Doomsday predicted for wetlands

Dec. 9. Wetlands in Bangalore or for that matter in the State are being rapidly lost. Thirty-five of the wetlands lost in the past decade in Bangalore were due to their conversion for residential, commercial, and agricultural purposes.

A study titled "Status conservation and management of wetlands," by T.V.Ramachandra, R. Kiran, and N.Ahalya of the Energy and Wetlands Research Group, Centre for Ecological Sciences, IISc., and published by Allied Publishers, warns that Bangalore's wetlands, all man-made, built for hydrological purposes and to support irrigated agriculture and drinking water supply, may soon vanish.

Wetlands occupy about 4.8 per cent of the geographical area in Bangalore (640 sq. km.).

Most of the wetlands are to be found on the outskirts and rural fringes of the City.

As the N.Lakshman Rau Report on lakes and tanks noted in 1986, the number of man-made tanks fell from 379 in 1973, to 246 in 1996, and it is now 81. Over 133 water bodies have been lost -- 42 in North Bangalore and 91 in South Bangalore, over two decades.

Investigation has revealed that nearly 30 per cent of the lakes are used for irrigation. Fishing is carried out in 25 per cent of the lakes surveyed. About 30 per cent are used for washing, and only three per cent for drinking.

In 21 per cent of the lakes, cultivation along the lake margins is prevalent. Mud-lifting is common in 30 per cent of the water bodies, and brick-making in 38 per cent of the lakes. The spread of the City meant choking up of the water bodies.

In the past two years, 23 per cent of lakes were dry due to lack of rain, and 25 per cent had a little water. When the presence of sewage and degrees of eutrophication was recorded in 1996, about 28 per cent of the lakes were found to be functioning as sewage receptacles. About 25 per cent of the lakes have suffered from green waters, and eight per cent of the lakes had other effluents. And dishearteningly, 30 per cent of vegetables sold in the City are grown on these tank-beds and banks.

Encroachment and reclamation are other "killers" as far as wetlands are concerned. Nearly 30 per cent of the lakes have been encroached, and 30 per cent drained for residential purposes, or for conversion to layouts. Land-filling and walling of the lake margins claimed Miller Tank which became a housing layout, the Shulay Tank is today a football stadium, the Akkithimmanahalli Tank (Langford Garden) is a hockey stadium and a residential colony, the Domlur Tank is a residential area, while the Kanteerava Stadium stands on the Sampangi Tank.

Poaching of birds has killed the species diversity. Larger birds such as ducks, geese, storks, ibis, and cormorants have been hunted out of extinction, even while their habitat is being eaten into for development. Poaching of water birds was recorded in eight lakes recently. These facts and figures were shared with The Hindu on the sidelines of the Lake-2002, a symposium on "Conservation, restoration and management of aquatic ecosystems," which began here today.

The five-day symposium is organised by the Centre for Ecological Sciences, IISc., the Karnataka Environment Research Foundation, and the Canada-based Commonwealth of Learning.