the International Association of Geomorphology (IAG) held its fourth International Conference on Geomorphology (ICG) at Bologna, Italy. The conference is held every four years and since the inaugural meeting in Manchester in 1985 it has established itself as a benchmark event in the lives of academic and practising geomorphologists worldwide. The significance of the IAG conference can be illustrated by reference to just a few indicative statistics. The Bologna conference attracted 969 registered participants from 72 countries. They presented several hundred papers (20 per cent verbal presentations, 80 per cent posters) in 10 Thematic Sessions, eight Symposia and one Workshop. Additionally, there were postconference excursions and both the IAG Council and its General Assembly held meetings that moved forward the business of the Association. Very large conferences tend to be excessively ceremonial, to be punctuated by too many self-congratulatory bun fights and self-effacing plenary lectures, and to be memorable mostly for the frustration caused by having parallel technical sessions with annoying clashes of interest. The Bologna ICG managed to avoid most of these pitfalls and where it didn't it wrapped them up in a culture and ambience that was so palatable and satisfying that nobody noticed them anyway.
There was, for many years, an unfilled niche for a high-profile multinational geomorphology conference and, in our opinion, the IAG should be congratulated for filling that niche successfully and, in the process, promoting the international dimension of geomorphology. Of course, a meeting on the scale of the ICG can never satisfy all the legitimate expectations of the geomorphological community and important roles remain for the conference series convened by the national associations, research groups and the professional societies with which geomorphologists are affiliated.
The papers presented in this Special Issue of Earth Surface Processes and Landforms are drawn from the session on Fluvial Geomorphology at Bologna. This was one of the larger sessions with over 69 posters and four presentations during a double-length time slot in the programme. Contributions were made by authors from 24 countries and covered a vast array of topics. Prominent themes included catchment and channel sediment dynamics, fluvial hydraulics, bank mechanics, morphological evolution and response of the fluvial system to environmental change and human impacts.
The general theme of sediment dynamics and transport processes received the most attention, with papers and posters presenting results from field investigations, laboratory flume studies and theoretical analyses. Several posters investigated coupled slopeΒ±channel systems and particular emphasis was placed on seasonal adjustments in alluvial fans. The still intriguing issue of the downstream fining of the bed material grain size was addressed, as well as interactions between sediment size and both channel and floodplain morphology. Linking fluvial processes and channel morphology was also a popular topic. New light was cast on the physical processes affecting bank and channel stability, and the effect of micro-and macro-bedforms on turbulent flow structures and channel morphology.