Analysis on the flood characteristics and its change trend in the Kuye River basin

Based on the flood data of Wenjiachuan station which is the export station of the Kuye river,annual and monthly change and its trend about flood flow from 1954 to 1990,2006 and 2008 were analyzed.With the method of comparison among different floods and analysis about the discharge-water level hydrograph of the maximal flood,we can see that in the Kuye river basin,annual flood flow changed greatly,the frequency of flood was high before 1980s while flood peak discharge sharply decreased,even the minimum one was only 89.9m3/s in 2008.Obviously,the maximum flood peak discharge decreased rapidly since the beginning of 1980s influenced by runoff in flood season and human activities,especially different soil conservation measures;The discipline of flood flow distribution was as the same as the one of runoff distribution in flood season,which concentrated from July until September.In this work,the discharge-water level hydrographs of the maximal flood in Wenjiachuan station occurred in the typical years has been revealed and listed below: single line,clockwise loop,anticlockwise loop,and 8-shape plus line.These relations reflected the channel bed was eroded or deposited.And the chance of anticlockwise loop occurred was more than other loops,it was maybe because of hyper-concentrated flow,terrain feature and landform composition unit.