Impact Of Urbanization On Hydrological Processes

With the rapid development of urbanization,active human activities have changed the underlying surface conditions under natural conditions.Changes such as the rapid expansion of urban areas and the reduction of vegetation coverage have had a significant impact on the hydrological process,leading to frequent urban floods.This paper relies on the National Natural Science Key Fund Project "Research on Theory and Method of Urban Flood Forecasting and Early Warning Based on Big Data"(51739009).Taking Zhengzhou as an example and on the basis of analyzing the characteristics of urbanization development,the changes and influencing factors of the hydrological process in urbanization are qualitatively and quantitatively studied from the perspective of hydrology.The research is of great significance for understanding the impact of urbanization on the hydrological process and reducing the hydrological effects of urbanization.The main research contents and results are as follows:(1)Analysis of urbanization development:Based on the economic and social data of Zhengzhou from 1978 to 2018,study the characteristics of the phased development of Zhengzhou's urbanization.Through the comparison of the distribution of land use in Zhengzhou in different periods,the characteristics of the spatial change of urbanization development are analyzed.The development of urbanization has shown obvious phased characteristics in time,and the uneven development between regions has increased.(2)Analysis of the impact of urbanization on rainfall factors:Based on the actual rainfall data of Zhengzhou from 1971 to 2012,analyze the changes of rainfall intensity and rainfall center.Combining the characteristics of urbanization development,select representative indicators to study the impact of uneven urbanization development on rainfall centers.The average slope can reflect the influence of topography on the distribution of rainfall centers.The distribution of construction land can reflect the impact of land use changes on rainfall centers.As the unbalanced development of urbanization space intensifies,the distribution of building land within the city has become the main influencing factor that affects the rainfall center.(3)Analysis of the impact of urbanization on runoff elements:Based on the rainfall data characteristics of Zhengzhou from 1971 to 2012,the corresponding runoff data from the Zhongmou Hydrometric Station in Zhengzhou is selected to analyze the changes in the runoff coefficient,flood peak and flood peak lag time in urbanization.Above,combined with the characteristics of urbanization development,analyze the main factors affecting the runoff process in urbanization.When rainfall is concentrated in areas with large changes in construction land,the flood peak changes greatly;when rainfall is concentrated in areas with rapid land use conversion,the peak delay and the change in runoff increase,and the change in runoff coefficient also increases;When rainfall is concentrated in areas where construction land is the main land use type,the runoff increases and the runoff coefficient increases accordingly.(4)Analysis of the impact of urbanization development on the hydrological process and its main links:the hydrological model is used to simulate the changes in the hydrological process of a typical rainfall process under land use scenarios in 1993,1998,2003,2008,and 2013,and quantitatively analyze the impact of urbanization development on the hydrological process.The impact of each link in the hydrological process.