Investigation Of Runoff Control Based On The Landscape Pattern Transition

With the rapid development of urbanization, especially the enlargement of city scale and the unreasonable land use, flood and runoff pollution problem become serious. Based on runoff control research progress at home and abroad.with the help of geographic information system, remote sensing and landscape ecology theory, using the three different periods of Hang Zhou (1991,2003,2010) LANDSAT-TM images, Hang Zhou is obtained by computing related landscape pattern index, secondly,using SCS runoff model to calculate the runoff depth in different periods, and then through the literature and experiments, we get the runoff water quality data, Finally, Use of multivariate analysis methods to analyze the relationship between landscape indices runoff index. Basically have the following conclusion:(1) Landscape pattern transition is closely related to the urbanization process, from1991to2010,the green space and wetland area decreased by53.4%、84.7%,the water area is essentially unchanged, the construction land area increased by117.9%; the landscape fragmentation is increasing, the degree of structural heterogeneity is reducing and the shape become more complicated.(2) With the development of the city, runoff depth gradually deepened, and the runoff depth changes which caused by the landscape pattern changes in different periods of the study area are not the same.(3) Both CODMn and TN of rivers in Hangzhou were beyond standards, in the case of point source pollution is on control, river water quality index difference is mainly due to the different land use patterns changes which result from non-point source pollution.(4) A part of the Landscape pattern index significantly correlation with runoff index, and different types of land use conversion of hydrological sensitivity in different ways, in addition, reasonable control related landscape index can effectively control the runoff.(5) This research thought that through setting up reasonable river shore green buffer; strengthen the construction of dispersible group type green land and wetland; increasing appropriate ecological detention ponds, wetland, depression and low vegetation facilities and controling the conversion from green land&wetlands to constructive land can effectively improve the problem of urban runoff.