ONGC fights coastal erosion
By December 2025, ONGC expects to complete work to prevent coastal erosion near its Odalarevu gas receiving and processing terminal in Andhra Pradesh.
"We expect to begin work by December 2024," says an ONGC source. ONGC received the green light from the environment ministry last month (July 2024) to construct 'groynes' or low-lying structures extending from shore to check coastal erosion.
Under the Rs106cr ($13m) project, ONGC is proposing four transition fields totalling 21 groynes covering 6.2-km of the Odalarevu shoreline. "Groynes are like a wall or a breakwater built at seashores to control erosion," we hear.
Groynes will help "to tame the waves and the currents," according to a draft Environment Impact Assessment (EIA) report prepared by Chennai-based consultant Hubert Enviro Care Systems. "The proposed solution is expected not only to serve as a coastal protection measure but will likely enhance the rebuilding of the lost beach, although it may take a few years," adds the report.
The total groyne length is divided into four stretches, where each stretch of 1550 metres includes two 50-metre groynes, two 100-metre groynes and two 150-metre groynes. The 50-metre groynes will extend up to water depths of 0.6 metres, the 100-metre groynes will extend up to water depths of 1.6 metres, and 150-metre groynes will extend up to water depths of 2.2 metres.
ONGC commissioned the ocean engineering department at IIT Madras to suggest suitable coastal protection measures in 2020. IIT Madras carried out a bathymetry study of the underwater depth of the sea and a topography survey of the area while studying the wave patterns and characteristics.
ONGC wants to construct groynes using 37,251 tetrapods, each weighing two tonnes and 324,546 tonnes of stones. Dredging is proposed at 21 locations with a total volume of 18,985 cubic metres