Rain water harvesting


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Rain water harvesting

  1. 1. TOPIC=RAIN WATER HARVESTINGPresented To: Presented By:Davneet Singh Chawala Satinderpal Singh Ravinder Singh Sandeep Singh
  2. 2. Reasons of Shortage of Water• Population increase• Industrialization• Urbanization (a) Increase in per capita utilization (b) Less peculation area• In places where rain fed/ irrigation based crops are cultivated through ground water• Decrease in surface area of Lakes, talab, tanks etc. 1
  3. 3. Reasons of Shotrage of Water Continued…..• Deforestation (i) Less precipitation (ii) Absence of Barriers (a) Rain drops checked by leaves of tree (b) Water slowly descends through twigs & trunk © Humus – acts as reservoir (d) Tiny creatures – helps percolation 1 hectare of forest-6-7 Lac ton of water 2 3 (after filtering) top layer can hold 1.2 Lac tons of water
  4. 4. What is the solution ?• Rain water is the ultimate source of fresh water• Potential of rain to meet water demand is tremendous• Rain water harvesting helps to overcome water scarcity• To conserve ground water the aquifers must be recharged with rain water• Rain water harvesting is the ultimate answer 3
  5. 5. Why Rain water be harvested• To conserve & augment the storage of ground water• To reduce water table depletion• To improve the quality of ground water• To arrest sea water intrusion in coastal areas• To avoid flood & water stagnation in urban areas 4
  6. 6. What is rain water harvesting ?• It is the activity of direct collection of rain water• Rain water can be stored for direct use or can be recharged into the ground water aquifer 5
  7. 7. The roof catchment are selectivelycleaner when compared to the ground level catchment• Losses from roof catchment are minimum• Built & Maintained by local communities• No Chemical contamination & only required filtration• Available at door step with least cost 16
  8. 8. The typical roof top rain water harvesting system comprises• Roof catchment• Gutters• Down pipe & first flushing pipe• Filter Unit• Storage Tank 17
  9. 9. Roof catchmentThe roof of the house is used as the catchment forcollecting rain water. The style construction andmaterial of the roof effect its suitability as acatchment, Roofs made of corrugated iron sheet ,asbestos sheet, Tiles or Concrete can be utilizedfor harvesting the rain water 18
  10. 10. GuttersGutters are channels fixed to the edges ofroof all around to collect & transport therainwater from the roof. Gutters can bemade in semi-circular and rectangular shapewith cement pipe, plain galvanized ironsheet, PVC pipes, bamboos etc. Use oflocally available material reduce the overallcost of the system. 19
  11. 11. Down PipeIt is the pipe which carries the rainwaterfrom the gutters to the filter & storage tank.Down pipe is joined with the gutters at oneend & the other end is connected to thefilter unit of the storage tank. PVC or GIpipe of 50mm to 75mm (2 to”) arecommonly used for down pipe. Bamboo canbe also used wherever available andpossible 20
  12. 12. First Flush PipeDebris, dust & dirt collect on the roofduring non rainy periods when the first rainarrive. A first flush system arrangement ismade to avoid the entering unwantedmaterial into the Filter media & storagetank. This is a simple manually operatedarrangement or semi-automatic system witha valve below the ‘T’ junction 21
  13. 13. Filter UnitThe filter unit is a container or chamberfilled with filter media such as coarse sand,charcoal, coconut fiber, pebbles & gravelsto remove the debris & dirt from water thatenters the tank. The filter unit is placed overthe storage tank or separately. It may be ofFerro cement filter unit, Aluminum, Cementrings or Plastic bucket etc. 22
  14. 14. Storage TankIt is used to store the water that is collected from the roofthrough filter. For small scale water storage plasticbuckets, jerry cans, clay or cement jars, ceramic jars,drums may be used. For larger quantities of water, thesystem will require a bigger tank with cylindrical orrectangular or square in shape constructed with Ferrocement or cement rings or plain cement concrete orreinforced cement concrete or brick or stone etc. Thestorage tank is provided with a cover on the top to avoidthe contamination of water from external sources. Thestorage tank is provided with pipe fixtures at appropriateplaces to draw the water to clean the tank & to dispose ofextra water. A provision for keeping the vessel to collect 23the water is to be made.
  15. 15. Size of Storage Tank• Based on – No. of person in the House hold – Per capita water requirement – No. of days for which water is required Example Drinking water requirement for a household with 5 family members, period 8 months & 6 lpcd = 5x 180x 6 = 7200 Liters 24
  16. 16. Water available from RoofAnnual rainfall (in mm) x roof area (in sq. m) x co-efficient of run off for roof co-efficient of run off GI sheet 0.9 Asbestos 0.8 Tiled 0.75 Plaster on bricks/ Concrete 0.7Water available from roof top 800mmx 20 sq.m=12800Liters per annum 25
  17. 17. Water available from Roof continued……Size of Tank =1.2 m dia 1.8 m heightNo. of Tanks 4Volume of Tanks 3.14x1.2x1.2x1.5/4 2.03 cum 2000 litersVolume of of 4 tanks = 4x2000 8000 Liters 26
  18. 18. How the problem can be minimized 1 By providing pipe water system with source (electric based) (a) Surface water (b) Deep tubewells 2 Recharging stratas through rainwater harvesting methods (No. of villages of lower range concentration can be decreased) 3 Storing rain water for drinking purpose (a) In areas where electricity problem is more (b) In areas where concentration is more © In areas where PWS is uneconomical (d) In areas where dependable source is not available 36
  19. 19. Thank You 37