A few years ago the Government launched a powerful campaign for rainwater harvesting in the city and it worked wonders. Not only did the groundwater table get recharged, the storage levels in various tanks and reservoirs in the city also improved. This is all to the good, for it answers immediate citizen concerns. But the news as far Pulicat Lake, a vital water body that plays an important role in the eco system of which Chennai is a part, is alarming and in the long run it could spell disaster.
A recent study done on the Pulicat Lake by the Loyola Institute of Frontier Technology has shown that the lake which was once 460 sq km and was hence the second largest water body in the country after the Chilka Lake in Orissa, has now shrunk to 350 sq km in extent and its depth has reduced from four metres to 1.5 metres. This shrinkage of the lake is largely due to the rapid silting up of its northern end. The reduction of water spread and depth has led to lower aquatic life. The silting up of the mouth of the lake through which vital sea water enters the lake has further endangered the aquatic life in the water body. This has led to formation of sand dunes and in summer when the inflow is even less, there could be greater loss to aquatic life.
While silting and deepening can be handled by quick action, there are several other factors that need going into in greater detail and this requires political will and putting into place certain policy decisions. Firstly there is indiscriminate dumping of plastic waste into the lake which needs to be stopped. Indiscriminate fishing is a second reason for loss of aquatic life. Fishing in the lake, which was a hereditary profession and which was allowed only in certain parts of it, has now become widespread. Farmers have taken to it and several among them use fishing nets of very fine mesh which go by the name of Padi Valai in local parlance. This net manages to capture even small organisms and eggs and also ensures a heavy catch. The tiny organisms being vital to the food chain in the lake, this practice does not therefore allow for recharging of aquatic life in the lake. The study has demanded that the tiny living creatures should be let back into the lake after the catch of fish has been taken.
Motor boats are used indiscriminately in the lake where only paddle and row boats were used earlier. Traffic continues throughout the day and night and this unsettles both aquatic and bird life thereby affecting the ecology. Prawns that traditionally entered the lake only late in the night when the water was relatively calm, have reduced in numbers now. The study has demanded the setting up of an independent organisation on the lines of the Chilka Lake Development Authority in Orissa for managing Pulicat.
Pulicat extends between North Tamil Nadu and South Andhra Pradesh and is 80kms away from Chennai. There are problems on both sides of the lake and decisions by both states have adversely affected it. In Andhra around 4700 ha of land has been released for a marine chemicals and salt manufacturing industry. On the Tamil Nadu side, the petrochemical complex, the power plant and the satellite port on Ennore Creek have been major threats.
The lake which is a salt water lagoon is home to over 60,000 migrant water birds and around 40,000 people living in 34 villages on the Tamil Nadu side of it depend on it for their livelihood. A water body that is perhaps over a million years old may well be on the verge of extinction.
Can something be done before it is too late?