1. Integrating Environment, Climate-Change & Water
Ashvani K. Gosain
Professor, Civil Engineering Department
Indian Institute of Technology Delhi

2. Water resource development
Shall always remain one of the preferred options to cater to
Inherent Spatial and Temporal variability of this resource
Climate change impacts as an additional factor
Going to further enhance complexity
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3. Implications of Development
Water resource is finite (within natural variability)
Any development big or small involves in moving the water around (more often upstream)
Every development/intervention has associated impact
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4. Issues around water resources development
Many parallel programs with competing demands
No mechanism for tradeoffs between competing demands
Ignoring environmental demand
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5. Sustainability – Major concern
This brings us to the question of sustainability
Which is about maintaining the hydrological and environmental health of the drainage basins
IWRM philosophy has been the scientific option available but seldom used
Watershed being the natural system where water balance can be resolved and thereby impacts of the manmade interferences quantified
Hydrological modeling is the tool to be used

6. Preferred Attributes of a Model
a model that can handle river basin as well as small watersheds
can quantify the impact of land management practices
can handle climate change implications

7. SWAT Model Components

8. Objectives of SWAT
Predict the impact of man-made changes & management practices as well as water balance components
water, sediment, nutrient and pesticide yields
generate alternate scenarios

9. Model Output
Model outputs include all the water balance component at various levels ie basin, subbasin or watershed level and at intervals of daily, monthly or annual
surface runoff
evapotranspiration
lateral flow
recharge
percolation
sediment yield
Nutrients

10. Doddahalla (Bijapur, Karnataka) Watershed - Salient Features
Taluks: Indi, Bijapur (30 villages)
Area: 30,000 ha (~61,000 ha from automatic delineation – entire watershed)
Contour: 20 m interval digitized contours,1:50,000
Land use: 1:50,000 from satellite imagery
Soil: 1:50,000 digitised
Drainage: 1:50,000 digitised
Weather station: one IMD station at Bijapur

11. DEM & Drainage

12. Automatically Delineated Watersheds with Weather Station Location

13. Watersheds overlaid with Landuse

14. Watersheds overlaid with Soil

15. Water Yield Map

16. Sediment Yield Map

17. Average Annual Basin Values (All units are in mm)
Water Balance Components mm % of rainfall
Rainfall
Predicted Surface runoff
Shallow Aquifer runoff
Shallow-Deep Percolation
Shallow Aquifer Recharge
Predicted Water Yield ET
PET
Basin Sediment Yield T/Ha

18. Prioritization - Criteria
Social Economic
Economically weaker
SC/ST population
Uniform land holdings and many others
Physical
Head water
Erodability, land degradatiom, water scarcity problem
Rainfall less than 750 mm
Net cultivated area is not more than 20 %.
Proportion of irrigated area should not exceed the state average or 30 %
Cropping pattern – no long duration crop or water intensive crops
Villages fully falling in watershed

19. Watershed prioritization layers

20. Climate Change impact studies
India’s National Communications (NATCOM) to UNFCCC Coordinated by MoEF
The first communication was made in 2004 and the Second in 2012
Work on quantification of climate change impacts on water Resources was entrusted to IIT Delhi

21. River Basins Modeled – NATCOM II

22. Modelling Outcomes
Detailed outputs include all the water balance component at spatial and temporal scales which are analysed for
Changes in magnitude and frequency of flood peaks
Severity of droughts
Changes in flow patterns
Changes in groundwater recharge

23. Change in Water Yield towards 2030s and 2080s

24. Change in Evapo-transpiration towards 2030s and 2080s

25. Change in Sediment Yield towards 2030s and 2080s

26. Change in monsoon drought weeks towards 2030s & 2080s

27. A shareable information base
To keep pace with the fast changing baseline
To provide an integrated information
Generate scenarios and provide information on implications thereof
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31. Conclusions
Integrated Watershed Management plans are required to be formulated keeping the planning unit as River Basin
Creation of sharable information is essential for sustainable use of water resources through engagement of stakeholders
Implications of climate change needs to be integrated in the planning process
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32. Thank you