Studies On Channel Connectivity Of Small Towns In Northern Shaanxi Valley Based On Fractal Geomorphology

The Loess Plateau in North Shaanxi is one of the important birthplaces of Chinese civilization.It has profound Chinese traditional culture genes.At the same time,the Loess Plateau in North Shaanxi is also the largest loess accumulation area in the world.It is facing serious problems such as soil erosion and ecological environment damage.In the process of accumulation and covering of Loess layer,erosion of river system has been accompanied for a long time,and special topography of gullies has gradually formed in northern Shaanxi.Because of the topographic and geomorphological reasons,most of the small towns in northern Shaanxi have the typical morphological characteristics of zonal Valley cities.With the rapid development of urbanization,the social and economic development is advancing,and the level of science and technology is also gradually improving.The construction of small towns in the Loess Plateau area of northern Shaanxi is accelerating,and the development of towns is relatively concentrated at the county level.In this process,the demand for land space in urban construction has formed a prominent contradiction with the narrow landscape in the valley of northern Shaanxi.Urban space has also begun to expand to secondary ditches.Due to the constraints of topography and landform,sub-ditches and Zhimaogou-level settlements are at the relative end of the ditch system.Their connectivity is poor,and there is no effective connection with the outside world.The connection of human flow,logistics and information flow isgreatly limited.It is difficult for urban space to form an effective network structure,and the terminal connection between sub-ditches.Tong has also become an important issue restricting the development of cities and towns.In the construction of small towns in the valley area of northern Shaanxi,sub-gully and branch-mao gully are important components of urban space,which need to be taken into account in urban development.Because it is in the ecologically sensitive area,considering the level of urban development and construction cost,the land expansion of "cutting mountains and building cities" should not be the final solution for the development of small towns in the valley.Strengthening the construction of urban ditch system and speeding up the effective connection among different grades of ditches should be the way to conform to the fractal geomorphological conditions of northern Shaanxi.The construction and improvement of the ditch system also follows the "gene" of the development of valley towns for thousands of years,which is of great significance and value.Based on the study of the urban spatial development of small towns in the valley area of northern Shaanxi,this paper analyses the spatial connectivity between urban rivers and roads,explores the appropriate channel connectivity mode and connectivity effectiveness under the fractal geomorphology conditions,and takes Qingjian County as an example to study the relevant evaluation index of channel connectivity and the actual utility under different connectivity modes,and summarizes the regional,characteristic and ecological adaptability.The related strategies of improving the channel connectivity of small towns in northern Shaanxi valley area form a unique channel space system.