HYDROLOGICAL PROCESSESHydrol. Process. 15, 159–161 (2001)

BOOK REVIEW

Changing a winning formula: the hydraulics of openchannel flow: an introduction

By Hubert Chanson,1999

Arnold, 495 pp.ISBN 0-340-74067-1Co-published in North, Central andSouth America by WileyISBN 0-470-36103-4

Reviewed by:Paul BatesSchool of Geographical Sciences,University of Bristol, UK

Tradition and change in the teaching of open channel flowAt first sight, one wonders whether there is a gap in the market place foran open channel hydraulics textbook given the still dominant positionof such classic works as those by Ven Te Chow (1959) or RichardFrench. Despite being published almost 50 years ago, I still find myselfreferring back to Chow for basic information that one cannot so readilyfind elsewhere. To date, alternative volumes to Chow and French havetended to follow a very similar path through the subject (why changea winning formula?), but this very homogeneity repeatedly sends oneback to the original sources. Nevertheless, the field of hydraulics haschanged enormously in the intervening years, and an attempt to producea modern open channel flow text is thus timely.

Much recent change in hydraulics has been stimulated by the interestshown in the subject by academics outside the civil engineering fieldwhich has been its traditional home. This has been primarily the resultof two distinct forces. First, the growth of numerical hydraulic modellingand the availability of sufficient computing power has opened up asubject previously dominated by physical modelling and its attendantneed for large-scale laboratory infrastructure. Such facilities were rarelyfound outside Civil Engineering Departments and Hydraulic Institutes,and this impacted on who was able to conduct hydraulics research. Itis now possible to conduct sophisticated experiments in hydraulics on adesktop PC running commercial CFD software, and the incorporation ofsuch technologies into the environmental sciences has been a dominanttheme of the last decade. For example, geomorphologists have becomeincreasingly interested in hydraulics (e.g. Wiele et al., 1996; Lane et al.,1999; Hardy et al., 2000) as a way of connecting short-term flowprocesses with landform creation over much longer time scales. Thisability to connect cause and effect in geomorphology in a way nothitherto possible has fundamentally changed our approach in this fieldand is beginning to filter strongly into PhD programmes and to a lesserextent onto undergraduate curricula. Similarly sophisticated flow modelsare beginning to be used in ecology for habitat modelling (e.g. Crowderand Diplas, 2000) and in hydrology to attempt to understand the spatialvariability in floodplain water and solute transfers (e.g. Stewart et al.,1998) and connections between hillslope hydrology and channel flow(e.g. Stewart et al., 1999). A second force for change has been therise of environmentally sensitive river engineering and the resultantinvolvement of ecologists and geomorphologists in design projects

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P. BATES

that were traditionally the preserve of the hydraulicengineer.

Whilst at a research level the hydraulics commu-nity has become increasingly diverse, undergraduatecourses in hydraulics (and consequently text books)are still largely dominated by a civil engineeringapproach. For this reason open channel flow textshave tended to follow the structure of Chow’s volumein what could be thought of as the ‘classical’ modelfor this type of book. Flow physics, numerical mod-elling and environmentally sensitive design are littlecovered in such volumes, and the focus is on flowclassification, basic one-dimensional flow equationsfor steady and gradually varied flow and design ofhydraulic structures. Sediment transport and disper-sion modelling are rarely considered (the book byChadwick and Morfett, 1998 is an exception here).From a numerical modelling point of view the physicscovered in such texts does not provide a sufficientcoverage of fluid mechanics and such processes asflow turbulence to allow research level papers onhigher dimensional models to be interpreted by stu-dents. Further, the treatment of modelling techniques,numerical analysis and model conceptual issues islimited. In terms of environmental engineering, thedesign of weirs and spillways probably still representsthe tasks a practising hydraulic engineer would mostroutinely be called on to perform. Nevertheless, forundergraduate courses in the geosciences such mate-rial is pretty much wasted. Further, environmentallysensitive engineering requires a holistic treatment offlow and sediment transport that the classical openchannel flow book does not provide.

Hubert Chanson’s book meets some, but not all,of the needs for an open channel text in environ-mental hydraulics. It is split into four sections ofroughly equal weight. Basic principles of open chan-nel hydraulics are introduced in the opening sectionand then the topics of sediment transport, hydraulicmodelling (both physical and numerical) and designof hydraulic structures are introduced in turn. In termsof a civil engineering undergraduate market this isabout right, and the book is a worthy alternative tomore traditional texts. For the geoscientist the bookmay be more useful than most of its competitors.For example, the coverage of flow physics com-mences (properly) with the Navier–Stokes equations,although more on flow turbulence would be extremelyuseful. Whether discussing hydraulics or sediment

transport, each section is structured in a highlylogical manner. Physical properties are discussedinitially, followed by a consideration of the basicdynamic equations. In both cases, these descriptionsare extremely clear. Too often this clarity is lost inopen channel textbooks and the fundamentally sim-ple Newtonian mechanics that form the physical basisof hydraulics can often be presented in a rather heavymanner. These sections are also both admirably com-prehensive. Other useful features of the text are adetailed glossary, list of symbols and a section onphysical constants, properties and conversions. Thereis also a useful reprisal of basic mathematics suchas trigonometric functions, basic calculus and vec-tor notation, complex numbers and polynomials thatthis reader, for one, often finds himself in need of asschool and undergraduate studies become an increas-ingly distant memory! Lastly, the production fromArnold is excellent, and includes some very nicecolour plates.

The coverage of both sediment transport and hy-draulic modelling is a departure from the ‘classicalmodel’ of open channel flow texts and very muchto be welcomed, however, neither in my opinionreally goes far enough. Whilst physical modelling isdealt with in admirable detail, numerical modellingis restricted to a discussion of backwater calculationsand wave routing, and higher dimensional models areonly mentioned in passing. This might be appropriatefor undergraduate courses, but even here studentsare beginning to encounter research level modelsand an introduction to such schemes geared to theundergraduate market would have been a very usefuladdition. In the same way, approximately a quarterof the book is devoted to the design of hydraulicstructures that not all readers will find useful. In thisrespect, the volume caters rather better for the civilengineering, rather than the environmental science,market, and those of us in the latter field are stillwaiting for a text more fully tailored to our specificneeds.

The ultimate test of such a textbook is whether itcan be useful for a range of problems and be accessi-ble to a wide readership. To do this the hydraulicsgroup at Bristol has been ‘road testing’ this vol-ume for the past three months, turning to it as afirst source of information to solve the day-to-dayproblems of a varied group of physical hydraulic,numerical hydraulic and sedimentological modellers.

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BOOK REVIEW

In that time, a diverse range of queries has been ini-tially researched in Hubert Chanson’s volume, and ithas passed each test with flying colours. All graduateand postdoctoral researchers who have used the vol-ume have commented favourably on its clarity andcompleteness, and I can think of no better recom-mendation than this. This is an excellent book forundergraduate and graduate students in civil engineer-ing interested in open channel flow, and a very usefulresource text for those interested in hydraulics outsidethe engineering field.

ReferencesChadwick A, Morfett J. 1998. Hydraulics in Civil and EnvironmentalEngineering . Routledge: London, 600 pp.

Chow VT. 1959. Open Channel Hydraulics . McGraw Hill: NewYork, 680 pp.

Crowder DW, Diplas P. 2000. Using two-dimensional hydrodynamicmodels at scales of ecological importance. Journal of Hydrology 230:172–191.

French R. Open Channel Hydraulics . McGraw-Hill: New York;705 pp.

Hardy RJ, Bates PD, Anderson MG. 2000. Modelling suspendedsediment deposition on a fluvial floodplain using a two-dimensionaldynamic finite element model. Journal of Hydrology 229: 202–218.

Lane SN, Bradbrook KF, Richards KS, Biron PA, Roy AG. 1999.The application of computational fluid dynamics to natural riverchannels: three-dimensional versus two-dimensional approaches.Geomorphology 29: 1–20.

Stewart M, Bates PD, Price D, Burt TP. 1998. Modelling contami-nation in floodplain soils. Hydrological Processes 12: 1233–1266.

Stewart MD, Bates PD, Anderson MG, Price DA, Burt TP. 1999.Modelling floods in hydrologically complex lowland river reaches.Journal of Hydrology 223: 85–106.

Wiele SM, Graf JB, Smith JD. 1996. Sand deposition in the Col-orado River in the Grand Canyon from flooding of the Little Col-orado River. Water Resources Research 32: 3579–3596.

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