Three-Dimensional Water Quality Modelling for Tidal Lake and Coastal Waters with ROMS-ICM

Abstract

We have developed a three-dimensional water quality model (ROMS-ICM) that consists of hydrodynamic model of ROMS and eutrophication model of CE-QUAL-ICM. The ROMS in structured grid has been linked with the unstructured CE-QUAL-ICM model by using the new linkage codes. To have more flexibility on computational resource and efficiency, the coupling of ROMS-ICM has been developed for the external linkage. The ROMS-ICM has been tested for the seasonal variation of state variables by applying to the Saemangeum tidal lake and coastal waters of Korea. The model performance has been calibrated with observed field data of water quality parameters such as temperature, salinity, chlorophyll, dissolved oxygen, phosphorus, and nitrogen. The data have been collected at more than 15 points in the tidal lake and coastal waters at every month in 2009. Major loadings of nutrients from river flows and controlling points at sea water gates of the tidal lake allow us to estimate the annual cycle of state variables. A process-based validation has been conducted by comparing the salinity budget estimated by using the ROMS alone and the ROMS-ICM. The calibration and validation results show a promising tool for understanding of existing condition and for predicting the future condition of the water quality in Saemangeum tidal lake and coastal waters.