acres (18,153 ha)

Catchment : 542.94 km2

Capacity : 1,465 Mcft or 41.46 Mcum

3.9 OBJECTIVES OF THE TANK SYSTEM

The Tank was a full-fledged irrigation system for over a long,

historical period till recently, solely catering to the agricultural requirements

of the two taluks of Kattumannarkoil and Chidambaram. The scenario

considerably changed when it was identified as a source of drinking water to

supplement the ever-rising demand of the state’s capital city, which was

facing a severe crisis for several consecutive years. The Tamil Nadu

Government was taking all possible efforts to combat the drinking water

crisis of Chennai. The name of the project being New Veeranam Project,

after various stages of planning on a major scale was launched in February

75

2003 and was implemented since November 2004, to supplement Chennai’s

dwindling water storage.

During the severe drought in 2004,that is, upto October 2004, since

all the sources supplying water to Chennai City were dry and there was no

water received from the Kandaleru reservoir under the Telugu Ganga

Project, about 100 MLD (Million Litres per Day) of water was transported

from distant sources like Gummidipoondi, Minjur, Tamaraipakkam,

Periyapalayam, Poonamallee, Mamandur-Palur, Thiruporur, and

Karunguzhi, covering a distance of about 120 km to 150 km and the total

quantity transported was 23,439.79ML (million litres) during the period

from 27/6/2003 to 9/11/2004. The water Supply to Chennai City was

maintained through mobile tankers by way of filling 14,602 stationary tanks

and 8,000 street supplies. The Government undertook this massive and

onerous task of distribution through the Chennai Metropolitan Water Supply

and Sewerage Board (CMWSSB or Metro Water) at a cost of Rs.1966.9

million during 2004-2005(CMWSSB Draft Policy Note 2005-2006). The

CMWSSB was constituted in 1978 for exclusively attending to the growing

needs and was responsible for planned development and appropriate

regulation of water supply and sewerage services in the Chennai

Metropolitan Area.

76

The first phase of the Telugu Ganga Project having been

commissioned in 1996 expected to bring a total of 12 tmcft (thousand

million cubic feet) in two instalments from the Srisailam reservoir across the

Krishna, through an open channel to Poondi. But the anticipated amount did

not reach Chennai, as the project delivered only a total of 15 tmcft to

Chennai over 7 years from 1996 to 2003, against the projected 84 tmcft.

Moreover, the quantity that arrived in the city was less than one-third of the

original receipts at the state border because of the seepage in channels and

other losses. In February 2004, the Krishna water released from the

Kandaleru reservoir in Andhra Pradesh which reached the state border near

Uthukottai in Tamil Nadu, travelling 152 km to reach Poondi. But hopes

evaporated on account of the illegal tapping of water by the farmers and the

withdrawal of water to meet the demands of Tirupati town in Andhra

Pradesh. More to add, was the increase in height of the Alamatti dam in

Karnataka (Water Sovereignty Series 7, 2005). As a result, only

disappointment was in store for the CMWSSB, Tamil Nadu. The storage of

water available in the main surface sources of Chennai city, namely, Poondi,

Cholavaram and Redhills as on 01/01/2005 was 1,859 Mcft against the total

capacity of 7,412 Mcft and they were not in a position to meet the demand

on account of the scanty rains of the southwest monsoon in 2004. The

question posed was: how to handle the drinking water crisis of Chennai?

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It was at this juncture, the New Veeranam Project was resorted to, to

rescue the thirsty Chennai as it was known, as it was the solution of all the

problems. Under the project, a pipeline was laid, planning to send 180 MLD

of water to Chennai from the Veeranam Tank in Sethiyathope over 235 km.

The New Veeranam Project was launched in February 2003, and the project

was executed and completed on a fast track basis in June 2004. But the

World Bank funded Rs.7200-million project was unable to provide the

lake’s water to Chennai when it needed the most, as it was dry when the

project was over. Invariably every year, from February to July, the lake stays

dry. So, initially water from the 45 bore wells drilled along the length of the

pipeline under the Drought Contingency Plan was used to extract 20 MLD,

which was gradually stepped up to 90 MLD. After the Veeranam Tank

received freshes and filled up quickly, the full supply of 180 MLD of water

to Chennai city through the New Veeranam Project commenced

on13/10/2004 (CMWSSB Draft Policy Note 2005-2006).

During the end of 2004, it was this project, which saved Chennai. It

was realized that the tank had a promising sustainable water supply at least

for a few months to cater to the city’s water requirements in addition to

irrigation supply. Of course, there was a lot of objection on the part of the

riparian districts with regard to their claim on this valuable resource as they

were forced to share with others who lived far off. The villages along the

pipeline felt that water going into the pipeline was irrigation denied to them.

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Repeated droughts caused several farmers to run into heavy debt. Most

farmers had to stop growing their first crop (July-September) over the past

thirty years because the tank gets very little water from the Cauvery, the

affair being a 30-year-old bitter dispute between Tamil Nadu and Karnataka.

This has led to farmers relying solely on the second crop (September-

January), irrigated by the tank waters during the Northeast monsoon. Most

often they do not have sufficient water for a single crop. The Government

states that it is only the excess water from the Veeranam that is supplied to

Chennai but it is, in reality, otherwise, in the opinion of the farmers of the

area. The conflict remains alive. The water is pumped from an intake

structure at Sethiyathope and the raw water is treated at a place called

Vadakkuthu between Vadalur and Panruti and the quantum of water

transported to Chennai however varies based on the availability. Table 3.4

shows Hydrological particulars of the Veeranam tank.

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3.10 HYDROLOGICAL PARTICULARS OF VEERANAM TANK

Table 3.4: Hydrological Particulars of the Veeranam Tank

Full Tank Level (F.T.L.) : 47.50 ft (14.470 m)

Maximum Water Level

(M.W.L.): 50.00 ft (15.240 m)

Tank Bund Level (T.B.L.) : 54.00 ft (16.460 m)

Capacity at F.T.L. : 1465 Mcft

Water spread at F.T.L. : 15 sq.miles (or) 38.40 sq.km.

Maximum width of tank : 5.63 km

Circumference : 40.225 km

Length of main bund : 15.30 km

Width of main bund : 8m (average)

Length of fore shore bund : 35.32 km

Number of sluices : 34 (28 in the main bund and 6 in

the foreshore bund)

Sill level of lowest sluice : Periyamadagu,+27.67 ft(8.44m)

Sill level of highest sluice : Anaikkal,+39.81 ft (0m)

Sill level of highest sluice of

foreshore: Kudigadu, +41.00 ft (12.50m)

Tank reference sluice Radha +31.90 ft (11.92m)

Source: Public Works Department – Water Resources Organization 2014.

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3.11 THE VEERANAM PROJECT, CITY WATER SUPPLY

SCHEME

Table 3.5 shows some details of the Veeranam Project, City Water

Supply Scheme. The sill level of intake tower is 30 plus feet and the number

of vents is 6. Of the six vents, the sill of two vents is 39 plus feet, two others

is 41 feet and the last two is 43 feet.

Table 3.5: The Veeranam Project City Water Supply Scheme

Sill level of intake tower : +30.00 ft

Number of vents : 6 Nos.

Sill of vents : 2 Nos. at +39.00 ft

2 Nos. at +41.00ft

2 Nos. at +43.00 ft

Sill of RCC Box conduct : +32.00 ft

Source: Public Works Department – Water Resources Organization 2014.

3.12 CODIFICATION OF WATERSHED

According to the All India Soils and Land Use Survey Organization

(AISLUS, 1990), the codification of the micro-watersheds as part of the sub-

catchment ‘4B1A5f’, (the letters insist the following: ‘4B1A5f’-sub-

watershed of the Lower coleroon Watershed), Cauvery basin, Tamil Nadu.

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4-Region : The region covering reverse draining into Bay of

Bengal Except Ganges and Brahamaputra.

B-Basin : River basin between Cauvery and Krishna.

1- Catchments : Between Cauvery and Palar

a - Sub-catchment : Between Cauvery and Pennaiyar.

5- Watershed : Lower Coleroon watershed.

f – Sub-watershed : Lower Coleroon sub-watershed.