密云水库入库径流演变特性及成因分析

Evolution characteristics of the Miyun Reservoir inflow and its cause factors analysis

密云水库是北京唯一的地表饮用水源地,水库水量的多少直接关系到首都人民的生活。根据密云水库1960—2009年年入库径流量和汛期径流量2类序列,采用随机水文学方法结合序列统计性质揭示了入库径流演变规律,从降雨、人类活动和土地利用变化角度探讨入库径流演变的成因。结果表明:年入库径流和汛期入库径流都呈现减小趋势,1999年以后减小趋势更为明显,年径流减小程度比汛期显著,年际变化有明显的阶段性。受多种因素影响的密云水库入库径流序列包含相依成分,特别是年径流序列相依关系较强。入库径流减少的趋势不是单一由降水造成,流域内人类活动和土地利用变化是径流量锐减的主要原因。

The Miyun Reservoir is the only reference to Beijing surface water source, reservoir water is directly related to the lives of people in the capital. According to the Miyun Reservoir, 1960-2009 annual incoming runoff and flood runoff 2 kinds of sequence, using random sequence of hydrology method and combining with the incoming runoff statistical properties reveals the evolution law, from rainfall, human activities, the change of land use and the evolution of the incoming runoff. The result has shown that annual runoff and flood runoff tend to decrease. Decreasing trend since 1999 is more obvious. Decrease of annual runoff was significantly greater extent than flood runoff, and interannual changes are obvious stages. The factors affected the Miyun Reservoir incoming runoff series include dependent components, especially annual runoff series dependent relationship is stronger. Incoming runoff declining tendency is not a single by precipitation is caused, the basin of human activities and land use change is the main reason for the sharp reduction in runoff.