Study On The Dynamic Interaction Mechanism Of Hydraulic Erosion And Gully Consolidation And Highland Protection Based On GeoWEPP On The Loess Plateau

Gully Consolidation and Highland Protection(GCHP)is a major project for water and soil management in the new period.Based on the GeoWEPP model,with Yangjiagou(YJG)and Dongzhuanggou(DZG)as prototypes,the erosion and sediment production in different scenarios of the GCHP were simulated and studied.At the same time,according to the simulation data,the Dynamic Interaction Mechanism between the GCHP and hydraulic erosion was studied.The main conclusions are as follows:The GeoWEPP model has good applicability in YJG and DZG watershed.Based on meteorological data of YJG and DZG watershed,combined with DEM map,land-use map and soil type figure,by the use of GeoWEPP model,the soil erosion and sediment yield process of YJG and DZG watershed has been simulated.This paper has taken manual fixed method,calibrated the important parameters of the model,when the model simulated runoff of the watershed,the correlation coefficient between simulation value and measured value was more than 0.95,a level of significance,the Nash-Sutcliffe efficiency coefficient was more than 0.90,it showed the model has a preferable applicability in YJG and DZG watershed.Under the individual rainfall,the GCHP has a protective effect in small Watershed.In order to study the Dynamic Interaction Mechanism of GCHP and hydraulic erosion,three GCHP scenes were designed: gully head landfill;terracing;Warping dam.Initial state was as control group.Then simulated soil erosion and sediment yield of the three scenes by GeoWEPP model respectively,the results showed that: under the individual rainfall,the runoff and sediment yield of the three scenes showed different degrees of reduction.In a short period of time,the GCHP has a positive effect on water and soil control,while under long-term conditions and continuous heavy rain conditions,secondary disasters are likely to occur,which exacerbating soil erosion in small watersheds.According to the results of the scenario simulation and the sediment production distribution map,the Dynamic Interaction Mechanism between the GCHP and hydraulic erosion was analyzed.The results show that: from the comparison of simulated data,it can be seen that in a short period of time,the GCPH project has a positive effect on soil and water control;from the distribution map of sand production,it can be seen that: after the gully head landfill,the sand production is concentrated at the location of the landfill;the distribution of sand production from terrace shows a stripe distribution according to the terrain,not ever concentrated;the Warping dam is mainly intercepted at the position,which results in a reduction in sediment production and runoff.That can be seen under the condition of long-term rainfall or continuous heavy rain,without the subsequent maintenance of the project,it is very likely that secondary disasters will occur,and exacerbating soil erosion in small watersheds.Judging from the research results,during the implementation of the GCHP project,a scientific and effective design should be carried out,and the project should be regularly inspected and maintained.The research results of this paper can provide a certain basis for the implementation of the subsequent GCHP.