Wave-beach sediment interaction with shoreline changes along a headland bounded pocket beach, West coast of India

Grain size analysis was carried out to understand the behavior of sediment distribution in a pocket beach and to examine the relationship between the sediment distribution on surficial beach sediments with the wave energy and shoreline changes. Three seasons surficial beach sediment were sampled, and statistical characteristics were analyzed for September 2014, February 2015, and July 2015. The Mike-21 spectral wave model was utilized to estimate the wave energy distribution and shoreline changes were also mapped using Resourcesat-2 (LISS IV) satellite images and net shoreline movement method was adopted for shoreline change analysis. Because, shoreline changes directly indicate the erosion and accretion pattern of coastal zones. The analyzed sediment statistical parameters were correlated with the wave energy and shoreline changes. Based on the correlation, it was found that wave determines the sediment distribution pattern on Vengurla sandy beach. The result suggests that the beach sediment was mostly medium sand with moderately well sorted, fine skewed to coarse skewed with platykurtic, mesokurtic, and leptokurtic characteristics. The study area was under influenced medium wave to high wave action. The backshore samples have an average skewness of 0.030 Phi, which suggests depositional settings, whereas the bermline and foreshore have an average skewness of - 0.392 and -0.075 Phi, respectively, illustrating the erosional conditions. The sediment categorization results indicated that the backshore is stable, while the bermline is partly eroded as well as accreting in nature. The results show that the wave energy is playing a vital role in sediment distribution and transportation.