Discussion of 'Impact of the Sanmenxia and Xiaolangdi Reservoirs Operation on the Hydrologic Regime of the Lower Yellow River' by Yunyun Li, Jianxia Chang, Huan Tu, and Xuebin Wang

摘要

Because reservoirs are one of the most efficient ways to alleviate water disasters caused by droughts or floods and take advantage of any excess water for profit regulation (Chen et al. 2016), more attention is being paid to improving the effectiveness and efficiency of reservoir operation (Labadie 2004). The way a reservoir operates generally has a great influence on the downstream flow regime (Huang et al. 2011), water temperature regime (Casado et al. 2013), and sediment transportation (Yang et al. 2006). Research on the extent to which cascade reservoirs affect a hydrological regime is of great significance. In order to evaluate changes to the hydro-logical regime of the lower Yellow River, the authors employed a range of variability approach to analyze the degree of change observed in 33 indicators of hydrologic alteration for different modes of operation of the Sanmenxia and Xiaolangdi reservoirs. Their results showed that the comprehensive degree of hydrologic alteration (D_o) was 69 and 84% in single- and joint-operation mode, respectively. Additionally, both modes belonged to the high-change group. Therefore, the authors inferred that the operation of these two reservoirs has a significant impact on the hydrological regime of the lower Yellow River, and that the impact of joint operation on the river's hydrological regime is more serious than that of single operation. Furthermore, the characteristics of the ecohydrological variation in the lower Yellow River were also analyzed. The systematic analysis provided by the authors may help readers understand the impact of single and cascade reservoir operation on hydrological regimes and the characteristics of the ecohydrological variation.