Preface

Fluid flow and sediment transport processes in geomorphology:innovations, insights, and advances in measurement

We live in an era of rapid and innovative techno-logical development. Advances in instrumentationhave allowed researchers to strive for a deeperunderstanding of fundamental geomorphic processes.Recent progress in the measurement and character-ization of fluid flow and sediment transport hasprovided new insight into sedimentary processes andlandform responses. For instance, instruments thatmeasure flow turbulence have allowed for the devel-opment of new and improved models of both sedi-ment transport processes and bedform dynamics. Thisresearch relies on the ability to measure at a hightemporal resolution with increased precision and tocharacterize the three-dimensional components of theflow over a wide range of spatial scales. For example,ultrasonic anemometers are able to measure high-frequency, three-dimensional variations in airflowwhile acoustic Doppler profilers can characterize flowturbulence in rivers over an extensive and continuousspatial field. Geomorphologists now require suchinstruments to improve understanding of these pro-cesses and, increasingly, are involved in designing andtesting new instruments.

Despite the promise that these advances hold, itremains to be seen if such an improvement in thespatial and temporal resolution of measurement willlead to anything more than the collection of extensivesite- or event-specific empirical datasets. Perhaps dueto our relative inexperience with these technologiesand the complexities and limitations of their designs,we continue to learn about what these measurementscontribute to our understanding of geomorphic pro-cesses. There is also a concern that these small-scale

measurements may be difficult to incorporate intomodels of landform- or landscape-scale dynamics atlonger time scales.

This special issue addresses some of these ques-tions and is based on papers presented in three specialsessions held at the 53rd Annual Meeting of theCanadian Association of Geographers (CAG). Themeeting was hosted from 27 to 31 May 2003 by theDepartment of Geography, University of Victoria,British Columbia, Canada, and was cosponsored bythe Canadian Geomorphology Research Group(CGRG). The purpose of these special sessions andan associated instrumentation workshop also heldduring the conference was to present new develop-ments in instrumentation for the study of geomorphicprocesses and to highlight some results obtained fromthese innovative techniques and approaches. Thesessions also emphasized the role of flow turbulencein the dynamics of aeolian and fluvial systems, an areathat has benefited enormously from recent technolog-ical advances. This was a particularly timely endeav-our on the 20th anniversary of Leeder’s (1983)influential work, bOn the interactions between turbu-lent flow, sediment transport and bedform mechanicsin channelized flowsQ. Because much recent progressin aeolian bedform research has drawn uponapproaches derived in the fluvial environment, itwas our intent to bring together researchers from allgeomorphic environments, techniques, and scales ofstudy to stimulate discussion and exchange that mightfurther our understanding of fluid flow, sedimenttransport, and bedform dynamics. Emphasis wasplaced on a critical appraisal of key innovations,

0169-555X/$ - see front matter D 2004 Elsevier B.V. All rights reserved.

doi:10.1016/j.geomorph.2004.09.029

Geomorphology 68 (2005) 1–2

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insights, and advances in measuring and modellingthe dynamics of flow and sedimentary processes ingeomorphic systems.

To this end, the first two papers present new,innovative technologies for measurement of fluid flowand sedimentary processes developed by geomorphol-ogists such as Orwin and Smart’s turbidimeter andLamoureux’s lacustrine sedimentation sensor. Thenext five papers provide critical insight on the useof existing instrumentation and/or models to charac-terize geomorphic processes. Kostaschuk et al. dis-cuss the measurement of flow velocity using anacoustic Doppler profiler and examine the applicationof this instrument to the measurement of sedimenttransport. Pearce and Walker analyze frequency andmagnitude biases in the widely used dFrybergerTaeolian sediment drift potential model. Walker pro-vides an in-depth discussion of the physical andlogistical considerations for using ultrasonic anemom-etry in aeolian research. Critical insights on temporaland spatial considerations in measuring and character-izing flow behaviour in fluvial channels are offered byBuffin-Belanger and Roy and by Lamarre and Roy,respectively. The final two papers present newfindings from very different scales of investigationresulting from recent advances in measurementtechnologies used to characterize aeolian systems.This includes Davidson-Arnott et al.’s event-basedexamination of the effects of wind turbulence,moisture content, and fetch on sand transport overbeaches and Hugenholtz and Wolfe’s regional assess-ment of recent stabilization of Canadian Prairie dunesin response to climate variation using GIS and digitalimage processing. Not only does each of thesecontributions document recent advances in character-izing the dynamics of geomorphic systems andidentify important research gaps and opportunities,

but they also highlight some of the cutting-edgeresearch in process geomorphology that is ongoing inCanada today.

The guest editors managed the review process andwe wish to acknowledge the final editing by RichardMarston. We also extend our gratitude for their cons-tructive reviews on the manuscripts to: Alan Arbogast,Peter Ashmore, Pascale Biron, Joanna Bullard, MikeChurch, Robin Davidson-Arnott, Dirk deBoer, JoeDesloges, Patrick Hesp, Ray Kostaschuck, MichelLapointe, David Muhs, Steven Namikas, Ellen Petti-crew, Colin Rennie, Andre Robert, John van Boxel,Paul Villard, Giles Wiggs, and Steven Wolfe.

References

Leeder, M.R., 1983. On the interactions between turbulent flow,

sediment transport and bedform mechanics in channelized

flows. In: Collinson, J.D., Lewin, J. (Eds.), Modern and Ancient

Fluvial Systems, Special Publication of the International

Association of Sedimentologists, vol. 6, pp. 5–18.

Ian J. WalkerBoundary Layer Airflow and Sediment Transport

(BLAST) Research Unit, Department of Geography,University of Victoria, P.O. Box 3050, Station CSC,

Victoria, BC Canada, V8W 3P5E-mail address: ijwalker@uvic.ca.

Corresponding author. Tel.: +1 250 721 7347;fax: +1 250 721 6216.

Andre G. RoyDepartement de Geographie,

Universite de Montreal, C.P. 6128,Succursale Centre-ville, Montreal, Quebec,

Canada, H3C 3J7

1 September 2004

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