The Study On Hydrological Toughness Of Kushui River Basin Based On The SWAT Model

This study focuses on the research hotspots of watershed hydrological response issues and the resilience of watershed hydrological systems to external interference.It explores the impact of land use change on watershed hydrological resilience and hydrological elements,and is of great significance in promoting the hydrological resilience index as an early warning indicator for water resource management organizations.During the research period from 2001 to 2020,the sensitivity analysis,calibration and verification of parameters were carried out by establishing a Hydrological model for Kushui River basin in Ningxia.Set four different land use scenarios and analyze their hydrological cycle evolution characteristics to calculate hydrological resilience.Main research content and conclusions:(1)Establish SWAT Hydrological model,and use SWAT-CUP software to conduct parameter sensitivity analysis,calibration and verification based on measured runoff data.The results show that the maximum canopy interception,average slope length,permeability ratio of deep aquifers,number of runoff curves,and snow melting base temperature have the highest sensitivity to runoff changes;The Nessler’s efficiency coefficient(Ens)of the model during both the periodic and validation periods is greater than 0.6,and the correlation coefficient(R2)is greater than 0.7.This model can be applied to the study of hydrological cycle evolution in the watershed.(2)By changing climate change conditions and setting different land use conditions,and through multiple simulations and analysis,it can be concluded that the overall change trend of various hydrological elements is consistent under different land type conditions.Due to its superior water retention effect,forest land has the greatest reduction in watershed runoff when farmland is converted to forest land,followed by grassland.Through designing climate change scenarios,it was found that under the same temperature conditions,runoff,evapotranspiration,and precipitation show a linear positive correlation;Under the same rainfall conditions,there is a significant negative correlation between runoff and temperature changes,while evapotranspiration shows a positive correlation with temperature changes.(3)This article introduces resilience indicators Pi to reflect the resilience of a watershed The multiyear average value of the resilience index Pi of forest land is higher than that of grassland and arable land and the multi-year average value of grassland’s resilience index Pi is higher than that of arable land.In water resource management,protecting and restoring forest cover and grassland cover are important measures to improve hydrological resilience.