CHENNAI: Several spells of rain, mostly at nights since June 1, has helped improve reservoir levels and the groundwater table in Chennai. It has also ensured that there will be sufficient drinking water, at least till mid-October. The northeast monsoon season kicks in after that.
The city has received 11% surplus for the southwest monsoon this season, starting June 1. Mandatory rainwater harvesting system, though not followed uniformly, and some desilting work done by the corporation have helped the groundwater level to improve. In most parts of the city, groundwater is now at 10ft to 15ft while it used to be at 20ft to 25ft or more in May.
Regional meteorological centre director N Puviarasan said : “The upper air circulation was the main reason for the city getting good rains. This happened three times. Last year, most of the rain was on the sea. Indian Ocean dipole, which is irregular oscillation of sea surface temperature, and La Nina, cooling of surface water of the ocean, may have played a role.”
In a bid to improve rainwater harvesting structures, the Chennai corporation has inspected 3.27 lakh houses. Out of them about 2.58 lakh had the system while 43,543 newly set up houses didn’t have one.
Around 311 community wells in parks and residential colonies, 2,500 wells in parks, drains and roadside and 10,500 rainwater harvesting structures helped collect rainwater.
“We haven’t started the de-silting process due to the lockdown. But will begin next week. All vulnerable areas and low-lying areas will be desilted first,” said superintendent engineer, storm water drains department, Sankar. Desilting of 110ponds is over.
However, a lot needs to be done to ensure that the rainwater from the northeast monsoon will not just drain out into the sea. Founder director of Rain Centre Sekhar Raghavan said though the civic body and the Metro water claimed to have inspected large number of houses in the city to check the RWH structures, the work was not completed properly.
For example, in many houses, the rainwater harvesting structures were created with a sinking of a PVC pipe in 15 ft depth. This could have worked for the first couple of years. Once the pipe is clogged, water will not go down into the soil, he said.
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As published on https://timesofindia.indiatimes.com/city/chennai/rain-water-harvesting-helps-improve-citys-water-table/articleshow/77474963.cms
Vardhman Envirotech
India’s Passionate Rain Water Harvesting Company