Relationship Between Landscape Pattern And Surface Runoff Based On GIS In Fuzhou

Our country is in a period of rapid development of urbanization,urban population increasing rapid and urban scale expanding rapid,which adds to land use surged,changes the land use/cover types in natural watersheds and forms the urban pattern that different form the natural pattern.Urban construction leads to serious reduction of green space,destroys the ecological function of rivers and lakes,increases the ratio of impermeable underlying surface,blocks the connectivity between surface water and groundwater,changes the process of urban runoff greatly,and brings a series of urban environmental problems.This study bases on the analysis of land use transition in Fuzhou city during 1991--2016,by means of the geographic information system(GIS),the landscape index calculation software Fragstats and SCS model,to discuss the relation between the landscape pattern evolution and surface runoff transition.In order to provide theoretical support for the rational planning and utilization of land,the construction of urban landscape security pattern and the solution of frequent flood disasters in the process of urbanization.The main research contents and conclusions can be summarized as the followding:(1)During the years from 1991 to 2016,the urban landscape pattern of Fuzhou changed significantly,the construction land area increased markedly and the green space and water area reduced sharply.The wet land area tended to decrease from 1991 to 2011 and recovered to some extent from 2011 to 2016.The landscape pattern of the city gradually tend to Highly fragmented,complexly shaped,poorly connected and steady equalized.(2)Using SCS model to simulate surface runoff transition in Fuzhou.First of all,the model is calibrated according to the hydrological data and slope in Fuzhou area,adjusted the ? value in response to the ratio of Ia to S.When the ? value is 0.2,the model fitting degree is the best,and the model efficiency is the highest The surface runoff in Fuzhou increased by 10.29mm from 1991 to 2001,1.84mm from 2001 to 2011,and 1.57mm from 2011 to 2016,which indicated that the urban landscape pattern has an increasing retention effect on the surface runoff.(3)The landscape pattern index and the regression analysis of runoff indicated that the landscape density PD,landscape shape index LSI,the multivariate combination of the connectivity index CONNECT and the contagion index CONTAG had a good explanatory ability for the runoff,R2=0.718,and PD has a positive correlation functional relationship with runoff Q,while LSI,CONNECT and CONTAG have negative correlation functional relationship with runoff Q.The CONNECT has the strongest sensibility to the runoff change.(4)In accordance with the research foundation,combining with the actual situation of Fuzhou City,the integrated management for optimization of urban landscape pattern and reduction of the urban surface runoff in Fuzhou was discussed on the basis of the foregoing study.