Rainwater harvesting in a megacity presentation for BWSSB


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How a city strategy for water management can incorporate rainwater harvesting too.
Policies and bye-laws , demonstration , from the house to the city as an approach.

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Rainwater harvesting in a megacity presentation for BWSSB

  1. 1. Rainwater Harvesting in a megacity The experience of Bangalore, India S.Vishwanath www.rainwaterclub.org zenrainman@gmail.com
  2. 2. India- Policy recognition for rainwater harvesting • The National Water Policy and the State Water Policy recognize and stress on the role of rainwater harvesting • .. The efficiency of utilization of water will be improved and awareness about water as a scarce resource fostered. Rainwater harvesting and water conservation will be encouraged. Conservation consciousness will be promoted through education, regulation incentives and disincentives. Source : http://waterresources.kar.nic.in/state_water_policy-2002.htm Bangalore has put the State Water Policy to action
  3. 3. Bangalore Water – some firsts • One of the first city to use steam engines to pump water from Hessarghatta reservoir -1894 • The first city to get electricity and use it for pumping water – 1904 • The first city water utility to be set up in India BWSSB -1964 • One of the first to use an Increasing Block Tariff and also a pro-poor approach • One of the first to use tertiary treated water for industrial use • One of the highest heads and distance to pump water 95 kms and 300 Metre up. Embodied energy 1.80 units of water per kilo-litre to pump it to the city. • One of the costliest waters in India cities . Production cost Rs 32 per kilo- litre • The first to charge for the use of groundwater as a resource. It is charged as a sanitary cess from nearly 200,000 bore-wells at Rs 50 a month. • Now is the notified authority for the city as part of the creation of the Groundwater Authority in the State.
  4. 4. The geographical setting • City on a ridge line at 920 metres above sea level . • City falls into 2 river basins – Cauvery and Palar • Allocation for city from Cauvery is limited and therefore a physical limit to the water that it can draw from the river. • The river Arkavathy – the first source now almost dry and the reservoirs (Hessarghatta and T.G.Halli) on it no longer reliable . 35 + 135 = 170 m.l.d no longer available to the city.
  5. 5. The Cauvery river basin – Red colour is the Arkavathy basin , now drying Bangalore
  6. 6. Bangalore Bangalore Bangalore gets its water from the Cauvery river 95 kms and 300 meters below the city. Embodied energy 1.8 units per kilo-litre of water to pump water to the city.
  7. 7. The Bangalore context • High price of water – both in energy and cost. • Physical limit to availability 1500 MLD • Rapid expansion of city 3 million people added between 2001 and 2011 • Current population around 9 million • A fast growing non-domestic and industrial demand from predominantly the service sector and also the manufacturing sector
  8. 8. A tradition of tanks and wells • The city had many tanks and wells. • For many years in decline but now with a revival plan getting in place.
  9. 9. Bangalore- The culture of the well
  10. 10. Network of tanks and lakes
  11. 11. Urban watershed map and ready for planning
  12. 12. Groundwater mapped and ready for integration
  13. 13. Groundwater contamination reported • Can be addressed through removal of source of contamination and through dilution through recharge.
  15. 15. The new approach • Reduce leakages and introduce demand management through tariff setting • Reuse wastewater through a series secondary and tertiary treatment plants • Rainwater harvesting and groundwater recharge • Develop and protect surface water bodies in the city • Look also for new sources of fresh water • Adopt an Integrated Urban water management approach
  16. 16. Source: SWITCH Project
  17. 17. Rainwater harvesting strategy
  18. 18. MONTH DAYS QUANTITY (mm) JAN 0.2 2.70 FEB 0.5 7.20 MAR 0.4 4.40 APR 3.0 46.30 MAY 7.0 119.60 JUN 6.4 80.80 JUL 8.3 110.20 AUG 10.0 137.00 SEP 9.3 194.80 OCT 9.0 180.40 NOV 4.0 64.50 DEC 1.7 22.10 TOTAL 59.8 970.00 Rainfall pattern in Bangalore – bimodal and well distributed, ideal for rainwater harvesting 30 years data
  19. 19. • New paradigm of water smart cities emerging • 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
  20. 20. The slogan- EVERY ROOF A CATCHMENT
  21. 21. Rain barrel : easiest way to begin rainwater harvesting
  22. 22. Rainwater harvesting in an industry- Industry pays a high price for water , Rs 72 a kilo- litre and are the first to harvest rainwater
  23. 23. Recharging an open well
  24. 24. Bangalore rainwater Bye-laws Simple and easy to understand • For every square metre roof area 20 litres of storage or recharge to be created • For every square metre of paved area 10 litres of storage or recharge to be created • Recharge well to be a minimum depth of 3 metres
  25. 25. What it has done • Created jobs estimated at Rs 7000 million (112 million US $) for plumbers • Spurred the design of rainwater filters with more than 40 products now available in the market • More than 1000 licensed plumbers trained in a 2 day certificate course • Provided Livelihood and jobs for well diggers
  26. 26. Been followed by many… • The Bangalore Metro harvests rainwater on all its stretch and in the stations • The BBMP – Bruhat Bangalore Mahanagara Palike – has adopted rainwater harvesting in all its parks and many of its buildings • The Vidhan Soudha , the General Post Office , the Raj Bhavan and many government buildings harvest rainwater
  27. 27. Learning skills have been imparted to over a 1000 plumbers
  28. 28. Muniappa, the well digger who has dug more than 2000 recharge wells
  29. 29. Rainwater Harvesting Theme Park
  30. 30. Aerial View of Theme Park
  31. 31. Porous Pathways
  32. 32. Green storm- water drains
  33. 33. Leaky well
  34. 34. • Locate recharge well in the channel or off the channel • Make arrangements to remove silt and leaves before water enters recharge well • Monitor the rate of recharge and decide on the number of recharge wells necessary for the catchment
  35. 35. Don’t forget the maintenance
  36. 36. Open wells and bore-wells are being revived
  37. 37. Photo : Norma Angelica Hernandez Bernal