北洛河上游植被恢复对河川径流组分影响的定量区分

Quantitative discrimination of impacts of vegetation restoration on runoff components in the upper reaches of the Beiluo River

  • 摘要: 植被恢复和气候变化对半干旱黄土区径流及其组分的定量贡献仍不明确。采用弹性系数法定量探讨了植被恢复和气候变化对北洛河上游吴旗、志丹、刘家河水文站径流深及其组分变化的贡献。结果表明:1970—2010年间,3站径流深、地表径流深均呈显著减少趋势,地表径流占总径流的45%~56%,各站基流深变化趋势不一致,突变点均在2002—2003年;1999年以来北洛河上游林草地面积占比增加15.1%,且以林地为主;植被恢复、降水和潜在蒸散发对3站径流深减少的平均贡献率分别为73%、19%和8%,对地表径流深变化的平均贡献率为67%、19%和14%,且植被恢复程度越好其贡献率越大。良好的植被恢复显著减少河川径流、地表径流,但可能增加基流,研究结果可为该区水资源开发利用提供依据。

     

    Abstract: Quantitative contribution of vegetation restoration and climate change to changes in runoff and its components is largely unknown in semi-arid loess areas. The effect of vegetation restoration and climate change on runoff and its components was evaluated using the elasticity coefficient method for the Beiluo River at Wuqi, Zhidan, and Liujiahe stream gauging stations. Surface and total runoff showed significant decreasing trends at these three stations from 1970 to 2010, surface runoff accounts for 45% to 56% of total runoff; abrupt changes all occurred around 2002—2003. Changes in baseflow on the other hand were not consistent among the three stations. Forest and grassland areas in the upper Beiluo River Basin has increased by 15.1% since 1999. Contributions of vegetation restoration, precipitation, and the potential evapotranspiration to the reduction in total runoff at the three stations were 73%, 19%, and 8%, respectively, on average; and the average contribution to changes in surface runoff were 67%, 19%, and 14%, respectively. The greater the extent of vegetation restoration, the greater its contribution to changes in runoff. Vegetation restoration can significantly reduce surface runoff and total runoff, but may increase the baseflow at the same time. This research has implications for developing and managing water resources for the region.

     

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