EARTH SURFACE PROCESSES AND LANDFORMS Earth Surf. Process. Landforms 35, 64–77 (2010) Copyright © 2009 John Wiley & Sons, Ltd. Published online 29 June 2009 in Wiley InterScience (www.interscience.wiley.com) DOI: 10.1002/esp.1838 John Wiley & Sons, Ltd. Chichester, UK ESP Earth Surface Processes and Landforms EARTH SURFACE PROCESSES AND LANDFORMS Earth Surface Processes and Landforms The Journal of the British Geomorphological Research Group Earth Surf. Process. Landforms 0197-9337 1096-9837 Copyright © 2006 John Wiley & Sons, Ltd. John Wiley & Sons, Ltd. 2006 Earth Science Earth Science 9999 9999 ESP1838 Research Article Research Articles Copyright © 2006 John Wiley & Sons, Ltd. John Wiley & Sons, Ltd. 2006 State of Science Experimentation at the interface of fluvial geomorphology, stream ecology and hydraulic engineering and the development of an effective, interdisciplinary river science Interdisciplinary experiments and integrated river science Stephen P. Rice, 1 Jill Lancaster 2 and Paul Kemp 3 1 Department of Geography, Loughborough University, Leicestershire, UK 2 Institute of Evolutionary Biology, University of Edinburgh, Ashworth Labs, Edinburgh, UK 3 School of Civil Engineering & the Environment, University of Southampton, Southampton, UK Received 12 August 2008; Revised 8 March 2009; Accepted 27 April 2009 * Correspondence to: Stephen Rice, Department of Geography, Loughborough University, Leicestershire LE11 3TU, UK. E-mail: S.Rice@lboro.ac.uk ABSTRACT: One ‘2020 vision’ for fluvial geomorphology is that it sits alongside stream ecology and hydraulic engineering as a key element of an integrated, interdisciplinary river science. A challenge to this vision is that scientists from these three communities may approach problems from different perspectives with different questions and have different methodological outlooks. Refining interdisciplinary methodology is important in this context, but raises a number of issues for geomorphologists, ecologists and engineers alike. In particular, we believe that it is important that there is greater dialogue about the nature of mutually-valued questions and the adoption of mutually-acceptable methods. As a contribution to this dialogue we examine the benefits and challenges of using physical experimentation in flume laboratories to ask interdisciplinary questions. Working in this arena presents the same challenges that experimental geomorphologists and engineers are familiar with (scaling up results, technical difficulties, realism) and some new ones including recognizing the importance of biological processes, identifying hydraulically meaningful biological groups, accommodating the singular behaviour of individuals and species, understanding biological as well as physical stimuli, and the husbandry and welfare of live organisms. These issues are illustrated using two examples from flume experiments designed (1) to understand how the movement behaviours of aquatic insects through the near-bed flow field of gravelly river beds may allow them to survive flood events, and (2) how an understanding of the way in which fish behaviours and swimming capability are affected by flow conditions around artificial structures can lead to the design of effective fish passages. In each case, an interdisciplinary approach has been of substantial mutual benefit and led to greater insights than discipline-specific work would have produced. Looking forward to 2020, several key challenges for experimentalists working on the interface of fluvial geomorphology, stream ecology and hydraulic engineering are identified. Copyright © 2009 John Wiley & Sons, Ltd. KEYWORDS: flume experiments; ecohydraulics; macro-invertebrates; refugia; fish passage Introduction The fascinating scientific arena in which fluvial geomorphology and river hydraulics meet stream ecology is of growing strategic as well as academic interest. Fluvial geomorphologists and hydraulic engineers recognize the importance of in-stream and riparian ecological processes for understanding sediment fluxes, water flow and land-forming processes at a variety of scales (e.g. Millar, 2000; Gottesfeld et al., 2004; Butler and Malanson, 2005; Cotton et al., 2006; Johnson et al., 2009). Equally, ecologists have long recognized the importance of open-channel hydraulics, sediment stability and the other processes that provide and maintain channel morphology, for understanding the distribution and behaviour of aquatic organisms (e.g. Minshall, 1984; Newbury, 1984; Statzner et al., 1988; Hart and Finelli, 1999; Lancaster, 2008). Research at this interface is not new; ecologists and biologists have been interested in physical–biological coupling in streams for 100+ years, as indicated by early work on insects (Steinmann, 1907, 1908) and on fish (Hora, 1922) (see Statzner, 2008, for a historical review). However, scientific and methodological advances in recent decades have lead to disciplinary specializa- tion and polymaths are becoming rare, so future research in this field is likely to be carried out by collaborative teams rather than by individuals. There is widespread recognition that such interdisciplinary effort is likely to yield substantial benefits (e.g. Palmer and Bernhardt, 2006; Vaughan et al., 2009), but it is also apparent