Modelling Analysis of Flow Patterns in the Palu River Estuary

The Palu River estuary is a potential area for the socio-economic development of the surrounding community. The problem that often occurs in the river estuary is siltation due to the sedimentation process. The purpose of this research is to analyze the condition of the current pattern of the Palu River estuary against tides and river discharge that affect the sedimentation process in the estuary. The current pattern in the estuary was analyzed with a 2D mathematical model using MIKE ZERO software. This study used tidal, bathymetry and river discharge data. Three river discharge conditions were used, namely maximum conditions, normal conditions, and minimum conditions, which were obtained from field measurement data. The results of the analysis of this study showed that the type of tide that occurs in the Palu River estuary is a mixed type of double daily inclination. The tidal current pattern at the mouth of the river is dominated by the river discharge current. Minimum discharge current moves at a speed of 0.015-0.026 m/s, normal discharge current moves at a speed of 0.025-0.035 m/s, maximum discharge current moves at a speed of 0.031-0.051 m/s. The current pattern that occurs when the maximum discharge is the direction of the vector that moves away from the river. At high tide, the tidal current pattern moves towards the mouth of the river and is blocked by the river current so that there is a deflection of the tidal current. The accuracy level of the model results based on the RMSE value is 12%, this value can be categorized as good for the accuracy level.