Sustainable Coastal Protection in Pasuruan City : Jetty Structure in Rejoso Estuary

Rejoso Estuary has an unstable river mouth and threatens the existence of residents in the surrounding area. The rainy season, marked with high water discharge and river water overflows, affects flood in residential areas located around the coast. It happens due to sediment deposits formed closes the flow of the river to the sea. This study aims to find out an alternative, by processing data such as location maps, wind speed data, tidal data, current velocity, and sediment transport. From the calculation results, the researcher obtained the amount of longshore sediment transport amounting to 205837.7 m3 / year with the rate of perpendicular sediment transport of the coast which was 677915.27 m3 / year. The jetty is planned as the main alternative in this study to concentrate the flow of river water on a predetermined path to the sea, and to anticipate sedimentation due to sediment transport along the coast. The jetty was planned to be installed on the left and right of the estuary with a depth of 1.2 meters and length 25 meters. In this study, the jetty was considered quite effective to protect the estuary from the backwater effect and sedimentation which could cause flooding in the city area.