Chennaiites can hope for fewer mosquito bites and less stink emanating from Cooum river in the years to come. But, for that to happen, the state local administration ministry should keep a close watch on Chennai Metro Water when the latter spends Rs300 crore the CM sanctioned on Thursday for preventing sewage discharge into Chennai rivers.

For, CMWSSB (Chennai metropolitan water supply and sewerage board) has twice failed in projects envisaged to contain sewage discharge into Chennai rivers. The Rs1,700 crore Chennai City River Conservation Project (CCRCP) and another Rs598 crore project implemented with Japan Bank of International Cooperation (JBIC) and later shelved stand out among them.

CMWSSB had spent not less than Rs2,000 crore over the last decade, trying to plug the outfalls polluting city water bodies and improve the city sewer system. However, it is yet to achieve the desired results.

Studies conducted by Environment Management Authority of Tamil Nadu and even CMWSSB are testimony to its miserable failure or rather poor track record. The number of outfalls in Chennai increased from 416 to 473 in 10 years from 1995, the period in which CCRCP and leak detection and rectification (LDR) project were implemented.

Worse, the number of outlets discharging sewage into Cooum and Buckingham Canal swelled from 125 and 130 in 2005 to 181 and 141 in 2010, four years after CCRCP completion.

Ironically, the then managing director of CMWSSB, in his affidavit filed before the Madras high court in a related case, admitted that the 16 packages of CCRCP were completed and commissioned in 2006 in stages and field problems were encountered in some packages during stabilisation period. He sought time till 2010 to attend and complete the problems.

Prior to this, the MAWS department issued a GO (MS no: 24) in February 2001, wherein it sough to drop some components of the Rs598 crore project implemented with JBIC funding citing “technical and operational problems at each and every stage”.

Realty hotspots in sewage mess

Besant Nagar, Gandhi Nagar, Adyar, Mylapore, Kotturpuram, Tiruvanmiyur and Velachery might be on demand on the realty front, but in reality, these areas are most vulnerable to sewer overflow in Chennai.

Flaws identified during the stabilisation process of the multi-crore CCRCP, which was implemented to overhaul the entire city sewer network, particularly these areas, remains unplugged.

The main line conveying sewage from pumping stations in the said areas to Perungudi treatment plant ends abruptly two kilometers ahead of the plant owing to flaws unattended in CCRCP.

Senior CMWSSB sources told DC that 2,000mm diameter pipelines, supposed to be laid up to Perungudi STP and which was stopped near Kandanchavadi then due to road cutting problems, remains incomplete till date.

Meanwhile, most of the untreated sewage in this line is let in to Buckingham canal near Neelanakari and Chepauk among other areas.

Residents of Tiruvanmiyur, north and south Mylapore witness frequent sewer overflow due to pressure from pumping stations at upper end of the sewer line. CMWSSB set 10 months to set right the flaws it suffered in the 16 packages of CCRCP, the most recent of the outfall plugging projects.

In fact, the CMWSSB even failed to construct a flyover proposed near Anna flyover under CCRCP. Worse, the costly PLC boards that automatically control sewer conveyance across the city remain by far defunct in most places.

As the EMAT (environment managed agency of TN) report and private studies conducted over the last ten years indicate, the successive projects had failed to plug outfalls pouring sewage in to Chennai rivers.

The city in fact suffered more sewer overflow cases after the implementation of various projects, while untreated sewage continues to be diverted through storm water drains and illegal outfalls to prevent sewage overflow in the posh Chennai backyards.