Despite crores being spent on cleaning up the Cooum, nothing has happened

What starts as a freshwater source becomes an eyesore when it reaches Poonamallee. In the last five decades, committees were formed, studies made and to restore the Cooum to its original glory. But, a Cooum without sewage still remains a distant dream.

In its 72 km run to the sea, just 18 km come under city limits. A landmark of the city, the waterway bifurcates beneath Col.Law's bridge near Chintadripet into north and south arm and meets again near Napier bridge.

Historians have recorded that Pachaiyappa Mudaliar, a philanthropist in Madras Presidency, would regularly bathe in the river before offering prayers at the Komaleeswaranpet temple, Chintadripet, in the 1790s. There are records showing that the river was used by residents from the north to bring flowers by coracles to festivals at the Komaleeswaran temple. Until the 1950s, the river was clean and was an important source of groundwater recharge.

Rapid urbanisation only reduced the waterway into a carrier of sewage with plastics, thermocol and other waste floating.

To sustain the opening at its estuary, the earliest recorded proposal was in 1890. It was to provide a link canal to connect the river with the harbour. One of the main challenges to ensure free water flow in the river is the formation of sand bars near Napier bridge caused by a littoral drift. The Water Resources Department (WRD) gets Rs.10 lakh every year to de-weed and dredge the estuary.

A total of 11 suggestions came up between 1905 and 2000 to help tidal flushing and prevention of stagnation. One of the early projects implemented to clean the river was Cooum Improvement Scheme, inaugurated by the then Chief Minister C.N.Anna Durai in September 1967.

Officials of the WRD recalled that the project implemented between 1968-73 involved construction of a sand pump and regulator, and also beautifying the stretch between Chetpet and Napier bridge. Boat jetties were also built for short rides on the Cooum. However, the project worth Rs.2.2 crore could not be sustained because the design of the regulator proved inadequate and the problems developed in sand pump in three years.

Several studies, such as that by Seven Trent Consultancy in 1991 and Mott Macdonald that came up with projects worth Rs.34.8 crore in 1994, were undertaken to improve the waterway.

While all the initiatives till the turn of the century were more of a piecemeal approach, a comprehensive Chennai City River Conservation project was started at a cost of Rs.1,200 crore. Funded substantially by the Central Government in 2001, it sought to strengthen the sewerage network and plug sewage outfalls.

Some of the treatment plants of Chennai Metrowater, which was to be built in the Rs.750 crore allotted, were constructed under the CCRCP. Former officials of Metrowater said the problems were not fully addressed as the capacity for which it was planned did not match the requirements of the city's burgeoning population. It did not help arrest sewage outfalls, either.

Nearly 100 million litres of sewage is still being let out by residents living along the banks into the city waterways. Sources in the Metrowater said of this, about 30 per cent of the raw sewage gets into the Cooum river. About 340 sewage outfalls were identified into the waterways, some of them are connected from manholes to the Cooum. The biochemical oxygen demand is reported to be more than 375 mg/l in the river at various locations.

Measures are afoot to strengthen the inadequate sewage collection and conveyance system in the 12{+t}{+h}five year plan, they said.

The eco-restoration of the Cooum and its tributaries took shape once again in 2008 with the formation of Chennai Rivers Restoration Trust. The ambitious project targeted multi-pronged approach and even drew up a package of solutions along with World Bank at a projected cost Rs.2,300 crore, sources at CRRT said. “We found that the problems start from city fringes where sewer tankers dumped loads of raw sewage into the Cooum. Floating garbage clogs 75 per cent of the river width,” sources said.

A team comprising officials from various departments visited San Antonio River Authority in Texas, USA in 2008 to study its restoration. Another team headed by the then Deputy Chief Minister M.K.Stalin visited the Singapore river in 2009.

The significant works include encroachment removal in a few parts and creation of parks and parking space as in Langs Garden Road and Dams Road. Eviction of encroachment along the banks poses a problem. A total of 15,000 encroachments were identified and only a minimal of sewage outfalls were plugged.

So far, only 8-10 per cent of the work has been completed. The memorandum of understanding with the Singapore Cooperation Enterprise did not take off as the project cost of Rs.33 crore was not viable then. The CRRT then held a meeting with experts from research organisations and universities here. By then there was a change of regime.

The project now is dormant for the past few months except for schemes devised by Metrowater for improving sewerage pipeline capacity, creating more treatment facility as suggested by CRRT.