Research On The Causes Of Waterlogging In Historical Building Areas At Multi-Scales And Management Countermeasures

Historic buildings are important cultural resources in cities,but with the continuous development of cities and climate changes,they are vulnerable to waterlogging.To cope with the waterlogging disasters around historic buildings and improve the waterlogging prevention capacity around historical buildings,this paper explored the causes of waterlogging in the area of historical buildings from the grid scale,block scale,and catchment scale,respectively took the central city of Suqian City as an example.A hydrological model was constructed for the area of Xinsheng historical and cultural street to further investigate the specific influencing factors of waterlogging in the historic building area.Finally,based on the findings of the first two parts,flooding management strategies are proposed for each scale and the global perspective and targeted management strategies are also proposed focusing on the historic building areas.The research content of this paper made up for the research results on the causes of waterlogging and waterlogging prevention strategies in historic building areas at multiple scales and also proposed some targeted management strategies for areas containing historic buildings,as well as providing management strategies for urban flooding disaster management.This paper draws the following conclusions:First,the strength of the correlation between internal waterlogging and various factors changes with the scale of the study,and there is an obvious scale effect;therefore,the optimal scale of the internal waterlogging study needs to be determined according to the characteristics of different study areas and influencing factors.For example,for regions with small topographic differences or regions with large differences in spatial patterns of land cover,an analysis scale of 2 km or more can be selected for the study.At all scales,the influence of topographic factors on waterlogging occupies a more important position.As the study scale increases,the contribution of topographic factors to waterlogging gradually decreases,while the contribution of spatial land cover patterns to waterlogging gradually increases.The contribution of drainage network density to waterlogging gradually increases with increasing study scale,while the contribution of land cover composition to waterlogging gradually decreases with increasing study scale.The results of the investigation of waterlogging in the historical building area at each scale are similar to the findings of the investigation of the causes of waterlogging in the central city of Suqian City as a whole.Second,the formation of historical in-waterlogging points in the area of Xinsheng Historical and Cultural Street is mainly related to the topography,the proportion of impervious surface,and the proportion of green space,which corroborates with the conclusions explored in Chapter 3.The overall elevation in the area of Xinsheng Historical and Cultural Street gradually decreases from east to west,and the historical waterlogging point is located at the lowest point of the area(except for the river).The pipes near the historical waterlogging point have no drainage pressure in all scenarios,and the inspection wells do not show overflow.In all rainfall scenarios,the runoff coefficient of the drainage subdivision where the historical waterlogging point is located is between 0.7 and 0.8,with a large runoff coefficient,and the drainage subdivision has a great proportion of impervious surfaces and a low proportion of green areas,indicating a high risk of waterlogging in this drainage subdivision.Third,the influence of scale effects should be considered for the influencing factors of waterlogging in each scale,and differential waterlogging management strategies should be proposed.When focusing on the historical building area,the overall appearance of the historic building should be ensured first,and a more hidden way should be adopted to manage and renovate as much as possible.When waterlogging renovation is carried out in the historical building area,the protection type of the building should be divided first,and the subsequent waterlogging management measures should be carried out according to the protection requirements.It is also necessary to examine the soil and sub-base of the area and the surrounding environment to determine the appropriate management strategy.For Xinsheng historical and cultural district,due to its special cultural value and land use type,as well as its proximity to the water system,the main point in waterlogging control is to make good use of the natural open space such as green space and water bodies for storage.