BHOPAL: Upper Lakeconsidered to be the lifeline of the state capital is dying a slow death. A large part of the city's sewage, chemical and toxic waste finds its way into the millennia old water body, degrading its quality. Each day, the Upper Lake which is source of drinking water for 40% of the city is filled with some 7,500 cubic metric million litre of sewage.
Treatment plants that handle the task of sewage filtration do exist, but environmentalists question the effectiveness. "The sewage treatment plants are not in line with the capacity requirement. These can only filter water not the chemicals," says environment activist, Subhas C Pandey.
A senior government scientist, during a discussion on air pollution in the city, warned that the unchecked sewage that is flowing in the Upper Lake is causing drastic water quality degradation.
The only man-made lake mentioned in the list of Ramsar sites under the Ramsar Conversation on Wetland, Upper Lake, is also the only one on the list that doubles as a source of drinking water.
The degeneration of water quality is enhanced by unabated flow of sewage mixed with storm water run-off into the lake. "As the lake fills up, the mean depth and detention time of the water body decreases. Excessive plant growth like green colour, decreased transparency, excessive weeds are all signs of degradation," added the scientist.
The Bhoj Wetland Project — a large area of around 33.78 square km — has had severe weed infestation in the entire fringe area.
However, the threat at present is from the surrounding colonies. During an inspection of the area along the Upper Lake, Bhopal Citizen Forum (BCF) found that the Shireen Nadi — which was once an active water spring system — releases high levels of pollutants into the lake.
Shireen Nadi, originates from Idgah Hills and flows into the Upper Lake passing through Koh-e-Fiza. The poor quality of water is leading to the loss of biodiversity in the ecosystem. Hypolimnetic loss of dissolved oxygen and loss of species diversity including fisheries, is very much apparent at Halalpura and Biaragarh area.
Industrial pollutants to agricultural chemicals have made the water on the western side of the lake undrinkable. This area is the main source of catchment for the Upper Lake. Much of the water that streams into the lake during monsoon is from this belt.
The pollution levels in the Upper Lake have reached alarming levels, necessitating immediate action to conserve the water body. "The government has yet to wake up to the reality of loss of water spread and permanent damage to the source of drinking water," says Pandey.
