Decadal shoreline assessment using remote sensing along the central Odisha coast, India

One of the major requirements of planning coastal protection works is to understand the processes of erosion, deposition, sediment transport, flooding and sea level changes which continuously alter the shoreline. Significant erosion can affect the stability and productivity of aquatic environment which may have severe implications for coastal inhabitants. The middle coastal plains of Odisha State on the east coast of India were investigated for morphological assessment of shoreline. Accurate demarcations of shorelines were carried out at parts of Odisha coast specifically along Gahirmatha, Paradip and coast above Devi River to quantify erosion and accretion at annual to decadal scale for the years 1990, 2000 and 2012. Satellite-derived remote sensing data (Landsat and IRS P6) were used in the study. Digital shoreline analysis system discovered the eroded and accreted parts of the study area. Gahirmatha and coast above Devi River experienced heavy erosion during 2000-2012 compared with 1990-2000, whereas Paradip coast has comparatively undergone accretion during 2000-2012. Some accreted spots are identified nearby river mouths, which are attributed to heavy accretion of eroded materials by the action of sediment transport. The detailed analysis reveals a maximum erosion of 124, 33 and 154 m in a decade at Gahirmatha, Paradip and coast above Devi River, respectively. Southern parts of Gahirmatha coast showed highly dynamic behavior near Hukitola Bay and Barrier Island and are acting as a natural breakwater to conserve the shoreline. This region had undergone severe geomorphologic changes due to natural as well as human interventions and poses a threat. This coast exhibits unique reasons for erosion with various degrees of combinations of sediment depletion, human activities, high frequency of cyclones and floods, sea level rise, etc. This study concludes that the shoreline of Odisha coast is under heavy erosion and needs scientific and management attention.