“Building a rigid wall is not the right solution to sea surge and soil erosion on the Visakhapatnam beach. A rigid wall will divert the energy of the waves upstream. What we need is a technology that absorbs the energy and at the same time stops erosion of the beach,” said Prof. C.N.V. Satyanarayana Reddy.
An expert in soil mechanics, he pointed out that the sea sand in Visakhapatnam was fine silty, and it was less in cohesion and lacked binder property, making it erosion-prone.
According to Prof. Reddy, rigid structures, including boulders, will not arrest erosion, and what is needed at the moment is a flexible retaining structure.
“Boulders can be dumped, but before dumping them, the entire slope or stretch needs to be covered with carbon-coated geo-textile fabric sheet. This will allow water to seep in but not erosion. Thus, the energy will be absorbed averting problems upstream. The fabric sheet can be extended a few metres into the beach, and even underwater, if required, to serve as apron,” he said.
To make the system fool-proof, the expert suggests covering the erosion-prone areas with PVC-coated gabion mattress. “This will hold the rocks and boulders, even if the sea surge is high and violent,” Prof. Reddy added. According to him, the system has proved successful across the globe, and in India, it was implemented at Ankaleshwar in Gujarat.
In the recent past, sea surge eroded the sand under Beach Road, resulting in the road caving in. The most sensitive area is from Kurusura Submarine Museum to about 600 metres towards Ramakrishna Beach.
The technology is estimated to cost Rs. 35 lakh per 100 metres.
