Prospects for developing a minor port facility at Betul, Goa

Abstract

Marine and Coastal Surveys Division of Geological Survey of India, initiated preliminary, integrated geological, geotechnical and geophysical surveys off Betul for making an appraisal of the developmental possibilities of setting up a minor port in this sector. Detailed surveys helped generate a bathymetric map of the area indicating a smooth and gently sloping seafloor without any hazards, ideal for port development. Sediment cores were studied to evaluate the sub-seabed sediment package and visualize the seabed sediment distribution. Mean size of the seabed surface sediments broadly signifies a sediment milieu encompassing variants from silt to clay, broadly classified as silty clay. Geotechnical analysis of the sediments helped to evaluate the engineering properties of the seabed and sub-seabed sediments quintessential for development of a port in this sector. Clayey sediments have a high degree of plasticity with a <i>very high swelling</i> <i>potential. </i>Shear resistance is almost unregistered at almost all levels of the sediment package. Geotechnical characteristics

of the sediments are generally conducive for offshore structures. Side scan sonar surveys brought out a clear seafloor, generally monotonous and thus well suited for a navigational channel access. Current Observations carried out in the nearshore sector indicate low velocity currents and are not influenced by tidal variations. Environmental parameters including Temperature, <i>p</i>H, Salinity, Conductivity and Dissolved Oxygen were studied to record the conditions prevalent in this sector, for post-development comparison.