While in the Hyderabad area, we visited a brilliant project headed by one of the board of directors of Aranya Agricultural Alternatives, named Subash Reddy. He created a technique to directly recharge bore wells with rain water. An important task in a city where population pressure has created many dry wells, and wells up to 2000 ft deep. Everywhere in the city you see water trucks delivering water to apartment buildings. When it rains, the city has issues with flooding since it is not properly infiltrating its rain water, not understanding this precious resource.
The method not only recharges wells, turning dry wells into abundant ones after the first rainy season, but also has the ability to recharge the deep aquifer. Rain water is harvested from clean surfaces, such as rooftops and is put through a simple to build filtration system. The filtration system involves baffles and a silt trap, then the water filters through charcoal before it enters the main settlement pit which contains layers of sand, gravel, rocks and then boulders. After the water is cleaned in that way, it is sent directly through a screen into the well casing pipe, recharging the well and the aquifer.
I love this method for many reasons. One of which is that no tank is needed to be constructed in order to be using the rainwater for drinking, taking out the embodied energy cost of storing rainwater for household use.