Abstract
The International Association of Hydrological Sciences (IAHS) celebrated its centennial in 2022 during the 11th Scientific Assembly held over 29 May–3 June in Montpellier(France); and is celebrating in 2024 a century of publications. This volume materializes the proceedings of the 2022 Assembly and marks the anniversary of the long-term publi cation dynamics, with articles tackling very actual problems and questions, from across many countries of the World. The International Association of Hydrological Sciences/Association Internationale des Sciences Hydrologiques (IAHS) was created in 1922 in Rome (Italy) in the form of the International Section of Scientific Hydrology/Section Internationale d’Hydrologie Scientifique of the International Union of Geodesy and Geophysics/Union Internationale de Géodésique et Géophysique (IUGG), itself member of the International Research Council/Conseil International de Recherches both created in 1919 in Brussels (Belgium) (Nature, 1928; Schroeder-Gudehus, 2014, Ismail zadeh and Joselyn, 2019) (Names in French language are kept here as it was the language used for the proceedings at the time). The IAHS developed over a century as described by osbjerg and Rodda (2019), alongside the parent IUGG (Joselyn and Ismail-Zadeh, 2019; Joselyn et al., 2019) and sister learned societies (including the emergence in 2007 of the international Association of Cryospheric Sciences (IACS); Allison et al., 2019) and with strong partnerships in the United Nations system, in particular with UNESCO IHP and WMO (see e.g. Young et al., 2015a, b; Dixon et al., 2022). The records of the first plenary meeting of the Section in 1924 shaped the first volume of the Section’s bulletin (Sec-tion Internationale d’Hydrologie Scientifique, 1924), which then became the Red Book series in 1951 with volume 32 (where the red colour was first used to highlight the cover)