Formation, growth and variability of sand spit at Rushikulya River mouth, South Odisha coast, India

摘要

Sand spits are depositional landform and most active features near the coastal bays and inlets. The combine interactions between the wind, wave transformation, tidal variation, availability of sediment and river discharge decide the spit morphology, growth and orientation. The beaches around Rushikula river inlet is known as one of the largest rookeries of the olive ridley turtle. The spatial and temporal evolution of the sand spit, geomorphology changes and sediment distribution based on the data collected during 2005-2011 at different time intervals on the both sides of the inlet are assessed. Shoreline oscillation and geomorphology are monitored using real time global positioning system (RTK-GPS). The shoreline undergoes natural phases of erosion and deposition process, however, the entrapment of huge longshore sediment during southwest monsoon months near the river inlet triggers northerly progression of the sand spit and small temporary islands that are highly conducive for formation of nesting habitat. Sediment samples (n=210) collected at different transects representing fore, mid and backshore are analyzed to understand the role of grain size in erosion/ accretion process.