Training of Trainers in Entrepreneurship Development in Rain Water Harvesting Techniques of rain water harvesting Workshop Conducted By Eureka Forbes Institute of Environment For Maharashtra Centre for Entrepreneurship Development

Water Harvesting

Simplest rain water harvesting During Rainy season, Drinking water needs of 35-house village are 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.Catchments 2.Channels/rainwater or down-take pipes 3.First flush devices / tricks 4.Storm water drains 5.Filter units 6.Storage tanks 7.Recharge structures Terrace SWD Subsoil water Ground water

Catchments Roof 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 Maintenance Catchments 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.

Catchments

Clean Roof Haveli Storage tank in the Raised Plinth Harvesting for Future Use – Storage in Tanks

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 Maintenance Their slopes and sizing should be proper They need to be cleaned before monsoon. And realigned if disturbed

Channels / rainwater down-take pipes

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 Maintenance Timely opening and closing of the first flush gives maximum good quality water for harvesting

First Flush Devices

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 Maintenance Passive filters are easy to maintain Active ones are not so …particularly in housing society set up

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 Maintenance Appropriate cleaning recharge structures Retaining porosity and cleanliness of the filter media

Simple Ground Water Recharge Pit Terrace Building Use through well/ Bore well Permeable strata Subsoil water Ground water Harvesting for Future Use – Storage in Soil Strata-I Recharge Pit 1

Recharge Pit With a deeper shaft Terrace Building Use through well/ Bore well Impermeable strata Subsoil water Ground water Harvesting for Future Use – Storage in Soil Strata-I Recharge Pit Type 2

Combination well Impermeable strata Less Subsoil water Main Source Ground water Harvesting for Future Use – Storage in Soil Strata-I Recharge Type combination well

Terrace Building Recharge through well Use through well/bore well Permeable strata Subsoil water Ground water Harvesting for Future Use – Storage in Soil Strata - II Recharge through Dug well

Terrace Building Recharge through bore well Use through bore well Ground water Harvesting for Future Use – Storage in Soil Strata - III Recharge through Bore well

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 Maintenance Cleaning before the rainy season and if need be during the rainy season

Improved Ground water Harvesting for Future Use – Storage in Soil Strata - IV Recharge through trenches or punctured storm drains

Terrace Building Recharge through soil Use through well/bore well Ground water Harvesting for Future Use – Storage in Soil Strata - V Improving 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 Maintenance Appropriate cleaning for man made tanks Retaining 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 Varuna Natural Solutions Water scarcity on the Banks of mighty Ganga

River Varuna Varuna River Assi Water works One who makes and preserves ponds gets to taste sweetness of water

Ancient water harvesting sites A few relics of once glorious tradition and … a way of life

Jalashayanam Vishnu Temple … Mahabalipuram, sweet water pond hardly 200 ft from sea water

Rameshwaram shrine a few hundred feet from sea. Note the gaps (kept on purpose in Foundation and the Sweet water in the foundation reflecting the Gopuram

Fort Dindigul, Tamil Nadu plenty amongst scarcity