A 14 kilometers long continuous stretch of sand, Marina Beach extends from the Cooum estuary (near Fort St. George) in the north to the Adyar estuary (around Besant Nagar) in the south. An estuary draining into the Ocean is part of a large river up to which the tidal waters flushing take place. The world famous natural beach developed gradually by the trapping and deposition of sediments, over the course of a century, primarily attributed to the construction of man-made/artificial Chennai Port.
Waves and tides are the architects of a shoreline. Currents induced through them propagate along the coast and transfer sediments from one point to another. Is the shoreline along the Chennai city stable? If unstable, is it accreting sediment or is it losing its existence to erosion? What places along the shoreline are being affected? A study carried out by Prof.Vallam Sundar, Prof. S.A. Sannasiraj and Dr. Gracy Mary at the Department of Ocean Engineering, IIT Madras, just answers the concerns.
Using the satellite-imagery data for a period of 20 years, 2000-2019, they calculated the changes in Marina beach shoreline and found that the accretion of sediments occurred about 5.6km along the urban part of the Marina beach and the Cooum region (Zone 1). Whereas the 9 km region extending northward from Adyar river mouth (Zone 2) exhibited an eroding trend.
https://tech-talk.iitm.ac.in/erosion-and-accretion-across-the-chennai-shoreline/