Analysis Of The Influence Of Urbanization Spatial Pattern On Hydrology

With the rapid development of urbanization in China,a series of problems caused by rapid urbanization have been exposed.For example,water security problems in the process of urbanization,the rapid development of urbanization has led to the natural underlying surface of green space,grassland and woodland.With varying degrees of damage,the destruction of the natural underlying surface changes the runoff generation process of the original natural surface,thereby affecting the safety of surface water,thus causing urbanization flooding disasters in the basin.The factors affecting the occurrence of flood disasters are complex.At present,the level of human understanding cannot guarantee accurate simulation and prediction of floods.Flood events can only be analyzed and processed as random events to quantitatively estimate the possibility of flood disasters in a certain basin.This paper will provide a theoretical basis for the urbanization of the basin by simulating the possibility of flood disasters in the basin where the study area is located.The research on flooding and urbanization of river basin is also an important part of sponge construction and ecological city construction in China.Therefore,the purpose of this study is to provide scientific and theoretical basis for urban green space system planning in the basin by using the theories and experiments of hydrological science.This paper takes Hubei Province River Basin as the research object,and combines the traditional disciplines of remote sensing,landscape ecology and hydrology with interdisciplinary research methods to analyze the impact of urbanization spatial pattern on river basin hydrology.Using remote sensing and GIS technology to extract urbanization information of the study area.Analysis of the spatial pattern of urbanization in the Fu River Basin from 1990 to 2017.Mainly by extracting the sub-basin of the study area and the land cover over the years,the HEC-HMS hydrological model was combined with the flood data of the study area to simulate the relationship between land cover change and flood,and the influence of urbanization spatial pattern on flood effect was discussed.Finally,according to the conclusion,combined with landscape ecology,urban green space system planning,eco-city planning,sponge city planning,etc.,provide theoretical basis for urban flood control and disaster mitigation.The main research contents of this paper are as follows:1.Review the research background and significance of this research,analyze the research status at home and abroad,summarize the research progress of HEC-HMS hydrological model and CA-Markov model at home and abroad,and summarize the importance of urban hydrology to the construction of sponge city.2.Obtain data such as meteorological data,satellite image data,and digital elevation model in the study area,extract land use information from the study area based on satellite image data,and divide the land use in the study area into impervious surface,water area,vegetation,and bare land.The urbanization development process of the Fu River Basin.In order to explore whether urbanization in the basin will have a greater impact on future floods in the basin,land cover in 2022 and 2030 will be predicted based on the trend of land cover changes from 2013 to 2017.The relationship between impervious surface and basin flood is studied separately by constructing a basin urbanization scenario,and then the urbanization spatial pattern is constructed to study the relationship between different spatial distributions of impervious surfaces and basin floods.3.Obtain hydrological data of the basin,including the water outlet data such as flood peaks and floods.According to the characteristics of the HEC-HMS distributed hydrological model,input the hydrological data of the study area to determine the parameters of HEC-HMS,so that HEC-HMS is applicable to the basin.Finally,the HEC-HMS hydrological model suitable for the study area was established.4.Through the scenario analysis method,according to the HEC-HMS hydrological model determined in the previous step to simulate the hydrological effect of the urbanization of the basin,so as to explore the impact on the flood runoff in the basin during the urbanization development of the basin,and then according to the four basins constructed.Urbanization spatial pattern is used as a conditional input HEC-HMS hydrological model to simulate the impact of four urbanization spatial patterns on runoff.(1)Simulating the impact of urbanization process on different floods: By simulating the flood process under multi-year urbanization scenarios,the impact of river basin urbanization on flood floods is analyzed.According to the research conclusions of this paper,under the same flood,the flood peak and flood volume increase with the increase of the impervious surface of the basin.The simulation results show that in the urbanization process of the basin,the rainfall runoff increases with the increase of the impervious surface.The increase of rainfall runoff will inevitably lead to flood disasters,so how to properly control the development of the urbanization impervious surface of the basin It is a problem that must be faced in the construction of an ecological city.(2)Simulating the impact of spatial pattern of urbanization on different floods: By simulating the flood process of the same flood in different urbanization spatial patterns,the impact of spatial pattern of urbanization on flood runoff is analyzed.According to the research of this paper,under the same flood,the impacts of urbanization spatial pattern on the flood peak and flood growth rate of the four basins are: downstream > periphery > average distribution > upstream.From the simulation results,it can be concluded that in the urban green space system planning process,the distribution of the green space and the urban impervious surface can help to mitigate the occurrence of flood disasters.