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Reservoir-Induced Changes in Flow Fluctuations at Monthly and Hourly Scales: Case Study of the Qingyi River, China
AbstractReservoirs play an important role in modifying the natural hydrological regime. Reservoir-induced changes in flow fluctuations at monthly and hourly scales were analyzed through a case study of a tributary of the Yangtze River (China), the Qingyi River, where the Chencun reservoir is located at the upper reaches. Monthly and hourly flow data were collected from two flow gauging stations monitoring the inflow and outflow regimes, respectively. The flow fluctuations were characterized by coefficient of variation (CV) and concentration degree (Cd). Continuous Morlet wavelet transform was applied to detect diurnal period. The influence of the reservoir was revealed comparing the postdam with the predam conditions by and comparing the affected with the natural conditions. The results indicate two opposite change patterns. Reservoir impoundment may mitigate flow fluctuations at both of the monthly and the hourly scales. At a monthly scale, reservoirs usually impound water in the flood season for the dry season. At an hourly scale, reservoirs may restrain a flood pulse and strictly control the outflow. Thus, the reservoirs reduce variation and concentration of the runoff distribution within a year and within a day. In contrast, the reservoirs may aggravate the hourly flow fluctuation by releasing hydropeaking waves for hydropower generation and superimpose a diurnal period to the downstream flow regime. But the artificial diurnal fluctuation is of some uncertainty in terms of appearance time and duration. This work may deepen the understanding of the reservoirs influence mechanism on the downstream flow regime.
Reservoir-Induced Changes in Flow Fluctuations at Monthly and Hourly Scales: Case Study of the Qingyi River, China
AbstractReservoirs play an important role in modifying the natural hydrological regime. Reservoir-induced changes in flow fluctuations at monthly and hourly scales were analyzed through a case study of a tributary of the Yangtze River (China), the Qingyi River, where the Chencun reservoir is located at the upper reaches. Monthly and hourly flow data were collected from two flow gauging stations monitoring the inflow and outflow regimes, respectively. The flow fluctuations were characterized by coefficient of variation (CV) and concentration degree (Cd). Continuous Morlet wavelet transform was applied to detect diurnal period. The influence of the reservoir was revealed comparing the postdam with the predam conditions by and comparing the affected with the natural conditions. The results indicate two opposite change patterns. Reservoir impoundment may mitigate flow fluctuations at both of the monthly and the hourly scales. At a monthly scale, reservoirs usually impound water in the flood season for the dry season. At an hourly scale, reservoirs may restrain a flood pulse and strictly control the outflow. Thus, the reservoirs reduce variation and concentration of the runoff distribution within a year and within a day. In contrast, the reservoirs may aggravate the hourly flow fluctuation by releasing hydropeaking waves for hydropower generation and superimpose a diurnal period to the downstream flow regime. But the artificial diurnal fluctuation is of some uncertainty in terms of appearance time and duration. This work may deepen the understanding of the reservoirs influence mechanism on the downstream flow regime.
Reservoir-Induced Changes in Flow Fluctuations at Monthly and Hourly Scales: Case Study of the Qingyi River, China
Chen, Qihui (author) / Xia, Ziqiang / Li, Fan / Huang, Feng / Chen, Yunyun / Zhang, Xiao / Qiu, Liying
2015
Article (Journal)
English
| British Library Online Contents | 2015