| Dongzhiyuan is located in the hinterland of the Loess Plateau.When facing the national strategic deployment and development,it has become a key area of the"Belt and Road","Western Development" and "Targeted Poverty Alleviation".Large-scale projects such as trench construction and many lifeline projects have been launched.However,the plateau surface is fragmented and the valley erosion is developed in Dongzhiyuan area.And most areas of Dongzhiyuan belong to erosion areas.The area of soil erosion is about 2735.95 km2,accounting for 96.5%of the total area.The average annual erosion modulus is above 6000 t/km2 and the total annual sediment transport is up to 16 million tons.Therefore,based on the research on the spatial distribution characteristics of gully erosion development in the Dongzhiyuan area of the Loess Plateau,the characteristic areas were divided into the region,and the corresponding comprehensive management model was proposed according to the erosion characteristics of each characteristic subarea,which is of great significance for the implementation of major projects such as "Solid Groove Tableland".This paper takes the loess Dongzhiyuan area in the eastern part of Gansu Province as the research object,and takes the spatial differentiation characteristics of valley erosion and development as the entry point.Based on indoor basic data collection and field investigation,it takes advantage of high-resolution remote sensing images and drone images.The data,using Arcgis,Ecognition,Erdas and other remote sensing image processing software,interpreted the Dongzhiyuan gully water network,the network shoulder line of valley,the distribution of houses in Dongzhiyuan and the distribution of unhardened roads.Thus,using nine quantitative indicators of the characteristics of the network of the water system and the network shoulder line of valley and human engineering activities established a comprehensive and multi-factorial quantitative index system of gully erosion and development distribution,and quantitatively analyzed the spatial differentiation characteristics and development of the gully development and distribution in the region through various indicators.The division of characteristic areas,followed by analysis of the gully erosion characteristics and influencing factors of different characteristic areas,the "Gully Control and Highland Protection" comprehensive management model of different characteristic areas was proposed according to local conditions.The main work and conclusions are as follows:(1)The quantitative index system of valley erosion development in Dong-zhiyuan was constructed,and the quantitative analysis of the spatial distribution of valley erosion development was realized.Using a variety of software operation techniques,the network shoulder line of valley,the distribution of houses in Dongzhiyuan,the distribution of unhardened roads and the gully water system network were extracted.The omnidirectional and multi-factor quantitative index system of gully erosion development distribution of the activity characteristics,realizes the quantitative analysis of the spatial distribution of gully erosion development in Dongzhiyuan.(2)Describes the spatial differentiation characteristics of erosion development distribution in Dongzhiyuan valley.?The valley development area in the north of Dongzhiyuan is large,the spatial shape along the valley border is complex,and the approach distance is small.The development of the gully water system and branch gully is high,and the erosion phenomenon of unhardened roads is serious;?The gully erosion undercut in the south of Dongzhiyuan is severe,the vertical descent of the gully and the overall erosion potential of the gully are relatively large;?The development of the valley in the central area of Dongzhiyuan is low,but the population density is high,and the development of the valley erosion caused by human engineering activities is more prominent.(3)The division of erosion development characteristics of Dongzhiyuan valley is divided.Eight quantitative indicators with insignificant correlation are selected,and the ISODA method of the ERDAS image classification operating platform is used to automatically divide the Dongzhiyuan gully erosion development distribution area,and four types of gully erosion development distribution area are obtained.(4)Analyzed the erosion characteristics of each district of Dongzhiyuan.?:low development of gully,high population density,prominent development of gully erosion caused by engineering activities;?:general development of gully,severe undercutting of gully erosion,relatively large vertical drop of gully,overall erosion potential of gully is large;III:The valley has a high degree of development,the valley has a large area of development,and the valley water system and branch gully have a high degree of development;IV:the valley has a high degree of development,the spatial shape of the gully is complicated,and the approach distance is relatively small relative to the watershed,the gully erosion caused by the unhardened road is serious.(5)The factors influencing the erosion characteristics of each district of Dongzhiyuan were evaluated.It was found that there are natural environmental factors such as topography,rainfall,vegetation,geological structure,etc.At the same time,the soil as the main body of valley erosion,its own anti-erosion ability is also an important factor affecting the development of valley erosion.(6)Put forward the comprehensive governance model of each district of Dong Zhiyuan.?:Control the runoff on the surface of the plateau so that the water does not fall into the plateau;protect the gully head to avoid traceable erosion;guide and drive the masses and reduce man-made erosion.?:With the gully head protection project as the supporting point,establish a plateau runoff prevention and control system on the upper side,and build a gully prevention and control system on all levels of the gullies below,so that no water will flow out of the ditch.?:According to the distribution of the trench and the topographical characteristics,from upstream to downstream,from branch ditch to main hook,protection is carried out step by step.?:The governance measures in this area should start from "Gully Control",combining the slope protection project and the trenching and land reclamation project,so as to achieve the goal of "Highland Protection". |
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