The Importance Of Groundwater In Urban India: S. Vishwanath
Post on 14-Jun-2015
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The importance of groundwater in urban India
S.VishwanathAdvisor
Arghyam
Urban India 2001
• 285 million (27.8%) of 1.02 billion
• 5161 cities• 35 metros - million plus• 388 large towns• 4738 small and medium < 10 lakhs
• Projected 368 million by 2012
Photo : Norma Angelica Hernandez Bernal
Groundwater.....provides for the poor , since the poor are usually not connected to the piped water supply
Water from a recharge well
What does urbanization do to urban groundwater?
•Increase it in the core area through leaking pipes (50%) and uncollected sewage
•Impair quality through point/non-point pollution•75% of surface water is polluted by untreated
municipal waste water
Typology
• Lithology determines typology
• Coastal• Hilly• Hard Rock• Alluvial• Arid
Groundwater dependence
• 75 % of urban areas in alluvial areas depend on groundwater
• 80 % of cities in hard rock areas depend on external surface sources of water
• - Ankit Patel,S. Krishnan
But water is a state subject..
Karnataka
• 223 towns• 46 completely dependant on groundwater• 137 partially dependant on groundwater
• Bangalore (pop- 6.6million) for example has 20 to 40 % dependence on groundwater but is counted as non groundwater dependant
The issue in cities
• Exploding water demand in cities
• Problems of urbanization : water shortage and flooding
• Need to manage water in cities holistically
Case study of a city as an example
• New paradigm required• Multiple sourcing of water• Source control for flood management• Institutional coordination• People’s participation in solution’s• More space for ‘softer’ solutions like education
Realities
Water tanker Bore well
Water in the city
Lakes and tanks :261 in 196081 in 199755 in 2000
Lake development authority created to preserve and enhance surface water bodies in city
The Cauvery river basin Bangalore
Groundwater use
• Impacts surface flows – The Arkavathyriver, 4000 sq km catchment, is now dry.
• 150 MLD supply source is now finished• This water now must come from
groundwater within the city or from another surface source
Surface water
• 800 mld is pumped 300 meter high• 80 MW of energy is used• 200,000 bore wells pump groundwater
from 100 to 300 metre depths• ? MW of energy
• The gw energy nexus
Local hydrologic cycle
The change
• Before construction After construction
• Runoff 15 90 (75)• Percolation 10 5 (-5)• Evapo-transpiration 75 5 (-70)
Rain barrel : Does storing water from rain reduce pumping of water?
What should be the quality of recharge water?
Sub-optimization is inevitable
Price will determine use
• Bangalore – Rs 72/ KL for industrial water• Resulted in resource substitution – about
100 mld less demand on BWSSB , which presumably came from groundwater
• Open well Rs 3/per KL• Bore well Rs 15-18 / kl• Cauvery iv stage Rs 48 per KL
The monitoring..
• Each connection is metered• Each bore well pays Rs 50 /- a month as
sanitary cess . Can bore wells be metered and volumetrically priced?
• Will people manage groundwater better if it is cheaper than piped supply?
The construct of the problem determines the solution
• Mulbagal town : 70,000 population• Arghyam initiative for IUWM• Grey area according to the CGWB• Mines and Geology suggests 600 feet as
g.w. depth• Studies indicate g.w. at 20 feet depthBGL
in a well defined shallow aquifer enough for Mulbagal’s needs
Energy cost
• Approx 60 % of the muncipality’s budget goes for energy charges towards pumping costs annually
Sustainability
• Socially-• Technically• Institutionally- Where are the urban gwi’s?• Legally- Where is the law? • Economically- What is the incentive?• Ecologically- How do we protect aquifers
and base flows?
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