Rainwater Harvesting in an Urban Context : Training of Urban Local Bodies

1. Water
Rainwater harvesting
Rebuilding an urban water culture
Avinash Krishnamurthy
Biome Environmental Trust

4. Rani ki Vaav
800 years ago

6. Vijayanagar Kingdom – 500 years
ago

7. Surangas – living history (from
persia 500 years ago)

8. Bangalore – living history
(100 years old)

13. Photo : Norma Angelica Hernandez Bernal
Ultimate source of all water :
RAIN

14. Twin problems
Urban FloodingWater Scarcity

15. How much water do I use ?
Use Litres/person
Drinking 3
Cooking 4
Bathing 20
Flushing 40
Washing-clothes 25
Washing Utensils 20
Gardening 23
Total 135
Real Consumption range :
from 50 to 300 liters per person per day
National Town planning Norms :
Urban : 135 Lpcd
Rural (Karnataka) : 55 Lpcd

16. How to do Rainwater Harvesting ?
1. Catchment
2. Conveyance
3. First Rain separator
4. Pre-Filter
5. Storage / Recharge
6. Point of use Treatment

17. Rainfall pattern in Mysore
MONTH DAYS QUANTITY (mm)
JAN 0.2 1.9
FEB 0.4 5.2
MAR 0.5 8.5
APR 3.9 61
MAY 7.4 148.3
JUN 5.6 72.7
JUL 8 80.4
AUG 5.7 63.7
SEP 6.3 106.2
OCT 8.9 166.5
NOV 3.6 58
DEC 1.1 16.5
TOTAL 51.6 788.9

18. Rainfall pattern in Bangalore
(970mm annually, 60 rainy days)

19. How much water from the terrace ?
Site
size
Terrace
area
Amount of water for one 30mm
rain
30*40 ft 900 sq ft (900 sq ft * 0.9 * 30mm)
-------------------------------
(3.3 * 3.3)
= 2231 litres
Coefficient of runoff
Terrace absorbs water
Depends on material
Quantum of rain
Terrace Area
To get litres

20. What about the rain ? : Local hydrologic cycle
Site : 30 * 40 (Area 110 sqm)
Annual rainfall on it in B’lore : 106700 Litres
Before construction After construction
Runoff : 10%
10670 Litres / annum
Runoff: 80%
85360 Litres / annum
Difference :74690 Litres / annum
Who should manage this excess ?

21. Let’s look at the numbers more closely…..
Rainfall Water falling on the roof
(30 * 40 site)
10 mm (small shower) 1000 litres
30 mm (Average shower) 3000 litres
60mm (heavy shower) 6000 litres
Annually in Bangalore – 970mm 87300 litres
4 member household, @ 135 lpcd needs 540 litres / day
i.e. in Bangalore there is enough rain falling for 161 days of a family
Or
For nearly 5.5 months of the year
that is
Almost 50% of a household’s needs !!!
Can we capture this store it or recharge it into our borewells
(or can we do rainwater harvesting) ?

22. ….So how clean is Rainwater ?....
Rainwater in a Glass
Cauvery water in a Glass
-
Guess
Which is which ?
A Bucket of Rainwater in
Kurubarakunte village, Bangalore

23. A clean roof means clean water

24. Join all the pipes……

25. Bring it to a Storage

26. Clean Rainwater :FRS & Filtration

27. First rain separation – let the rain clean the roof

28. Filter

29. Rain barrel : easiest way to begin rainwater harvesting

31. Storage

35. LEVELS !!!!

36. Groundwater recharge : Wells & Borewells

37. Wells

38. The pit has reach the silt layer
Pit and concrete rings
Placing of the rings
Recharge Well :The making of a recharge well

39. Recharge wells details
Silt and leaves trap in a stormwater drain
Covers : grilled or
perforated RCC

40. Rainwater sent for recharge
Recharging a bore well
Outlet pipe in recharge well

41. LEVELS !!!!

42. Schema Front Section - Recharge

43. Borewells !
How does it look inside ?

44. Recharging directly into borewells
Need to be very very careful
About water quality

45. Capital cost – in Bangalore
• Piped water supply :
1,500 Million Litres per Day
• Rainwater :
close to 2,125 Million Litres per Day

46. Rainwater harvesting and
Building bye-laws
Implementing Rainwater harvesting:
• Key instrument building bye-law ?
• How do you ensure effectiveness of
implemented projects ? (technical standards)
• How do you incentivize people who adopt it?
(Can you tie it up with tariffs, property tax
etc? – the importance of metering)
• How do you monitor effectiveness ?

47. Bangalore : An example
Two laws –
1. Building bye-law in 2005 (BBMP
implementer)
2. Amendment of BWSSB Act 2010 (BWSSB
implementer)
3. Imposed on all properties that will be built
30*40ft and more
4. Applicable to already built buildings (as of
2010) 60*40ft and above

48. Bangalore: An example
5. Technical standards
Every square meter of roof area : 20 L
storage/recharge
Every square meter of non paved area : 10 L of
recharge
(i.e. a 20mm design – captures 80% of rain for
Bangalore)
6. Incentives & monitoring ineffective (?)

49. CASE STUDY : RAINBOW DRIVE
Location Sarjapur Road, Bangalore – Ground water stressed area
Size 34 acres, approx 350 plots, 200 occupied
Details Currently governed by Plot owners association (Society)
since 2002.
No BWSSB connection
Dependent on Ground water ( owned bore wells)

50. Entrance:
Prone to Flash
Floods during
Rain

51. WATER SUPPLY - SOURCE
Currently Yielding Borewells
Currently 2 such borewells
Over last 6 years 4 Borewells dried
One in this photo was highest yielding borewell
Around 2 years back – now totally dry.
…….and Individual homes calling Tankers when layout supply not enough!!!

52. WATER SUPPLY - DISTRIBUTION
Two Centralised overhead tanks with
Piped connection to Each household.
Infrastructure Owned, Managed and
Operated by Plot owners association

53. Every household connection
METERED !!!!

54. WASTE WATER & SANITATION
Two STPs given by the builder
STPs functioning questionable
What to do with “treated” waste
water?
Infrastructure Owned, Managed and
Operated by Plot owners association

55. SUMMARY OF KEY PROBLEMS
•Increasing water insecurity – borewells drying up.
•Community as a whole not aware of the problems – wasteful consumption
•Water Tankers not reliable.
•Flash flooding at entrance during heavy rains
•STP output water stagnating at entrance drains

56. IUWM INTERVENTIONS – FOUR PHASES
Phase Purpose Activities Results
Phase I Problem diagnosis,
Getting people on
board
Data collection,
communication to
people
Water literacy and
problem statement
Phase II Ground water and
Demand
management
Sourcing expertise,
Implementation of
RWH
Kick off of RWH at
HH and collective
level
Phase III Ground water and
Demand
management
Finalising new
Tariff regime,
continued
investment in RWH
Second phase of
RWH and New Tariff
regime
Phase IV Waste Water
management
Yet to start Intended to improve
treatment and reuse
waste water for
landscape

57. GROUND-WATER MANAGEMENT : RECHARGE
Land use % land area
Roof-tops 60%
Roads 25%
Open spaces 15%
Means Strategy for layout :
1.First target roof tops (Use
Common areas to demo)
2. Target Roads and storm water
drains

58. RECHARGE WELLS – THREE TYPES
Wells in Storm water drains invested
in by RWA
(Collective Investment)
Wells in Storm water drains
invested in by House hold
(Just outside the house -
individual Investment)
Wells inside the House
(individual Investment)
Resulted in reduced flooding leading to greater support
Total of 38 recharge wells in 34 acre layout already completed.
Highest well density in Bangalore !? – starting of project
NOW 150 recharge wells across 300 houses. No private borewells !

59. About Recharge wells
About Drain management
About Catchment management

60. New Water Tariff Policy – Increasing block tariff based on production
costs (Rs 16 – 17 / KL) understood during Phase I
• Households invested in recharge at Household level get Rs 100/- discount
on bill!
• Monthly Billing, not Bi-monthly any more !
• Rs 10/- per day fine for late payments !
• No supply of water to construction sites!
Consumption slab Tariff
0 – 10 KL Rs 10/-
10 – 20 KL Rs 15/-
20 – 30 KL Rs 25/-
30 – 40 KL Rs 40/-
> 40 KL Rs 60/-
DEMAND MANAGEMENT : REVISED TARIFF REGIME

61. DEMAND MANAGEMENT : HH RWH

62. PIONEER SPEAK
“ An Organized Minority is a political Majority – Jesse
Jackson
• Few people with conviction can provide the spark
to mobilize the inactive majority in the community.
• Analytical approach to price resources accurately
and reward conservation and penalize wastage is
critical
• Non-interference from government,
empowerment of the community to manage its
resources is the key ”
-Jayawant Bharadwaj
Management Committee
member and Key driver of RBD’s
Water Reforms

63. IUWM INTERVENTIONS – RESULTS
Immediate Impact observed
No Flooding during 2008 monsoon despite heavier than
normal monsoon.
People keeping track of their bills and consumption:
Far less hosing of cars prevalent than before
Fixing of leaky pipes, valves, tanks

65. Biome Environmental Trust
(Rainwater Club)
avinash@biome-solutions.com
www.rainwaterclub.org
www.biome-solutions.com
1022, 1st floor, 6th Block,
HMT Layout, Vidyaranyapura,
Bangalore – 560 097,
Phone : 080 41672790

66. Multi sourcing : Increasing urban reality
(Case of Bangalore)
Piped Water : Cauvery River
• Unreliable/erratic ?
• Scarcity
• Infrastructure growth
• Too cheap
• 100km from B’lore
• 500m below B’lore
Ground Water :
Bore/Open well
• Drying up
• Bad quality
Ground Water :
Tanker Water
• Availability ?
• Quality ?
• Cost ?
Bottled Water
•Groundwater ?
•Why ?
• Is it really
necessary or worth
it ?