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Advancing frequency analysis of nonstationary hydrological extremes for reducing flood risk in a changing climate

Partners and participants in the project carried out an excursion in 2019 from Wuhan City to Yichang City (Three Gorges Dam site), China. This is a group photo taken in Yichang City. Photo: Private.

Partners and participants in the project carried out an excursion in 2019 from Wuhan City to Yichang City (Three Gorges Dam site), China. This group photo is taken in Yichang City. Photo: Private.

About the project

Flood frequency analysis (FFA) is one of the cornerstones in the planning, design and management of hydraulic projects for flood control and water usages. The project relates to Norway's strategy shift toward sustainable development and global environmental protection. In the past decades, global climate change and/or large-scale human activities have significantly changed the characteristics of the hydrological extremes, such as floods. This change has made the traditional methods of flood frequency analysis powerless, and hydraulic structures designed based on conventional methods may not provide the assumed level of protection.

Numerous lessons have been learnt about the failure of hydraulic structures related to climate change or changing characteristics of flood series. The research project is built on the current-state-of-the-art of hydrological analysis in a changing environment and on the extensive experience of the applicants in the field.

The primary objective of the project is to improve methodologies of hydrological frequency analysis for non-stationary hydrological extremes, with the ultimate goal to support future water resources management strategies and hydraulic engineering design. The key user groups (stakeholders) are the hydropower industry, river basin management society, and authorities (both national and local), who are responsible for planning, design and operation of hydropower reservoirs, for adaptation to climate change in planning of land use and infrastructure at various levels, and for flood forecasting, prevention, protection, floodplain mapping and mitigation, etc.


In this project we aim to expand current knowledge of non-stationary hydrological frequency analysis by incorporating original thinking and scientific renewal. A goal is also to develop an integrated frequency analysis approach incorporating nonstationarity and uncertainty for hydrological design and sustainable water resources management. The secondary objectives are:

  1. Assessment of the concepts and inference procedures involved in nonstationarity analysis of hydrological extremes and their relationship with stationary concepts.
  2. Development and evaluation of frequency analysis approaches incorporating nonstationarity and uncertainty, and emphasis will be paid on the role of uncertainty in stationary and nonstationary models.
  3. Evaluate the practical use of the resulting approach and quantitatively highlight the difference and operational difficulties of moving from stationary to nonstationary frequency analyses facing with real-world applications.


During the project period 2018 – 2019, various activities have been implemented effectively, which include visiting Norwegian and Chinese hydropower stations, construction of database from selected world large rivers, evaluation of methods for detection of the non-stationarity of hydrological extremes, discussion of the research results with the stakeholders in Norway and in China, attending and presenting research results at international conferences, writing and publication of high quality scientific articles in international top journals, etc. Above activities have resulted in 9 publications in international journal, 4 talks at international conferences, 3 invited lectures at regional training programs and workshops.

More results from the project listed here ...

A regional training course with trainees from southern African countries is currently under planning with the support and help of the University of Malaw, and will be organised at University of Malawi in spring 2022. The training course will provide an opportunity for the young hydrologists in the region to learn:

  1. how to detect the nonstationarity of hydrological time series,
  2. how to do frequency analysis of stationary and nonstationary hydrological processes. 


Full name of the project is 'Advancing frequency analysis of nonstationary hydrological extremes for reducing flood risk in a changing climate'.

The project is financed through The Research Council of Norway (NFR) in the FRIPRO funding scheme for independent projects programme with NFR-project number 274310.

The project started in 2018, and have an ending in 2023.


The project is a cooperation with several universities from across five continents and several Norwegian research institutions. The project partners are these:


View all works in Cristin

  • Wang, Weiguang; Chen, Lu & Xu, Chong-Yu (2021). Editorial: Hydrological Modeling in Water Cycle Processes. Water. ISSN 2073-4441. 13(14). doi: 10.3390/w13141882. Full text in Research Archive
  • Qi, Wenyan; Chen, Jie; Li, Lu; Xu, Chong-Yu; Xiang, Yiheng & Zhang, Shaobo [Show all 7 contributors for this article] (2021). Impact of the number of donor catchments and the efficiency threshold on regionalization performance of hydrological models.
  • Wan, Yongjing; Chen, Jie; Xie, Ping; Xu, Chong-Yu & Li, Daiyuan (2021). Evaluation of climate model simulations in representing the precipitation non-stationarity by considering observational uncertainties.
  • Zhou, Yanlai; Xu, Chong-Yu; Ngongondo, Cosmo & Li, Lu (2021). Detection, attribution and frequency analysis of non-stationary flood peaks in 32 big rivers worldwide.
  • Li, Hong; Xu, Chong-Yu; Sæthun, Nils Roar; Braskerud, Bent Christen & Volden, Erland Per (2019). Identification of floodways by four approaches.

View all works in Cristin

Published Feb. 27, 2020 2:35 PM - Last modified Sep. 16, 2022 12:43 PM


Chong-Yu Xu, Professor and Project leader

Int. Advisory Board:

  • Vijay P Singh,Texas A&M University, USA
  • Nils Roar Sælthun, UiO
  • Sharad K. Jain, National Institute of Hydrology, India
  • Shenglian Guo, Wuhan University
  • Stein Beldring, NVE