The presentation puts forward some examples of rooftop rainwater harvesting in rural and urban Karnataka State, India. Rainwater harvesting is now part of policy at the National and State level. Cities are also making it mandatory to supplement water requirements

1. Water management in India The role of rainwater harvesting

6. The well has been the lifeline of water in India for centuries

7. A good water harvesting system will revive the dynamic water table and keep the wells full

8. Traditional water withdrawal systems like the Sakia can be revived

10. Indian Context: The “looming” crisis is now here Nation-wide 29% of the blocks are critical, semi-critical or over-exploited In some states as high as 75%

12. Therefore the need to conserve every drop of rain Photo : Norma Angelica Hernandez Bernal

15. Rural rainwater harvesting

16. A simple traditional rainwater harvesting system

17. A modern one with a capacity of 2500 litres storage. Implemented 20 structures in 1000 villages.

18. Good clean rainwater with a clean catchment and a good filter

19. The rainwater tank is a great place to do homework

20. .. and is multipurpose , other waters can be stored. Storage is access

21. Rooftop rainwater harvesting is now replicated in many places

23. A ‘Sachetana’ rainwater harvesting system with details painted on the wall

24. The rainwater filter has 45 cm. of coarse washed sand

25. PVC pipe , first rain separator and filter with an underground storage tank

26. An above the ground storage tank

27. Quality check- using the H2S strip test for e.coli identification

28. Simple treatment using SODIS www.sodis.ch

31. Rainwater harvesting in urban areas

34. With very little catchment management

35. Old forest release water or do they?

36. The Cauvery river basin – rivers drying up Bangalore

37. Bangalore need Bangalore Bangalore gets its water from the Cauvery 95 kms and 500 meters below the city

38. Water in the city Lakes and tanks : 261 in 1960 81 in 1997 55 in 2000 Lake development authority created to preserve and enhance surface water bodies in city

42. Local hydrologic cycle – seeking bio mimicry with rainwater harvesting

44. How much water do I use in urban Bangalore? Consumption range : from 50 to 300 liters per person per day 135 Total 23 Gardening 20 Washing Utensils 25 Washing-clothes 40 Flushing 20 Bathing 4 Cooking 3 Drinking Litres/person Use

45. What is rainwater harvesting ? The collection and storage of rain for future productive use

49. Rainfall pattern in Bangalore 30 years data 970.00 59.8 TOTAL 137.00 10.0 AUG 194.80 9.3 SEP 180.40 9.0 OCT 110.20 8.3 JUL 64.50 4.0 NOV 80.80 6.4 JUN 22.10 1.7 DEC 119.60 7.0 MAY 46.30 3.0 APR 4.40 0.4 MAR 7.20 0.5 FEB 2.70 0.2 JAN QUANTITY (mm) DAYS MONTH

50. EVERY ROOF CAN BE A CATCHMENT

51. Gutters Gutter-for sloping roof transmitted through - PVC - Polycarbonate - GI - Aluminium - Stainless steel PVC GUTTER

52. Downpipes Down water pipes made of - HDPE - PVC -AC PIPES ARE OK TOO

53. The aesthetics of rainwater harvesting

54. Filters

55. Double drums filter When the roof area is bigger than 100 m², it is possible to use two drums as filter. Drum filter of the roof top harvesting system of an appartment Collecting pipes from the roof Overflow pipe to the recharge well Pipe to the sump tank

56. Water harvesting and water reuse in a house

57. Rain barrel : easiest way to begin rainwater harvesting

58. Rain barrels at work

59. Details of a rain barrel Aluminium basket filter Plastic basket filter

60. Rainwater harvesting in an industry 4 acres > objective 0% runoff Rain Barrels harvesting rooftop rainwater

61. .

63. If the pit aims to recharge a borewell, it should be built as close to it as possible. Ideally it should be in the valley of the surface layout. The making of a recharge pit : l ocality Borewell and recharge pit

64. Site identification The site should have a sufficient clean and large catchment. It should also permit fast infiltration and percolation.

65. Excavation The excavation should reach porous soil / weathered rock / fracture. Digging the pit

66. Backfilling. Round hard material. Smaller stones on top Filling of the pit

67. Finished recharge pit

68. Recharge pit around bore wells

69. The pit has reach the silt layer Pit and concrete rings Placing of the rings The making of a recharge well

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

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

73. Don’t forget the maintenance

74. Recharge wells in storm-water drains

75. Chikkabettahalli .....wells provide for the poor. Recharge helps the poor

76. A recharge well in an IT office

78. Roofs and Terraces are 60 % of Bangalore

80. How about? A roof that grows rice

81. Grown using a 8 cm organic mulch on pond lining sheets

84. Harvesting rainwater Harvests rain

85. Uses the Sun- solar energy for cooking, lighting and water heating

86. Using grey-water from the washing machine and bath water