Auditor’s report says indiscriminate discharge of water from Chembarambakkam lake burdened the Adyar river

The Comptroller and Auditor General of India (CAG) has been scathing in its criticism of the government’s handling of the Chennai floods of 2015, going so far as to categorise it as a “man- made disaster”. It has held the government of Tamil Nadu responsible for the scale of the catastrophe, which the latter had termed a “natural disaster”.

The CAG report, ‘Flood management and response in Chennai and its suburban areas’, was tabled by the AIADMK government on Monday.

Though the report was submitted to the government in March 2016, it was not tabled, and the opposition had raised the issue in the Assembly during the last budget session.

Tabled in the Assembly during the last day of the session, the report has found fault with the government on many counts, with the Water Resources Department (WRD) drawing the maximum flak.

The report said that there was indiscriminate discharge of water from the Chembarambakkam reservoir, in excess of inflows, which burdened the Adyar river, leading to floods in the city and its suburbs.'

The WRD had claimed that a supervision mechanism was in place but the CAG report said that no record was made available on any communications between the Section Officer (in-charge of the tank) with departmental/government officials.

Even if there was communication with the Chief Engineer as claimed by the WRD, the fact remains that the actual inflow and outflow was not regulated as per Central Water Commission (CWC) norms, the report charged.

The WRD had the opportunity to store 0.268 thousand million cubic feet (tmc) more at the tank where the storage stood at 3.377 tmc on December 1, 2015 at 2 pm when the discharge was increased from 12,000 cusecs to 20,960 cusecs.

Also Read A wrong call that sank Chennai

The CAG was of the view that the discharge could have been maintained at 12,000 cusecs for another six hours. The indiscriminate discharge was done to save patta land allowed in the foreshore area from submergence.

“This action by the SO and WRD warrants detailed enquiry,” the CAG report said.

The discharge of water at 29,000 cusecs continuously for 21 hours on December 1 and 2 into the Adyar river, coupled with surplus water from upstream tanks and catchment areas, caused a huge flow of flood waters into the river. The CAG also charged the WRD with not taking up desiltation of the river.

Rules not revised

Also, despite CWC guidelines, the Compendium of Rules of Regulations (COR) for Chembarambakkam tank was not revised by the WRD taking into account the regulated discharge of surplus water and enhancement of the height of the tank to 24 feet.

Also Read Understanding Chembarambakkam

In the absence of an Emergency Action Plan (EAP) and due to the government’s failure to update its system / manuals as per CWC guidelines, the water was released in an unsustained manner.

The outflow of water was more than the inflow into the tank for 13 hours, in contravention of the CWC guidelines for dam safety, resulting in increased flow of water to the already swollen Adyar river.

The government replied in March 2017 that the water release was based on COR, and added that formulation of an EAP was under progress.

The CAG, however, said that the reply was not tenable as WRD failed to revise the compendium even after a lapse of 23 years from the date of installation of a regulated arrangement at the tank, and no lessons were learnt from the damage to life and property in the 2005 floods.