Water managers gear up for monsoon

Two years ago, when the city was ravaged by torrential monsoon rains, millions of litres of water was let off into the sea. By some estimates, just a month into that monsoon, Chennai wasted as much water as it required to meet its annual drinking water need. This time it would be different, claimed officials from the Water Resources Department (WRD), which is in charge of the upkeep of major waterbodies in Chennai region.

Ahead of the monsoon that is only weeks away, officials said the department, which functions under the PWD, has stepped up preparedness works including taking up maintenance of the major reservoirs – some of them for the first time – and canals in the city.

“All major water sources will be taken up for desilting,” said a senior WRD official, noting that the government is laying emphasis on improving the condition of waterbodies and water management.

In Chennai region of the WRD, which includes Cuddalore, Tiruvallur, Kancheepuram, Vellore, Tiruvannamalai, Villupuram, Krishnagiri, Dharmapuri and Salem districts, 189 monsoon preparedness works are being carried out. These have been taken up at an estimated Rs 8 crore, of which Rs 5.85 crore would be utilised to clean up the water sources in Chennai.

Since 2005, the PWD has been issuing circulars alerting the regional engineers on carrying out monsoon preparedness works in the months of August and September, and the WRD carries out works before the onset of monsoon. “The tank bunds will be strengthened along with de-weeding and dredging in the tank storage area. Construction of regulators on the bund are also being carried out,” said a senior PWD official, adding that they would complete it before end of September.

The WRD is responsible for the maintenance of waterways including the South, Central, North Buckingham canals, Otteri Nullah, Virugmabakkam-Arumbakkam canal, marshlands and wetlands in its jurisdiction, besides ensuring continuous removal of sand bars from the mouths of Cooum and Adyar rivers.

Other than these canals, the officials have begun work on the four major reservoirs that supply drinking water to the city. Poondi, Cholavaram, Red Hills and Chembarambakkam reservoirs have a combined storage capacity of 11,057 tmc ft. In the case of Poondi and Cholavaram, maintenance and augmentation works are being taken up for the first ever time, sources said.

For the first time, the PWD is carrying out maintenance works at Poondi reservoir. The accumulated silt near the slider would be cleared to ensure smooth flow of water. “It is intended to augment the storage capacity of the reservoir,” said an official.  The engineers are hoping to wrap up the maintenance work before the water released from Krishna river reached the city by the end of the month.

Between July and October, Chennai receives 8 tmc ft of Krishna water under the Telugu Ganga Project. The city would receive this water only when the Kandaleru reservoir in Andhra Pradesh receives surplus water from Somasaila reservoir. The water is discharged to the Kandaleru reservoir when the water level rises to 8 tmc ft in Somasaila reservoir.  Cholavaram reservoir

The WRD has commenced maintenance works at the Cholavaram reservoir at a cost of Rs 5.25 crore. After conducting soil tests, the PWD has decided to excavate sand up to five feet till the impervious strata of soil. “The work is carried out after 100 years of its construction. Besides desilting, the works include maintenance of sluice gates and shutters among others. This will take at least five years to complete,” a senior WRD official said.

The excavated sand is planned to be auctioned, said the official, adding: “This sand is suitable for construction. It can operate on a revenue model unlike the vandal scheme where the potters and others utilise the sand excavated from the tanks for their livelihood.” Similar works would be carried out at other reservoirs in a phased manner, said a WRD official, noting how augmenting the storage would help during the lean period in summer.

In addition to these preparedness works, 313 works at a cost of Rs 68 crore have been undertaken as part of the Kudimaramath project in the nine districts that fall under the Chennai region, which is expected to be completed by this month end.

“The works includes maintenance of tanks and sluices, strengthening of bunds, and desilting,” said a senior official. The works are expected to be completed by September 30, he said.