The Journal of Hydraulic Research (JHR) publishes research papers in theoretical, experimental and computational hydraulics and fluid mechanics, relating to rivers, lakes, estuaries, coasts, constructed waterways, and some internal flows such as pipe flows. To reflect current trends in water research, articles that explore outcomes of interdisciplinary hydro-environment studies with a strong fluid mechanical component are especially welcome. Although preference is given to fundamental issues, papers focusing on important unconventional or emerging applications of broad interest are also appreciated.

 Overview

The fourth issue of the Journal of Hydraulic Research comprises one Forum Article, five Research Papers, one Technical Note, one Discussion/Closure, and two book reviews. These original contributions cover a wide range of subjects in hydraulic engineering and employ various approaches, such as analytical, experimental, computational, and combinations thereof.The Forum Article presents the key findings of a workshop that examined the critical role of data collection in assessing and improving the performance of urban drainage systems.
Among the Research Papers, the first contribution – on the role of grain size distribution in spatial dam breaching – is published as open access and inaugurates a new Article Collection entitled Breaching of earthen dam and dike structures: lessons learned from recent field, laboratory and numerical studies. This Collection will be expanded with further papers in the coming months. The other Research Papers in this issue address the development of a method for estimating the sediment transport capacity of a river at the reach scale; the instabilities of flows on half-round circular weirs investigated through physical modelling; the effects of an air-core vortex generated at the inlet of a bulb turbine on internal flow phenomena and its impact on turbine output and efficiency; and the application of an implicit large eddy simulation methodology to assess the influence of channel cross-sectional shape at the entrance of a basin and of the domain slope on gravity current propagation.
The Technical Note examines the dependence of air concentration in self-aerated skimming flow over stepped chutes on flow rate, slope angle, and step height. This issue concludes with reviews of two books: An introduction to advanced fluid dynamics and fluvial processes by B.S. Mazumder and T.I. Eldho, and Non-equilibrium transport of non-uniform suspended load by Q. Han and M. He.
Undoubtedly, these contributions inform both researchers and practitioners about the latest developments on subjects of importance to our profession.

IAHR members can access the latest issue online.
Non IAHR members must access through Taylor & Francis website.

 Forum Paper

The value of urban drainage systems data: facts, discussions and recommendations |
María Alejandra Pimiento, Jesper E. Nielsen, Michael R. Rasmussen, Elodie Brelot, Jean-Luc Bertrand-Krajewski, Alma Schellart, Simon Tait, Thomas Brüggemann, Francois Clemens-Meyer, Jörg Rieckermann, João P. Leitão, Andrea Ciambra, Juan Naves and Jose Anta
Pages: 417-424 | DOI: 10.1080/00221686.2025.2528652

 Article Collection: Breaching of earthen dam and dike structures: lessons learned from recent field, laboratory and numerical studies

Composite modelling of non-cohesive homogeneous spatial dam breaches with varied grain size distributions |
Matthew C. Halso, Frederic M. Evers, Robert M. Boes and David F. Vetsch
Pages: 425-444 | DOI: 10.1080/00221686.2025.2516783

 Research Papers

A novel method of reach-scale sediment transport capacity calculation and its application in the Lower Yellow River
Meirong Zhou, Junqiang Xia, Xiangyang Ge and Cheng Yifei
Pages: 445-458 | DOI: 10.1080/00221686.2025.2519318

Hydraulic modelling of instabilities on half-round circular weirs at three scales |
Hubert Chanson
Pages: 459-472 | DOI: 10.1080/00221686.2025.2532522

Effects of air-core vortex on the hydraulic instability of a bulb turbine
Zhixiang Li, Zixuan Yang, Huixiang Chen, Hui Xu, Shangtuo Qian and Kan KanPages: 473-488 | DOI: 10.1080/00221686.2025.2521355

Numerical simulation of gravity currents considering the effect of variable channel geometry on basin entrance
Karina Ruschel, Bruno Avila Farenzena, Bruno Alvarez Scapin, Sara María Mata Sosa, Jorge Hugo Silvestrini and Guilherme Fuhrmeister Vargas
Pages: 489-502 | DOI: 10.1080/00221686.2025.2519384 

 Technical Note

Predicting air concentration in self-aerated skimming flow over stepped chutes of varying slopes and step heights
Zhong Tian, Zhongtian Bai, Ruidi Bai, Hang Wang, Jingjie Feng, Shanjun Liu and Faxing Zhang
Pages: 503-513 | DOI: 10.1080/00221686.2025.2507904

 Discussion

Discussion of ‘Vertical slot fishway design for fluctuating water-level reservoir’ By Tiegang Zheng, Chengyi Tu, Zhiguang Zhang, Shuangke Sun, Huichao Dai, Guangning Li and Haitao Liu, Journal of Hydraulic Research, 63(1), 117–125. https://doi.org/10.1080/00221686.2024.2436917
Weiyang Zhao, Zhipan Niu and Qi Zhang
Pages: 514-515 | DOI: 10.1080/00221686.2025.2515847

 Closure

Closure to ‘Vertical slot fishway design for fluctuating water-level reservoir’ By Tiegang Zheng, Chengyi Tu, Zhiguang Zhang, Shuangke Sun, Huichao Dai, Guangning Li and Haitao Liu, Journal of Hydraulic Research, 63(1), 117–125. https://doi.org/10.1080/00221686.2024.2436917
Tiegang Zheng, Chengyi Tu, Zhiguang Zhang, Shuangke Sun, Huichao Dai, Guangning Li and Haitao Liu
Pages: 516-517 | DOI: 10.1080/00221686.2025.2516777

 Book Reviews

An introduction to advanced fluid dynamics and fluvial processes

by B. S. Mazumder and T. I. Eldho, Boca Raton, London, New York, CRC Press, Taylors and Francis Group, 2023, 660 pp.,
Luca Solari
Pages: 518-519 | DOI: 10.1080/00221686.2025.2539314

Non-equilibrium transport of non-uniform suspended load
by Qiwei Han and Mingmin He, Springer Nature, Singapore, 2024, 673 pp., 
Maohua Le
Pages: 519-520 | DOI: 10.1080/00221686.2025.2537958