Comparative Evaluation of the Performance of SWAT, SWAT+, and APEX Models in Simulating Edge of Field Hydrological Processes

Hydrologic and water quality models are often used in assessing the response of environmental processes to human activities climatic change. However, these differ terms their complexity, requirements, underlying equations, assumptions, as such performance simulating landscape varies. Consequently, a key question that has be addressed is select most suitable model gives results closest reality for an intended purpose. In this study, basin-wide older version SWAT compared with small watershed APEX assess both at field scale level. The new restructured (SWAT+) determine whether changes incorporated SWAT+ have improved performance, particularly watersheds. three were simulate edge 6.6 ha plot located USDA-Agricultural Research Station near Riesel, Texas, predict yield, soil, mineral phosphorous loss from micro watershed. Results showed all uncalibrated over-predict soil Uncalibrated simulated yield satisfactory albeit low-performance metrics. calibrated versions indices close optimal values. PBIAS assessment metric was determined overly sensitive prone numerical errors. will helpful understanding hydrological watersheds considering it addresses structural flaws associated version, manually matches SWAT, despite latter two undergoing rigorous automatic calibration.