An improved nonstationary model for flood frequency analysis and its implication for the Three Gorges Dam,China |
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| Authors: | Qianjin Dong Xu Zhang Upmanu Lall Yan-Fang Sang |
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| Institution: | 1. State Key Laboratory of Water Resources and Hydropower Engineering Science, Wuhan University, Wuhan, China;2. Hubei Provincial Key Lab of Water System Science for Sponge City Construction, Wuhan University, Wuhan, China;3. Columbia Water Center, Columbia University, New York, New York, USA;4. Key Laboratory of Water Cycle and Related Land Surface Processes, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China |
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| Abstract: | This study proposes an improved nonstationary model for flood frequency analysis by investigating the relationship between flood peak and flood volume, using the Three Gorges Dam (TGD), China, for verification. First, the generalized additive model for location, scale and shape (GAMLSS) is used as the prior distribution. Then, under Bayesian theory, the prior distribution is updated using the conditional distribution, which is derived from the copula function. The results show that the improvement of the proposed model is significant compared with the GAMLSS-based prior distribution. Meanwhile, selection of a suitable prior distribution has a significant effect on the results of the improvement. For applications to the TGD, the nonstationary model can obviously increase the engineering management benefits and reduce the perceived risks of large floods. This study provides guidance for the dynamic management of hydraulic engineering under nonstationary conditions. |
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| Keywords: | nonstationary model flood frequency analysis copula function teleconnection Three Gorges Dam China |
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