Shoreline Change Associated with Coastal Structures at Gopalpur Port, Odisha, East Coast of India

Abstract

Gopalpur port is now functioning as an all-weather direct berthing port and is being developed since 2008. Southern and northern groins were constructed during 2008, and following it a series of ten groins were constructed on the north side of northern groin during 2009–2011. Intermediate and southern breakwaters were constructed during 2011–2012 and a berth in between the two breakwaters was constructed during 2012. Shoreline changes associated with these coastal structures are studied through a long-term monitoring (June 2012–June 2016) carried out at monthly interval at south and north of the port covering a stretch of 9 km. Observations include shoreline change using Differential Global Positioning System (DGPS) Arcpad along the berm line, beach profile at every 500 m interval using total station/Real-Time Kinematics Global Positioning System (RTK GPS). It is observed that due to round the year south-to-north longshore sediment transport, accretion occurs at south of coastal structures and erosion occurs to the north of coastal structures. In order to study the shoreline change in detail, Net Shoreline Movement (NSM), Shoreline Change Envelope (SCE), End Point Rate (EPR) and Linear Regression Rate (LRR) are computed at all the transects using Digital Shoreline Analysis System (DSAS) version 4.2, an extension to ESRI Arc-GIS developed by the United States Geological Survey (USGS). The results are presented under three categories such as accretion, moderate erosion and high erosion. The study reveals that the shoreline of Gopalpur port experiences both erosion and accretion. The major stretch of shoreline, mostly on the south of the port, is under accretion category while 2 km shoreline on the north of the port, inside the groin field, is under medium erosion category. However, the sector covering about 1 km stretch under high erosion category lies on the north of the northern groin field. The results clearly show the distinct impacts of the groins and breakwaters on shoreline change at Gopalpur port and have significant implications on the future development of the port.