Hydrological parameter sensitivity analysis for a cold and arid watershed based on EFAST

In cold and arid watersheds, streamflow is mainly contributed by snowmelt runoff in the ablation period and rainfall runoff during summer. Surface runoff and snowmelt may have important influence on the water cycle. In this study, the extended Fourier amplitude sensitivity test (EFAST) method was employed for SWAT model parameter sensitivity analysis. The test involved hydrological parameters that describe multiple processes including rainfall runoff, snowmelt, evaporation, percolation, baseflow, and lateral flow. Peak flows in non-melting and snow-melting periods as well as average annual flow were all considered in the sensitivity analysis. In addition, the reasons for the sensitivity of the parameters and the associated hydrological processes that affect the water cycle in the watershed were analyzed. Results showed that the surface runoff, percolation, and snowmelt have significant influence. Besides, the total-order sensitivity of the parameters related to snowmelt process was significant whereas the first-order sensitivity was not significant, indicating that the total-order sensitivity obtained using EFAST is more reasonable. The findings will help hydrological models improve their capability for simulating/predicting water resources during different seasons for snowmelt-precipitation-driven watersheds.

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