Research On Measures Of Rainwater Resource Utilization In Reclamation Area Based On SWMM

The social and economic development of coastal areas is limited by land shortage,and reclamation is a common phenomenon.As a special urban ecological model,the reclamation area not only has problems such as insufficient water resources,frequent floods and waterlogging in the process of urban development,but also a series of ecological and environmental problems,such as soil salinization and corrosion of underground structures caused by sea water invasion and fluctuation of groundwater level.As a valuable fresh water resource,rainwater resources can be collected to relieve the pressure of urban water use,and the problem of soil salinization can be improved by setting up rainwater infiltration measures to increase the infiltration of rainwater.At present,the traditional mode of municipal drainage is lagging behind,and can no longer adapt to the rapid development of the city.With the development of the concept of "spongy city",a new urban rain and flood management concept,low impact development shows its unique advantages in the construction of environmental friendly rainwater utilization system.It is of guiding significance for the sustainable development of reclamation area to improve the ecological environment of reclamation area by using the idea of low impact development.Based on the low impact development concept,this paper uses the SWMM-rainstorm and flood model to establish a rainwater system simulation model with regional applicability for the underlay characteristics of the reclamation area.According to the requirements of the underlying surface of the reclamation area and the planning pipe network,the regional runoff analysis of the single LID facilities is carried out.The design scheme of rainwater resources utilization in reclamation area is set up from three angles of economic benefit,emission reduction benefit and ecological benefit.Taking the reclamation area of Dalian new airport as the research area,the scheme design and project evaluation of the new rainwater system are carried out.First,by analyzing the actual conditions of meteorological hydrology,topography,geology,land use,soil conditions and rainfall,the SWMM model is established according to the characteristics of the research area network and the properties of the underlying surface.By sensitivity analysis of the model parameters,the parameters of high sensitivity are found out and the rationality of the parameters is determined.Secondly,according to the characteristics of the reclamation area and the underlying surface,the LID primary selection index is set up,the LID facilities suitable for the research area are selected,and the SWMM model is used to design and simulate the single LID facilities in the research area,and the simulation results are analyzed.The evaluation factor of the design scheme is identified by three angles,the benefit of emission reduction and the ecological benefit.The method of evaluating the benefit of the LID facilities combination scheme is established by the analytic hierarchy process.Finally,the combination scheme design of the rainwater utilization system for various LID facilities is carried out in the research area,the optimization of the entry plan and the quantitative evaluation are carried out.Some research results have been obtained in this study.On the basis of studying and absorbing advanced LID rainwater management measures abroad,the scheme design of rainwater utilization system in reclamation area with LID as the design concept is deeply studied.The design system of the new rainwater system is further perfected from the design level of site planning and the selection of LID facilities,and the new rainwater in Dalian reclamation area has been established.The SWMM simulation model of the system provides the source model for the local similar project evaluation,and the design scheme evaluation of the study area is selected by the analytic hierarchy process,which provides some reference for the design of the rainwater utilization system in the study area.