Discussion of 'Reservoir-Induced Changes in Flow Fluctuations at Monthly and Hourly Scales: Case Study of the Qingyi River, China' by Feng Huang, Qihui Chen, Fan Li, Xiao Zhang, Yunyun Chen, Ziqiang Xia, and Liying Qiu

摘要

Reservoirs are one of the most efficient tools for integrated water resources development and management. More attention is focused on improving the operational effectiveness and efficiency of existing reservoir systems (Labadie 2004). Reservoir operation influences the natural hydrological regime, riverbed development, water environment, and water ecology. Understanding how reservoir operation influences a river would help to enhance the reservoirs' operating level. The authors took the Qingyi River as a case study and revealed how the reservoir operation influenced the flow fluctuations at monthly and hourly scales. The C_v and C_d differences between postdam and predam conditions demonstrated that reservoirs usually mitigate the monthly flow fluctuation. Two opposite patterns exist for the reservoir's influence on hourly flow fluctuation: (1) it mitigates the hourly flow in flood seasons; and (2) it aggravates it by releasing hydropeaking waves when there is no risk of flood. In addition, the hydropeaking waves superimpose an artificial diurnal period, which is of some uncertainty, on the downstream flow regime. The authors' detailed analysis helps readers to systematically understand the mechanism of how reservoir operation influences the monthly and hourly flow fluctuations.