Asia-Pacific Water Forum

RAINWATER HARVESTING IN A PERIURBAN AREA, KOLKATA

A Japan Water Forum Funded Project - ‘Promising Rain’

The rapid growth of cities has caused unplanned sprawl including Kolkata in India. The fringe or periurban areas of such metropolis have water scarcity. There is falling ground water tables and even such water is found to be contaminated. Women and children are to queue up at municipal taps which are few, far between and crowded. This takes away productive time. Rainwater harvesting is an ancient system in Asia. Its revival has great potentiality. With the help of a small grant from Japan Water Forum, Centre for Built Environment, initiated the project in Anandapalli, in northeast Kolkata.

Local youth club and school were contacted and there was awareness campaign ‘Bhoroshar Borosha’ (The promising rain). With acceptability of people rain water harvesting project was taken up. The roof over the detached toilet block in the school was selected for plecement of storage tank. Rain Water from the 60 sqm. terrace would yield 75000 litres water annually (Kolkata’s average annual rainfall is 1.5m and roof run off coefficient 0.85) which during the monsoon period would give 500-625 litres of water every day. This would meet substantial demand of both drinking water and sanitation. Water from terrace (eliminating dirt with first flush) is carried in 75 mm dia. pipes to first tank which is to be used for drinking water. The tank is connected to top for drinking water via simple filter with washable cartridge. Overflow from this tank could fill up the next and the rest of interconnected tanks.

The project is simple with cost effective system and replicability. There are interest of other youth clubs to take up such project. This is an example of participatory sustainable development.

Centre for Built Environment, is involved in actual projects of Rainwater harvesting within buidings. For further details please contact : Centre for Built Environment, e-mail : (dcsgmail@yahoo.co.in).

(Poster: Prof. Santosh Ghosh)