Research On Urban Waterlogging Risk Assessment And Systematic Management Based On MIKE Model

With the frequent occurrence of extreme weather,flooding is becoming an increasingly serious problem in many cities,and flood management has become an increasingly prominent issue.For flood-prone areas with severe waterlogging,extensive impacts,and difficulties in remediation,it is not enough to simply renovate drainage channels or build low-impact development facilities.A more comprehensive,systemic urban flood management plan needs to be developed based on the existing drainage system in conjunction with urban planning and construction,in order to minimize the impact of flooding and ensure stable social development.In this paper,the current status of domestic and international research on waterlogging management is firstly comprehensively analyzed,taking J area as an example.Then,the current situation of the drainage and waterlogging prevention system in District J was investigated,and the existing problems were identified.The MIKE software was used to construct a rainfall model for District J,combining drainage facilities,river channels,topography,and rainfall data,and the model was rated and validated.The model was then used to evaluate the drainage capacity of the pipes and the risk of flooding,and the results of the model evaluation and research were combined to develop a systematic management plan.Engineering measures were implemented into the model,simulated,and analyzed using data from previous years’ heavy rainfall,and compared the drainage capacity of the pipes and the risk of flooding before and after the engineering improvements to quantify the effectiveness of the engineering measures.At the same time,non-engineering measures were proposed in the areas of information construction and emergency management,and together with engineering measures,a comprehensive flood control implementation plan was built.The key findings are as follows:(1)The MIKE software was used to generalize the stormwater network,rivers,and pumping stations;to divide sub-catchment areas;to construct the MIKE model;and to validate and assess the model based on the measured data of the location of the flooding points,the depth of the flooding,and the changes in the water level of the rivers,in order to obtain a MIKE stormwater model with a high degree of accuracy that can be used for research.(2)The model is used to evaluate the drainage capacity and waterlogging of the pipeline in the J area.The total length of the pipeline recurrence period P≤1a is about 66.81 km,accounting for 22.59% of the total.Furthermore,as the simulated rainfall return period increased,the depth and area of waterlogging increased,and part of the study area was classified as high risk,indicating an urgent need for treatment.(3)Based on the research and model simulation results,the root cause of the urban flooding problem was identified,and engineering measures were proposed to address issues in urban construction,stormwater network systems,and urban drainage systems.These measures were supplemented by non-engineering measures to develop a comprehensive and systematic treatment plan.(4)The treatment effected of the engineering measures was evaluated and analyzed in terms of the improvement of the capacity of the urban drainage network,the assessment of the risk of flooding,and the effect of flood removal.The results show that the length of the pipeline with a return period of P≤1a has been reduced by 26.44 km or 39.57% after the rectification,and the drainage capacity of the pipeline has been significantly improved.In terms of flooding risk assessment,the high-risk areas under four precipitation conditions(10a,20 a,30a and 50a)were reduced by 4.28 ha,4.55 ha,4.71 ha,and 4.72 ha respectively,and the high-risk areas were basically eliminated.In terms of flood removal effectiveness,the extent of urban waterlogging was reduced by more than 85%.The remaining waterlogged areas can be treated according to the nonengineering measures in the implementation plan.The results show that the systematic management scheme is reasonable and will greatly reduce the risk of flooding in District J,providing some reference value for other cities’ flood management.