黄土高原昕水河流域径流变化归因定量分析

Attribution of Runoff Change for the Xinshui River Basin in the Loess Plateau of China

近几十年来,黄土高原昕水河流域实测径流量减少显著,对区域生态环境及用水安全造成严重影响。采用水文模拟途径,还原了天然径流量系列,在此基础上,定量评估了气候要素和水土保持等人类活动对河川径流量的影响。结果表明,考虑融雪过程的水量平衡模型对昕水河流域径流量具有较好的模拟效果,率定期及检验期Nash-Sutcliffe确定性系数均在70%以上,模拟的相对误差也小于3%。径流量系列自1966年发生了较为明显的变化,1966—2010年流域径流量深较前期减少29.2mm,其中,包括流域水土保持措施的人类活动对河川径流量变化的影响约站49.3%,气候要素变化的影响略微偏高,约占50.7%。因此,在未来流域治理及生态文明建设中,气候要素变化对流域水文水资源的影响必须引起足够的重视。

The recorded runoff of the Xinshui River has experienced significant declining trend during the past decades, which has taken a huge challenge to local ecological environment restoration and utilization of water resources. Runoff series was naturalized by using hydrological simulation approach, impacts of climate change and human activities, including soil and water conservation measures implementation, were then ana- lyzed. Results show that SWBM model performs well for monthly discharge simulation, Nash-Sutcliffe coef- ficients for calibration and verification periods are both above 70%, while relative errors are less than 5 %. The recorded abrupt change of runoff series has occurred since 1966. Runoff depth over the basin in 1966— 2010 reduced by 29. 2 mm as compared to that in previous period, in which human activities contributed 49.3% of total runoff reduction, while climate change contributed to 50.7%. Therefore, impact of climate change on hydrology and water resources of the Xinshui River basin should be attracted sufficient attention with respect to soil and water conservation and ecological civilization construction.