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=Rain water harvesting =-

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=Rain water harvesting =-

  1. 1. Rainwater Harvesting .ppt (1)
  2. 2. Rain Water Harvesting?. • Rain Water Harvesting RWH- process of collecting, conveying & storing water from rainfall in an area – for beneficial use. • Storage – in tanks, reservoirs, underground storage- groundwater • Hydrological Cycle
  3. 3. What Is Rainwater Harvesting? RWH technology consists of simple systems to collect, convey, and store rainwater. Rainwater capture is accomplished primarily from roof-top, surface runoff, and other surfaces. RWH either captures stored rainwater for direct use (irrigation, production, washing, drinking water, etc.) or is recharged into the local ground water and is call artificial recharge. In many cases, RWH systems are used in conjunction with Aquifer Storage and Recovery (ASR). ASR is the introduction of RWH collected rainwater to the groundwater / aquifer through various structures in excess of what would naturally infiltrate then recovered for use .ppt (3)
  4. 4. Why Rainwater Harvesting? Conserve and supplement existing water resources Available for capture and storage in most global locations Potentially provide improved quality of water Supply water at one of the lowest costs possible for a supplemental supply source. Capturing and directing storm water (run-off) and beneficially use it Commitment as a corporate citizen - showcasing environmental concerns Public Mandate (India) Replenishing local ground water aquifers where l owering of water tables has occured .ppt (4)
  5. 5. Why Not RWH? Not applicable in all climate conditions over the world Performance seriously affected by climate fluctuations that sometimes are hard to predict Increasingly sophisticated RWH systems (ASR) necessarily increases complexities in cost, design, operation, maintenance, size and regulatory permitting Collected rainwater can be degraded with the inclusion of storm water runoff Collected water quality might be affected by external factors Collection systems require monitoring and continuous maintenance and improvement to maintain desired water quality characteristics for water end-use Certain areas will have high initial capital cost with low ROI .ppt (5)
  6. 6. Condensation Let’s take a look at Precipitation The Water Cycle Evapotranspiration Evaporation Infiltration Surface Runoff Grou Consumption Surface Water n dw ater Sea water intrusion .ppt (6)
  7. 7. Condensation Rainfall Definitions Intensity – Quantity per time of Precipitation the rainfall event (mm/hour) Duration – period of time for the precipitation event Average Annual and Monthly Precipitation – Average rainfall over one year period and monthly intervals and usually based on 30 or more years of Consumption data Grou ndw ater Surface Water .ppt (7)
  8. 8. Rain Water as Source Water Design Considerations 1 2 Typical Diagram Recomendation 4 3 5 6 Raw water tank or Aquifer 7 1 Roof 4 Pre-filter 2 Screen 5 Storage tank 3 Discharge of water 6 Flow meter 7 Storm water discharge .ppt (8)
  9. 9. Ground Water Recharge Under natural conditions it may take days to centuries to recharge ground water by rain water. As we need to replenish the pumped water, Artificial Recharge of Ground water is required at some locations. .ppt (9)
  10. 10. Appropriate Water conservation and groundwater Technology recharge techniques Water harvesting cum supplementary irrigation techniques in Jhabua
  11. 11. Ground catchments systems channel water from a prepared catchment area into storage. Generally they are only considered in areas where rainwater is very scarce and other sources of water are not available. They are more suited to small communities than individual families. If properly designed, ground catchment systems can collect large quantities of rainwater. .ppt (11)
  12. 12. Storage • Storage devices may be either above or below ground • Different types include  Storage Tanks  Water Containers  Lagoons or Lined Ponds  Infiltration Ponds  Size based on rainfall pattern, demand, budget and area .ppt (12)
  13. 13. Percolation Pit To divert rainwater into an aquifer, The percolation pit is covered with a perforated concrete slab The pit is filled with gravel/ pebbles followed by river sand for better percolation. The top layer of sand must be cleaned and replaced at least once in two years to remove settled silt for improving the percolation .ppt (13)
  14. 14. RWH – Methodologies • Roof Rain Water Harvesting • Land based Rain Water Harvesting • Watershed based Rain Water harvesting • For Urban & Industrial Environment – • Roof & Land based RWH • Public, Private, Office & Industrial buildings • Pavements, Lawns, Gardens & other open spaces
  15. 15. Recharge Wells The runoff water from rooftops or other catchments can be channelized into an existing /new well via sand filter to filter turbidity and other pollutants Abandoned wells can also be used Cost-effective process, which not only conserves rainwater for immediate use but also helps to enhance the local ground water situation .ppt (15)
  16. 16. Quality Issues Roofs contain: bird droppings, atmospheric dust, industrial and urban air pollution .ppt (16)
  17. 17. Operational Procedures and Design Considerations • Storage tank – dark materials to exclude light and algae formation • Corrosion resistant materials • Tank in protected shaded area – lower temperature • For multiple storage tanks – design for frequent turnover • Regional wind direction and industrial activity – Lead, Mercury, other heavy metals .ppt (17)
  18. 18. RAIN W ATER HARVESTING FOR OFFICES – Developing a GREEN BUILDING in Nairobi, Kenya RAIN WATER ACCUMULATION IN LIEU OF STORM WATER ATTENUATION POND GREEN ROOF GREEN ROOF MANICURED LAWN GARDEN POROUS PARKING OZONATION FILTRATION OVERFLOW BACKUP MUNICIPAL SUPPLY Co nc e p t & De s ig n Princ ip le s GROUND WATER REPLENISHING WELLS .ppt (18)
  19. 19. PRINCIPLES OF A GREEN BUILDING - WATER SYSTEM OF RAIN WATER HARVESTING AND GREY WATER ARE COMBINED TO ACHIEVE THE FOLLOWING: • 25% OF POTABLE WATER CONSUMPTION REDUCTION • 100% OF POTABLE WATER PROVIDED BY RAIN • 50% REDUCTION OF SEWER QUANTITIES .ppt (19)

Notas do Editor

  • Narration: T he hydrologic or water cycle is the continuous flow of water between reservoirs at or near the earth’s surface. As water falls to the ground as precipitation, it may develop as surface runoff into nearby surface waters or infiltrate into the ground and become stored as groundwater. Water stored in open areas, know as surface water, can evaporate into the atmosphere. In addition, water used by plants for normal growth or transpiration is also returned to the atmosphere. Once in the atmosphere water can condense into clouds and precipitate as rain or snowfall, initiating the cycle over again. Water is a renewable resource that, managed properly, can sustain the activities in the watershed for an indefinite period of time. Animation: shows water cycle
  • Narration: T he hydrologic or water cycle is the continuous flow of water between reservoirs at or near the earth’s surface. As water falls to the ground as precipitation, it may develop as surface runoff into nearby surface waters or infiltrate into the ground and become stored as groundwater. Water stored in open areas, know as surface water, can evaporate into the atmosphere. In addition, water used by plants for normal growth or transpiration is also returned to the atmosphere. Once in the atmosphere water can condense into clouds and precipitate as rain or snowfall, initiating the cycle over again. Water is a renewable resource that, managed properly, can sustain the activities in the watershed for an indefinite period of time. Animation: shows water cycle
  • The collection device usually represents the biggest capital investment of an RWH system. It therefore requires careful design- to provide optimal storage capacity while keeping the cost as low as possible. While above-ground structures like tanks are easily purchased or made with a variety of designs, and water extraction is in many cases by gravity; they also are expensive, require more space and are prone to attack from the weather. Below-ground structures like cisterns, lagoons etc. are generally cheaper due to lower material requirements and unobtrusive. However, water extraction often requires a pump, contamination is more common, and present a potential danger to children and small animals if left uncovered.
  • Whenever the depth of clay soil is more, recharge through a percolation pit with bore is preferable. This bore can be at the centre of the pit, which is filled with pebbles. The top portion is filled with river sand. The pit itself is covered with a perforated concrete slab. If the area is prone to flooding, it is advisable to provide an air vent to the percolation pit to avoid air locking. Roof water and surface water from buildings can be diverted to percolation pits. It is advisable to have at least one percolation pit in every house with open area for every 20 square metres.
  • Existing structures such as defunct bore wells, unused/dried up open wells, unused sumps, etc. can be very well used for RWH through this technology of recharge wells instead of constructing recharge structures to reduce the total cost

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