Spit dynamics along the Central West Coast of India: implications for coastal zone management

Abstract

Spit growth is observed across many rivers of the central west coast of India. Studies on the seasonal dynamics of the spits of the central west coast of India on the basis of the multidate satellite images LISS III, landsat™ data, panchromatic camera (PAN) data etc. in a geographic information system (GIS) environment using ERDAS imagine 9.0 version followed by field-check and wave data analysis have been discussed in this paper. All types of spits such as paired spits, winglike spits, single spits, etc. are observed along the coast of Karnataka, central west coast of India. Spit growth is responsible not only for shifting of the river mouths, but also for rapid changes in estuarine morphology and in turn on the sedimentation process. It is observed that river mouths with a spit across them have a submerged bar in front of them, whereas rivers devoid of spits are also devoid of submerged bars in front of them. This spatial association of spit and submerged bar is believed to have a genetic relationship. Along the coast many perpendicular faults and uplifts have been observed. Rate of spit growth, along with their direction and inland drainage pattern, suggest a role of sea-level changes and tectonic control in addition to alongshore currents. Rapid spit growth is observed near the inferred tectonic axis. Seasonal dynamics and modification in the spit configuration are related to alongshore drift as well as the wave refraction around the mouth of the rivers.