| Soil erosion has become a global environment issue which threat to the modern society and agricultural sustainable development,taking mall watershed as a unit to implement comprehensive control of soil and water loss is the successful experience of soil and water conservation work in our country.Slope gully system is a basic structure which made of gully small watershed along the flow direction from hill slope to bottom of trench land between gullies and gully region which continuous distributed,is the basic unit of the research on soil erosion rule,also the basic unit of channel water loss and soil erosion of small watershed governance.The study of phenomenon and law of inquiry will provide slope gully erosion a scientific basis for optimized configuration of soil and water conservation measures,which has great significance for the rehabilitation and reconstruction of ecological environment.In this paper,the research use The loess plateau model test hall of The Yellow River water conservancy science research institute Model base of the Yellow River's full automatic control artificial rainfall system and Generalized model slope gully system and The ground laser radar scanner,through the artificial rainfall experiment selected 66 mm/h,85 mm/h,120 mm/h three rainfall intensity research slope soil erosion on ditch system,conclusion can be obtained:(1)The erosion and sediment yield time distribution characteristic of slope gully systemIn the process of 100 min of rainfall,before 30 min rainfall period sediment process showed a trend of obvious increase,30 ~ 60 min rainfall period sediment process fluctuations relatively stable state,after 60 min erosion processes enter into a new stage of increased volatility.(2)Water sand along the temporal and spatial distribution of slope gully systemAlong with the rainfall runoff of slope gully system each section of the sediment content showed a trend of increased volatility,especially the ditch slope part and lower part of slope are the most obvious.Tests have shown that,with the extension of rainfall duration,66 mm/h slope gully system development to five section at the bottom of the slope,the sediment concentration significantly higher than the 2-4 section;85 mm/h and 120mm/h rainfall,Slope gully system slope gully erosion gully in the transitional zone is traceable to the slope surface erosion development in the middle of 3,4,section,Section 3-4 parts of the sediment concentration data points increased with the increase of rainfall phase fluctuations,Visible,85 mm/h and 120mm/h rainfall on the slope gully system surface morphology damage is more serious,central of gully slope slope and system transition areas are erosion prone areas in gully slope.(3)The relationship between water and sediment transport slope gully systemUsing the test conditions downhill ditch system of runoff and sediment yield observation data,analyze 6 rainfall time of three kinds of rainfall intensity downhill ditch system sediment concentration(Sp-g),slope runoff sediment concentration(Sp)and gully slope runoff sediment concentration(Sg)results indicates: with the extension of rainfall(rainfall time continuity),the runoff sediment concentration overall increased,especially the 85 mm/h and 120 mm/h rainfall is more obvious;under the condition of rainfall intensity 85 mm/h and 120 mm/h,there was a positive correlation with Sp and Sp-g Sg relations;under the condition of 66 mm/h rainfall intensity,Sp-g and Sg were positively correlated,and negatively correlated with Sp;further analysis found the Sg and Sp coefficient,under the condition of 66 mm/h rainfall intensity coefficient of the Sg and Sp 1.36:1.00,85 mm/h and 120 mm/h rainfall intensity coefficient of the Sg and Sp were 3.18,1.00 and 29.35,1.00,which showed that the rainfall intensity greater,ditch slope sediment yield effects the degree of sand of slope runoff ditch system increases more. |
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