CHENNAI : With extreme weather events becoming more frequent and majority of dams being decades-old, the State government is preparing an emergency action plan (EAP) for each dam in line with the guidelines issued by the Central Water Commission (CWC). The purpose of EAP is to identify emergency situations that could threaten dam and to plan an expeditious and effective response to prevent failure of the dam and warn downstream residents of impending danger.
This plan defines the notification procedures to be followed in the event of a potentially hazardous situation. The procedures are intended to protect lives and prevent property damage from excessive release of water from dam spillways or an uncontrolled outflow of water from the dam’s breached portion. The government is also reviewing the hydrology particulars of a few large dams as studies based on past 100 years rainfall data reveal drastic changes in rainfall pattern. This assumes significance in view of the recent Kerala floods for which mammoth discharges from the Idukki and Mullaperiyar reservoirs are predominantly blamed.
As part of the ongoing Dam Rehabilitation and Improvement Project (DRIP) under the Ministry of Water Resources, River Development and Ganga Rejuvenation, the EAP is being prepared for 89 dams, of which 69 dams are operated by the Tamil Nadu Water Resources Department and 20 by the Tamil Nadu Generation and Distribution Corporation Limited (TANGEDCO). The preparation of EAP for all dams is one of the important activities under DRIP.
S Asokan, Chief Engineer (Operations and Maintenance), Dam Safety Directorate, told Express that the government had prioritised preparation of EAPs. “We have appointed a private consultant, who has already submitted inundation maps for 35 dams. Currently, we have standard operating procedure for controlled flooding, but the EAP will spell the protocol for uncontrolled flooding and potential dam failure in the face of an extreme weather event,” he said. The official said inundation maps prepared shows possible flooded areas from a dam failure “Currently, EAPs are being reviewed and corrections will be made based on the comments from all stakeholders before getting final approval from the CWC,” Asokan said.
A model EAP has been prepared for the Vaniar dam near Pappireddipatti in Dharmapuri. Vaniar dam was constructed in 1985. The same model will be replicated for all other dams. “We have time till 2020, but our target is to complete preparing EAPs for all dams in one year,” he said.