Nearshore Morphological Changes due to Severe Cyclonic Storm Activity along the East Coast of India

• Published in: Journal of coastal research 2024-03, Vol.40 (4), p.696-713
• Main Authors: Prasath, J. Guru, Sannasiraj, S.A., Chandramohan, P.
• Format: Article
• Language: English
• Subjects: Beach erosion; Beach processes; Beach profiles; Beaches; Berms; cross shore sediment transport; cyclone; Cyclones; field instrumentation; Foreshore; modelling; Morphology; Ocean bottom; Ocean floor; Sand bars; Sediment; Sediment movement; Sediment transport; Sediments; storm surge; Storms; Tidal currents; Transport rate; Wave breaking; Waves; Winds
• ISSN: 0749-0208; 1551-5036
• DOI: 10.2112/JCOASTRES-D-23A-00016.1

Guru Prasath, J.; Sannasiraj, S.A., and Chandramohan, P., 2024. Nearshore morphological changes due to severe cyclonic storm activity along the east coast of India. Journal of Coastal Research, 40(4), 696–713. Charlotte (North Carolina), ISSN 0749-0208. Nearshore waves, wind, and tidal current mobilize seabed sediments; sort, transport, and redistribute the sediments; and modify the nearshore seabed morphology. Waves play a dominant role in morphological changes among winds, waves, and tidal currents. The nearshore wave breaking induces the initiation of sediment movement, and the associated alongshore current transports a large volume of sediments that tend to either accrete toward or erode from the beach face and seabed. Sediment transport rate in the nearshore waters during cyclones is higher than that under normal conditions. The measured changes due to Cyclone Nivar in November 2020 in the nearshore morphology along the Mahabalipuram coast are examined to understand the response of nearshore morphology to cyclonic wave-induced forcing. The beach-profile measurements across 10 transects at 100 m spacing covering about 1000 m along the coast were measured before and after the passage of Cyclone Nivar as a part of the present field study. The evolving beach profiles during Cyclone Nivar were simulated using the storm-induced beach change (SBEACH) model, which is a cross-shore profile evolution model. The changes due to berm erosion and deposition of nearshore sand bars have been compared from field measurements data and model prediction. The calibrated model was then used to simulate the beach profile response at two other locations along the cyclone-affected coastline to examine the shoreline impact. The calibrated model can be used along the coast to understand the poststorm profiles of the beach with reasonable accuracy.