Posted on February 15, 2023
Recently referring to a question from Rajya Sabha member G.V.L. Narasimha Rao, Union Minister of State for Earth Sciences Jitendra Singh has said that about 294.89 kms or 28.7% of the coastline in Andhra Pradesh is under varying degrees of erosion.
The Minister was referring to findings and surveys by the National Centre for Coastal Research (NCCR) and he had quoted that about 28.81 km of coastline in Visakhapatnam is prone to erosion.
The erosion of beaches in Visakhapatnam is not new. It has been since 1930, ever since two ships were sunk near the Dolphin’s Nose to create a breakwater to stop the process of sedimentation at the mouth of the Visakhapatnam harbour, during the construction phase of Viskhapatnam Port.
This was just the beginning. Erosion aggravated with the construction of two breakwaters during the construction of the Outer Harbour during the 1970s, said K.V.S.R. Prasad, former professor from the Department of Meteorology and Oceanography, Andhra University.
Beaches are dynamic landforms and should be treated as part of the sea and not part of the land. The erosion and deposition of sand are primarily due to the high wave action and high wave energy and the problem arises when man tries to occupy them or meddle with them, he said.
As per the experts, the beaches act as cushion between the high wave action of the sea and the landmass. Continuous nourishment of beaches is a must through the natural process and if disturbed, they will face severe erosion, which may lead to issues to the landmass, as we frequently see the caving-in of roads on the Ramakrishna Beach stretch.
Transportation of sand
In Visakhapatnam the sand transportation takes place from the south side (Dolphin’s Nose) to the RK Beach and above on the north side for about eight months in a year and from north to south for around four months. ‘
From south to north, about 8 lakh cubic metres of sand would be transported in the natural process to the north side and only 2 lakh cubic metres of sand is deposited from the north side, said B.S.R. Reddy, former professor from the Department of Meteorology and Oceanography, Andhra University.
Due to the construction of the breakwaters on the south side, the sand no longer reaches the beaches in the north such as RK Beach and hence the beaches are not nourished, he said.
As per the experts, the sea has advanced at least by about 100 metres between Naval Coastal and Rushikonda, in the last couple of decades.
They say about 50 years from now, if adequate precautions are not taken then the other side of the beach road and the building that abut the road could be in danger due to the erosion. “We may not have a beach and it could become like the Marine Drive of Mumbai,” they say.
What needs to be done
The best way to protect the RK Beach is by taking up continuous beach nourishment operations. The Visakhapatnam Port Authority and the Dredging Corporation of India do it once in a while, but that is not sufficient. It needs to be done on a continuous basis, throughout the year and at least 6 lakh cubic metres of sand needs to be pumped in, said Prof. Reddy.
Apart from beach nourishment, construction of submerged breakwater about 500 metres from the shoreline could also act as a solution. This would break the energy of the waves and stop the erosion caused by the wave current, said Prof. Prasad.
He also added that groins or geo tubes can also act as solutions, but they are temporary measures.