Evaluating the influence of tides on surface water quality in the coastal areas of Ho Chi Minh City

Abstract

This study uses Utide software for the purpose of assessing the trend of water level change and forecast tides at coastal water level measurement stations in the Southern region. Using tidal forecasting results from Utide software as input to the hydrodynamic mathematical model set (MIKE 11, MIKE21) with two hydrodynamic and ecological modules to evaluate the flow regime and water quality in the coastal area of Ho Chi Minh City. The model is calibrated and verified with the input data set including topography,
hydraulic data, hydrology and real measured water quality. The simulation results show that the water quality is quite complicated due to fluctuations in the flow, at some locations where the water quality is within the allowable limit of QCVN 08-MT:2015/BTNMT column B1, the water quality index (WQI) fluctuates from 52 - 87, only Water quality numbers (WQI) ranged from 52 to 87, suggesting that tidal dilution plays a dominant role. The results of this study are also the basis for short-term forecasting of water quality parameters in the future.