Hydrodynamic modeling using Delft3D for port safety in Bawean waters, Indonesia

Abstract

This study aims to assess the hydrodynamic conditions of the waters around Bawean Port, Gresik, using Delft3D numerical modeling to support navigational safety. A quantitative approach was applied using nested-grid simulations to capture both large-scale and detailed hydrodynamic processes. The model incorporated bathymetry, tidal forcing, wind, and wave data obtained from global datasets, including GEBCO, TPXO 8.0, and ECMWF ERA5. Simulations were conducted for two representative monsoon seasons, namely the west monsoon (January) and east monsoon (July), with each simulation covering a one-month period. The results indicate that water depths in the study area range from 0 to 6 m, highlighting the need for careful management of port and shipping lane depths to ensure navigational safety. Tidal analysis indicates a mixed tide with a predominantly semi-diurnal character. Model validation showed good agreement with observed data, with RMSE and MAE values of 0.0581 m and 0.0426 m, respectively, indicating good model performance. The hydrodynamic analysis revealed distinct seasonal variations in wind and wave characteristics, with dominant winds originating from the west and northwest during the west monsoon and from the east and southeast during the east monsoon. Maximum wave heights reached 1.55 m during the west monsoon and 1.83 m during the east monsoon. Current velocities were generally low, ranging from 0 to 0.4 m/s, with flow directions influenced by tidal conditions and coastal structures, particularly harbor piers. Based on these findings, dredging of the shipping lanes is recommended to provide sufficient depth for larger vessels, while appropriate speed restrictions are recommended to maintain vessel stability and navigational safety. Overall, the modeling results provide important insights into the tidal, current, and wave dynamics of Bawean waters and can support shipping lane management, port planning, and coastal management.