Rain Harvesting is a process of collecting and storing rain water using different technologies. Systematic collection and recharging of ground water has become a feasible and easy way to check hydrological imbalance and to meet the water requirement during crisis period.
How does Rainwater Harvesting work?
Rain is harvested by collecting run-off from rooftops, local catchments, capturing seasonal flood water from streams and conserving water through watershed management. The collected water is stored in soil or man made dams, tanks and containers.
Types of Rainwater Harvesting System
Rain harvesting is of two types namely, in situ and ex situ harvesting. During heavy rainfall the undeveloped lands has the capacity to hold certain amount of rainwater in soil (in situ harvesting). The excess water gradually drains away in rivers or streams. In developed areas where rain falls on roofs of houses, concrete and tarmacs, water drains away straight into rivers. The water level rises and flood occurs. In these areas rain has to be collected in containers (ex situ harvesting) to avoid flood.
Why harvest Rainwater?
Rain harvesting offers a reliable source of clean drinking if maintenance measures are followed properly. It has been found that less than three percent of freshwater is stored as ground water in the world’s aquifers. The total renewable water resources of India are about 1,897 sq. km/annum. It has been said that by 2025 a large part of India would face water crisis.
Benefits of Rain Harvesting
Ecosystem offers provisioning, regulating, cultural and supporting services. Rain harvesting benefits all of them in several ways. It helps to increase crop productivity and food supply; water and fodder for livestock and poultry; rainfall infiltration; and improves biodiversity.
Apart preventing floods and supplying water during droughts, it reduces soil erosion. It also supports spiritual, religious and aesthetic values and helps to flow support nutrients including water purification in landscape.
Why does water crisis takes place? Do we harvest rain in India?
Water crisis occurs due to the unavailability of sufficient amount of portable and unpolluted water in a particular region. In India, rain harvesting began long ago in states such as Rajasthan and Gujarat. It has now gained importance in other parts of the country. It is common in Shillong, Meghalaya, Chennai, Bangalore and Kerala.