44-Environmental problems of Vembanad — Kol Wetland and management strategies

Abstract

The Vembanad wetland, the largest tropical estuary on the South west coast of India identified recently as a Ramsar site, lies between 9° 00' and 10° 40'N latitude and 76° 00' and 77° 30'E longitude . It extends from Alappuzha in the South to Azheekode in the North. The low lying Kole lands lying between 10° 20' and 10° 40'N latitude and 75° 58' and 76° ll'E longitude also joins the Vembanad wetland. A variety of reasons have contributed to the environmental crisis of this wetland. It includes large scale pollution, indiscriminate exploitation of its resources and human interventions like land reclamations, unscientific operation of the Thaneermukkom barrage and Thottappally spillway. About 18005 Ha of the wetland was reclaimed during the last 150 years for various agricultural and allied purposes. The Thaneermukkom salt water barrier constructed for facilitating the raising of a third crop has led to the decline in salinity levels in the backwaters, causing depletion of fishery resources, and stagnation of pollutants in the wetland. The Thottappally spillway constructed as a measure to control the floods in Kuttanad has led to saline water intrusion into the agricultural fields through spillway channels. A total of about 230 million litres/d of domestic sewage, 260million litres/d of trade effluents and 187 Tonnes of solid wastes are estimated to be discharged into the wetland. The boom in tourism in this sector has led to destruction of mangroves and deposition of waste materials from about 200 house boats and 50 passenger boats. Indiscriminate exploitation of resources of the wetland has led to the depletion of many renewable resources. The annual landing of fishery resources have declined by about 89%.The paper reviews the problems, causes and management objectives for the conservation of the wetland system.