Runoff simulation in Yiluo River Basin based on SWAT-TGRU coupled model

Abstract

[Objective] Considering the spatial heterogeneity of river basins and the transmission of multi-station runoff information between upstream and downstream is essential for improving runoff simulation accuracy in river basins. A coupled runoff simulation model based on the Soil and Water Assessment Tool(SWAT) and Tree-Structured Gated Recurrent Unit(TreeGRU) was established. [Methods] The SWAT model was employed to simulate the hydrological and physical processes in sub-basins to obtain outputs of key physical variables such as precipitation, evapotranspiration, and surface runoff. These variables, along with simulated runoff data from upstream hydrological stations, were used as inputs to establish the SWAT-TGRU coupled model. By incorporating a tree-structured framework, the model enabled the transmission of hydrological information from upstream to downstream, while fully accounting for the spatiotemporal relationships among hydrological stations in the river network. [Results] The SWAT-TGRU model improved the Nash-Sutcliffe Efficiency(NSE) at four hydrological stations of Tantou, Longmenzhen, Lushi, and Heishiguan by 49%, 11%, 13%, and 15%, respectively, in the Yiluo River Basin, compared to the SWAT model. [Conclusion] Compared with SWAT-GRU and SWAT-TLSTM models, the SWAT-TGRU model exhibits higher accuracy and stability in multi-station runoff simulations. It effectively overcomes the significant increase in model complexity that arises when non-treed-structured approaches are not utilized, providing an efficient and accurate method for multi-station runoff simulation in complex river basins.

Keywords

runoff simulation / SWAT Model / tree-structured GRU / Yiluo River Basin / multi-station / influencing factors