Temporal and Spatial Variation of Hydrological Connectivity and Its Effects on Flood Probability of Typical Tributaries in the Middle Reaches of the Yellow River
Clarifying the relationship between hydrological connectivity and flood probability is an important basis for scientific development of flood management measures.In this paper,the hydrologic connectivity index(RIC)of the Kuye River(KYH)catchment was measured by using a modified hydrologic connectivity model based on hydrologic observations and remote sensing data.Advanced spatial analysis tools and statistical tests,including the Theil-Sen Median and Mann-Kendall methods,were employed to analyze the spatial-temporal evolution patterns of RIC.An ordered logistic regression model was then used to examine the influence of RIC on flood probability.The results indicate a signifi-cant decline in the yearly average RIC value.Significant reductions in RIC are primarily observed in specific regions.Spatially,RIC concen-trations with high-high agglomeration are in the downstream rock mountainous areas of KYH.Notably,low-low aggregation is found in the Ulan Mulun River catchment,particularly in the Kangbashi and Yijinhuoluo.The trend of long-term significance change is dominated by highly significant decrease and significant decrease.Floods in KYH are mainly concentrated in the summer,with their frequency and annual maximum instantaneous streamflow(AMS)showing a significant downward trend.The mutation point of AMS is found to be in 1998 by the Mann-Kendall test in KYH.The RIC significantly contributes to the probability of flood occurrence.Specifically,when all other variables are fixed and unchanged,for each unit increase in the RIC,the probability of a flood becoming a larger magnitude increases by 5.999 times.
hydrological connectivitytemporal and spatial variationordinal logistic regressionflood effectsKYH catchment
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