Evaluation of Qual2kw Model in Qualitative Simulation of Khorramabad River

In this study, the water quality of Khorramabad river was simulated using a one-dimensional QUAL2Kw model over a distance of 35 km from the river. For this purpose, important water quality parameters such as dissolved oxygen (DO), carbon biochemical oxygen demand (CBODf), chemical oxygen demand (COD), nitrate (NO3), electrical conductivity (EC) and acidity (pH) and temperature parameter in two months July and September 1397 were used for calibration and validation of the model, respectively. The results of evaluation indices showed that the NRMSE index in the calibration and validation stage of the model was obtained for the lowest value for pH and equal to 8.83 and 9.22 percent and for EC was calculated as 11.05 and 13.86 percent, respectively. The simulation of the DO parameter also had fluctuations along the river, while the statistical indices NRMSE, RMSE and MAE for this parameter in both calibration and validation stages were obtained to an acceptable level, so that the above indices in the calibration stage of the model 12.49, 0.917 and 0.72, respectively, and in the validation stage of the model, 24.65, 1.78, and 1.55, respectively, were calculated. Also, the model was able to simulate the temperature parameter with good accuracy in July (RMSE = 1.92 and MAE = 1.57) and September (RMSE = 2.77 and MAE = 2.5709). Finally, the results of this study showed the appropriate accuracy of the QUAL2Kw model in simulating the above parameters in the Khorramabad River.