The Hindu                        27.03.2013

Water table in Chennai dips

K. Lakshmi 

Insufficient rainfall and a prolonged spell of dry
weather have taken a toll on the groundwater resources in and around the
city.

The water table is now at an average of four
metres below the ground. This is a metre less than the level recorded at
this time last year, according to data of State Ground and Surface
Water Resources Data Centre, a wing of Water Resources Department.

Residents
of several areas, particularly the suburbs, who are dependent on
groundwater, are already feeling the heat as the water level in their
open wells has come down by a few feet.

Prema Sriraman, a resident of Villivakkam, said the kind of decline in water levels seen now usually occurred in peak summer.

The
water is also turning saline in many areas. The declining water level
has only increased the burden on residents who are already staring at a
water crisis as water levels in major reservoirs supplying drinking
water to the city has come down. 

Hydrogeologists in
the WRD said that the localities in the southern parts of the city are
worst affected as groundwater resources are over-exploited.

Besides
burgeoning population, indiscriminate extraction of groundwater by
private water suppliers has also led to the fall in the water table.

The
water level has declined to six metres below ground in areas such as
Kovilambakkam, Medavakkam, Pallikaranai and Tambaram.  However, water
quality has not deteriorated much compared to last year.

The
total dissolved solids in water ranges between 500 parts per million to
1,200 ppm across the city according to the soil condition.

The Adyar creek is one area where the TDS level is as high as 3,000 ppm due to tidal action.

The permissible limit for drinking water is 500 ppm.

In areas such as Virugambakkam and Koyambedu, the iron content in the water will be high, they said.

Seawater incursion, though, is still at manageable levels, said officials.

Seawater
has however intruded up to few hundred metres in areas close to the
coast such as Besant Nagar and Thiruvalluvar Nagar, Thiruvanmiyur.

Over-exploitation by private water suppliers has affected the southern parts of the city.