气候变化和人类活动对白洋淀上游水源区径流的影响

白洋淀是华北平原最大的湖泊湿地,对维持华北平原生态平衡具有极其重要的作用。近年来,白洋淀流域水源减少已经引起了严重的生态环境问题,本文以唐河上游流域为例,根据流域内1960-2008 年水文气象数据,采用气候弹性系数和水文模拟方法,研究了气候变化和人类活动对白洋淀上游水源区径流量的影响。结果表明：年径流下降趋势显著,下降速率为1.7 mm/a,且径流在1980 年前后发生了突变;气候变化对唐河上游流域径流减少的贡献率为38%~40%,人类活动对径流的减少起主导作用,为60%~62%。为维持白洋淀的生态功能,必须保证一定的最小生态需水量,开展湿地生态用水调度与监管。     

气候变化和人类活动对白洋淀水源区径流的影响(英文)

As the largest wetland in the North China Plain(NCP),the Baiyangdian Lake plays an important role in maintaining water balance and ecological health of NCP.In the past few decades,the decreasing streamflow in the Baiyangdian Basin associated with climate variability and human activities has caused a series of water and eco-environmental issues.In this study,we quantified the impacts of climate variability and human activities on streamflow in the water source area of the Baiyangdian Lake,based on analyses of hydrologic changes of the upper Tanghe river catchment(a sub-basin of the Baiyangdian Basin) from 1960 to 2008.Climate elasticity method and hydrological modeling method were used to distinguish the effects of climate variability and human activities.The results showed that the annual streamflow decreased significantly(P>0.05) by 1.7 mm/a and an abrupt change was identified around the year 1980.The quantification results indicated that climate variations accounted for 38%-40% of decreased streamflow,while human activities accounted for 60%-62%.Therefore,the effect of human activities played a dominant role on the decline of the streamflow in the water source area of the Baiyangdian Lake.To keep the ecosystem health of the Baiyangdian Lake,we suggest that minimum ecological water demand and integrated watershed management should be guaranteed in the future.     

华北山区坡地产流规律研究

Simulated rainfall is a valid tool to examine the runoff generation on the slope. 13 simulated rainfall experiments with different rainfall intensities and durations are completed in a 5 m ×10 m experimental plot in mountainous area of North China. Simultaneously, rainfall, surface runoff, soil-layer flow, mantel-layer flow and soil moisture are monitored respectively. From the results, it is found that the hydrographs in all layers have the characteristics of rapid rise and fall. The recessions of surface flow and soil-layer flow are much faster than that of mantel-layer flow. Surface flow, the main contributor, makes up more than 60% of the total runoff in the study area. It even exceeds 90% in the cases of high intensity rainfall events. Runoff coefficient (ratio of total runoff to rainfall amount) is mainly influenced by rainfall amount, rainfall intensity and antecedent soil moisture, and the relationship can be well ex-pressed by a multiple linear regression function a = 0.002P + 0.1821 + 4.88Wa - 0.821. The relation between the rainfall intensity and the lag time of three flows (surface runoff, soil-layer flow and mantel-layer flow) is shown to be exponential. Then, the result also shows that the recession constant is 0.75 for surface runoff, is 0.94 for soil-layer and mantel-layer flow in this area. In this study area, the dominant infiltration excess runoff is simulated by Horton model. About 0.10 mm/min percolation is observed under the condition of different rainfall intensities, therefore the value is regarded as the steady infiltration rate of the study area.