78-Summer Training Report on Ground Water Recharge Through Rainwater Harvesting.

Abstract

India is blessed with good rainfall but however large of it lost through runoff and it can be impounded on the surface at suitable sites for surface storage. In recent decades groundwater is also threatened by over exploitation, contamination etc. The exploitation of groundwater resources more than its annual replenishment has caused continuous decline of water level, declined well yields, dry of shallow wells and deterioration of groundwater quality. Kolkata has no exception to it. According to KMC reports, declining trend of ground water level at the rate of 0.33m/year has been observed. In order to overcome the situation and increase the groundwater levels, the present study has been carried out to identify Rainwater Harvesting potential in campus area of Heritage Institute of Technology, Kolkata. The analysis of 15 years daily rainfall data (2001-2015) shows that the annual rainfall in Kolkata varies from 1049mm-2265mm with an average rainfall of 1581.85mm. 80% of the rainfall occurs during the monsoon season, and it gets wasted due to poor management. Therefore, there is a need to adopt rainwater harvesting structures. The maximum quantity of rainwater that can be recharged through the soil in the study area comes out to be 258.69 cum.