Mountain City Based On Natural Hydrological Processes Research On Spatial Control Of Stormwater

This paper takes stormwater space in mountain cities as the research object.By summarizing and refining existing stormwater management and control principles,the shortcomings of stormwater space management and control in mountain cities are found,and the natural hydrological process and spatial scale of small watershed are further interpreted,which are translated into urban planning research objects and summarized urban stormwater management and control issues.Focus on runoff space construction in the process of hydrological impact on urban Cheng Hong toughness non-spot space control mechanism,and based on this,advances the mountain urban rain flood space planning and management strategy,in order to realize the integration in the process of urban construction land management concept,perfecting the national spatial development in protection pattern and reasonable construction of mountain cities sponge.The main research contents of this paper are as follows:(1)SCS-CN flow generation model was used to construct a 2-hour rainfall event based on 20-year rainfall intensity,and four land use scenarios were interpreted and simulated by remote sensing every five years from 2005 to 2020 in the area covered by the watershed of Guangyang Island Eco-Smart Innovation City.Meanwhile,ecological and gray stormwater space in the study area were analyzed.The characteristics and problems of regional stormwater involved in the study area were summarized to provide a basis for the subsequent construction of targeted stormwater management and control system and the proposal of target strategies.(2)According to the characteristics of storm water in mountain cities and the problem of stormwater management and control,the objectives of the management and control are proposed,and the content and methods of the management and control are systematically constructed.The connotation of mountain natural hydrological process is interpreted from the perspective of research,and the corresponding relationship between natural hydrological process and natural hydrological process is analyzed with the basic principles of landscape ecology as theoretical support.The coupling relationship between the spatial scale of small watershed and urban planning management and control is interpreted,and the coupling between GIS and SWMM is used as technical support.The technical ideas of stormwater spatial management and control in mountain cities are formed,and the key spatial elements and spatial scales of stormwater management in mountain cities are clarified,as well as the technical methods adopted.According to the basic stormwater characteristics of mountain cities,three progressive management and control objectives of stormwater safety,stormwater ecology,and stormwater comfort are proposed,and corresponding control indicators such as basin water surface rate,underlying surface impermeability rate,stormwater runoff control rate,peak runoff reduction rate,and drainage system sub-maintenance number are proposed.Finally,three strategies are proposed to deal with the problem of stormwater spatial control in mountainous cities,namely,the reconstruction of stormwater space based on regional natural hydrological processes,the stormwater spatial control measures taking small watershed as the control unit,and the stormwater spatial control of plots according to the local situation.(3)From the small watershed scale of the study area,the core area of the Ecosmart City of Guangyang Island is taken as the characteristic area to analyze the hydrological characteristics and the existing problems in the stormwater regulation space,and find out the key elements and the spatial distribution of problems affecting the stormwater control in the study area,so as to provide specific problem guidance for the implementation of the following strategies.Analysis found in the underlying surface runoff unit space rainwater infiltration capacity strength of runoff regulation is limited,underlying surface impervious rate can reduce the rainfall return period is less than 10 years of rain flood regulating effect,when the rains return period is more than once every 10 years,the improvement of the underlaying surface impervious to enhance the adjustment effect has no obvious effect of the rain flood;Green ecological land,such as green land and agricultural and forestry land,plays an important role in stormwater regulation and storage,which has the characteristics of slow runoff growth rate,slow stormwater response rate and slow decline of runoff production intensity.Industrial land and land for road transportation facilities are the main land types that weaken flood resilience,which have little effect on the adjustment and mitigation of rain and flood damage.Residential land,public and commercial service land can adjust the low return period intensity rainstorm,but have little effect on the high intensity rainstorm.(4)With the proposed control method,the core area of Guangyang Island EcoSmart Innovation City as the target area,the control objectives and control strategies are applied and implemented,so as to form a new rainfall and flood control pattern and land use layout guidance in the study area,and the SWMM model is used to verify the effect before and after scheme adjustment.The verification results show that,after the adjustment of the scheme,when the regional water surface rate rises to 5.3%,the number of water system components remains at 1.52,the total flow yield of each flow intensity decreases by 15.40% on average,the peak flow yield decreases by 12.70% on average,and the flood duration of drainage pipe and channel nodes decreases by 19.93%on average.The maximum peak flow of each node decreased by 13.99% on average.The time at the overflow water level in the stormwater pipe section decreased by26.95%,and the resilience of urban rain flood bearing was significantly improved.