水电梯级开发的水资源效率及节水效应

The water resource efficiency and water-saving effect of cascade hydropower development

【目的】揭示水电梯级开发过程中其水资源效率的演变规律,以提升水电梯级开发的水资源效率来促进节水开发。【方法】本文构建1996—2020年间中国22条流域水电开发的面板数据,共纳入331座大中型水电站,运用固定效应与调节效应模型,分析水电梯级开发规模对流域水资源效率的影响,并检验开发模式在该影响过程中的调节机制。【结果】研究发现:(1)随着水电梯级开发规模增长,水资源效率呈先下降后上升的U型变化趋势。(2)针对该U型相关关系,集约性开发模式与多样性开发模式都发挥正向调节作用,且多样性开发模式的调节效应更强。(3)流域水资源禀赋与水电梯级开发的水资源效率间呈正相关关系,相比集约性开发模式,多样性开发模式更有利于加强这种正相关关系。【结论】上述结果证明了水电梯级开发能节水,但只有当开发规模超过59%的阈值后,节水效果才稳定且明显。为促进节水开发,在梯级开发起始阶段,宜推广集约性开发模式;当开发规模超过阈值后,宜推广多样性开发模式;径流资源禀赋越稀缺,越应实行多样性开发模式。

[Objective]The aim of this study was to reveal the pattern of change of water resource efficiency in cascade hydropower development,in order to improve the water resource efficiency of cascade hydropower development and promote water-saving development.[Methods]We employed the panel data of 22 hydropower development basins in China from 1996 to 2020,including 331 large and medium-sized hydropower stations.Using fixed effects and moderating effects models,this study analyzed the impact of the cascade hydropower development scale on its water resource efficiency,and tested the moderating mechanism of the development mode in the process.[Results]This research found that:(1)With the increase of cascade hydropower development scale,water resource efficiency showed a U-shaped trend of decreasing first and then increasing.(2)For the U-shaped correlation between cascade hydropower development scale and water resource efficiency,intensive development mode and diverse development mode all had a positive moderating effect,and diverse development mode showed a stronger positive moderating effect.(3)There was a positive correlation between basin water resource endowment and water resource efficiency of cascade hydropower development,and the diverse development mode was more conducive to strengthening this positive correlation when comparing with the intensive development mode.[Conclusion]These results prove that watershed cascade hydropower development can save water,but only when the development scale exceeds the threshold of 59%,the water-saving effect is stable and obvious.In order to promote water-saving development,intensive development mode should be implemented in the initial stage of cascade development,the diverse development mode should be implemented when the development scale exceeds the threshold,and the diverse development mode is more suitable for the rivers where water resource is scarce.