Model And Application About Layout Optimization Of Multi-function Artificial Water System In Urban

With the development of modern city and the urge for water, water planningattracts more and more attention across our country. The cities with natural watersystem have strengthened the ecology restoration and the rectification of rivernetwork, while the cities without natural water system increase the surface area ofwater only by building artificial water system. However, there has not been acomplete and unified design system model for the determining of the project scale.The paper attempted to establish an optimized mathematical model of artificial watersystem layout after integrating each aspect. The model provided a very systematicapproach to calculate the size of urban artificial water system, which offered a frameof reference for the urban artificial water system design.The principal content and achievement are concluded as followed:(1) Based on the relation analysis, the paper defined function relevancy betweenthe urban artificial water system and urban drainage system, as well as artificialwetland ecosystem. Accordingly, the paper focused on the urban artificial watersystem, urban drainage system and artificial wetland ecosystem as a whole in view ofdesign scale.(2) From the view of the whole system, the system investment costs and overalleffectiveness were identified and their quantitative methods were given according toengineering practice and previous studies. On this basis, taken urban drainagerequirement, urban water environment capacity, available water supply and otherconstrains into account, the layout optimization model targeting with the net benefitsmaximization was established to determine the optimum capacities of the projects,which followed the principle that the principal part causing cost was consistent withbenefits.(3) The paper applied the model into the internal artificial water system ofnorthern group in Tianjin Binhai New Area, Central city. Through optimization, theoptimized scale of the projects was determined: the internal artificial water area is4.03km2, excavation depth is3.51m, the pumping stations capacities is33m3/s, andthe artificial wetland area is0.4751km2.(4) Furthermore, the sensitivity analysis of varieties and parameters in the model was conducted later. The results demonstrated: the efficiency value generated bysystem, except the drainage efficiency was a constant value that because it depends onthe drainage standard, was positively correlated with the artificial water system area.In another word, the larger the artificial water system area, the greater the benefit;Under the certain drainage standard, for the system total invest, increasing theartificial water system size was more economic than increase the drainage pumpinstalled capacity. To determined size of the artificial water system, increasingexcavation depth was more economy than enlarge the area.