Depleting water table leads to sharp drop in water supply


Photograph by M. Moorthy

Rapid depletion of the groundwater table and consequent fall in yield from the city’s main water sources on the Cauvery River has caused a sharp drop in the quantum of drinking water supplied to the city residents over the past fortnight.

Tiruchi city and some neighbouring districts depend heavily on the Cauvery to meet their drinking water requirements. With the river remaining dry for the last six months, the yield from almost all water pumping stations on its bed has gone down sharply.

The check dam built a few years back across the river at Kambarasampettai, near the city’s water sources to shore up some water to tackle such problems during summer, has gone bone dry leading to the fall in water table in the area. Surprisingly, the city was facing a water shortage during July this year after the Corporation managed the situation comfortably during peak summer.

The yield from the Corporation’s main drinking water sources on the Cauvery River has slumped by 25 to 30 per cent over the past 20 days, according to sources in the civic body. Normally, the Corporation supplies about 125 million litres a day (MLD) to the city residents.

Corporation officials are now pinning their hopes on an increase in the discharge from Mettur Reservoir, which could provide a much needed wetting to the water sources on the river, for the Aadi Perukku festival.

Although the Public Works Department is currently releasing about 2,000 cusecs from the Mettur Dam for drinking water purposes, the realisation at Mukkombu (Upper Anicut) has been meagre due to the high absorption rate.

Despite the commissioning of the new drinking water augmentation scheme with its source on the Coleroon River, the Corporation has been forced to fall back on the supplementary borewells sunk around its major drinking water pumping stations on the Cauvery River bed some years ago.

The additional borewells were meant to meet possible shortfall during summer.

Yet Corporation officials were facing problems in filling up at least 19 major overhead tanks, which supply water to different parts of the city.

The yield from the Kambarasampettai Collector Well, Main Pumping Station and Pirattiyur Combined Drinking Water Supply Scheme has fallen sharply. Consequently, water supply to several parts of the city, which were getting twice a day supply, has been restricted to once a day.

While residents in low lying areas of the distribution lines manage to get adequate supply, those in higher plains are facing short supply.

Corporation Commissioner N.S.Prema conceded that there has been a drop in yield in the water sources on the Cauvery River.

However, the quantum of water release from the Mettur Dam is likely to be increased to 5,000 cusecs in the next few days.

The problem would be overcome, within the next few days, once the collector wells of the water sources get a wetting, she said.

The Corporation had arranged for water supply through tankers to places facing short supply, she added.