Ingress of salinity in coastal area

Transcription

1 Ingress of salinity in coastal area P re p a re d B y : - Patel Hardik P. Patel Dax S. Patel Sapana S. Patel Hiral J. (En No ) (En No ) (EnNo ) (En No ) Guided By:- Prof.Mr Bhavik G Patel Prof. Mr Utkarsh Nigam 1

2 Presentation Preview Introduction Problem Objective Literature Methodology Data collection and monitoring Scope of work 2

3 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. 3

4 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 4

5 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. 5

6 Ghyben-Herzberz Relation 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 The depth to the interface between freshwater and saltwater is approximately 40times the height of the water table above sea level. 6

7 Sea level rise Land move down Tectonic uplift Change in hydrological regime Change in natural recharge: Precipitation evapotranspiration Costal zone Costal erosion Tidal effect Costal aquifers River & Estuaries Back water effect Saline surface water Human activates Countermeasures Ground water extraction Mining gas oil sand Effects Salt water intrusion Salt damage crop Decrease ground water resources Extraction saline groundwater Increase natural recharge Physical obstruction 7

8 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

9 Saltwater intrusion construction cost increase 9

10 land has become barren due to seawater intrusion increase in TDS, Fluoride & Chloride contents 10

11 Literature 1) Climate change and environmental problem in world Author : Biplab Das Dr.Aditya Bandyopadhyay Issue 6, December 2012 Indian Institute of Engineering, Science and Technology, Kolkata Climate is one of the more complex physical systems in nature, its behavior being fundamentally non-linear and chaotic. 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. 11

12 Literature 2) Ingress of salinity in Bhavnagar City Author: PRASHANT N. BHATT JIGNASU P. MEHTA HITENDRA J. JANI AND S. KURUP PP , O Jcutolyb e 2r A preliminary survey of the coastal city-bhavnagar was undertaken to assess salinity ingress probed through groundwater quality. The quality of ground water in some of the areas was found high saline and can not be used even for irrigation purpose. 12

13 Literature 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 is one of the most important environmental problems that degrade groundwater resources 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. 13

14 Literature 4) Salt water in costal aquifers Author: S.M Seth National institute of hydrology jay vigyan bhavan Roorkee Costal area characterized by the interaction of land, sea and atmosphere so management of all the interactive components in a rational and comprehensive manner 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 14

15 Literature 5) MANAGEMENT OF GROUNDWATER IN SALT WATER INGRESS COASTAL AQUIFERS Author : C. P. Kumar National Institute of Hydrology Roorkee (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

16 Study Area Detail 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, 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. 16

17 Study Area Detail 17

18 Need Of Study 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 hector area, 534 villages, persons and 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. 18

19 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. 19

20 Methodology METHODOLOGY Data 1.TDS DATA 2.Reduced Water level Data 3. SEA WATER INTRUSION RATIO INDICATOR USE OF SURFER SOFTWARE RUN CONCLUSION 20

21 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 21

22 Cont. 3. Water levels Groundwater levels and surface water level 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. 22

23 Use Of Surfer Software 23

24 Use Of Surfer Software 1.To Create XYZ data file with use of longitude, latitude & reduced water level 24

25 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 25

26 Use Of Surfer Software 4. To create a Post map show data locations on a map 26

27 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 27

28 TDS contour map of Rajkot (may 1991) 28

29 TDS wireframe map may

30 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 30

31 Ingress of salinity (km) in Rajgath ( ) Salinity ingress (km) Year 31

32 Area Affected By Salinity In Rajgath ( ) Affected area (hec)

33 Average rainfall (ml) in Rajgath Avg rainfall (ml) 1600 Details of Rainfall (ml) In Una Year Year 33

34 Salinity ingress in affected area Affected area (hec) Salinity ingress (km) Salinity Ingress V/s Affected area In Rajgadh Affected Area Salinity Ingress (km) 34

35 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. 35

36 Scope of of work Intrusion of saline water in coastal environments occurs all over the world. 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. 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. 36

37 Thank you for your attention 37