`Declare catchment area of T.G. Reservoir a conservation zone'

By Harichandan A.A.

BANGALORE, OCT. 10. The report on a study conducted by the ISRO on the 1,453-sq.km. catchment area of the Tippegondanahalli Reservoir has proposed that it should be declared a ``conservation zone''.

The study has identified regions in the catchment area for protection, regulation, and monitoring, especially for regulating urbanisation and industrialisation.

The reservoir, built in the early Thirties, at the confluence of the Kumudvati and the Arkavati, provides about 120 million litres of water daily to the City. That is 20 per cent of the daily supply of water to the City.

Concern over the reduced inflow of water into the reservoir led the Bangalore Metropolitan Region Development Authority to commission a comprehensive remote sensing-based evaluation of the inflow in 1998. Ironically, the authority has allowed several ``development'' projects in the catchment area.

The study was conducted by the Indian Resources Information and Management Technologies (IN-RIMT) Private Limited. Inputs were provided by the ISRO (satellite data), the Drought Monitoring Cell (hydro-meteorological data), the Bangalore Water Supply and Sewerage Board (data on storage of water in the reservoir and the Hesaraghatta tank upstream), the Department of Mines and Geology (data on observation wells), the Forest Department, and the Department of Science and Technology.

IN-RIMT submitted its first report in June 2000, and is now in the final stages of preparing an action plan.

Depletion of water table

The report says that there is depletion of water table in the catchment area. In the past 10 years, water was stored at the peak level in the reservoir only once, between December 1991 and January 1992, according to the records of the Bangalore Water Supply and Sewerage Board.

From a decade from 1988, the built-up land in the catchment area increased by 200 per cent. Agriculture is the main economic activity in the area, where crop land decreased by 15 per cent and commercial plantation increased by 13.7 per cent.

The hills in the area have been denuded, and forest cover has decreased. The scrub land have been converted into residential/industrial layouts.

There are over 9,400 borewells in the area from which water is pumped out indiscriminately. In the past 15 years, the depth to which borewells have to be sunk rose from an average of 200 feet to about 450 feet.

Pollution of water

The Peenya industrial area occupies a portion of the Arkavati sub-catchment area (one of the three distinct sub-catchments that the catchment area is divided into). There is ribbon development as long rows of buildings are built along the two national highways passing through the area. This can contaminate surface water and groundwater.

Sewage and effluents seeping into the Arkavati have been noticed in a few places. Groundwater contamination in certain parts of the Arkavati sub-catchment area has also been confirmed, the report says.

Protected zones

The report proposes the identification of specific zones in the catchment area for protection against indiscriminate development. The recommendations include declaration of a zone of 10 km. radius around the reservoir as a ``protected area'', regulation of a buffer zone of two km. on either side of the Arkavati and the Kumudvati in the catchment area, establishment of a network of rain gauges and run-off gauging stations in the area and water quality monitoring sites, and setting up of a mechanism to monitor the activities in the area.

IN-RIMT is now working to put together the policy guidelines required to implement the recommendations, sources said.

If the action plan is backed by the Government, it can be the first step to achieve a compromise between land use for purposes other than agriculture and conservation of the catchment area.

Send this article to Friends by E-Mail

Section  : Southern States
Previous : L&T Ramboll bids for consultancy contract again
Next     : Panels' meet on tribal issue today