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ABSTRACT: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.

Assessing the preparedness of the coastal region to the anticipated sea level rise is a major task among the coastal management authority, where identification of relative vulnerable of coast is a prime concern. The present research work has utilized Remote Sensing and GIS techniques for assessing vulnerability of the Gujarat coast due to predicted sea level rise. Synergetic use of satellite remote sensing, numerical simulations and filed observations has been done to generate coastal thematic information followed by validation. Coastal vulnerability assessment of the entire Gujarat coast on 1:50, 000 scale were carried out considering five physical parameters. They are; coastal geomorphology, coastal slope, shoreline change rate, mean spring tidal range, and significant wave height. The rank values of all the five physical variables are integrated through additive method to compute a Coastal Vulnerability Index (CVI) where the relative ranking is assigned to various coastal segments based on the vulnerability level. The CVI values categorize Gujarat coast into four risk level classes. The results show that 785 km (45.67 %) of the Gujarat coast is under high to very high risk category and 934 km (54.33 %) of the Gujarat coast is under Moderate to Low risk category due to an anticipated rise in sea level. The coastal regions under very high risk category are along northwestern parts of the Gulf of Khambhat, the northernmost parts of the Gulf of Kachchh and western parts of the Kachchh coast. The southern parts of the Saurashtra coast and southwestern parts of the Kachchh coast is under the low risk category along with isolated segments along the eastern parts of the Gulf of Khambhat. The approach developed for assessing vulnerability of the coast to predicted sea level rise using remote sensing and GIS techniques can be used effectively by coastal management authorities and decision makers to devise better coastal zone management plans as well as to ensure efficient mitigation measures to minimize the losses due to possible impact of predicted sea level rise through which appropriate measures to protect life, property and environment can be timely planned.