Spatio-Temporal variability of Water resources in the Ganga basin

By

Subashisa Dutta

Associate Professor

E-mail : subashisa@iitg.ernet.in

DEPARTMENT OF CIVIL ENGINEERINGINDIAN INSTITUTE OF TECHNOLOGY GUWAHATI

GUWAHATI, ASSAM-781039

For

National Students’ Conference On River Basin PlanningIIT Kanpur, 4 to 5th November 2011

Sattriya dance-Assam,http://

www.gurleenmehak.blogspot.com/

Overview of the lecture

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1. Spatio-temporal variation of surface water resources in the basin ( annual water yield, monsoon flow, non-monsoon flow,

lean month flow, dependable flow)

2. Current Ground water utilization : crop statistics and GIS analysis

3. Spatio-temporal variability of Ground water Resources in the Basin

4. Fertilizer application and crop productivity : an indicator for non-point source pollution

5. Resilience in the Water Resources system: How long ?

Hydrological Storage, release function and interdependency

3

Surface water storage

M J S D J

M J S D J

M J S D J

Q

Q

Q

Monsoon recharge

Ground water storage

Flood recharge

Irrigation

ETETP

SM

ET : Evapo-transpiration, P: Precipitation, SM: Snow Melting Run-off, Q: Discharge

Note for Ganga Basin: •Ground water Irrigation controlled by the farmers and Agricultural Economy,•Flood recharge depending upon the frequency of wet-Monsoon•ET depending upon the distribution of Landuse/landcovers remains fairly constant•Hydrological links between groundwater and surface water storage defined by Hydro-geological characteristics

Study Area: Ganga River basin in Bihar

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Data used:1.Hydrological data (1960 to 1992)

2.Satellite Altimetry data (1993 to 2003)

3.Ground water level data (2001 to 2009)

4.Agricultural statistics (Crop water requirement, productivity, Area, Crop type etc.)

5.Other ancillary information (Bhuvan satellite imagery,)

Hydrological Trends of the Ganga river flow* at the downstream of Farakka

* Webster, J. P., Jian, J., Hopson, M. T., Paula, A. A., Chuang, H., Curry, J. A., Grossman, R. L., Palmer, T. N., Subiah, A. R., (2010) “Extended-range probabilistic forecasts of Ganges and Brahmaputra floods in Bangladesh .” Bulletin of the Am. Met. Society., 2911.1.

5

Pre-Surface water development

Project

Ground water development

Project

Hydrological trends of Major tributary flows

* Report of the 2nd Bihar State Irrigation Commission 1994

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Monsoon season Water yield: 43215 MCMHydrological trend : Variable

Non-Monsoonal Season Water yield: 9491 MCM

Hydrological trend : Fairly Constant

Annual variation of water yield of the Kosi river at Saptakosi station

Monsoon season Water yield: 72287 MCMHydrological trend : Variable

Non-Monsoonal Season Water yield: 11467 MCMHydrological trend : Variable

Flow duration curve and dependable annual water yield

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Long term Average February month flow in Ganga river

8

106

Main Ganga

Bay of Bengal

Tons-Karmnasa

Chambal

Yamuna

Sone

Bhagirathi

Indo-Bangladesh Border

Azamabad

Farakka Barrage

Ramganga Gomti Ghaghra

Gandak-Burhi Gandak

Ground water(Buxar

to Azamabad)

Mahananda

Kosi

Buxar

Mahananda

3888

1184

3164

228

899

712 21

5

393

67

723

349

217

(148

7)

All data are 75% dependable flow (Million Cubic Meter)

Findings:Indo-Bangladesh Ganga water sharing treaty: 3888 MCM at FarakkaGround water contribution: 1487 MCM

* Report of the 2nd Bihar State Irrigation Commission 1994

Long term Average March month flow in Ganga river

9

114

Main Ganga

Bay of Bengal

Tons-Karmnasa

Chambal

Yamuna

Sone

Bhagirathi

Indo-Bangladesh Border

Azamabad

Farakka Barrage

Ramganga Gomti Ghaghra

Gandak-Burhi Gandak

Ground water(Buxar to Azamabad)

Mahanandaa

Kosi

Buxar

Mahananda

3888

1184

3120

235

922 71

5 220

298

49

767

365

199

(123

6)

All data are 75% dependable flow (Million Cubic Meter)

Findings:Indo-Bangladesh Ganga water share treaty: 3888 MCM at FarakkaGround water contribution: 1236 MCM

* Report of the 2nd Bihar State Irrigation Commission 1994

Long term Average April month flow in Ganga river

10

215

Main Ganga

Bay of Bengal

Tons-Karmnasa

Chambal

Yamuna

Sone

Bhagirathi

Indo-Bangladesh Border

Azamabad

Farakka Barrage

Ramganga Gomti Ghaghra

Gandak-Burhi Gandak

Ground water(Buxar to Azamabad)

Mahanandaa

Kosi

Buxar

Mahananda

3888

1018

2967

246

953

715 22

8

279

31

920

246

129

(502

)

Findings:Indo-Bangladesh Ganga water share treaty: 3888 MCM at FarakkaGround water contribution in April Month : 502 MCMTotal three lean month flow GW = 3225 MCM ( 27%), Kosi and Gandak River flow = 4552 MCM ( 40%), U/S catchments at Buxer : 3386 MCM ( 29%)

* Report of the 2nd Bihar State Irrigation Commission 1994

Satellite Altimetry measurement* for water level

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Main River

Tributary

Wet land

Performance of Satellite altimetry for water level prediction in Brahmaputra

Minimum water level variation from altimetry measurement

* http://www.legos.obs-mip.fr/soa/hydrologie/hydroweb

Spatio-temporal variation of ground water depth

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Analysis of Groundwater variation: Depletion, Recharge and withdrawal

13* Report of the 2nd Bihar State Irrigation Commission 1994

Water requirement for Agriculture system

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Multiple cropping during Non-Monsoon season

Estimated Ground water irrigation = 9800 MCM

Total crop water requirement and Annual variation of recharge

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2004: Flood year

Temporal variability of Groundwater and Potential recharge

MSS (1970’s)

TM (1990) ETM (2000)

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Temporal trend of annual recharge/depletion zones in three districts

Flood Area

Flood inundation in Bihar in 2007 showing potential recharge zones

Field photograph of a wetland

District-wise variation of fertilizer Application

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Agriculture productivity and Fertilizer Application

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Conclusion

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Ground water irrigation, controlled by the farmers, is expected to be the major water resources user ( 10,000 MCM to 15,000 MCM)

Conflict between Ground water irrigation and lean period flow in the river

Wet monsoon year produces large-scale flood inundation based recharge system

Availability of monsoon water yield is high and efficient management of the surface water projects

Now, the water resources system is at resilience stage. How Long ?

ACADEMIC Building, IIT Guwahati

Research Group

Thank You

1. Dr Subashisa Dutta2. Dr. Bimlesh Kumar3. Dr Suresh A. Kartha4. Amit Kr Dubey5. Ikram Ali6. Pritam Biswas7. Sangita Devi8. Titas Ganguly Farmer in a wheat field crop harvesting at Bihar