• Seasonal variation in longshore sediment transport rate and its impact on sediment budget along the wave-dominated Karnataka coast, India

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      https://www.ias.ac.in/article/fulltext/jess/129/0234

    • Keywords

       

      Littoral cell; wave characteristics; XBeach; sediment transport; sediment budget.

    • Abstract

       

      The Karnataka coast is subjected to high wave activity during the southwest monsoon when most of the sandy beaches undergo erosion. Based on the littoral cell concept, the Karnataka coast is broadly divided into 14 major littoral cells and 26 stations are selected in the present study. WaveWatch III global wave model data at 0.5$^{\circ}$ interval were used to derive the nearshore wave characteristics from XBeach numerical model. The model results were validated with the measured wave rider buoy data of the Indian National Centre for Ocean Information Services. The beach orientation, nearshore slope, median sediment size, significant wave height, mean wave direction, and the peak wave period were used in the estimation of longshore sediment transport rate. The mean significant wave height along the Karnataka coast was about 0.86 m, wave direction was about 210$^{\circ}$ and peak wave period was about 13 sec. The wave height during southwest monsoon (June–September) was higher, post-monsoon (October–December) was moderate and pre-monsoon (January–May) was the calmest period. Direction of longshore sediment transport was southwards during pre- and post-monsoons when waves were from the south–southwest. Whereas, northwards during monsoon when the wave approach from west–southwest to west. The annual net longshore sediment transport rate estimated was about 0.65$\times$10$^{6}$ m$^{3}$ towards the south and the sediment budget investigation depicts the loss of 0.067$\times$10$^{6}$ m$^{3}$ during the study period.

      $\bf{Highlights}$

      $\bullet$ WaveWatch III global wave model data at 0.5$^{\circ}$ interval were used as input to derive the nearshore wave characteristics from XBeach numerical model.

      $\bullet$ The wave height during southwest monsoon (June to September) was higher, post-monsoon (October to December) was moderate and pre-monsoon (January to May) was the calmest period.

      $\bullet$ Direction of longshore sediment transport was southwards during pre- and post-monsoons when waves were from the south-southwest. Whereas, northwards during monsoon when the wave approach from west-southwest to west.

      $\bullet$ The annual net longshore sediment transport rate estimated was about 0.65$\times$10$^{6}$ m$^{3}$ towards the south, and the sediment budget investigation depicts the loss of 0.067$\times$10$^{6}$ m$^{3}$ during the study period.

    • Author Affiliations

       

      ATEETH SHETTY1 JAYAPPA K S1

      1. Department of Marine Geology, Mangalore University, Mangalagangothri, Mangaluru, Karnataka 574 199, India.
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