Comparison of SWAT and GWLF Model Simulation Performance in Humid South and Semi-Arid North of China

Abstract

Watershed models have gradually been adapted to support both decision and policy making for global environmental pollution control. In this study, two watershed models with different complexity, the Soil and Water Assessment Tool (SWAT) and the Generalized Watershed Loading Function (GWLF), were applied in two catchments in data scarce China, namely the Tunxi and the Hanjiaying basins with contrasting climatic conditions (humid and semi-arid, respectively). The performances of both models were assessed via comparison between simulated and measured monthly streamflow, sediment yield, and total nitrogen. Time series plots as well as four statistical measures (the coefficient of determination (R 2 ), the Nash-Sutcliffe efficiency (NSE), percent bias (PBIAS), and RMSE (root mean square error)-observations standard deviation ratio (RSR)) were used to estimate the performance of both models. The results show that both models were generally able to simulate monthly streamflow, sediment, and total nitrogen loadings during the simulation period. However, SWAT performed better for detailed representations, while GWLF could produce much better average values of the observed data. Thus, GWLF offers a user-friendly prospective alternative watershed model that requires little input data and that is applicable for areas where the input data required for SWAT are not always available. SWAT is more suitable for projects that require high accuracy and offers an advantage when measured data are scarce.

Estimation of the Source Apportionment of Phosphorus and Its Responses to Future Climate Changes Using Multi-Model Applications

“…Based on the outputs of the model applications, the non-point sources from farmland discharge through runoff and septic systems discharge through groundwater were detected as the current main contributing sources of Dis-P in studied watershed. The fluxes and source apportionments of Dis-P were variable in different months, in accordance with previous studies [34,46,47,49].…”

“…However, both the R 2 NS and r 2 were higher than 0.80 in the calibration period and that both statistics declined slightly in the verification period but neither was below 0.75. Such statistics were in accordance with the standard level of watershed model applications for the estimation of the monthly hydrological process [45,46], and all the calibrated transport parameter values could make sense within reasonable physical range, which indicated that the calibrated ReNuMa model could provide reliable modeling of the watershed hydrological processes, based on which the nutrient parameters of ReNuMa could be estimated for Dis-P modeling.…”

A Guideline for Successful Calibration and Uncertainty Analysis for Soil and Water Assessment: A Review of Papers from the 2016 International SWAT Conference

“…19-Qi et al [41] compared SWAT to a simpler Generalized Watershed Loading Function (GWLF) model. The performances of both models were assessed via comparison between simulated and measured monthly streamflow, sediment yield, and total nitrogen.…”

Soil Erosion Modelling and Risk Assessment in Data Scarce Rift Valley Lake Regions, Ethiopia

“…It was also tested and used in many regions in Africa [26][27][28][29][30][31][32][33] to estimate sediment yields from both gauged and ungauged watersheds and good results were reported. Similarly, the performance of SWAT model was tested in Germany [34], USA [35], China [36][37][38][39][40] and Jamaica [41] to predict the amount of sediment as well as stream flow from gauged and ungauged river basins Due to its wide applicability, SWAT model was selected in this study to estimate the sediment yield of Lake Ziway basin, Ethiopia. The SWAT model is a watershed scale model that incorporates the features of several other models [42].…”