Water management in India- Role of rainwater harvesting

4,597 views

Published on

This is a talk given at an Engineer Association meet on the role of rainwater harvesting in rural and urban areas in the current context of India's water situation.

Published in: Education
2 Comments
5 Likes
Statistics
Notes
No Downloads
Views
Total views
4,597
On SlideShare
0
From Embeds
0
Number of Embeds
29
Actions
Shares
0
Downloads
1,033
Comments
2
Likes
5
Embeds 0
No embeds

No notes for slide

Water management in India- Role of rainwater harvesting

  1. 1. Urban water management in India The role of rainwater harvesting Case studies and technical feasibilities
  2. 2. Groundwater • India has the single largest exploitation of groundwater in the world with over 20 million bore-wells • 65 % of the net irrigated land gets water from bore-wells • 85 % of rural habitations depend on groundwater
  3. 3. Photo : Norma Angelica Hernandez Bernal
  4. 4. Rainwater harvesting • Collecting and storing rainwater for future productive use. • System consists of catchment , conveyance, filtration and storage
  5. 5. The issue • 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
  6. 6. • 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
  7. 7. Law of the jungle
  8. 8. Old forest release water or do they?
  9. 9. The Cauvery river basin Bangalore
  10. 10. Bangalore need Bangalore Bangalore gets its water from the Cauvery 95 kms and 500 meters below the city
  11. 11. 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
  12. 12. Bangalore need : limitations • Production cost of water is very high at Rs 18/ ( Rs23.47)- a kilo-liter. It will become Rs 26/- a kilo-liter. • Ceiling on the availability : 1,500 mld. Good enough for 7 million people only i.e. by the year 2011. • Surface and groundwater on the decline.
  13. 13. Why harvest rainwater ? • Provides supplemental water for city • Recharges groundwater potential lost due to urban ‘crusting’ • Reduce ecological footprint of water (power/water nexus) • Helps manage urban floods • Prevents salinity ingress in coastal area
  14. 14. The new rwh bye-law • Create recharge or storage – @ 20 litres per square metre of roof area – @ 10 litres per square metre of paved area Minimum depth of recharge well 3 metres
  15. 15. Local hydrologic cycle
  16. 16. Hydro-flows • Surface runoff 15 90 • Recharge 10 5 • Evapo-transpiration 75 5 • The aim of rainwater harvesting is bio- mimicry.
  17. 17. 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 Consumption range : from 50 to 300 liters per person per day
  18. 18. What is rainwater harvesting ? The collection and storage of rain for future productive use
  19. 19. Capital cost – in Bangalore • Piped water supply : 1,500 Million Litres per Day Investment Rs.60,000 million ($ 1500 million) • Rainwater : 3,000 Million Litres per Day Rs. “0.00”(zero) ? Can a better balance be reached ??
  20. 20. How to harvest rainwater ? • Understand rain (quantum/pattern/intensity) • Cascade capture • House/Apartment/Institution/Industry/Park • Storm water harvesting in ‘tanks’/lakes • Ground water recharge
  21. 21. 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 30 years data
  22. 22. EVERY ROOF CAN BE A CATCHMENT
  23. 23. Gutters Gutter-for sloping roof transmitted through - PVC - Polycarbonate - GI - Aluminium - Stainless steel PVC GUTTER
  24. 24. Downpipes Down water pipes made of - HDPE - PVC -AC PIPES ARE OK TOO
  25. 25. 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
  26. 26. Water harvesting and water reuse in a house
  27. 27. Rain barrel : easiest way to begin rainwater harvesting
  28. 28. Rain barrels at work
  29. 29. Details of a rain barrel Aluminium basket filter Plastic basket filter
  30. 30. Rainwater harvesting in an industry 4 acres > objective 0% runoff Rain Barrels harvesting rooftop rainwater
  31. 31. .
  32. 32. Site Selection for Infiltration Many factors affect the suitability of a site as an infiltration facility for the disposal of stormwater. Among these, the following are most important: • Depth to groundwater • Surface soil type • Underlying soil type • Vegetation cover of the infiltrating surface • The uses of the infiltrating surfaces • The ratio of tributary impervious surface to the infiltrating surface
  33. 33. 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 : locality Borewell and recharge pit
  34. 34. Site identification The site should have a sufficient clean and large catchment. It should also permit fast infiltration and percolation.
  35. 35. Excavation The excavation should reach porous soil / weathered rock / fracture. Digging the pit
  36. 36. Backfilling. Round hard material. Smaller stones on top Filling of the pit
  37. 37. Finished recharge pit
  38. 38. Recharge pit around bore wells
  39. 39. The pit has reach the silt layer Pit and concrete rings Placing of the rings The making of a recharge well
  40. 40. Recharge wells details Silt and leaves trap in a stormwater drain Covers : grilled or perforated RCC
  41. 41. Rainwater sent for recharge Recharging a bore well Outlet pipe in recharge well
  42. 42. Procedure ….. continued • 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. 43. Don’t forget the maintenance
  44. 44. Chikkabettahalli .. ...and provides for the poor
  45. 45. Stormwater collected into a sump and used for the garden > 10 lakhs litres of water stored every year
  46. 46. Increasing soil moisture Swales
  47. 47. The storm drain keep it clean make a recharge well
  48. 48. The electric line put conduits on electric lines
  49. 49. The road address road cutting prevent damage Keep an eye on the contractors work
  50. 50. The roadside trees Make saplings, Plant trees,Take care of them
  51. 51. Roofs and Terraces.............
  52. 52. Most of the time are • Sterile, • Uninteresting and • Heat sinks
  53. 53. Roof • 100 sq. mt. 100,000 litres of water • 100 sq. mt 200 kgs of rice and vegetables • 100 sq. mt. All the grey water –100 ltrs/day • 100 sq.mt All the urine 1500 litres / year • 100 sq. mt All the solid waste generated • 100 sq mt 32 different species of birds • 100 SQ mt heat 100 litres daily • Light 12 bulbs • Cook for 4 people lunch and dinner
  54. 54. Can they be smarter ???? – Since they receive---------- – maximum sunlight and heat – all the rain – lots of wind and – a whole bunch of birds, butterflies and bees – Can they solve Bangalore’s water, wastewater, energy, sewage, food and bio-diversity problem ?
  55. 55. Can they be smarter ???? – Since they receive---------- – maximum sunlight and heat – all the rain – lots of wind and – a whole bunch of birds, butterflies and bees – Can they solve Bangalore’s water, wastewater, energy, sewage, food and bio- diversity problem ?
  56. 56. How about? A roof that grows rice
  57. 57. So what can a smart roof do? • Provide – Food security… and grow rice, banana, vegetables – Water security .. and treat waste water – Energy security… and keep the house cool – Ecological security… and help save the sparrow
  58. 58. Harvests rain
  59. 59. Uses the Sun
  60. 60. Uses treated grey water to grow it
  61. 61. Where do the children play?
  62. 62. 2007 – moved out 2005 GOOGLE IMAGE 2007 GOOGLE IMAGE
  63. 63. 2009 – nowhere to go
  64. 64. No pavement, no play space But barbed wire and parking
  65. 65. thankyou

×