Theoretical Approach And Planning Of Urban Clusters Stormwater Control In Loess Plateau From The Perspective Of Watershed Landscape Pattern

The Loess Plateau region faces regional contradictions such as soil erosion but drought and water shortage,low flood control capacity and fragile regional ecology.Rainwater runoff control and rainwater resource utilization are the effective ways to relieve these contradictions.Traditional research and practice of soil and water conservation are mostly focused on the use of engineering measures to control runoff or sediment on a small scale or within a small watershed.In this study,from the perspective of large-scale landscape ecology,we consider the influence of spatial pattern of land cover on "water-soil process",and improve the watershed production and sink process by optimizing the landscape pattern,which provides a new theoretical direction for soil and water conservation research and has practical value for regional ecological restoration.The theoretical and empirical research is carried out in a multi-disciplinary way through landscape pattern analysis,water-heat balance analysis,model simulation and other technical methods,taking the towns formed in typical medium-sized watersheds on the Loess Plateau as the research object.Firstly,through the analysis of the spatial characteristics of ecological and habitat environment and the law of production and sink flow in the Loess Plateau region,combined with the practical experience of soil and water conservation and reflection on the problems,the research proposes the paradigm of ecological rainwater control in the Loess Plateau region based on the existing ecological rainwater control concept and case practice,and explains the "landscape pattern" of rainwater safety in the Loess Plateau region.The theoretical basis,construction principle,planning method and technical route of the "landscape pattern" of rainwater safety in the Loess Plateau region are explained.Secondly,taking the typical research area,the town cluster of Sanchuan River basin in west Jin,as an example,the empirical study proves that the spatial layout of different attribute landscape elements such as arable land,forest and grassland and their spreading index,under the change characteristics of main hydrological elements and substrate elements of rainfall,runoff and sediment in Loess Plateau region and the mechanism of interrelated action among elements.The spatial layout of different landscape elements,such as cropland,forest and grassland,and their spreading and aggregation indexes have positive and negative effects on the watershed production and sink process respectively.Based on the qualitative analysis,a quantitative study was conducted using SWAT.Through controlled experiments,we summarize the influence of upstream,midstream and downstream distribution and the width of land distribution along the river channel on the water-sand process in the watershed,and refine the countermeasures for the downstream layout of production and living land,the upstream layout of ecological space and the 400 m range layout along the river channel.Based on this,the regional water and ecological security planning scheme and the planning model of corridors and rainfall control units are proposed in coordination with the "watershed-town cluster" boundary,relying on the existing planning and taking over the territorial spatial planning system.The innovative features of this study are the integration of interdisciplinary theories and multi-disciplinary techniques from the perspective of landscape architecture,and the proposal of landscape pattern solutions for soil and water conservation and ecological construction in the Loess Plateau region.At the level of planning theory,it promotes the regional application of landscape planning theory and method in the Loess Plateau region and clarifies the position in the territorial spatial planning system;at the level of technical path,it builds a complete chain of planning practice system with rainfall and flood control as the main line and integrates multiple technologies to provide a scientific basis and verification path for landscape planning and design;at the level of practical results,it fills the gap of landscape ecological planning in the Sanchuan River Basin.In terms of practical results,it fills the gap of landscape ecology planning in the Sanchuan River Basin and provides unified solutions and planning ideas for ecological protection and urban and rural construction in the Loess Plateau region.