Amidst a deficient northeast monsoon, groundwater level is 1.3 metre lower than last year

Amidst what looks like a deficit northeast monsoon, a lot of residents are keeping a close watch on groundwater levels at their rain-water harvested houses. According to officials, there has been a marginal dip in the levels across the city over the past year.

The average water level in the city was at 4.87 metre in November, nearly 1.30 metre lower than in November 2012. However, the drop was not alarming in and around the city, according to State Ground and Surface Water Resources Data Centre of Water Resources Department (WRD).

Officials of the WRD said prolonged dry weather and inadequate rainfall, both in 2012 and this year, had led to the drop in the water table.

The inadequate rainfall since last year has led to depletion of the water table in about 30 of the 32 districts across the State. The water level in Tiruvallur and Kancheepuram districts had gone down by about 0.37 metres and one metre, respectively.

Krishnagiri and Erode were the only districts that witnessed a rise in level. But, this too was a marginal increase of one metre, said a hydrogeologist of WRD.

According to the meteorological department, last year, Chennai recorded 102 cm and 115 cm of rain in Nungambakkam and Meenambakkam, respectively, against the normal of 140 cm. This year, the city has registered about 110 cm.

The slight dip in the water level has raised concerns of water shortage. L. Suganthi, a resident of Karapakkam, was worried, though she said the water level had increased by a few feet after recent rains. “The water from the rooftop flows into the well. It has not gone dry. But, if there are no rains for some more months, I may face a shortage,” she said.

Officials of the WRD said the rise in groundwater level when compared to that before the onset of northeast monsoon indicated a good rainwater harvesting system. But it was an interim rise and the recharge is observed more in open wells than borewells. It would take a couple of weeks for the level to stabilise.

WRD had collected data from 4,100 open and borewells. Of this, 500 are located in and around the city.

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