A Unique Volume Balance Approach for Verifying the Three-Dimensional Hydrodynamic Numerical Models in Surface Waterbody Simulation

The hydrodynamic numerical modeling is increasingly becoming a widely used tool for simulating the surface waterbodies including rivers, lakes, and reservoirs. A challenging step in any model development is the verification tests, especially at the early stage of development. In this study, a unique approach was developed by implementing the volume balance principle in order to verify the three-dimensional hydrodynamic models for surface waterbody simulation. A developed and verified three-dimensional hydrodynamic and water quality model, called W3, was employed by setting a case study model to be verified using the volume balance technique. The model was qualified by calculating the error in the accumulated water volume within the domain every time step. Results showed that the volume balance reached a constant error over the simulation period, indicating a robust model setup

One-dimensional Model Predictions of Carbonaceous Biological Oxygen Demand and Dissolved Oxygen for Hilla River Water Quality, Iraq

Water quality of Hilla River, located in Iraq, has been varying due to the presences different illegal point and non-points sources along the river stream. This study highlights biochemical oxygen demand (CBOD) and dissolved oxygen (DO) levels for safe usage by applying QUẠL2K model and depending on hydraulic and water quality data collected along 6.8 km passing through the main city (Hilla City) on October 2022 (low flow season) and January 2023 (high flow season). The modeling results showed that the simulated predictions are in good agreement with field data. The outputs revealed the two parameters (CBOD and DO) ranged between (1.425 - 3.075) mg/L and (9.5 - 10.65) mg/L, respectively, during low flow season and between (0.745 - 2) mg/L and (9.5 - 10.5) mg/L, respectively, during high flow season. The river CBOD levels along the river follow same pattern during the high and low flow seasons, but the DO levels behaved inversely. However, both parameters were within the acceptable limits. Thus, the river health can be considered good for basic human usage