This presentation was made at "Orientation Programme for Government officials on Urbanization, Climate
Change and Water Issues" held on the 23rd of July.
Climate Variability, Urbanization and Water in India
1. Climate Variability, Urbanization and
Water in India
M. Dinesh Kumar
Executive Director
Institute for Resource Analysis and Policy
Hyderabad-82
Email: dinesh@irapindia.org/dineshcgiar@gmail.com
Prepared for the Orientation Workshop organized by SaciWaters
2. Purpose
• The purpose of this presentation is to add a new dimension
to the debate on how climate change and urbanization
could impact on India’s water resources vis-à-vis its
availability and demand, in the face of the country’s climate
reality
3. Plan of Presentation
• Conceptual Framework on the Impacts of Climate Variability and
Change and Urbanization on Water
• India’s Climate Reality
• India’s Urban Growth Reality
• Issues with climate predictions
• Potential Impacts of Climate Change on Water Resources
• Potential Impacts of Urbanization on Water Resources
• Areas of Future Concern
4. Conceptual Framework
• Farming is the largest consumptive user of water in India
• Change in temperature and CO2 can alter crop yields by affecting plant
bio-physical processes: depends on plant type (C3 or C4)
• Temperature change can also alter evapo-transpirative demand of water
(ET) in crop production
• Either way, the amount of water required for producing a unit of
biomass would change, changing the aggregate water demand in
agriculture
• Temperature changes can alter the hydrological system, by changing
infiltration rate, soil moisture storage, and thereby run-off, affecting the
overall water availability within a basin
5. Conceptual Framework
• Urbanization can affect hydrology and water resources in many ways
• Urban centres create points of concentrated water demands, often
making it difficult for the local natural water systems to sustain
• Urbanization pushes the growth rate in domestic water demands as per
capita water demands are much higher in urban areas
• Urbanization changes land use, creating impervious catchments and
increasing the runoff from precipitation, thereby increasing the chances
of floods, while reducing natural recharge to groundwater
• Urbanization increases the level of toxic pollutants and sediment load in
storm water runoff, making it unfit for human & animal consumption
6. India’s climate reality
• Spatial variability in climate is very significant:
– Hot & arid to hot & humid, to cold & sub-humid to cold & humid
• Within the same river basin, agro climate vary significantly
• Day time and night time temperature of a day can vary from year to
year; so are humidity and wind speed
• Monsoon records for 104 years (1901-2003) do not show any linear
trend (Kelkar, 2010)
• Also data for 1813-2006 do not show any uniform trend (Sontakke et
al., 2008)
7. India’s climate reality
• Spatial variation in rainfall is remarkable
• So is the variation in number of rainy days
• Regions of low rainfall receive it in very few showers; regions of high
rainfall have long wet spells
• Regions of high mean annual rainfall has low inter-annual variability
and vice versa
• Regions experiencing fewer days of rains experience high variability in
number of rainy days between years
8. India’s urban growth reality
• Urban population growth in India is much higher than that of rural
population growth ; large cities are growing faster
• Cities in ‘naturally water scarce regions ‘ are experiencing faster
growth than those in water abundant regions
• Water demands in these cities are growing exponentially; while their
local fresh water bodies are either drying up or getting deteriorated;-
tanks and lakes and hard rock aquifers in South India
• These urban areas are increasingly dependent on water resources in
rural areas, often competing for water from public irrigation systems
9. Issues with climate prediction for India
• GCMs predict higher rainfall for Indian sub-continent, with varying
“increments”; not robust for Indian monsoon (Kelkar, 2010)
• The observed trends in “global temp. rise” are not uniform. Greater
warming is predicted for n. hemisphere
• GCM predictions are too broad (150 km X 150 km area.), and do not
have much relevance for understanding river basin hydrology
• Different models predict different trends (Mujumdar, 2010). Often,
errors in rainfall predictions are higher than the predicted values
• Generally, temperature predictions are found to be more accurate than
the rainfall predictions at the global scale
10. Climate change impacts on water resources
• Even if climate change is a reality, its impacts on water resources in India
would not be uniform across basins and regions; but would depend on
the region
• In low to medium rainfall regions, rise in temperature could lead to
faster soil moisture depletion and reduced runoff and recharge
• In low to medium rainfall semi arid regions, basins are water-scarce
• Temp. rise could also lead to further increase in the demand for water
for crop production, thereby increasing magnitude of water scarcity
• The impacts of droughts due to monsoon failure in these regions would
become more severe
11. Climate change impacts on water resources
• In high rainfall, (above 1,000mm), hot & sub-humid to cold & humid
regions), an overall rise in temperature rise could lead to higher rainfall
increasing surface water availability
• Water demand for crop production is quite low in these regions.
• A rise in temp. won’t cause much increase in irrigation water
demand, as more water would be available from soil moisture for crop
growth
• Further, the basins in these regions are water-abundant basins
(Ganges, Brahmaputra-Meghna), with limited amount of arable land
for crop production
12. Climate change impacts on water resources
• On the contrary, temperature reduction can cause opposite trends in
these two distinctly different hydro-climatic regimes.
• The naturally water-scarce regions could receive more rainfall, and
that in naturally water rich regions could decline
• Accumulation of particle aerosol in the atmosphere over the Gangetic
plains is reported to be leading to lower temperature, and reduction
in rainfall in that region and also crop yield losses owing to decline in
incident solar radiation
13. Impact of climate variability and urbanization
on water resources
• Low to medium rainfall regions in India experience high variability in
stream flows and groundwater recharge
• The variability might increase if the temperature in these regions
experience rise
• Fast growing urban centres in naturally water-scarce regions induce
huge pressure on the limited freshwater, with excessive increase in
water demands, depleting local aquifers and highly variable flows
• With climate change, the occurrence of climate induced water-related
disasters like droughts and urban floods are likely to be more i
14. Areas of concern for future
• Water scarcity are growing in India, and challenges of managing water
would be greater in years to come
• There are issues associated with climate predictions for India,
particularly rainfall. But, even under the best case scenario, there
could be some human induced climate impacts, which are negative
• But, there are priority issues in water management, which need to be
addressed
• Generating accurate scientific data on climate and hydrology is one
among them (temp., rainfall & its intensity, stream flows, base flows,
groundwater recharge & withdrawal, glaciers etc.)
15. Areas of concern for future
• Addressing these fundamental issues would help plan for climate
induced impacts
• More importantly, India has capabilities to adapt to the changes
which the current predictions on climate shows
• Further strengthening these capabilities would require :
– Management of aquifers in the water-scarce regions
– Building multi-annual storage in reservoirs
– Improving water productivity in irrigated agriculture would be key to
strengthening our adaptive capacities and reducing emissions
16. Rainfall and ET0 in Nine agro climatic sub-
zones in Narmada basin
2000
1800
1600
millimetres
1400
1200
1000
800
600
400
200
0
CNV - Jabalpur CNV - Kymore Plateau Malwal Plateau Nimar Plains Northern Hill Satpura Plateau Satpura Plateau Vindhya Plateau
Hosangabad & Satpura Hills Region of
Chhattisgarh
Annual ET0 (mm) Average Normal Rainfall (mm)
17. Variations in daily min. and max. temperature
between years
Temperature of Aurangabad (2009 and 2010)
50.0
45.0
Temperature in degrees C
40.0
35.0
30.0
25.0
20.0
15.0
10.0
5.0
0.0
12
23
34
45
56
67
78
89
100
111
122
133
144
155
166
177
188
199
210
221
232
243
254
265
276
287
298
309
320
331
342
353
364
1
Daily Max Temp-2009 Daily Max Temp-2010
Daily Min Temp-2009 Daily Min Temp-2010
23. City Size Vs Surface water Contribution to
Water Supply
24. Water-scarce basins & regions
Average Reference Evapo-transpiration Against Effective Annual Water
Resources in Selected River Basins in Water-Scarce Regions
Sr. No Name of the Mean Annual Rainfall Average Effective Reference
Basin (mm) Annual Annual Evapo-transpiration3
Water Water (mm)
Resources Resource2
Upper Lower 1mm) (mm) Upper Lower
Catchment Catchment
1 Narmada basin 1352.00 792.00 444.70 937.60 1639.00 2127.00
2 Sabarmati basin 643.00 821.00 222.84 309.61 1263.00 1788.80
3 Cauvery basin 3283.00 1337.00 316.15 682.80 1586.90 1852.90
4 Pennar basin 900.00 567.00 193.90 467.80 1783.00 1888.00
5 Krishna basin 2100.00 1029.00 249.16 489.15 1637.00 1785.90
25. Water-abundant basins & regions
Name of the Average Annual Average Average Mean Annual Reference Water
basin Rainfall in the basin Renewable Effective Evapo-transpiration Demand
(mm) Water Water (mm) for
Resources Resources Agriculture
(m3/capita/ (m3/capita (m3/capita
annum) / annum) /
Upper Lower Upper Lower annum)
Catchment Catchment
Ganga 1675.0 1449.0 1179.9 1399.4 710.0 1397.0 721.5
Brahmaputra 2359.0 2641.0 1737.1 2052.8 1064.0 1205.0 1180.9
26. Annual Yield of three Sub-basins of Sabarmati River
Basin
Total Yield from Dharoi
6000
Total Yield from Watrak
5000
Yield in Million Cubic Metres
Total Yield from Hathmati
4000
3000
2000
1000
0
1977
1983
1989
1950
1953
1956
1959
1962
1965
1968
1971
1974
1980
1986
