Detection of Shoreline Changes in Ratnagiri Block, Maharashtra, India using Remote Sensing and GIS Techniques

Shoreline of Ratnagiri block, Maharashtra inhabits different species of aquatic flora and fauna and is characterised by different manmade structures supporting various fishery activities. The changes along the shoreline pertaining to erosion and deposition during 1989 to 2009 were studied using remote sensing and Geographic Information System techniques. Temporal and multispectral satellite images of the year 1989, 1999, 2004 and 2009 taken from different satellite sensors were processed through ERDAS Imagine 9.1 image processing software for mapping of shoreline and associated changes pertaining to erosion and deposition. The study revealed an average accuracy of 97.33% for shoreline mapping with Root Mean Square error in the range of 0.1910 to 0.3255 pixels. The study revealed addition of 160 ha area during 1989 to 2009 pertaining to the deposition of 233 ha and erosion of 73 ha. Dhamankhol Bay, Kachare, Varvade, Ganpatipule, Areware, Kalbadevi, Mandovi, Bhatye, Ranpar and Gaonkhadi were the major areas of deposition whereas, erosion was prominent along Nandivade, Kachare, Ganpatipule, Mirya and Mandovi beach areas. Navigational difficulties were seen at Mirkarwada fishing harbour due to deposition of sand material eroded from Mirya beach during 1989 to 2009 whereas Dhamankhol Bay showed accretion during 2004 to 2009 due to land filling activity carried out for port construction.