Numerical Modeling of Water Mass Structure Distribution at the Estuary Jeneberang River, Makassar

This study aims to model the distribution pattern and stratification of water mass structures by the influence of hydrodynamics using a two-dimensional numerical model. Data recording was performed in spring tide and neap tide conditions for 18 days at the Stuary Jeneberang River in Makassar. 2D numerical models with flexible mesh bases are used in this study. This model can configure the coastline and bathymetry and applied in the estuary. Model validation shows the error rate of water level elevation at stations 1 and 2 of 2.26% and 5.47%. Likewise, the model validation of the measurement results of current, u-velocity of 9.7% and v-velocity of 4.8%. The simulation results show the pattern of salinity and temperature distribution follows the flow pattern so that it affects the distribution of the structure of water mass in the estuary waters of the Jeneberang River. The interaction that occurs between the mass structure of water with the hydrodynamic factor results in a moving current carrying a number of water masses, namely salinity and temperature. Well-mixed occurs at a distance of 400 m - 1000 m from the mouth of the estuary.