Bhubaneswar: Sea erosion at the Puri beach, which threatens to swallow the roads and the nearby hotels could be related to the new mouth formed at the Chilika lake, observed the Wildlife Society of Orissa, while calling for a detailed study by experts .
Geologists and oceanographers are puzzled over the recent rate of sea erosion at the beaches of Puri. It has never faced this kind of destruction before, and it is surprising, since the beach has been in quite a stable state, since the last 100-200 years, according to WSO.
In a recent letter to the chief minister, the Wildlife Society of Orissa has pointed out the need for a detailed study to establish the impact of Chilika's new mouth on the beach erosion at Puri. According to it the erosion at Puri is associated with the opening of the new mouth at Chilika lake on 23 September, 2000.
It is surprising that the beach erosion at Puri has come to the forefront since the last 4-5 years.
There are doubts whether the construction of a proposed sea wall at Puri could solve the problem. Undoubtedly it would lead to the loss of a very popular beach as well as incur huge maintenance cost.
According to a scientific paper called the Coastal process along the Indian coastline published by four scientists of the National Institute of Oceanography in August, 2006, it has been observed that the annual net long shore sediment transport rate (LSTR) of 9,40,000 cubic metres per year at Gopalpur and Orissa was northerly, which is similar to that observed between Prayagi and Puri . The gross LSTR is about 10,00,000 cubic metres per year along south Orissa.
Measurements conducted by the scientists, prior to the opening of the new mouth show that the net LSTR at Gopalpur and Prayagi, both of which are located at the south of Chilika is 830,046 cubic metres per year and 887,528 cubic metres per year respectively, according to WSO. However, at Puri, the net LSTR figure dropped to 735,436 cubic metres per year which clearly indicates that the currents arrive at Puri only after depositing a part of their load south of the town.
Evidence shows that the rate of deposition has increased after the Chilika new mouth was opened, since massive movement of sediments has led to the formation of long sand spits and sand banks near the new mouth during the last 4-5 years. The Chilika new mouth is only 36 kms away from Puri town.
The delicate equilibrium which was maintained earlier, is now disturbed due to the new mouth at Chilika, where the tidal flux forces the currents to deposit a part of their load near the mouth, before reaching the Puri beach. During the high tide, when the sea water gushes into the lake, the sediments are deposited in front of Sipakuda village. Similarly during the low tide when the water recedes, the deposits grow in front of the new mouth inside the sea.
As a result of this, WSO strongly feels that an expert study, using advanced mathematical models can confirm the extent of the impact of the Chilika new mouth on the erosion process seen at Puri beach.
Once the findings are available, the only way to save the Puri beach would be by mitigating the effects of the new mouth through dredging and sand nourishment or through the building of breakwaters.
The statement of WSO issued today referred to an earlier study by the National Institute of Ocean Technology (NIOT) on the progressive loss of beaches in the Gahirmatha Marine Sanctuary due to the establishment of the Paradip port in 1966.