| Abstract
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The objective of this study is to find a suitable model for predicting longshore sediment transport rate for Krueng Aceh Urgent Flood Control Project in Indonesia. Black Box approach was used in the study by employing the U. S. Army CERC-formula. To employ the CERC-formula, wave properties i. e., wave height, wave period and wave direction are required as data input. For longshore sediment transport estimation, a K-value of 0.39 was used since H{1/3} and T{1/3} were used in the study. Estimated longshore sediment transport was, then, compared to actual sediment trapped at the jetty which is in the study site. To estimate the volume of sediment trapped during periods of study, three cross sectional surveys were conducted. The first survey was in May 1992, second was in May 1993, and the last one was in August 1993. Three procedures in estimating wave properties were tried. First, wind speed and direction at the study site(Alue Naga station) were estimated using wind data of another station(Blang Bintang station) employing vector regression analysis. Since the vector correlation coefficients were found to be very low, the procedure was not continued. Second, linear regression was used to estimate monthly average wind speeds at Alue Naga using data of Blang Bintang. Using monthly average wind speed data, the correlation coefficient of these stations was quite good. The procedure was continued to predict wave data from estimated wind speed. Third, the available wave data of a previous period were used, since the wind climate of this period and the period of study are almost identical. The study revealed that using wave properties from hindcasting yield over estimated longshore sediment transport. While, using wave properties from available data yield estimated longshore sediment transport which is close to those observed.
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