Research On Hydrological Effects Of Urbanization In Xi'an-Xianyang Section Of Weihe River

The urbanization process has different degrees of influence on various aspects of the regional hydrological process.Xi'an and Xianyang are located on the south and north bank of the Weihe River respectively.The Xi'an-Xianyang section of the Weihe River is the core area with the largest urban area also the highest degree and level of urbanization in the Weihe River Basin.In addition,the hydrological effects of urbanization are also the most significant.This paper determines the research area from Xianyang and Lintong Hydrological Stations,and studies the impacts of Xi'an and Xianyang urbanization especially the main urban on the hydrological process of Xi'an-Xianyang section of the Weihe River from the perspective of the basin.The research results on the construction of Xixian New Area,the sustainable development of the city of Xi'an,and the sustainable use of water resources and the prevention of urban floods and disasters are of great significance.The main research results are as follows:(1)According to the rainfall data of 1975-2016 in 10 stations in or outside the region,the distribution?interannual variation and spatial distribution characteristics of precipitation during the year are analyzed.On this basis,the representative sites of the suburbs of the city are selected to compare the annual precipitation,the precipitation during the flood season and the precipitation days in different periods in the city and suburbs.The results show that urbanization has a certain effect of increasing rainfall and slowing the annual precipitation in urban areas.The decline of the suburbs has significantly reduced the difference in rainfall in the suburbs,and the impacts of different stages of urbanization are different.Urbanization has a significant effect on precipitation during the flood season and is stronger than the annual precipitation;urbanization makes the frequency of heavy precipitation increase.(2)Using ENVI5.3,ArcGIS10.3 and other software to interpret and statistically analyze the remote sensing images of the study area in 1995,2005 and 2016,and analyze the changes and causes of land-use.The results are as follows: The land-use types changed significantly from 1995 to 2016,and the cultivated land and forest land were the dominant types;the forest area increased first and then fluctuated,the cultivated land area decreased firstly slow and then quickly,the construction land area increased rapidly,and the grass land and water area firstly decreased then increased,the unused land is the opposite;urbanization is the main factor of change,and the improvement of social environmental awareness and national policy also have a certain impact.(3)Using the hydrological comparison method to calculate the runoff sequence data of the study area from 1975 to 2016,based on the analysis of the characteristics of runoff variation in the study area,the impact of urbanization on runoff is studied.The results show that urbanization has promoted The formation of runoff increases the runoff and adjusts the annual distribution of runoff to make it more uniform.In order to study the influence of urbanization on runoff and runoff,the SCS model was used to simulate the production and flow of the study area.The results are as follows: Determine the CN value adjustment coefficient k=1.04.It is proved that the SCS model has better simulation effect;Annual precipitation,AMCII conditions,1995,2005 and 2016 production flow,total production flow increased,including 1995-2005 increase of 7.55%,2005-2016 increased by 14.84%,and the trend of production flow is mainly affected by the impacts of land-use changes.