Water Quality Modeling of Dubai Creek using HEC-RAS

Abstract

The quality of the water resources is facing threats because of the continuous urbanization. This increase in human activities around the coastal areas changed the water quality, affecting the aquatic ecosystem. Eutrophication occurs when high levels of nutrients cause algal bloom. The water quality modeling can be a useful tool for assessing water bodies. Dubai Creek can be defined as a tidal marine water body located in Dubai, UAE. As Dubai witnessed a rapid urbanization in recent years, the creek has been detrimentally affected. The objective of this study was to develop a hydrodynamic model coupled with water quality model for the Dubai Creek to assess and understand the processes affecting the creek. A 1D hydrodynamic model of the Dubai Creek was constructed using the HEC-RAS software, and it was coupled with a water quality model to evaluate the amount, source and distribution of algae, dissolved oxygen, nitrate and orthophosphate. The hydrodynamic model was calibrated using historical water levels along the creek, and the water quality model was calibrated and validated for the targeted parameters by comparing them with the available data. The model results showed an increase in the algae from the Creek Mouth station to Sanctuary station, and the nutrients showed high concentrations in the STP Outfall station. However, dissolved oxygen had the highest concentration recorded in the Creek Mouth station and the lowest in Wharfage station. The different scenarios were also investigated, and the result showed that changing the algae concentration in Sanctuary station didn't impact the creek stations except STP Outfall recorded 0.0024 mg/L of algae. On the other hand, utilizing nitrate at 2 mg/L in STP Outfall showed a reduction the nitrate concentration along the creek.