大伙房水库汛期径流变化趋势及影响因素定量分离研究

基于大伙房水库1961—2004年汛期各月降雨径流资料,利用Mann-Kendall趋势检验法、Mann-Kendall突变检验法、Pettitt突变检验法和降雨—径流深双累积曲线方法,分析了大伙房水库汛期降雨、汛期径流深、最大月降雨和最大月径流深四类序列的趋势和跳跃特性,并利用累积量斜率变化率定量评价了降雨和人类活动对汛期径流深和最大月径流深的影响。结果表明:(1)流域汛期降雨和径流深下降趋势不显著,最大月降雨和最大月径流深上升趋势不显著;(2)汛期降雨、径流深、最大月降雨和最大月径流深突变不显著,降雨径流关系变异年份分别为1975、1985和1995年,1975年后流域汛期产流能力减弱;(3)大伙房水库汛期径流变化经历了4个阶段,人类活动是导致水库汛期径流深减少的主要原因,降雨变化是导致最大月径流深增加的主要原因。

Study on trend and impacting factors quantitative separation of runoff in Dahuofang Reservoir during flood season

Based on the monthly runoff and precipitation data from 1961 to 2004 in the flood seasons of Dahuofang Reservoir，the methods of Mann-Kendall tendency test，Mann-Kendall mutation inspection，Pettitt mutation inspection and rainfall and runoff double cumulative curve are adopted for analyzing mutability properties of the four serieses，i.e. the precipitation，the runoff depth，the maximum monthly precipitation and the monthly runoff depth of Dahuofang Reservoir during flood season，and then the slope changing ratio of cumulative quantity is applied to quantitatively evaluate the impacts from the precipitation and the human activity on the runoff depth and the maximum monthly runoff in flood season. The result shows that （1）the decreasing trends of both the precipitation and the runoff depth during flood season in the basin are not significant，while the increasing trends of both the monthly precipitation and the monthly runoff depth are not significant as well; （2）the mutations of the precipitation，the runoff depth，the maximum monthly precipitation and the maximum monthly runoff depth in flood season are not significant，for which the mutated years of the precipitation runoff relationship are 1975，1985，and 1995，moreover，the capacity of runoff yield during flood season in the basin after 1975 is decreased; （3）the change of the runoff in Dahuofang Reservoir experiences four stages，for which the human activity is the dominant factor to cause the decrease of the runoff depth of the reservoir in flood season，while the change of precipitation is the main causation for the increase of the maximum monthly runoff depth as well.