Shoreline change and impacts of coastal protection structures on Puducherry, SE coast of India

摘要

This study examines the shoreline changes that have occurred in past 23 years along Puducherry region, SE coast of India. Satellite data sets such as Landsat, Cartosat-1, Resourcesat-1 and 2 of different periods-i.e., 1991, 2000, 2006, 2008, 2012, 2013 and 2014, were used for shoreline change analysis. Shoreline extracted from these data sets was used for estimation of shoreline change rate at every 20-m interval. The overall result found that 55.9 % shows erosion, 34.9 % falls under stable, and 9.2 % shows accretion in Puducherry coast. High accretion rate of 5.0 (+/- 1.9) m/year was noticed along the Veerampattinam region located immediate south to the Puducherry port. Medium erosion of about -3.2 (+/- 1.9) m/year was observed along the Thengaithittu region. Remaining coast was noticed with stable to low erosion. Severe erosion was observed in northern side of the breakwater during 1991-2000 periods, whereas southern side high accretion was noticed. Groins constructed at Thandrayankuppam and Nadukuppam region protected the coast from erosion. Due to this groin construction, erosion was shifted toward the northern portion (Chinna Mudaliar Chavadi, Periya Mudaliar Chavadi and to certain extend of Bommaiyarpalayam). This study demonstrates that combined use of satellite imagery after considering the uncertainties and statistical methods can be a reliable method for shoreline change analysis for any coastal conditions.