Taluka level environmental sensitivity index (ESI) and vulnerability mapping for oil spills: A pilot study from Goa state, India

Abstract

Coastlines are at risk when floating oil slicks reach the shoreline. Oil spill causes major stress on the marine environment. To deal with oil spill problem in the coastal area, Environmental Sensitivity Index (ESI) maps are prepared as a guideline to help contingency planning. These maps are prepared in advance of arrival of oil spill. They show the respective vulnerability of coast. Goa state is selected for a pilot study because of its beautiful beaches and rich bio-diversity along its coast. The present study is carried out with the objective to map the vulnerability of the coast for oil spills up to taluka level using satellite images and field observations. Taluka is an administrative unit hierarchically above the local city, town, or village, but subordinate to a larger state or province. Goa is a small state which is located on the west coast of India. It occupies 100 km long. This coast is prone to the oil spill as it lies in the major traffic zone of oil transport. In the last decade, Goa coast experienced 4 spill incidents. Satellite images were used for the delineation of different shoreline types, mangroves, sand dunes, etc. Available existing marine ecological data and previous spill occurrence data along with Survey of India topographic sheet of 1:50000 were also used to prepare an ESI map. Several thematic maps were prepared based on NOAA guidelines. Accordingly, ranking was given on the scale of 1 to 10, where 10 are highly vulnerable and 1 is least vulnerable. As this study was carried out up to taluka level, it will be of immense help to initiate the preventive measures at local level decision makers in case of spill approaching the coast. It is necessary to have this kind of maps for all eco- sensitive coasts