Shoreline management plan for embayed beaches: A case study at Vengurla, west coast of India

Abstract

Embayed beaches play an important role in ensuring the environmental and morphological sustenance of coastal areas. Coastal processes along embayed beaches are different from that of open beaches. Shoreline management along embayed beaches is a major concern for engineers and policy makers worldwide, which requires a clear understanding of shoreline evolution. As shoreline evolution is the combined effect of natural and human activities, which vary over space and time, numerical models are vital to understanding shoreline change behaviour. The present study was carried out at Vengurla, an embayed beach along the west coast of India, using a well established numerical model. Wave climate, bathymetry, sediment characteristics and initial coastline were the primary inputs for the model. Nearshore wave climate at a depth of 15 m was collected using a wave rider buoy for the year 2015. Bathymetry and nearshore sediments were also collected during the same year. The initial coastline was extracted from satellite imagery of the year 2015. Shoreline change was studied over the preceding 26 years (1990–2016) using nine different satellite images. The model was then run for the following 26 years (2015–40), with present wave climate and future expected increase in wave heights. The results indicate that Vengurla embayed beach is not only affected by various anthropogenic modifications including the destruction of sand dunes, but also by future climate-change projections. We propose the implementation of a dune based shoreline management plan with strict regulations and awareness program. The findings of this study will interest policy makers and environmental managers, guiding them in developing management strategies for protection of this embayed beach. Overall, this paper demonstrates how numerical modelling can help in designing the shoreline management plan for an embayed beach, which can lead to save costs and to prevent further destruction of the beach.