The difference in the physiographic, topographic, rock types and rainfall leads to people in different islands to follow different methods of harvesting rain and groundwater. For example, the Southern part of the Great Nicobar Island has a rugged topography compared to the Northern part of the islands. The topography is completely used by the Shompen tribals to harvest water. Bunds were made using logs of hard bullet wood in the lower parts of the undulating terrain so that the water would collect in the pits so formed. In their water harvesting systems an extensive use of split bamboos was made. Along a gentle slope, a full length of bamboo, cut longitudinally is placed with the lower end leading into a shallow pit. They serve as conduits for rainwater and it is collected drop by drop in pits called Jackwells. To harvest the through-falls of rain through leaves, often the split bamboos are placed under trees. The Jackwells are built in a series of increasingly bigger ones connected by split bamboos so that the overflows from one lead to the other, leading to the biggest Jackwell with an approximate diameter of 6m and a depth of 7m.
In the western Rajasthan region Paar system is a common water harvesting practice. The rain water flows from the catchment area and then into this common place while percolating into the sandy soil on the way. Kuis or Beris are dug to access the percolated water in the storage area. The kuis or beris are generally constructed through traditional masonry technology and is 5m to 12 m deep. In a Paar six to ten are constructed.
In Kerala apartments builders are trying to use the best method to harvest rainwater. Due to the worldwide scarcity of water, it is important for each and everyone to contribute to saving maximum water.
