Coastal morphology: a case study of the Gulf of Khambhat (Cambay)

Abstract

Geomorphic processes greatly influence the industrial, commercial and recreational activities in the Gulf of Khambhat (Cambay). LANDSAT data with their synoptic and repetitive coverage have been used in studying the distribution of suspended sediments, currents and fronts and for mapping shoreline configuration and wetlands. Visual interpretation of LANDSAT Multispectral Scanner (MSS) band 6 and 7 images and diazo colour overlays was carried out for the above purpose. Colour density slicing was performed on all four MSS images for the qualitative estimation of suspended sediments. The observation of suspended sediments suggests that during the monsoon many sediments brought in by various rivers remain in suspension and start settling down with the onset of the winter season. Tides also play an important role in the movement of the suspended sediments and fronts. The concentration of the suspended sediments is high on the mainland side during the flood tide and in the centre of the Gulf during the ebb tide. The fronts are located along the mainland side during the flood tide and on the Saurashlra side during the ebb tide. The currents in the Gulf are observed to be mainly influenced by the tides. Seasonal variation in the currents are mainly due to riverine discharge. The mapping of shoreline changes and geomorphic mapping has shown significant changes taking place in the Mahi and the Narmada estuaries. These changes have threatened the cooling pond of the Dhuvaran thermal power station in the Mahi estuary.