Longshore Transport Based on Directional Waves Along North Tamilnadu Coast, India

Abstract

The accurate assessment of longshore sediment transport pattern along Nagapattinam-Poompuhar coastline bears significance due to the historical erosion and its geographical location adjoining the sheltered Palk Bay. Directional waves were measured off Nagapattinam coastline for one year to estimate the longshore sediment transport rate. It shows that the transport rate is relatively high about 0.1 X 10⁶ m³/month in November and December and is low showing less than 0.03 X 10⁶ m³/month in March, April and July. Though the annual gross transport is found to be 0.6 X 10⁶ m³/year, the annual net transport is very low showing less than 0.006 X 10⁶ m³/year (towards north), indicating the coastline tends to be a nodal drift regime. The temporary rise in wave activities during the cyclonic days often increases the southerly drift, which partly gets deposited in the Palk Bay and causes deficit for the northerly drift.