RIASSUNTO
ABSTRACT:
Seasonal sand accumulation problem in Kirinda fishery harbour is well known problem among the harbours in Sri Lanka. To elucidate the possible sand transport patterns close to the harbour area, wave climate study was carried out using SWAN modeling system. After analyzing global reanalysis wind data, SWAN model was executed for the selected representative simulation periods of southwest and northeast monsoon by wind forcing. On the basis of estimated wave parameters, sea and swell waves and longshore sand transport directions were investigated. During the southwest monsoon, sea and swell wave propagation from southwest direction is identified. For northeast monsoon, two distinct wave directions corresponding to the sea and swell waves were recognized. Finally, longshore sand transport process occurs during the southwest monsoon season, from southwest direction is recognized as the main cause for the seasonal closure of the entrance.
INTRODUCTION
The small natural harbour, which had been used by the fishermen in Kirinda and neighbouring villages, was expanded as "Kirinda Fishery Harbour" in 1985. The major objective of this harbour development project was to provide facilities for the local and migrant fishermen to engage in fishing industry throughout the year, irrespective of conditions such as the impact of monsoon climate. However, as a result of inadequate considerations on physical phenomena such as wave climate, sediment transport and littoral drift processes around the harbour area, harbour operations were suspended in 1986 due to the severe sand accumulation inside the harbour basin (ECL, 1992). In spite of the harbour being rehabilitated with proposed layout modifications in 1994, the sand accumulation process was not completely solved. At present, it occurs throughout the year and becomes severe during the southwest monsoon season. As a result, the harbour entrance is often blocked, diminishing the safe and convenient navigation access.