Research On Geomorphologic Development Characteristics And Their Spatial Variation Of Jinghe River Basin Based On DEM

The watershed is generally considered to be the best geographic unit for studying surface matter,energy flow and the interaction of various elements.Because as a natural terrain complex,it is both systematic and hierarchical.The Jinghe river basin is a complete watershed landform in the Loess Plateau region.However,the existing research on the watershed geomorphology of the Loess Plateau lacks a systematic discussion of the large-scale watershed geomorphological development process.The Jinghe river basin has a typical loess landform.It is located on the Ordos platform,which is the core area of the Loess Plateau.It is also located in the key loss area of the whole loess plateau,where the soil erosion is the most typical and obvious.At the same time,the Jinghe river basin is unique.It traverses multiple soil erosion zones and has diverse landform types.Therefore,from the comprehensive perspective of the river basin,scientific discussion and in-depth study of the typical and unique loess landforms of the Jinghe river basin are of great value.This is helpful for in-depth understanding of the evolution process of the landform of the watershed and can open up new ideas for the study of loess landform development.The main research contents of this paper are as follows:The Jinghe River Basin is the research sample area.Quantitative indicators are selected from two aspects of watershed development characteristics and gully profile characteristics,and the calculation methods and geological meanings of the quantitative indicators are elaborated in detail.The Jinghe river basin is divided by hydrological methods.From the two perspectives of ten small watersheds located in different soil erosion zones and different levels of watersheds in the Jinghe river basin,the regional differences in the development of the Jinghe river basin are studied.The main conclusions of this article are as follows:1.Geomorphic development characteristics of small watersheds in the Jinghe river basinThe results show that there are differences in the degree and characteristics of landform development among watersheds located in the same soil erosion zone.The gully density better reflects the differences between the soil erosion zones.In terms of spatial distribution,from north to south,the degree of landform development and gully development also showed a trend from higher to higher,and then gradually decreased.Gully profile combination(GPC)morphology and GPC indicators(gully concavity,gully slope,and gully development index)can better express the morphology and development characteristics of gully groups in the watershed.The gullies in the basin with low gully development index are more different.The group morphology of the gully longitudinal profile can also be used to identify the loess plateau developed on the monoclinic paleotopography.2.Regional differences in the development of landforms in the Jinghe River BasinThe results show that there are several high-value areas and low-value areas for different indicators.The loess plateau area in the center of the basin,the northeastern part of the basin,the upper reaches of the main stream of Jinghe river,the upper reaches of Malian river,and the area of Dongzhiyuan have clustering phenomena.It is found that the formation of these areas is closely related to the geomorphology,soil thickness,rivers and other factors.The spatial distribution rules between the indicators are not completely similar.Different indicators are applicable to different watershed scales.In general,the four-level watershed basically does not continue the spatial distribution law of the first three levels.The degree of landform development of the Jinghe river basin is quite different from the division of soil erosion.3.Geographical development degree division in the Jinghe river basinThe results show that the degree of landform development in the Jinghe river basin generally shows a gradual decrease from north to south.Among them,the most developed area is north of the center.The areas with a higher degree of development are more scattered,mainly located at the boundary of the basin.Finally,the rationality of the zoning results is discussed using the data of landform types.The results show that the landform types of each landform development level are diverse.There is a certain correlation between the types of landforms and the degree of landform development.The geomorphological development degree division of the Jinghe river basin can better reflect the geomorphological development degree of the Jinghe river basin.