02-env impacts - gw intensificaiton-sunderrajan

8/2/2019 02-Env Impacts - GW Intensificaiton-Sunderrajan

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Environmental impacts ofgroundwater intensification in India

Sunderrajan KrishnanTrishikhi Raychoudhary

Chaitali PurohitAnkit Patel


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Definition of problem

Any disturbance from the natural regime of

groundwater flows or geochemistry caused by

intensification of groundwater use that results in

significant impact on environment and on humans

Challenges:

To define natural regime

To isolate role of GW use on the impact,

eg. coastal salinity


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Which issues are being studied

- Fall in water tables and rise in water tables regionally

- Highly fluctuating water table

- Quality problems emanating from exploitation eg. salinity incoastal areas, increasing mineralization of deeper aquifers,release of geogenic heavy metals associated with exploitation

- Quality problems due to use of poor quality water for irrigation

-Related surface water issues eg. tanks that recharge aquifers,being in disuse , partly due to gw use


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Which issues are not considered

- Pollution from industries; pollution from agrochemicals

-Existing natural contaminants eg. Iron, Fluoride, Arseniccontamination when existing without any disturbance

- Ecological aspects eg. impact of phreatic plants due to deepeningwater tables, biomagnification of contaminants through

environmental media


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Building blocks of study

Region based (4 regions)

IssueBased

(2 issues)

Nation-wide analysis(at district level)


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IssueBased

(2 issues)



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Nation-wide analysis at district level

Objectives:

To delineate zones of GW vulnerabilty using different criterion:

a) Volumetric information: GW recharge, GW use for various purposes;Proportion GW used for irrigation

b) Depth to Groundwater Table: Median depth to water table; Medianfluctuation of water table

c) Impact of well interference: well density and hydrogeology togetherimpacting well interference

Overlap these zones to mark regions of varying vulnerablity


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Nation-wide analysis at district level contd

Objectives:

To demonstrate the impact ofa) Variability

b) Uncertainty

in district level figures ; therefore also on looking at GWvulnerability using these figures

This analysis will be performed for 5 districts by varying:

1. Rainfall: inter-annual variability2. Uncertainty on Hydrogeological parameter: eg specific yield


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IssueBased

(2 issues)



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- Bist-Doab of Punjab: overexploitation and agro-pollution; groundwater balance and trend analysis

- North Gujarat: overexploitation, Fluoride, Salinity, urbanexploitation and pollution

- Coastal West Bengal and Orissa: saline water intrusionand urban subsidence of land

- Central Tamil Nadu: Noyyal sub-basin of Cauvery:overexploitation, pollution, demand from urban areas

Studies in four regions


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Bist-Doab

North Gujarat

Coastal WB, N. Orissa

Noyyal sub-basin of Cauvery


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Objectives:

Detailed characterization of environmental impacts ofgroundwater use in the region

Extrapolation to parts of the country that are similar to thisregion

Eg. North Gujarat: overexploitation of aquifers; Fluoride contamination;Urban demand of groundwater from Ahmedabad area; Coastal and inlandsalinity of groundwater

Can be extrapolated to parts of Rajasthan


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Fresh studies:

- Collecting long-term groundwater hydrographs fromBist-Doab for better hold on groundwater balance

- Collecting geochemical data in Baleshwar district,Orissa to delineate zones of differing salinity content


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IssueBased

(2 issues)



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Issue 1: Coastal salinity of groundwater


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Issue 1: Coastal salinity of groundwater

Compiling the conceptual picture ofcoastal salinity across the coast

Information on: Geomorphology, Hydrogeology,Tidal patterns, Observed salinity data

Important regions:

Gujarat (Kutch, Saurashtra, South Gujarat)

Tamil Nadu (North)Central Andhra PradeshOrissa (Central to North)West Bengal


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Patterns of groundwater use in urban areas:

- Major growth of urban areas is happening in1,00,000 1 million population- Most of these cities are highly dependant on groundwater ;much more than million+ cities- The locus of future GW demand in urban areas will be thesetownsMain data: proportion dependence of urban area on GW

Issue 2: Urban groundwater exploitation

Million +1lakh 1 Million

0

100

% depOn GW


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Issue 2: Urban groundwater exploitation

Aquifers in urban areas are increasinglyexploitedData collection on coning in Ahmedabad city

Subsidence problems (Kolkata) because ofoverexploitation

The situation in various other cities: Chennai,Delhi,


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Structure of reportChapter 1: Summary

Chapter 2: A national picture

2.1 National level statistics and District level analysis

2.2 A theoretical description of each specific impact and regions experiencing them

Chapter 3: Analysis of four regions

3.1 Groundwater exploitation in Bist-Doab, Punjab

3.2 Exploitation, contamination and urban demands in North Gujarat

3.3. Salinity, Arsenic, Land subsidence and exploitation in Coastal West Bengal and North

Orissa

3.4 Exploitation, pollution and urban demands for groundwater in Noyyal sub-basin of

Cauvery in Tamil Nadu

Chapter 4: Coastal salinity of groundwater in India

Chapter 5: Groundwater exploitation in urban areas of India

Chapter 6: An ecological look at groundwater exploitation


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Timeline

March: presentation in Anand on work till then

- Preliminary analysis of nationwide district level data

- Initial data collection from all 4 regions

- A synthesis of coastal salinity

- Presentation of collected data in urban groundwater study

July: final report


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3860

32.4

7786

2132

33.3

8742

3359

46.2

9407

4754

63.6

10120

5379

67.6

10501

6743

900

2000

4000

6000

8000

10000

12000

Abstruction

structures

(000)

Mar

'51

Mar

'80

Mar

'85

Mar

'90

Mar

'92

Mar

'97

Dug wells

Pvt. TW

Pub. TW

Growth of AbstractionStructures

(000)


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Cumulative Irrigation Potential Created from

Ground Water (Mha)

6.5

22

27.82

35.62 38.89

50.31

0

10

20

30

40

50

60

irrigation

potential

(MHa)

Mar

'51

Mar

'80

Mar

'85

Mar

'90

Mar

'92

Mar

'97


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Distribution of

Fluoride in

Ground Water


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Objectives

1. Define coastal saline area of 500ppm2. A plan view specifying different concentration saline area Very highsaline area (salinity: more than7500mg/l) Highsaline area (salinity: 4000mg/l-7500mg/l) Moderatesaline area (salinity: 1500mg/l-4000mg/l)

Lowsaline area (salinity: 500mg/l-1500mg/l)3. Construction of a pictorial view of vertical cross-section of Aquifer

system of Indian coast4. Pictorial vertical cross-sectional of saltwater intrusion

mechanism of specified area.5. Agricultural and Aquaculture activity of Indian coast6. Preventive or Remedial measure taken in different part of Indian

coast


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Specific Objectives

Geomorphology Coastal area specification and Geography, river basin and other

natural surface details of the area Aquifer system coastal hydro-geology

Salinity related study Surface soil-salinity condition Seasonal variation of saltwater and groundwater profile in a

specific focused area Special variation of salinity over years (movement of salinity

profile of fixed concentration over time)

Groundwater table depletion over time in that area. ( to comparesaltwater intrusion with groundwater depletion)


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Methodology

1. Data Collection

Govt. Organization:CGWB, GSI, CSSRI, State Water and Irrigation Department(SWID)

Non-Govt. Organization andUniversities:Universities (BEC,Howrah etc) and NGOs

Literature Review:Published papers and Books

2. Linking, analyzing and processing of data

3. Preparation of Report


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Demographic studyMaximum growth in urban population is occurring in 1,00000 to 1 million population cities

Census population, 1971, 81, 91, 2001 & trend of 2011, 21, 31..cities of > 1 millions : 34 citiesClass I >100,000-1 millionClass II = 50-100,000Class III = 20-50,000Class IV = 10-20,000Total = 4378 cities> 1 millions = 35 citiesMethodology:Review of demographic studies done by UNDP, Kundu et al., Census projectionsIndividual studies done by others will be collected (literature review) for 35 cities.

Total water useProportion of SW & GW in total water useTo take @ 20 cities from these 35

Patterns of present and future groundwater in urban areas


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For rest, 400 cities will be classified into broad category, class I 100,000 to 1million and class II, III & IV as 10,000-100,000. We would consider Class Ifor our study

Cities in different regions will be identified based on several factors (i.e. citiesabove hard rock strata/ with alluvium strata, river bank, coastal, hill stations,rainfall, GW quality)Probable Source of data for,total water use:

Through, irrigation data - statewise (as many as possible), SW supply to thetownsCGWB district water data & estimating GW useSewerage disposal of towns & estimation of total water useSamples from various classifications - Tree, leaves @ 30 townsCheck histograms of population -True Vs Sample, for both cities/towns

Expected out put:Weighted Indicators with final GW use pattern, Ex. CART analysis (ref:Sunder)

02-env impacts - gw intensificaiton-sunderrajan

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