采用滑动平均和线性回归法对潘家口水库1956~2003年入库径流进行了分析,探讨了影响径流变化的基本因素,给出了降雨量、用水量和下垫面等因素变化对径流量变化贡献程度的定量估算方法。结果表明:入库径流呈不规则的周期波动变化,且整体呈较为明显的减小趋势;降雨量、用水量和下垫面等因素变化是影响径流量变化的主要因素,特别是下垫面的变化,其贡献程度可达70%左右。

In recent years, the water resources of Luanhe River Basin have changed significantly with a sharp decrease of runoff flowing into the Panjiakou Reservoir which may affect the water supply management of the water transfer project from Luanhe River into Tianjin city. So in this paper, auto-regressed method and moving average method were adopted to research the variation trend of the annual runoff reservoir inflow.The results show that the annual runoff presented a periodicity and a general decreasing trend on a long time series from 1956 to 2003, especially from the 1990s, the annual runoff decreased obviously. To seek the factors that affect the annual runoff, precipitation, water consumption and the underlying surface were analyzed. We found that the annual precipitation just changed slightly. Although the water consumption increases each year, it only occupies a small proportion of the runoff reduction. To quantify the impact of precipitation factor and human activity factor on runoff change, the method is derived based on the relationship between precipitation and runoff. We calculated the impacts of precipitation and non-precipitation factors on runoff change and found the contribution rate of non-precipitation is the main cause for runoff reduction, which means land cover change plays an important role in runoff reduction with a contribution rate to runoff change exceeding 70%. From the rainfall runoff correlation, the conclusion can be drawn that the runoff generation depth was lower after the 1980s than that before the 1980s under the same annual precipitation regime. It was also discovered that the decadal runoff change was affected greatly by the precipitation amount, but as to the general decreasing trend the precipitation's contribution is only about 7%; and the increasing water consumption is not the main influencing factor to the decadal mutative runoff but to the general decreasing trend its contribution is about 23%. The evapotransporation is a fuzzy factor influencing the runoff. The observed pan evaporation can not represent the actual evapotransporation, so it must be studied further. The results will have some reference values to the programming of Luanhe River Basin and the utilization of water resource transferred from Luanhe River.