| In recent years,with the rapid development of urbanization,the nature of many land sites has undergone radical changes,making the original drainage system unable to meet the drainage and flood control needs of the built cities and towns,and the flooding caused by poor drainage during the flood season has a great impact on people’s daily life.For this reason,it is of great significance to prepare drainage and flood control plan scientifically and reasonably,to guide the construction of drainage and flood control facilities,to ensure the safety of urban drainage and flood control system and the safety of life and property of residents.In this paper,we analyze the drainage and flood control standards of the Yangtze River Cultural and Tourism City,an important functional area of Yangtze River New City with an investment of 70 billion RMB,and formulate a drainage and flood control plan for the city,and adopts Infoworks ICM simulate the planning scheme and evaluates the effect of planning scheme its implementation.The main research results of this paper are as follows.(1)Confirm the planning objectives scientifically and reasonably,and draw up a planning scheme for drainage and flood control in Yangtze River Cultural and Tourism City.The existing drainage standard in the study area is 20-year rainfall of one day discharge in three days,and according to the geographical location of the city,the planned population and the importance of the project,the drainage and flood control standard of the Yangtze River Cultural and Tourism City is confirmed to be 50-year rainstorm.On the basis of investigation and study of the current situation of drainage system in the district,analysis of drainage and flood control planning constraints,combined with the topography and geomorphology,the drainage and flood control planning scheme of Yangtze River Cultural Tourism City was formulated.Its main contents include the planning of water system layout,the planning of drainage pipes and channels,the planning of pumping stations and ancillary facilities,and the comparison of stormwater discharge planning schemes outside the study area.(2)Planning of the pipe network system evaluation.With the Chicago rainfall process line method to design 1-year rainfall,2-year rainfall and 3-year rainfall,the Infoworks ICM model software was used to calibrate the planned stormwater pipe network system under the rainfall with a recurrence period of 3 years.The simulation results show that the number of overflow nodes,the number of overloaded pipe networks and the number of under-capacity pipe networks are increasing with the increase of stormwater recurrence period P.When P=3a,there are 14 sections of pipes in the planning area that are in the state of full pipe with pressure flow,accounting for12.64% of the total pipe length.It means that the proposed planning rainwater pipe network system basically meets the drainage requirements of the 3-year rainfall.(3)Risk assessment of waterlogging.Infoworks ICM model software was used to build a two-dimensional surface model of the study area after planning.The time and depth of waterlogging were selected as the assessment indexes and the threshold values were set,and the waterlogging risk maps were drawn under two design rainfall recurrence periods of P=20a and P=50a.The simulation results show that the flooding risk in the study area is significantly reduced by setting 90,000 m~3 storage ponds,but the reduction effect decreases with the increase of the design rainfall return period.Under the condition of 20-year rainfall,the integrated risk area is reduced by 40.61%;under the condition of 50-year rainfall,the integrated risk area is reduced by 36.26%. |
