Different types of rain water harvesting are practiced in different parts of India. A lot of importance is given to saving rain water due to the scarcity faced in different places.
The Apatani tribes of ziro in the lower Subansiri district of Arunachal Pradesh practice the Apatani method. It is wet rice cultivation cum fish farming method practiced in elevated areas of 1600m and gentle sloping valleys with an average annual rainfall of about 1700 m and where rich water resources like springs and streams are present. Both ground and surface water is harvested for irrigation.
In this system the valleys are terraced into plots separated by 0.6m high earthen dams which are supported by bamboo frames. There is an inlet and an outlet on the opposite sides of all plots. The inlet of the low lying plot is connected to the outlet of the high lying plot. The inlet points and outlet points are connected by deeper channels. By opening and blocking the inlets and outlets as and when required the terraced plot can be flooded or drained with water. Near forested hill slopes, the stream water is tapped by constructing a wall of 2-4 m high and 1 m thick. Through a channel network this is conveyed to agricultural fields.
Ooranis are tanks in South Travancore containing just enough water to cultivate the few acres of land dependent on them. The construction of only small tanks is facilitated due to the irregular topography of the region and the absence of large open spaces.
The builders of Cochin apartment are stressing on the use of rain water harvesting to save maximum water.