Seasonal Variations in Morpho-Textural Dynamics Foreshore from the Central West Coast of India: An Insight for Coastal Sedimentation

ABSTRACT Sediment transport pathways are the critical input for sediment-related coastal zone management programs. In the present study, seasonal variations in the granulometric characteristics, such as mean size and sorting of beach sands and corresponding changes in shore face morphology in response to near-shore wave climate and wave power distribution, are used to infer sediment transport pathways and depositional environment. For this study, the coastal stretch between Bhatkal on the north and Kundapura (Coondapur) on the south along the Central West Coast of India is considered. Significant wavebreaker heights, breaking wave group celerity and wave power were determined using Mike 21 software. Significant breaker height of the waves varied between 0.5 and 2.4m. The highest breaker energy of 7.25x103 Nm/m2 and wave power of 39.85x103 N/m2 was observed during the monsoon, while during the fairweather season, it was 0.45x103and 2.56x103N/m2respectively. The foreshore in the study area ranged from reflective to dissipative. The spatio-temporal cross-shore profiles and volumetric change analysis of the foreshore indicated dominant onshore- offshore sediment movement in the reflective beaches, and alongshore sediment movement in dissipative/transition beaches. Distinct variations in textural characteristics across different segments of the study area and foreshore morphology reflect the role of wave climate in driving the coastal dynamics.