Rain water collected from the rooftop is stored in a tank. This method has the following drawbacks
1. Unhygienic Water – Stagnant water, in a closed tank for a long period becomes the breeding ground for numerous forms of algae and other living organisms. This water cannot be used for drinking or cooking until it’s filtered using a water purification system. This defeats the purpose of collecting rain water which is the purest source of water on earth. The requirement of water is in times when there is no rain and not in the days following a heavy rain when water is available in plenty for a few days. Hence water has to be stored in a manner in which it will remain pure even if the period of storage extends for many months.
2. Limited Storage – Rains are an unlimited source of fresh water. Therefore the storage system for the limitless levels of rain water that is harvested should also have limitless volume to hold the water thus collected. When water tanks are constructed the location and monetary limitations decide the size of the tank to be constructed. If a 1000 liter water tank is used for storing harvested rain water, then the extra rain water that is collected will overflow from the tank and will subsequently be lost as drain water etc.
The Solution :-
HARVESTED RAIN WATER INJECTION SYSTEM
Grow Green International’s efforts to bring a lasting solution to the present fresh water crisis resulted in it's effective Harvested Rain Water Injection method which has solved the above said problems.
As seen in the above figure Antoji’s design is a very clever integration of the limitless volume of the water table and an injection system that transfers and retrieves limitlessly, the fresh water collected through Rain Water Harvest. This water injection system transfers water to the water table where water remains stored till its requirement many months later. Since water is stored in the water table there is no stagnation leading to the availability of fresh water even after many months of storage. Further it has been found that in all coastal areas where this water injection system was used, salinity levels have decreased in the entire water table, over a period of 1 to 3 years.
GGI has successfully implemented the rain water injection project in the Andamans.