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.

1. Rainwater Harvesting in a
megacity
The experience of Bangalore, India
S.Vishwanath
www.rainwaterclub.org
zenrainman@gmail.com

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. 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. 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. The Cauvery river basin –
Red colour is the Arkavathy basin , now drying Bangalore

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. 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. 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. Bangalore- The culture of the well

11. Network of tanks and lakes

14. Urban watershed map and ready for planning

15. Groundwater mapped and ready for integration

16. Groundwater contamination reported
• Can be addressed through removal of source
of contamination and through dilution
through recharge.

20. CHROMIUM EFFECTED

21. 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

23. Source: SWITCH Project

24. Rainwater harvesting strategy

26. 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

27. • 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

28. The slogan- EVERY ROOF A CATCHMENT

29. Rain barrel : easiest way to begin rainwater harvesting

30. Rainwater harvesting in an industry- Industry pays a high price for water , Rs 72 a kilo-
litre and are the first to harvest rainwater

31. Recharging an open well

32. 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

33. 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

34. 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

35. Learning skills have been imparted to
over a 1000 plumbers

36. Muniappa, the well digger who has dug more than 2000
recharge wells

37. Rainwater Harvesting Theme Park

38. Aerial View of Theme Park

39. Porous
Pathways

40. Green
storm-
water
drains

41. Leaky well

42. • 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

43. Don’t forget the maintenance

44. Open wells and bore-wells are being
revived

45. Photo : Norma Angelica Hernandez Bernal