The Gabal El-Asfar drain (GAD) is one of the contaminated drains in Egypt, it is receiving Gabal El-Asfar wastewater treatment plant (GAWWTP) treated effluent and other sub agriculture drains and subjected to contamination by its point and non-point disposal pollution. This study focused in the first 7 km of the GAD. The objective of this study was to develop a hydrodynamic model for GAD and simulate the fate of residual pollutants from GAWWTP and sub-drains using a water quality module. This is due to the lack of comprehensive hydrodynamic modeling of GAD, as well as the need to identify and understand the impact of residual pollutants after treatment on water quality in GAD. In order to build the water quality model, Delft3D-FLOW software was used firstly to develop the hydrodynamic model of the drain based on the historical geometric and hydraulic data. Then, Delft3D-WAQ was used to simulate the fate of residual pollutants in terms of BOD5, COD, NH4-N and TSS based on water quality measurements that were conducted from February to May 2023 in the field. For the sake of hydrodynamic calibration, the results showed a good match between the measured and modeled depth averaged velocity at the end of the drain as 0.94 and 0.90 m/s respectively. Different process parameters that impact the fate of the above mentioned water quality parameters were studied as a part of water quality calibiration and verification to reach good and reliable modelling results. The averaged measured and modelled BOD5 was 79.9 and 81.1 mg/l, COD 187.3 and 172.2 mg/l, NH4-N 19.7 and 19.4 mg/l, and TSS 25.3 and 30 mg/l. Variance between measured and modeled data was statistically studied using one-way ANOVA tool. It was found that there is no significant difference between measured and modeled outputs. From the results, Delfet3D-FLOW and Delft3D-WAQ were successfully able to model GAD from hydrodynamic and water quality point of views.
 
 
Special Issue of AEIC 2024 (Civil Engineering  Session)