Wave Tranquility and Littoral Studies for Development of a Mini Fishing Harbour

Hydraulic model studies were carried out to optimise a layout of a fishing harbour on the west coast of India, in Kerala. A layout consisting of two breakwaters, 80 m long north breakwater and 670 m south breakwater (150 m normal to the shore and 520 m along the shore) with 100 m wide opening at the harbour entrance was initially proposed. The tranquillity conditions of proposed breakwater alignments for the formation of the fishing harbour, for the maximum prevailing wave heights approaching from different directions were investigated through a numerical model. The appropriate alignment of the breakwaters was arrived based on the numerical results. From the analysis of the wave data, the annual sediment transport rates along the considered coastal area were also estimated based on well-established methods. The studies indicated that the proposed Layout can be safely operated for about 335 days in a year. The effect of post harbour construction on the shoreline was also assessed. The annual net littoral drift was estimated to be of the order of 0.1 M m3 with its direction towards north. The LITPACK studies indicated that there will be oscillatory movement of the sediment south of south breakwater. The sediment transport pattern near the adjoining drain will remain unaltered. Training walls on both the sides of the nearby drain are required to keep drain mouth open. Thus the hydraulic model studies enabled to arrive at an optimum layout of a fishing harbour with minimum dredging requirements.