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

Water Harvesting

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.

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

MaintenanceTheir slopes and sizing should be properThey need to be cleaned before monsoon. And realigned if disturbed

Channels / rainwater down-take pipes

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

MaintenanceTimely 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

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 Varuna

Natural Solutions

Water scarcity on the Banks of mighty Ganga

River VarunaVaruna

Varuna

River Assi

Water worksWater 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 inFoundation and the Sweet water in the foundation reflecting the Gopuram

Fort Dindigul, Tamil Nadu plenty amongst scarcity

Fort Dindigul, Tamil Nadu plenty amongst scarcity