Wetland, the prime component of the coastal zone is a dynamic ecosystem having complex inter-relationship of hydrology, soil and vegetation. They are lands transitional between terrestrial and aquatic systems where the water table is usually at or near the surface or land covered with shallow water. The coastal wetland of Vedaranyam, Tamil Nadu coast is a most productive ecosystem such as mangroves, salt marshes, lagoons and estuaries on the coastal area. It is extremely important as habitat for them. Due to increased anthropogenic activities, these ecosystems are under pressure on the coast. This leads to modification of wetlands ranging from various stages of degradation to irreversible loss. Spatial information has been propagated and is increasingly used for wetland management and conservation. The tsunami effect was extensive in and around Nagapattinam, but in Vedaranyam coastal wetland, located nearer to Nagapatinam (Nagapattinam district), the effect was less because of presence of mangroves. So it is necessary to protect this coastal wetland ecosystem to ensure sustainable development. Remote sensing has provided a great mean to study various ecosystems of the earth including wetlands by providing cost and time effective data. Over the years, remote sensing has been used as a tool to map large areas of wetlands. In this study, wetland change detection of the Vedaranyam coast within approximately eight years period was conducted. Three (IRS LISS III + PAN merged) images of different dates (1997, 2003 and 2005) were processed and analyzed, geometrically corrected (registered) and digitized to obtain more detailed information and identify the change. Based on the combined use of multi temporal satellite imagery and ancillary data, such as topographic maps and field check (ground truth) data, wetland maps with different classes were prepared, showing the changes, and usefulness of IRS data in detailed mapping and wetland change detection studies. The results showed that from 1997 to 2003, were found great loss of wetland and from 2003 to 2005 only inundated variation were studied at the period of tsunami in the study area.

Key words: CoastalWetlands, Eco System, Remote Sensing and GIS,Wetland Management and Conservation