Ingress of salinity in coastal area

P re p a re d B y : -

Patel Hardik P. (En No.110780106034)

Patel Dax S. (En No.110780106026)

Patel Sapana S. (EnNo.110780106011)

Patel Hiral J. (En No.110780106023)

Guided By:-

Prof .Mr Bhavik G Patel

Prof. Mr Utkarsh Nigam 1

Presentation Preview

Introduction

Problem

Objective

Literature

Methodology

Data collection and monitoring

Scope of work 2

Introduction

Salinity is the saltiness or dissolved salt content of a body of water.

Salinity is an important factor in determining many aspect of the

chemistry of natural water and biological process.

The “Salinity refers to the degree of saltiness of water or more

specifically the concentration of dissolved solids involved”

Seawater intrusion is the movement of seawater into fresh water

aquifers due to natural processes or human activities.

The amount of salinity in a given water is expressed as Total

Dissolved Solids (TDS) and specified either in terms of weight of

salts in solution or weight of salt per unit volume of water.

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Introduction

There are several different ways to measure salinity; the two

most frequently used analyses are described below :

Total Dissolved Solids (TDS) : TDS is a measure of all dissolved

substances in water, including organic and suspended particles that

can pass through a very small filter. TDS is measured in a

laboratory and reported as mg/lit.

Electrical Conductivity (EC) : The ability of an electric current to

pass through water is proportional to the amount of dissolved salts

in the water-specifically, the amount of charged ( ionic ) particles.

EC is a measure of the concentration of dissolved ions in water

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Seawater Intrusion

A natural process that occurs in

virtually all coastal aquifers.

Define as a movement of

seawater into inland fresh

groundwater aquifers, as a result

of

1. Higher seawater density than

fresh water

2. Ground water withdrawal in

coastal areas

This migration of seawater into

the freshwater aquifer is known

as seawater intrusion.

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The first physical

formulations of saltwater

intrusion were made by

W.Badon-Ghijben (1888,1889)

and A. Herzberz (19 01) thus

called the Ghyben-Herzberz

relation.

The Figure shows the

Ghyben-Herzberz relation.

Z= 40h

Ghyben-Herzberz Relation

The depth to the interface between freshwater and saltwater is

approximately 40times the height of the water table above sea level.

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Land move down Tectonic uplift

Sea level rise Change in

hydrological regime

Costal zone River & Estuaries

Human activates Countermeasures

Effects

Costal aquifers

Change in natural recharge: Precipitation evapotranspiration

Costal erosion Tidal effect

Back water effect Saline surface water

Ground water extraction Mining – gas oil sand

Salt water intrusion Salt damage crop Decrease ground water resources

Extraction saline groundwater Increase natural recharge Physical obstruction

Problem occurs due to sea water intrusion

Near costal area the crop fail problem is increase.

By salinity problem construction cost is also increase.

Irrigated land has become barren due to seawater intrusion.

Domestic water supply is difficult to manage by an individual.

An increase in TDS, Fluoride & Chloride contents has created many

human diseases.

Reduction in agricultural productions due to deterioration in ground

water quality. 8

Saltwater intrusion construction cost increase

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land has become barren due to seawater intrusion

increase in TDS, Fluoride & Chloride contents

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Literature

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1) Climate change and environmental problem in world

Climate is one of the more complex physical systems in nature, its

behavior being fundamentally non-linear and chaotic.

Author : Biplab Das

Dr.Aditya Bandyopadhyay Indian Institute of Engineering, Science

and Technology, Kolkata

Issue 6, December 2012

A ground water is the essential features of a natural hydro

geological system that uses the laws of considered as unsuitable for

irrigation and drinking purposes.

Literature

A preliminary survey of the coastal city-Bhavnagar was undertaken to

assess salinity ingress probed through groundwater quality.

2) Ingress of salinity in Bhavnagar City

Author: PRASHANT N. BHATT

JIGNASU P. MEHTA

HITENDRA J. JANI AND

S. KURUP

PP.. 312665- -313658, O

Jcutolyb e 2r0 200605

The quality of ground water in some of the areas was found high

saline and can not be used even for irrigation purpose.

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Literature

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Seawater intrusion is one of the most important environmental

problems that degrade groundwater resources

3) To study the control of seawater intrusion in coastal aquifers

Author: A.A. Javadi June 21 - 26, 2010

Computational Geomechanics Group,

College of Engineering

Seawater intrusion increases salt concentration in groundwater

which places limitations on its uses

This type control of seawater intrusion is very important to protect

groundwater resources from depletion.

Literature

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4) Salt water in costal aquifers

Costal area characterized by the interaction of land, sea and

atmosphere’ so management of all the interactive components in a

rational and comprehensive manner

Author: S.M Seth National institute of hydrology jay vigyan

bhavan

Roorkee - 247667

Quantitative understanding of the pattern of movement and

saline water and of the factor that influence these processes is

required to manage and protect the fresh water resources in the

costal regions

Literature

5) MANAGEMENT OF GROUNDWATER IN SALT WATER

INGRESS COASTAL AQUIFERS

Author : C. P. Kumar

National Institute of Hydrology

Roorkee – 247667 (Uttaranchal)

Schematic illustration of some of the modes of saltwater intrusion in

a multilayer, regional aquifer system caused by groundwater pumping

at wells. Saltwater moves into the unconfined aquifer from the ocean

and into the shallow part of the top confined aquifer from the major

bay.

Through the seawater intrusion has not yet assumed serious

magnitude, but in the coming years it may turn to be a major problem

if corrective measures are not initiated at this stage 15

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Junagadh district lies between 21º 10' and 21º 40' north latitude and

70º 18' and 71º 15' west longitude region, in the state of Gujarat India,

known as Kathiawar or Saurashtra. This district is bounded by the Rajkot

district in North Amreli district in East, Arabian Sea in Southand by the

Arabian Sea and Porbandar district in the West. Total geographical area

of Junagadh district is 6,996,011.21 hectares

My study area cover Simar village is located 15 km SE from Rajgath

& on the coast of Arabian sea.

Topographical flat with gentle eastward slope towards sea.

Study Area Detail

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Study Area Detail

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In the coastal area of Saurashtra, which is 765 km. long, the issue of

salinity has been observed due to natural factors of salinity of ocean

water and also due to human interference in the natural balance, a total of

700120 hector area, 534 villages, 1079733 persons and 32750 wells were

affected. The economical condition of this area was adversely affected

and issues of migration of people had also taken place due to

deterioration of underground water due to salinity and adverse effect on

agricultural products and industries based on agricultural due to

excessive lifting of water by the farmers. This study will try to check

improvement of water quality due construction of various recharge

structure by the government.

Need Of Study

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Objectives

1. To study the phenomena of salinity ingress in Rajgath taluka

2. To produce contour map of reduced water level, TDS & sea water

intrusion ratio indicator map by use of surfer.

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METHODOLOGY

Data

1.TDS DATA 2.Reduced Water level Data

3. SEA WATER INTRUSION RATIO INDICATOR

USE OF SURFER SOFTWARE

RUN

CONCLUSION

Methodology

Data collection and monitoring

A great variety of data is required for integrated water management

studies.

The types of data required for groundwater studies in coastal and

deltaic areas, where saltwater intrusion plays a role, are given below.

1. The subsoil

The geologic structure of the subsoil

Hydrological structure of the subsoil

2. The natural input

Climate data, in particular precipitation and evapotranspiration

Natural recharge

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4. Groundwater quality

Chemical and isotopic composition, in particular salinity, but also any

other contamination

Sources of groundwater pollution

5. Surface water

Natural outflow

Availability and quality of surface water for artificial recharge

7. Water demands, at present and estimates for the future

9. Relative sea level rise.

Cont….

3. Water levels

Groundwater levels and surface water level

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Use Of Surfer Software

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Use Of Surfer Software

1.To Create XYZ data file with use of longitude, latitude & reduced

water level

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Use Of Surfer Software

2.To Create a grid file [.GRD] from the XYZ data file using the grid

data command

3. To Create contour map by use of grid file

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Use Of Surfer Software

4. To create a Post map show data locations on a map

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Use Of Surfer Software

5. To create Vector map in this vector map an arrow represents a

vector’s direction and magnitude at a grid node, the length of the arrow

represents the magnitude of the slope

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TDS contour map of Rajkot (may 1991)

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TDS wireframe map may 1991

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Data Collection

1. Primary situation of salinity ingress

2. Salinity ingress & affected area in Rajgath

3. Average rainfall in Rajgath

4. Water level data of different wells

5. TDS data of different wells

6. Latitude, Longitude & RL of different wells

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Ingress of salinity (km) in Rajgath (1977-2010)

7.5 8.5

7.75 7.15

4.85 4.96

6.41

5.28 5.27 5.8

4.57 5.42

1977 1988 2000 2002 2003 2004 2005 2006 2007 2008 2009 2010

Salin

ity

ingr

ess

(km

)

Year

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Area Affected By Salinity In Rajgath (1977-2010)

0

5000

10000

15000

20000

25000

30000

Aff

ecte

d a

rea

(h

ec)

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Average rainfall (ml) in Rajgath

0

200

400

600

800

1000

1200

1400

1600

Avg

rai

nfa

ll (m

l)

Year

Details of Rainfall (ml) In Una

0

200

400

600

800

1000

1200

1400

1600

Avg

rai

nfa

ll (m

l)

Year

Details of Rainfall (ml) In Una

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Salinity ingress in affected area

0

1

2

3

4

5

6

7

8

9

0

5000

10000

15000

20000

25000

300001

97

1

19

73

19

75

19

77

19

88

19

93

19

94

19

95

19

96

19

97

19

98

19

99

20

00

20

01

20

02

20

03

20

04

20

05

20

06

20

07

20

08

20

09

Salin

ity

ingr

ess

(km

)

Aff

ecte

d a

rea

(hec

)

Salinity Ingress V/s Affected area In Rajgadh

Affected Area Salinity Ingress (km)

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Conclusion 1. It has been observed the study area having good aquifer to absorb

ground water.

2. Because of annual recharge, water table is increased which is

responsible for decreasing TDS

3. By using golden surfer software we prepared wireframe and contour

map of our study area which is affected by salinity.

3. It has been observed that pre monsoon and post monsoon data of the

TDS value is more than the desirable value which are alarming for

the health.

Scope of of work

Increase in salt contents is related to a series of factors such as the

permeability of the soils, drainage facilities, quantity of water

which is applied, crops in the area and climate in general.

Intrusion of saline water in coastal environments occurs all over the

world.

In places where groundwater is being pumped from aquifers that are in

hydraulic connection with the sea, the induced hydraulic gradients

may cause the migration of salt-water from the sea towards the well.

Investigation of saline intrusion is extremely important because it

constitutes probably the commonest of all pollutants in fresh water.

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Thank you for your

attention

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