Open AccessArticle
Multiple Changes in the Hydrologic Regime of the Yangtze River and the Possible Impact of Reservoirs
by
Feng Huang 1,2,*, Nan Zhang 3, Xirong Ma 4, Dayong Zhao 1,2, Lidan Guo 5, Li Ren 1,2, Yao Wu 1,2 and Ziqiang Xia 1,2
1
State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, Hohai University, Nanjing 210098, China
2
Department of City Resources and Environment, College of Hydrology and Water Resources, Hohai University, Nanjing 210098, China
3
Yellow River Institute of Hydraulic Research, Zhengzhou 450003, China
4
The Pearl River Hydraulic Research Institute, Guangzhou 510611, China
5
International River Research Centre, Hohai University, Nanjing 210098, China
Cited by 9 | Viewed by 6194
Abstract
This paper investigates hydrologic changes in the Yangtze River using long-term daily stream flow records (1955–2013) collected from four flow gauging stations located from the upper to the lower reaches of the river. The hydrologic regime is quantified using the Indicators of Hydrologic
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This paper investigates hydrologic changes in the Yangtze River using long-term daily stream flow records (1955–2013) collected from four flow gauging stations located from the upper to the lower reaches of the river. The hydrologic regime is quantified using the Indicators of Hydrologic Alteration, which statistically characterize hydrologic variation within each year. Scanning
t-test is applied to analyze multiple changes in the hydrologic regime at different time scales. Then, coherency analysis is applied to identify common changes among different hydrologic indicators and across different reaches of the Yangtze River. The results point to various change patterns in the five components of hydrologic regime, including the magnitude of monthly water conditions, magnitude and duration of annual extreme water conditions, timing of annual extreme water conditions, frequency and duration of high and low pulses, and rate and frequency of water condition changes. The 32 hydrologic indicators feature multiple temporal-scale changes. Spatial variations can be observed in the hydrologic changes of the upper, middle, and lower reaches of the river. Common changes in different reaches consist of hydrologic indicators including the monthly flow in October and the low-flow indicators. The monthly flow in October is dominated by decreasing trends, while the monthly flows between January and March, the annual minimum 1/3/7/30/90-day flows, and the base flow index are characterized by increasing trends. Low pulse duration and total days of low pulses feature downward trends. The coherency analysis reveals significant relationships between the monthly flow in October and the low-flow indicators, indicating that reservoir regulation is an important factor behind the hydrologic changes.
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