Simulation of 2D Depth Averaged Saint Venant Model of Shatt Al Arab River South of Iraq

Abstract

Basrah province southern Iraq is a tidal stream and it represents the main feeder of water to Basrah province. The river is characterized by having many branches during its course from upstream to downstream. The main aim of this study is to model a 2D hydrodynamic model for Shatt Al-Arab River with seven branches inside Basrah city which are Jubyla, Muftya, Robat, Khandek, Ashar, Al-Khora, and Saraji in addition to Karmat Ali river by the Hydrologic Engineering Centre's River Analysis System (HEC-RAS) software, where most of the previous studies relied on the consideration of the river as one-dimensional, i.e., neglecting the transverse or vertical directions. Accurate input data like Digital Elevation Models (DEMs) were provided and enhanced with the help of Geographic Information Systems (GIS) as well as a data for the year 2014 was used as boundary conditions to develop the hydrodynamic model. The discharge values at the Qurnah station were extracted from the results of a previous one-dimensional HEC-RAS mathematical model. To prove the efficiency of the model, mean absolute error (MAE), root mean squared error (RMSE), and Nash-Sutcliffe efficiency (NSE) were implemented to check the convergence between observed and simulated data through calibration and validation processes. The result of NSE was 0.836, and this indicates an acceptable convergence between the simulated and observed values. Also, the methods of RMSE and MAE support that convergence to zero. It is worth noting here that the NSE method was more sensitive to the change in the resulting values and therefore it can be recommended to use this method in hydrodynamic models. The hydrodynamic model can provide important information for models of sediment transport or water quality. Therefore, it is essential to have a good understanding of the hydrodynamic processes in a water system, before embarking on studies of sediment transport, or water quality.

Investigating the Hydraulic Behaviours of an Alluvial Meandering River Reach Between Two Barrages

“…The results demonstrate a robust link between the simulated and observed floods. Mawat & Hamdan (2023) [27] utilized the HEC-RAS2D software to conduct a 2D hydrodynamic model for the Shatt Al-Arab River. Mohamed et al ( 2023) [28] assessed the flood wave characteristics that arise from a dam breach caused by a piping failure within the dam structure and the subsequent transmission of the flood waves using HEC-RA2D software.…”