Adapting to Climate Change in Urbanizing Watersheds ( ACCUWa )
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Transcript of Adapting to Climate Change in Urbanizing Watersheds ( ACCUWa )
Adapting to Climate Change in Urbanizing Watersheds (ACCUWa)
SITUATION IN ARKAVATHY BASIN
Veena SrinivasanFellow, Ashoka Trust for Research in Ecology and
the Environment
June 18th 2013
Objective: Comparative study of climate change-water vulnerability and adaptation
in 2 urbanizing watersheds
Arkavathy Watershed: Peri-urban Bangalore, 4,250 sq.km
Noyyal Watershed: Peri-urban Coimbatore,
3510 sq km
CAUVERY BASIN
RiverBasin BoundaryState Boundary
TAMIL NADU
KARNATAKA
KERALA
Arkavathy Watershed Tributary of Cauvery ~1/3 of Bengaluru, 4
Class II towns
Sources of Water Arkavathy River
(almost dry) Import from Cauvery
(limited by Tribunal) Intensive pumping of
groundwater (declining)
Rainwater + wastewater (small)
Challenges in developing theoretical framework and methods
A. Multiple Stressors
B. Multiple scales with missing linkages
C. Multiple Concerns
A. Multiple Stressors:Traditional Natural Science Framework
Water Supply(Quantity and Quality)
StressorsShocksSeasonality
RainfallTemperature
InfrastructurePolicies
Livelihood / Domestic Water Security Outcomes
“Top-Down” View of Water Supply Vulnerability
A. Multiple Stressors:
Both climate models and station rainfall data suggest slight increasing trend in annual rainfall.
< -5%
-5% - 0%
0% - 5%
5% - 10%
10% - 15%
Projected Increase in Rainfall 2035 A1B Scenario
Source: BCCI-Karnataka, 2011
A. Multiple Stressors:
Both climate models and station rainfall data suggest slight increasing trend in annual rainfall
< -5%
-5% - 0%
0% - 5%
5% - 10%
10% - 15%
Projected Increase in Rainfall 2035 A1B Scenario
Source: BCCI-Karnataka, 2011
Arkavathy Basin
A. Multiple Stressors:
0
500
1500
1000
Both climate models and station rainfall data suggest slight increasing trend in annual rainfall
1900 1950 200019751925
Doddaballapur Annual Rainfall (mm/year)
A. Multiple Stressors:
YET inflows into the TG Halli reservoir, which supplies Bengaluru, exhibit a sharp declining trend. (No new upstream dams either)
Inflows into TG Halli Reservoir (mcft/year)
A. Multiple Stressors:Traditional frameworks inadequate
Clearly the approach of blindly applying historical rainfall-runoff relationships to predict future water supply is not valid.
Rainfall Water Supply
A. Multiple Stressors:Need to account for multiple change drivers
A. Multiple Stressors:Need to account for multiple change drivers
Hypothesis 1. Increase in evapotranspiration due to temperature increase => decrease in flow.
A. Multiple Stressors:Need to account for multiple change drivers
Hypothesis 2. Excessive GW Pumping reducing base flow
A. Multiple Stressors:Need to account for multiple change drivers
Hypothesis 3. Increase in “green water use” via plantations decreasing recharge
A. Multiple Stressors:Need to account for multiple change drivers
Hypothesis 4. Unplanned urbanization causing water to collect in a “million puddles” and evaporate
A. Multiple Stressors:set up rival hypotheses
Hypothesis 2: GW Pumping
Hypothesis 3: Eucalyptus Plantations
Hypothesis 4: “Million Puddle Theory”
Hypothesis 1: Temperature rise
B. Multiple Scales – Missing LinkagesClimate variability occurs at the basin scale, whereas vulnerability is
experienced at the household scale.
PoliciesInstitutio
nsProcesses
NS
FP
H
Household Individual
Vulnerability
ContextShocks
SeasonalityTrends
influenceLivelihood / Domestic Water Security Outcomes
Social Scientists “Bottom-up” View of Water Supply Vulnerability
Source: DFID’s Sustainable Livelihoods Framework
B. Multiple Scales – Missing Linkages
Institutions
Infrastructure
No transparency on how water is allocated both within towns, across different towns, and between industrial and city supply during wet and dry periods, so hard to determine how resource variability translates to household vulnerability.
B. Multiple Scales – Missing Linkages
Different areas are vulnerable to different supply variability pathways. E.g. selected pockets get “Cauvery supply” the rest are dependent on groundwater.
Cauvery water supply
Arkavathy water supply
C. Multiple Concerns
Human Well-being
T= 0Present
T= XFuture
Drought/ SeasonalVulnerability
C. Multiple concernsInadequate water supply
Overall- most parts of Arkavathy basin do not receive enough public supply.
(However, different data sources are not consistent.)
C. Multiple concernsInadequate water quality
• Groundwater and surface water highly contaminated
Groundwater samples by taluk (sub-district)
Concentration* (mg/L)Heavy metals Fecal coliform
Cr6+:0.05 mg/lAl3+:0.03 mg/l 0 MPN/100L
Anekal 0-364Peenya Cr6+ = 16-32 0-88Doddaballapur Al3+ = 35 0-300Kanakapura PresentRamanagara Present
C. Multiple concernsDeclining SW availability
In most places the Arkavathy River is completely dry.
C. Multiple concernsDeclining GW availability
1974 1996(14)
(9)
(0)
Water Level (meters below ground level)
Source: Srikanta Murthy, 2011
Sample hydrograph in Yelahanka*
*Although groundwater levels have been increasing in places within the city mainly due to pipeline leakage
C. Multiple Concerns
Human Well-being
T= 0Present
T= XFuture
Resource Unsustainability
T= 0Present
T= XFuture
Drought/ SeasonalVulnerability
T= 0Present
T= XFuture
Chronic Scarcity/ Inequity
Research Methods
Global Climat
e Chang
e
Land, Labor,
Commodity
Markets
Topography, Geology,
Soils
Water Users
Livelihood / Domestic Water / Economic Production / Environment Outcomes
Infrastructure
Land use decisions
Extraction
Adaptation, coping
InstitutionsWatershedTemp and Rainfall
Land useAssets, Income
Water Quantity
and Quality
Available
Wastewater
Need an approach that considers all these
A. Multiple Stressors
B. Multiple scales with missing linkages
C. Multiple Concerns
THANK YOU!!Team MembersIDRC CCWSharachchandra LeleVeena SrinivasanBejoy ThomasPriyanka JamwalShrinivas BadigerDurba BiswasPennan ChinnasamyMeghana EswarT. ZuhailKiruba HaranKarthik MadhyasthaSwati SulganaSanjeev Kenchaigol
InternsMalvikaSayan Tagore Nagaraju Shilpa
Tata Social Welfare Trust ProjectSheetalDeepthi