Chennai, Oct 10 (PTI) A preliminary flood alert was sounded on Sunday by authorities to people living close to the banks of Kosasthalaiyar River in Tiruvallur district as the Poondi Reservoir near here is expected to reach its full capacity.

In view of the rising inflow due to rains, 1,000 cusecs of surplus water would be released starting 2 PM on Sunday and if inflow continued to increase, additional quantum shall also be released in phases, a Tamil Nadu Water Resources Department communique said.

The WRD, sounding the initial alert, asked the Tiruvallur District administration to take steps to house people living in low lying areas to safe locations and alert residents.

A bunch of villages, including Nambakkam and Krishnapuram and Chennai's suburbs like Ennore and Manali, falling under Tiruvallur District, are among the downstream areas.

An important drinking water source for Chennai, the Sathyamurthi Sagar Reservoir, popularly known as Poondi Reservoir (34.58 square kilometers) is located in Tiruvallur District.

The dam's height (water storage level) is 35 feet and total capacity is 3,231 million cubic feet. As on Sunday, the water level is at 33.95 feet and the capacity has touched 2,807 mcft and the inflow is 1,691 cusecs.

As inflow increases due to seasonal rains, the reservoir's storage is rising fast. Since it is expected that the storage would touch 34 feet, it has been planned to discharge surplus water as a precautionary measure, considering the dam's safety as per rules.

If inflow continued to increase, phased discharge of additional surplus water (over and above the proposed 1,000 cusecs) would be made.