ASSESSMENT OF COASTAL EROSION ALONG INDIAN COAST ON 1:25, 000 SCALE USING SATELLITE DATA

The long stretch of coastline on the either side of Indian peninsula is subjected to varied coastal processes and anthropogenic pressures, which makes the coast vulnerable to erosion. There is no systematic inventory of shoreline changes occurring along the entire Indian coast on 1:25, 000 scale, which is required for planning measures to be taken up for protecting the coast at national level. It is in this context that shoreline change mapping on 1:25, 000 scale for the entire Indian coast based on multidate satellite data in GIS environment has been carried out for 1989-91 and 2004-06 time frame. The paper discusses salient observations and results from the shoreline change inventory. The results show that 3829 km (45.5%) of the coast is under erosion, 3004 km (35.7%) of the coast is getting accreted, while 1581 km (18.8%) of the coast is more or less stable in nature. Highest percentage of the shoreline under erosion is in Nicobar Islands (88.7%), while percentage of accreting coastline is highest for Tamil Nadu (62.3%) and the state of Goa has highest percentage of stable shoreline (52.4%). The analysis shows that the Indian coast has lost a net area of about 73 sq km during 1989-91 and 2004-06 time frame. In Tamilnadu, a net area of about 25.45 sq km have increased due to accretion, while along Nicobar Island about 93.95 sq km is lost due to erosion. The inventory has been used to prepare "Shoreline Change Atlas of the Indian Coast", brought out as Six Volumes for the entire Indian coast.