| With the continuous expansion of urbanization,the regional hydrology balance was destroyed,water shortage,frequent urban waterlogging and initial rainwater pollution and other issues have become increasingly prominent.Sponge city uses low-impact development systems to keep the hydrologic characteristics of the site the same after the city was developed.In this way,rainwater runoff flow,runoff peak flow,and runoff pollution can be reduced sufficiently.In this paper,the configuration optimization model is established by analyzing the effects of low impact development,and complete the simulation of runoff control and drainage pipeline of the community.Finally,the concept of carbon abatement is introduced to access the carbon benefits of low impact development in the region.The main contents and achievements are as follows:According to the three control indexes of sponge city construction—runoff flow,runoff peak flow and runoff pollution,based on the construction technology guide of sponge city,a linear programming of configuration optimization of low impact development techniques in communities was proposed with laws and regulations standard,comprehensive runoff coefficient and runoff pollution control as the main constraint conditions and the lowest cost as the objective function.The results of the example area showed that the optimal construction scheme is lowest cost and meets the constraint conditions and various standards.The runoff coefficient of the area is decreased from 0.67 to 0.44 and the removal rate of total TSS is reduced to 50%.With the optimization results of the linear programming,the layout of area and possibilities of applying low impact development on the area were analyzed.The rainwater system models of traditional and low-impact development were established combined with rainwater pipe network.The hydrological effects of the two kinds of development were evaluated under different rainfall intensities,rainfall period and patterns from the four aspects: the total amount of rainwater discharge,the integrated runoff coefficient,the runoff peak flow and the runoff pollution.Analyzing the ways of carbon emission reduction in sponge city from the perspective of emission reduction of fossil energy and greening system,and analyzing the carbon emission benefits of different measures from qualitative and quantitative levels.The result shows that the example area with low impact development reduce carbon dioxide emissions 150000 kg per year compared with traditional development. |
