Effects of model segmentation approach on the performance and parameters of the Hydrological Simulation Program – Fortran (HSPF) models

Although models are one of the most powerful tools for watershed management, their effectiveness is limited by prediction uncertainties resulting from not only model input data but also spatial discretization. In this paper, Hydrological Simulation Program – Fortran (HSPF) models were constructed for the Linyi watershed according to three segmentation approaches including model segments based on differences in: (1) sub-watershed, (2) meteorological station, and (3) physical characteristics. Then the static sensitivity method and dynamic sensitivity method were employed to evaluate the effect of the segmentation approach on model performance and parameters of HSPF. The main conclusions were: (1) modeling with 12 segments had the best simulation efficiency and the corresponding estimated parameters had a certain representation within the Linyi watershed; (2) HSPF model performance was significantly affected by the segmentation approach, especially by the model segmentation construction process which considering a meteorological station or not; (3) parameters INTFW (interflow inflow parameter), lower zone nominal storage, and upper zone nominal storage (UZSN) were most affected by the model segmentation approach, while parameter AGWRC (groundwater recession coefficient) changed indistinctly; (4) parameters UZSN and INTFW had the same variation tendency whenever the segmentation approach changed.