Modeling Streamflow and Sediment Yield with Determination of Soil Erosion Prone Areas by Using the SWAT Model

Abstract

In this study, the Soil and Water Assessment Tool (SWAT) was used to estimate the streamflow, sediment yield, and the identification of soil erosion prone areas at the sub-watershed scale to enrich the water management practices. The upper part of the Euphrates-Tigris basin called as Murat River basin was selected as a study area. Nash-Sutcliffe Efficiency (NSE), coefficient of determination (R2), and percent bias (PBIAS) were used for the assessment of the model performance with the observed data at two gage stations located on the watershed, E21A074, and E21A077. The Modified Universal Soil Loss Equation was used in the SWAT model in order to predict sediment yield and soil erosion. Sediment Delivery Ratio was also computed to identify its relationship with sediment yield at the sub-watershed scale. NSE, R2, and PBIAS for monthly streamflow prediction were calculated as 0.71, 0.72, and -11.6 in the calibration period, as 0.77, 0.79, and -9.1 in the validation period, at the station E21A077, respectively. Daily simulation the results of NSE, R2, and PBIAS were calculated as 0.56, 0.57, and -15 in the calibration period, while 0.55, 0.56, and 1.2, respectively, in the validation period at the station E21A074. The statistical results for monthly sediment yield calibration and validation were calculated as follows: 0.75 and 0.80 for NSE, 0.76 and 0.84 for R2, -0.9 and 12.2 for PBIAS from the station E21A074. 32% area of the total watershed is under severe and very severe soil erosion conditions. Most of the soil erosion occurred at the barren land use and in the sub-watersheds with a slope greater than 25%. Overall, the SWAT model satisfactorily simulated the streamflow and sediment yield at the Murat River basin which may help the researchers in water resource management.

Optimization of Dualistic Reservoir System Two-Dimensional Rule Curve with Three Allocation Rules

“…In Iraq, reservoirs play a vital role in managing water resources. They serve various purposes, including providing water for irrigation, meeting domestic and industrial demands, controlling floods, and generating hydropower [1][2][3][4].…”