Published on May 21, 2012
RAIN WATER HARVESTING: RAIN WATER HARVESTING MADE BY: Abhay goyal X-B 754 PowerPoint Presentation: 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 PowerPoint Presentation: 4.Recharge if there’s excess How? 1.Collect 3.Store 2.Use What can we use the rain water for?: What can we use the rain water for? If used for drinking, it is absolutely necessary to check water quality in a lab and treat as required PowerPoint Presentation: 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 RWH – Methodologies PowerPoint Presentation: Rain Water Harvesting– Advantages 1.Provides self-sufficiency to water supply 2.Reduces the cost for pumping of ground water 3.Provides high quality water, soft and low in minerals 4.Improves the quality of ground water through dilution when recharged 5.Reduces soil erosion & flooding in urban areas 6.The rooftop rain water harvesting is less expensive & easy to construct, operate and maintain 7. In desert, RWH only relief 8. I n saline or coastal areas & Islands, rain water provides good quality water PowerPoint Presentation: To arrest ground water decline and augment ground water table. To beneficiate water quality in aquifers. To conserve surface water runoff during monsoon. To reduce soil erosion. To inculcate a culture of water conservation. WHY Rainwater Harvesting? PowerPoint Presentation: HOW TO HARVEST RAIN WATER? Broadly there are two ways of harvesting rainwater: ( i ) Surface runoff harvesting :- In urban area rainwater flows away as surface runoff. This runoff could be caught and used for recharging aquifers by adopting appropriate methods. (ii) Roof top rainwater harvesting :- It is a system of catching rainwater where it falls. In rooftop harvesting, the roof becomes the catchments, and the rainwater is collected from the roof of the house/building. It can either be stored in a tank or diverted to artificial recharge system. This method is less expensive and very effective and if implemented properly helps in augmenting the ground water level of the area PowerPoint Presentation: ROOFTOP RAINWATER HARVESTING? Components Any rainwater harvesting system has three:- 1.Catchment 2. GUTTER AND DOWNTAKE PIPE 3.First flush & Filter 4.Delivery system 5.Storage PowerPoint Presentation: CATCHMENT Rooftops are favoured because of the large coefficient of run-off generated from them and relatively less likelihood of their contamination. PowerPoint Presentation: The water that leaves the rooftop may be 65 – 90% of the water that falls on it Roof material absorbs some water More water loss if roof is flat Evaporation losses GUTTER AND DOWNTAKE PIPE: GUTTER AND DOWNTAKE PIPE lead the water from the catchment surface to the storage tank FILTER AND FIRST FLUSH DEVICES remove grit, leaves and dirt that the rainwater may transport from the catchment, before the water enters the storage tank. When it rains after a long gap, the rooftops are usually very dirty and the rainwater also carries with it a lot of dissolved air pollutants. A first flush device diverts the water from the first rain so that it does not enter the storage tank.: FILTER AND FIRST FLUSH DEVICES remove grit, leaves and dirt that the rainwater may transport from the catchment, before the water enters the storage tank. When it rains after a long gap, the rooftops are usually very dirty and the rainwater also carries with it a lot of dissolved air pollutants. A first flush device diverts the water from the first rain so that it does not enter the storage tank. Filters: Filters Gravel Sand Inlet Out flow Over flow Gravel Recharge tank Filter Storage tank Down take pipes First flush Check and clean filters before and after each rainy season Make your own filter with sand, charcoal and gravel Or Buy a filter off the shelf First flush: First flush The first rain carries with it a lot of filth from the rooftop and dissolved air pollutants This rainwater should be diverted away from the storage tank using a first flush device. Some filters have a first flush system integrated in them Check and clean first flush devices regularly. First flush standpipe DELIVERY SYSTEM Piping systems that convey the stored rainwater till the point of end-use. It is not recommended to use harvested rainwater for drinking, cooking and dishwashing unless water quality issues are verified and necessary treatment or purification systems installed. : DELIVERY SYSTEM Piping systems that convey the stored rainwater till the point of end-use. It is not recommended to use harvested rainwater for drinking, cooking and dishwashing unless water quality issues are verified and necessary treatment or purification systems installed. PowerPoint Presentation: From the simplest ground level tank, surface lined ponds and large lakes storage options are many depending on the context of the rainwater harvesting design. STORAGE STORAGE: STORAGE Above ground Ground level or Intermediate floor level Just below roof Below ground Save on pumping cost Storage tank features: Storage tank features Durable and no leaks Built on a strong and stable substrate that can support the tank filled with water Opaque – presence of light can cause algal growth in tank Secure and impervious cover Vents to be covered with insect proof mesh Located as close as possible to demand and supply points to reduce plumbing Storage tank features: Overflow pipe should be provided close to the top, to reduce dead space . Overflow pipe diameter should be equal to inlet pipe diameter Overflow pipe should lead excess water away from the foundation of tank and other buildings . Preferably the overflow should be led into a groundwater recharge system or a garden There will be sedimentation in the tank. Taps and pipes to draw water from the tank should not be very close to the bottom to prevent sediments from entering the plumbing system and clogging it. Storage tank features STORAGE SIZE : STORAGE SIZE Depends on Rainwater availability Water requirement Budget (storage tank is most expensive part of (rwh system) Available space and aesthetics Excess water can be diverted into a groundwater recharge system Do a water audit to check water requirement. METHODS OF ROOF TOP RAINWATER HARVESTING?: Storage of Direct use Recharging ground water aquifers Recharging of bore wells Recharge Pits Soak away or Recharge Shafts Recharging of dug wells Recharge Trenches Percolation tanks METHODS OF ROOF TOP RAINWATER HARVESTING?