Water is a scarce resource. The reality of water crises can not be ignored. In India water resources management is poor. Extraction of ground water is being done in unplanned and uncontrolled way and this has created problems such as:
Rain water harvesting is an age-old system of collection of rain water for future use. The systematic collection and recharging of ground water recently gaining importance as one of the most feasible and easy to implement remedy to restore the hydrological imbalance and prevent a crisis.
There are two main techniques of rain water harvesting, one is storage of rainwater on surface for future use and other is recharge rainwater to ground. In this article we provide details about Building Bye-Laws, about use of ground water, rain water harvesting and roof top rainwater harvesting.
Amendment To Building Bye-laws:
The rising demands of water in urban area cannot meet through available surface water. To meet the demand, ground water is used and over-exploited resulting in decline of the ground water levels and deterioration of the ground water quality. To over come this situation, Government amended the Building Byelaws in august, 2001 making water harvesting through storing of water run off including rain water in all new buildings on plot of 100 sq. meters and above mandatory in National Capital Territory of Delhi with immediate effect.
Ban On Abstraction Of Ground Water:
Central Ground Water Authority, Ministry of Water Resources, has imposed a ban in the Notified area of Delhi and Haryana on abstraction of ground water by private agencies for commercial purposes. The indiscriminate abstraction of ground water has resulted in decline in ground water level and deterioration of ground water quality.
Adoption Of Roof Top Rain Water Harvesting System:
Central Ground Water Authority, Ministry of Water Resources, has also made mandatory in NCT Delhi adoption of roof top rain water harvesting systems for all Group Housing Societies for ground water recharge in their premises.
Rain Water Harvesting:
In the Rain Water Harvesting system, the rain water is collected and storage either for direct use or for recharging the groundwater. The term water harvesting means to prevent the losses of water either through evaporation and surface run off. In water harvesting system, it also includes engineering activities aimed at conservation and efficient utilization of limited water endowment of an area.
Rain is primary source of water and river, lakes and ground water all these are secondary source of water. At present times, we entirely depend on secondary sources of water. It is matter of great concern that ground water resources are receding day by day. To over come this problem, we should take full advantage from the primary source of water i.e. rain. Rain water needs to be scientifically pursued for the optimum utilization of its potential.
Roof Top Rain Water Harvesting System:
Roof top rain water harvesting is technique through which rain water is captured from the roof catchments and store in reservoirs to meet the house hold needs. The catchments area also includes compounds or artificially prepared impervious/ semi-pervious land surface. The latest development in efficient and scientific design of ground water recharge structures has provided impetus for systematic collection of roof top rain water for recharging the sub surface ground water aquifer. This process enhances the availability, reliability and quality of ground water at specific place and time.
Advantages of roof top rain water systems:
1. Rain water harvesting system to recharge the ground water, enhance the availability of ground water and assures continuous and reliable access to ground water.
2. Capturing and storing rain water for use is particularly important in dry land, hilly, urban and coastal areas.
3. Save the energy, for 1-meter rise in ground water level is around to save 0.40Kwh of electricity.
4.The problem of choking the storm water drain is reduced due to reduced surface runoff of rain water.
5.Avoid Flooding of roads.
6.Reduce soil erosion.
7.Reduce the cost of pumping of ground water.
8.Reduce ground water pollution and improve the quality of ground water through dilution.
9.Recharged ground water provides good quality water which is soft and low in minerals.
10.The roof top rain water harvesting is less expensive, easy to construct, operate and maintain.