Training of Trainers in Entrepreneurship Development
in Rain Water Harvesting
Techniques of rain water harvesting
Workshop Conducted By
Eureka Forbes Institute of EnvironmentFor
Maharashtra Centre for Entrepreneurship Development
Simplest rain water harvesting
During Rainy season, Drinking water needs of 35-house villageare met by a simple saree based rainwater harvesting system.Kerala – 7 months of rainy season (Pic: Shree Padre)
Components of an urban RWH system
1. Catchments2. Channels/rainwater or down-take pipes3. First flush devices / tricks4. Storm water drains5. Filter units6. Storage tanks7. Recharge structures
Terrace
SWD
Subsoil water
Ground water
CatchmentsRoof tops or other suitable surfaces
Roof tops can give very clean water
Paved areas also give moderately good water
Un paved areas give water mixed with soil/ silt
MaintenanceCatchments should also be cleaned regularly to remove dust, leaves and bird droppings so as to maintain the quality of the product water. Junk materials should not be dumped on it.
Channels / rainwater down-take pipes
Channels Are needed to collect water from sloping roof
Rain Water Down-take pipes Are needed for flat roof
Spouts/ open pipes need to be converted to the down-take pipes
MaintenanceTheir slopes and sizing should be properThey need to be cleaned before monsoon. And realigned if disturbed
First Flush Devices
First Flush Are needed to divert first few mm of rain water out of the system
Simple capped pipes / plug bends can act as first flush
More complicated structures can also be devised
MaintenanceTimely opening and closing of the first flush gives maximum good quality water for harvesting
Filter units
Filters Are used for additional cleaning of rain water Or storm water
These can be passive like devas filter, screen filters, sand and gravel filters
Or advanced passive multi-chambered filters
or Active like PSF, MGF (DMF) ACF etc
MaintenancePassive filters are easy to maintain Active ones are not so …particularly in housing society set up
Recharge Structures Recharge Structures Are needed for harvest for dry season approach
Harvested rain water is pushed under ground for retrieval later in the dry season
These could be simple recharge pits, punctured storm drains, recharge pits with bore holes, or recharge of wells/ bore wells with filtered rain water, WATs and ponds are needed for extremely large areas
MaintenanceAppropriate cleaning recharge structures Retaining porosity and cleanliness of the filter media
Simple Ground Water Recharge Pit
Terrace
Building
Use through well/Bore well
Permeable strataSubsoil water
Ground water
Harvesting for Future Use – Storage in Soil Strata-IRecharge Pit 1
Recharge PitWith a deeper shaft
Terrace
Building
Use through well/Bore well
Impermeable strataSubsoil water
Ground water
Harvesting for Future Use – Storage in Soil Strata-IRecharge Pit Type 2
Combination well
Impermeable strataLess Subsoil water
Main Source Ground water
Harvesting for Future Use – Storage in Soil Strata-IRecharge Type 3 --- combination well
TerraceBuilding
Recharge through well Use through well/bore well
Permeable strataSubsoil water
Ground water
Harvesting for Future Use – Storage in Soil Strata - IIRecharge through Dug well
TerraceBuilding
Recharge through bore well Use through bore well
Ground water
Harvesting for Future Use – Storage in Soil Strata - IIIRecharge through Bore well
Storm Water Drains
Storm Water Drains Are usually ground level channels/ gutters for specifically taking the storm-water out of an area
During harvesting exercise we may need to modify / puncture these however safe exit must be kept for the excess rain water
MaintenanceCleaning before the rainy season and if need be during the rainy season
Improved Ground water
Harvesting for Future Use – Storage in Soil Strata - IVRecharge through trenches or punctured storm drains
TerraceBuilding
Recharge through soil Use through well/bore well
Ground water
Harvesting for Future Use – Storage in Soil Strata - VImproving permeability of pavement
Storage tanks
Storage Is needed for ‘Use when available’ and also for keep for dry season approach
It can be man made like various types of tanks
Or it can be gaps in Mother Earth’s Crust
MaintenanceAppropriate cleaning for man made tanksRetaining porosity and serenity of the earths crust
Modified from Stephen Lemcke, 2002
River Varuna
Natural Solutions
River Varuna
Natural Solutions
Birth of water supply department in Varanasi
River VarunaVaruna
Varuna
River Assi
Water worksWater works
One who makes and preserves ponds gets to taste sweetness of water
Rameshwaram shrine a few hundred feet from sea. Note the gaps (kept on purpose inFoundation and the Sweet water in the foundation reflecting the Gopuram
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