Rain Water Harvesting
- Water forms the lifeline of any society. Water is essential for the environment, food security and sustainable development.
- All the known civilizations have flourished with water source as the base and it is true in the present context too.
- Availability of drinking water and provision of sanitation facilities are the basic minimum requirements for healthy living.
- Water supply and sanitation, being the two most important urban services, have wide ranging impact on human health, quality of life, environment and productivity.
- Despite the technological advancements, the global scenario still remains grim, as all the inhabitants of the world do not have access to safe water and adequate sanitation.
Rain Water Harvesting:
- Rain water harvesting is one of the most effective methods of water management and water conservation.
- It is the term used to indicate the collection and storage of rain water used for human, animals and plant needs.
- It involves collection and storage of rain water at surface or in sub-surface aquifer, before it is lost as surface run off.
- The augmented resource can be harvested in the time of need. Artificial recharge to ground water is a process by which the ground water reservoir is augmented at a rate exceeding that under natural conditions of replenishment.
- The collected water is stored and pumped in a separate pipe distribution. This is a very useful method for a developing country like India in reducing the cost and the demand of treated water and also economising the treatment plants operation, maintenance and distribution costs.
Need:
- To overcome the inadequacy of surface water to meet our demands.
- To arrest decline in ground water levels.
- To enhance availability of ground water at specific place and time and utilize rain water for sustainable development.
- To increase infiltration of rain water in the subsoil this has decreased drastically in urban areas due to paving of open area.
- To improve ground water quality by dilution.
- To increase agriculture production.
- To improve ecology of the area by increase in vegetation cover etc.
Advantages:
- The cost of recharge to sub-surface reservoir is lower than surface reservoirs.
- The aquifer serves as a distribution system also.
- No land is wasted for storage purpose and no population displacement is involved.
- Ground water is not directly exposed to evaporation and pollution.
- Storing water under ground is environment friendly.
- It increases the productivity of aquifer.
- It reduces flood hazards.
- Effects rise in ground water levels.
- Mitigates effects of drought.
- Reduces soil erosion.
Potential Areas:
- Where ground water levels are declining on regular basis.
- Where substantial amount of aquifer has been de-saturated.
- Where availability of ground water is inadequate in lean months.
- Where due to rapid urbanization, infiltration of rain water into subsoil has decreased drastically and recharging of ground water has diminished.
Methods and Techniques:
The methods of ground water recharge mainly are:
Urban Areas:
Roof top rain water/storm runoff harvesting through
- Recharge Pit
- Recharge Trench
- Tubewell
- Recharge Well
Rural Areas:
Rain water harvesting through
- Gully Plug
- Contour Bund
- Gabion Structure
- Percolation Tank
- Check Dam/Cement Plug/Nala Bund
- Recharge Shaft
- Dugwell Recharge
- Ground Water Dams/Subsurface Dyke