Water-sediment Scale Effect And Transfer Law Of Watershed In Loess Hilly Region

The water-sediment relationship at the watershed scale has always been the focus of regional water and soil conservation research.This paper takes the Luoyugou watershed,Luergou watershed,and Qiaozigou watershed in the third subregion of the Loess Plateau as objects to analyze the precipitation and runoff of watersheds at different spatial scales.And the basic change characteristics and related relationships of sediment.Provide scientific support for regional water and soil conservation,and draw the following conclusions:(1)Rainfall,runoff,and sediment transport in Luoyugou watershed,Luergou watershed,and Qiaozigou watershed from 1988 to 2010 all have alternating rainfall,runoff,and sediment transport,and their overall trend is decreasing(Lüergou annual sediment transport Except for the amount).(2)At different time and space scales,the characteristics of the water-sediment relationship in the Luoyugou watershed,the Luergou watershed and the Qiaozixigou watershed are different.The multi-year average rainfall-runoff and rainfall-sediment relationship change trends at different spatial scales are consistent.The average runoff and sediment transport have a linear relationship,and there is no significant difference in the relationship between water and sediment at different spatial scales.The annual average runoff has a linear transfer between small-medium-small-scale and small-medium-microscale;while the amount of sediment transport has a nonlinear transfer.(3)Based on flood events,the consistency of rainfall-runoff and rainfall-sediment transport in different spatial scale basins is weakened,but the water-sediment relationship shows a good linear relationship,and the runoff depth is on the small-medium-small-scale and medium-small-microscale.The transfer relationship appears as a non-linear transfer.The transfer relationship of flood and sediment transport is shown as a linear transfer in the small-to-medium-small scale,and in the medium-small-to-micro scale,it is shown as a linear transfer.(4)Under the time scale of the secondary flood process,the non-equilibrium sediment transport phenomenon causes the water-sediment relationship in different spatial scales to show no regularity.(5)The water-sediment relationship between runoff and sediment transport in the Luoyugou watershed is closer under short-term floods.The water-sediment relationship between Qiaozixigou and Qiaozidonggou at different time and space scales is not significant.The impact of the change of utilization method on the relationship of runoff and sediment transfer between watersheds is different.On an annual scale,the runoff depth and sediment transfer of the watershed under water and soil conservation measures are both nonlinear transfers,and the runoff of the watershed without water conservation measures.The transmission of deep and sediment transport is shown as non-linear and linear transmission.During a flood event,the runoff depth and sediment transfer in the basin under water and soil conservation measures are all shown as linear transfer,and without water conservation measures,it is nonlinear transfer.