GIS-BASED CHANGE DETECTION OF COASTAL FEATURES ALONG KARACHI COAST PAKISTAN

Abstract

The fontal Karachi Coast is widely exposed to human activities which impose ecological and environmental degradation of coastal environment and wetland biodiversity. This study aimed to analyze the changes in coastal belt features including built up land cover, mangroves & vegetation cover, and interrelationship of coastline morphology at frontal Karachi coast. We have utilized the satellite images of Landsat-5 TM and Landsat-8 OLI/TIRS to detect the changes and map coastal features using likelihood supervised classification and unsupervised algorithms (NDBI, NDVI). The spectral data analysis of principal components helped us to discriminate various coastal features by analytical interpretation of images whereas, supervised classification and change detection matrices provided quantitative estimates of variability among the thematic features. We have addressed the spatial changes with explicit references of Karachi Shipyard, Karachi Port, PNS Himalaya, Sandspit, Bundal/Bhundar Island and Far Island Mangrove Forest for the year 2010-2018. It was reckoned that major reduction in “dense mangroves” at Karachi Shipyard from 119.7 to 96.3 hectares and about 100 hectares at Bundal Island (over 2010-18), probably under the influence of the well built-up areas and futile coastal management in current scenario of regional climate changes.