Impact of Port Structures on the Shoreline of Karnataka, West Coast, India

Abstract

The changes in shoreline positions and geomorphic features along the Karnataka, West coast of India, were studied for the period from 1973 to 2014, using multi-dated satellite images and topographic maps. The ten hotspots which are mainly areas nearer to the port region were specially studied for the quantification of erosion and accretion. Dredging for port development normally lead to noteworthy changes in the configuration of the seabed. These changes can meaning fully modify the currents, waves and water quality. The statistical method incorporated with GIS has been used to estimate the rate of change and net shore movement of the coast. The study indicates that gradual recession and accretion at Tadri, Bhatkal, Honnavar, etc. Shorelines extracted for the years 1973, 1998, 2000, 2003 and 2014 indicate that the coastline adjacent to port area experienced both the erosion and accretion. Shoreline change rate of Karnataka coastline is estimated as -1.2354 m/year. Erosion and accretion of shoreline are major impacts of port/harbor. However, minor impacts are like an increase in pollution due to waste dumping and port-related industries, increase in coastal population and related activities and degradation of surrounding environment due to dredging and dumping material. Most of the shoreline sites, though largely get affected due to port structures, during monsoon season, achieve natural partial equilibrium during the non-monsoon season due to reversing currents and wind pattern. And hence, it may be concluded that port/harbors have limited impact on the coastal shoreline.