The shrinking backwaters of Kerala

Abstract

The most serious anthropogenic environmental alteration taken place in the estuaries of Kerala, India in the living memory, is it's alarming rate of reduction in extent. Vembanad Kayal, the largest backwaters system on the west coast of India, had an area of 36,500 ha in the last century. It has undergone man-made shrinkage at an alarming rate. As a result, only about 35% of its area remains as open brackishwaters at present. This shows that only about 17% of Vembanad system will be left as open brackishwaters by the dawn of 21st century, provided it is not further encroached for other purposes. The mean depth of the backwaters has also been decreased to 65.67% during the past fifty years as a result of siltation. The resultant reduction in volume together with other environmental alterations have adversely affected the fishery resources in this region. The carrying capacity of the system has been further threatened by the growing inflow of effluents from domestic, agricultural and industrial sources