Urban System Planning Based On Healthy Hydrological Cycle In Nansi Lake Basin

Taking the Nansi Lake basin as study area, the constraints and purpose is tomaintain and repair the basic structure and function of the watershed healthy watercycle, establish healthy face on basin scale, analysis of the healthy status of watercycle of different small watersheds, and targeted propose urban system planning. Thepurpose is to provide the scientific basis for coordinate the development of watershedurbanization with water environment and the sustainable development of the riverbasis.This paper statistical analysis the process of rainfall-runoff change in50years ofnine small watershed in study area though Mann-Kendall rank correlation test, doublecumulative curve method. Come to the runoff changes mutation characteristics of eastlake and west lake watershed, and calculate the contribution rate of human activitieson runoff change through the impact quantification division method of humanactivities and climate change.Analysis the current situation of urban system rating scale, spatial structure,functional structure and development of urbanize process. Come to the result that thestudy area is in the middle stages of the urbanization and speed of development is fast.Watershed healthy water cycle reflects the recognition of human on riverstructure and function play, should also have a social function and ideal nauralfunction. The sign of Watershed healthy water cycle should be: in the river basinnatural and social functions play a balanced case, a continuing flow of river networks,good quality and good water ecosystems. Create the evaluation system of basin watercycle healthy status from four fields of the natural conditions, the levelof urbanization, river water circulation and water security pattern. The evaluationresults show that water cycle healthy status of each small basin are quite different, Ingeneral that water cycle healthy status of west lake basin is better than east lake basin.This situation is related with the higher level of urbanization of east lake watershed.Propose appropriate urban system optimization program based on the results of acomprehensive evaluation of the health status of the water cycle, the basin is dividedinto first-level optimization control zone, second-level optimization control zone andurbanization coordinated development zone, make appropriate optimization schemefor different optimized regions, so that the entire river basin’s natural and socialfunctions coordination, improve the healthy status of watershed hydrologic cycle.