Introduction to Catchment Hydraulics (CIVL3110)
Teaching activities by Dr Hubert CHANSON

Introduction to Catchment Hydraulics (CIVL3110)

Lecture material
Tutorials, Exercises
Laboratory experiments
Useful links
    Basic Fluid Dynamics
    Numerical modelling : backwater calculations
    Hydraulic structures
    Roman waterworks
    River engineering
    Water quality issues
    Sediment transport
    Coastal engineering


Catchment processes: precipitation, evapotranspiration, infiltration & runoff; generation of flows from catchements; statistical analysis of hydrological data; behaviour of flows in channels; open channel flow.


Subject rationale: The term 'Hydraulics' is related to the application of the Fluid Mechanics principles to water engineering structures, civil and environmental engineering facilities: e.g., canal, river, dam, reservoir, water treatment plant.In the subject, the students are introduced to the hydraulics of a catchment : rainfall, runoff and streamflow. The section "Introduction to Open channel flows" applies the basic principles of fluid mechanics to open channel flows. Examples of open channels are natural streams and rivers. Man-made channels include irrigation and navigation canals, drainage ditches, sewer and culvert pipes running partially full, and spillways. The lecture draws upon the students' expertise in catchment hydrology and water runoff gained in Hydrology Part of the subject. The teaching is focused on the application of the fundamental principles to open channel flow and sediment transport. The interactions between hydrology and hydraulics (e.g. rainfall and river discharge) are further discussed and the students are introduced to real-world engineering situations including failures.
The subject is the first of a series of three subjects (CIVL3110, CIVL3120 and CIVL4120) dealing with hydraulic structures and their interactions with the environment.
The subject outline file may be downloaded : Click here (Word format) [Version 1, 12/2/2001].Timetable : Click there (Excel format) [Version 1, 18/2/2001]


  + CHANSON, H. (1999). "The Hydraulics of Open Channel Flows : An Introduction." Butterworth-Heinemann, Oxford, UK, 512 pages (ISBN 0 340 74067 1). {Support website :} [Bookshop order of book] Corrections & Updates [Newsletters No. 1, No. 2]
Reviews :
{1} Professor P. BATES, University of Bristol. "Changing a winning formula: the hydraulics of open channel flow: an introduction." in Hydrological Processes, Vol. 15, No. 1, Special Issue, 2001, pp. 159-161. {Read Full Review}
 "Hubert Chanson's book meet some of the needs for an open channel text in environmental hydraulics. [...] When discussing hydraulics or sediment transport, each section is structured in highly logical manner. Physical properties are discussed initially, followed by a consideration of the basic dynamic equations. In both cases, these descriptions are extremely clear. These sections are also both admirably comprehensive.
 The ultimate test of such a textbook is whether it can be useful for a range of problems and be accessible to a wide readership. To do this the hydraulics group at Bristol has been 'road-testing' this volume for the past three months. [...] In that time, a diverse range of queries has been initially researched in Hubert Chanson's volume, and it has passed each test with flying colours. All graduate and postdoctoral researchers who have used the volume have commented favourably on its clarity and completeness, and I can think of no better recommendation than this. This is an excellent book for undergraduate and graduate students in civil engineering interested in open channel flow, and a very useful resource text for those interested in hydraulics outside engineering field."
{2} Professor S.N. LANE, University of Leeds, Environmental Conservation, Volume 27 2000, Issue 3, pp 314-315.  {Read Full Review}
 "Without a doubt, this is the best introduction to the introduction of the hydraulics of open channel flow that I have yet to read.  The text deserves special credit for the explicit identification of the assumptions that exist behind relationships, something that can be (and is) easily over-looked by students whilst using other texts. As an introduction to the hydraulics of open channel flow, I would find it difficult to recommend anything that could improve upon the approach adopted.  My overwhelming conclusion is that as an introduction to the hydraulics of open channel flow, it would be impossible to produce a better result. This will appear on both my undergraduate and postgraduate reading lists as the core text. It is rare for me to be so readily persuaded, and Dr Chanson deserves full credit for an outstanding teaching resource."
{3} Professor D.A. ERVINE, Univwersity of Glasgow, Chemical Engineering Research and Design, Trans IChemE, Part A, Vol 78, Number A7, Oct. 2000, pp 1055.{Read Full Review}
"Hubert Chanson's latest book is really designed for a Civil Engineering readership with its emphasis on sediment movement in rivers and also hydraulic structures for rivers and dams. All in all, a well constructed book with many helpful examples and explanations for the student."
{4} Professor W.H. HAGER, ETH-Zürich (Switz.), Wasser, Energie & Luft, Switzerland, 2000, No. 1/2, p. 55
"The author has succeeded in producing yet another excellent piece of work. [...] All in all, this is a well-written and carefully illustrated book which is useful for all building and environmental engineers. [...] It easily meets highest expectations."
{5}WEBER, L.J. (2001), Jl of Hyd. Engrg., ASCE, Vol. 127, No. 3, pp. 246-247. {Read Full Review}
"The strength of the book is its breadth of coverage. Containing a wealth of information, as well as being appropriate for an advanced undergraduate course on open channel hydraulics, the book delivers a very good cross section of topics. The number of exercises is very impressive and worth the book's cost."
{6} Professor M. JOVANOVIC, University of Belgrade, Urban Water, Vol. 1, No. 3, p. 270. {Read Full Review}
 "This book stands apart from similar previously published textbooks in two ways. Firstly, its scope has significantly been extended toward applications. Secondly, by including many exercises,notes, discussions, relevant photographs,and appendices with additional information, it has an original, hand-book-like presentation, very convenient for quick referencing, and use in engineering practice. Being more than a simple introductory textbook in open channel hydraulics, this book can be strongly recommended to students and engineers."
{7} RAJARATNAM, N. (1999), Review for Edward Arnold, University of Alberta, Canada : "This manuscript is well written ans covers : the basics of open channel flows; uniforme and gradually varied flows; sediment transport; physical modelling and has a very good treatment of Hydraulic Structures. It has also numerous interesting historical notes. There also [are a] number of interesting problems."
{8} MONTES, J.S., and HOLLOWAY, D. (1999), Review for Edward Arnold, University of Tasmania, Australia : "[The book] is an Introduction to a very complex subject, and as such we think that it [will] be developed into a very distinct and useful text.[ ...]. It has undeniable unity and character and, with its unusual analysis of historic cases of Hydraulic Design, it [will] provide the student with a very attractive first view of this topic. The book is [....] quite different from the well known textbooks (Ven Te Chow, Henderson and French). It contains some great new material, in the form of a glossary, symbol list, many interesting photos and biographical notes, as well as additional notes that elucidate particular points within each Chapter."
+ Advanced Hydraulics, CIVL3120 website
+ Environmental Hydraulics, CIVL4120 website
+ Softwares : HydroChan by Hydrotools software

Lecture Material

Applications of the Bernoulli Equation to Open Channel Flows
2. Application of the Bernoulli equation - Specific Energy
2.3 Specific energy
    Typical applications of the Bernoulli principle and specific energy concept include the sluice gate in a horizontal channel (photo: (1), (2), (3), (4), (5) ; ref: Roth & Hager), the broad-crested weir overflow (photo: (1), (2), (3), (4) ).

3. Froude Number
    The Froude number is proportional to the square root of the ratio of the inertial forces over the weight of fluid. The Froude number is used generally for scaling free surface flows, open channels and hydraulic structures. Although the dimensionless number was named after William FROUDE, several French researchers used it before. DUPUIT (1848) and BRESSE (1860) highlighted the significance of the number to differentiate the open channel flow regimes. BAZIN (1865a) confirmed experimentally the findings. Ferdinand REECH introduced the dimensionless number for testing ships and propellers in 1852. The number is called the Reech-Froude number in France (CHANSON 1999, pp. 39-46).
    In rectangular channels, the Froude number is commonly defined as the ratio of the flow velocity to the square root of the product of g times d, where d is the flow depth and g is the gravity acceleration.

4. Properties of Common Open-Channel Shapes
    In practice, natural and man-made channels do not have often a rectangular cross-section. Critical flow conditions are defined as the flow conditions for which the mean specific energy is minimum (CHANSON 1999, pp. 46-48). In a horizontal channel and assuming hydrostatic pressure distribution, critical flow conditions imply :

g * Ac3  =  Bc * Q2
where Ac and Bc are respectively the cross-section area and free surface width at critical flow conditions, and Q is the flow rate.

Applications of the Momentum Principle : Hydraulic Jump, Surge, Flow Resistance in Open Channels
2. Hydraulic jump
    A hydraulic jump is a stationary transition from a rapid (supercritical flow) to a slow flow motion (subcritical flow). Although the hydraulic jump was described by LEONARDO DA VINCI, the first experimental investigations were published by Giorgio BIDONE in 1820. It is extremely turbulent and characterised by the development of large-scale turbulence, surface waves and spray, energy dissipation and air entrainment (eg CHANSON and BRATTBERG 2000). The large-scale turbulence region is usually called the 'roller'. Experimental observations highlight different types of hydraulic jumps, depending upon the Froude number of the upstream flow. An undular hydraulic jump is observed at low Froude numbers (1< Fr <3): looking downstream (Fr=1.2) and sideview (Fr=1.6). With increasing Froude numbers, other types of jumps include weak jump, oscillating jump (3.5< Fr <4.5), steady jump and strong jump (Fr >10).
    These photographs show surfers riding on a hydraulic jump roller in a river in Munich, Germany (Photo No. 1 : flow from right to left, Photo No. 2: looking downstream, Courtesy of Dale YOUNG).

3. Surges and Tidal Bores
    A surge in an open channel is a sudden change of flow depth (i.e. abrupt increase or decrease in depth). An abrupt increase in flow depth is called a positive surge while a sudden decrease in depth is termed a negative surge. This picture shows an undular surge (propagation from left to right).
    A positive surge looks like a moving hydraulic jump. The application of the momentum principle to the unsteady flow is based upon a quasi-steady flow situation analogy (CHANSON 1999, pp. 67-71).
    A bore is a positive surge of tidal origin. Tidal bores occur as the tidal flow turns to rising (e.g. Lynch 1982). Famous ones include the Hangchow (or Hangzhou) bore on the Qiantang river (photo: (1),  (2) ), the Amazon bore called pororoca (photo: (1), (2) , (3) ; info: see below ), the tidal bore on the Seine river (mascaret) (photo: (1) ; info: (2) ), the Hoogly (or Hooghly) bore on the Gange, the bore on the Mekong river. Smaller tidal bores occur on the Severn river near Gloucester, England (photo : (1), (2) , (3) ), on the Trent river (aegir) (photo: (1)), on the Garonne and Dordogne rivers, France (photo: (1), (2) ; info: (3) ), at Turnagain Arm and Knik Arm, Cook Inlet (Alaska) (info: (1) ; photo: (2) , (3) ), the bores in the Bay of Fundy (New Brunswick, Nova Scotia) like at Petitcodiac (info: (1) ), tidal bores on the Styx river QLD and on the Daly river NT (Australia), the tidal bore called benak at Batang Lupar (Malaysia) (photo (1)).
    The front of a positive surge absorbs random disturbances on both sides of the surge and this makes the positive surge stable and self-perpetuating. With appropriate boundary conditions, a tidal bore may travel long distances upsteam of the river mouth. For example, the tidal bore on the Pungue river (Mozambique) is still about 0.7 m high about 50 km upstream of the mouth and it may reach 80 km inland.
    Hubert Chanson observed the tidal bore of the Dordogne river on 27 Sept. 2000 (5:00pm).  The bore propagates first in the Gironde before separating and continuing both in the Garonne and in the Dordogne (Map). At St Pardon, the tidal bore was an undular bore on the 27 Sept. 2000. Photographs No. 1 and 3 illustrate the undular nature of the positive surge. Photo No. 1 shows the arriving bore. Photo No. 2 illustrates kayacks and surfers riding the bore. Photo No. 3 was taken just downstream of St Pardon while Photo No. 4 was shot in front of St Pardon.

 More pictures of tidal bores are here.
 More about the tidal bore (mascaret) of the Seine river ...

4. Flow resistance in open channel flows
    In open channel flows, flow resistance can be neglected over a short transition  as a first approximation, and the continuity and Bernoulli equations can be applied to estimate the downstream flow properties as functions of the upstream flow conditions and boundary conditions. But the approximation of frictionless flow is no longer valid for long channels. Considering a water supply canal extending over several kilometres, the bottom and sidewall friction retards the fluid, and, at equilibrium, the friction force counterbalances exactly the weight force component in the flow direction.
    The laws of flow resistance in open channels are essentially the same as those in closed pipes. In an open channel, the calculations of the boundary shear stress are complicated
by the existence of the free surface and the wide variety of possible cross-sectional shapes. The boundary shear stress equals :
    to  =  f/8 * r * V2
where f is the Darcy-Weisbach friction factor and V is the mean flow velocity (HENDERSON 1966, CHANSON 1999). As for pipe flows, the flow regime in open channels can be either laminar or turbulent. In industrial applications, it is commonly accepted that the flow becomes turbulent for Reynolds numbers larger than 2000 to 3000, the Reynolds number being defined for pipe and open channel flows as Re = V*DH/n where DH is the hydraulic diameter or equivalent pipe diameter.     The Darcy friction factor f may be calculated as a function of the relative roughness ks/DH and Reynolds number from the Moody diagram
    In open channels, the Darcy-Weisbach friction equation (see above) is valid using the hydraulic diameter as equivalent pipe diameter. It is the only sound method to estimate the energy loss. For various reasons (mainly historical reasons), empirical resistance coefficients (e.g. Chézy coefficient) were and are still used. The Chézy coefficient was introduced in 1768 while the Gauckler-Manning coefficient was first presented in 1865 : i.e., well before the classical pipe flow resistance experiments in the 1930s. Historically both the Chézy and the Gauckler-Manning coefficients were expected to be constant and functions of the roughness only. But it is now well recognised that these coefficients are only constant for a range of flow rates. Most friction coefficients (except perhaps the Darcy friction factor) are estimated 100%-empirically and they apply only to fully-rough turbulent water flows (CHANSON 1999).

Note : The Gauckler-Manning equation is often called improperly the Manning equation. In fact it was first proposed by the Frenchman P.G. GAUCKLER in 1867 (GAUCKLER 1867) based upon the re-analysis of experimental data obtained by H.P.G. DARCY and H. BAZIN (DARCY and BAZIN 1865). Robert MANNING (1816-1897), chief-engineer at the Office of Public Works, Ireland, presented two flow resitance formula in 1890. One was the 'Gauckler-Manning' formula but Robert MANNING did prefer to use his second formula.

Tutorials and exercises

Open channel hydraulics - Text book exercises with solutions: (or

Tutorial No. 1 : Fluid properties and basic equations. Bernoulli principle (1) (version 8/3/01).
Tutorial No. 2 : Bernoulli principle (2). Momentum principle. Hydraulic jump, surges, flow resistance (version 16/5/01).
Tutorial No. 3 : Uniform equilibrium and gradually-varied flows (version 10/5/01).

Tidal bore on the Dordogne river (27/9/2000)

Laboratory experiments

Open channel hydraulics
General information - Experiment description
Two experiments are performed. : a study of a broad-crested weir overflow (photo) and the hydraulic jump (photo). The former (broad-crested weir) is a smooth transition from an upstream sub-critical flow to a  downstream supercritical flow. The latter (hydraulic jump) is the transition from an upstream supercritical flow to a downstream subcritical flow.

Useful Links

Rating : [***] = superb, must see - [**] = excellent


Rivers Seen from Space [**]
EPA Multimedia projects (USA) (computations, remote sensing)
Structurae, International Database and Gallery of Structures [**]
Gallery of Photographs in Fluid Mechanics, Hydraulic & Environmental Engineering and Engineering History
Aerial photographs of American rivers and valleys [**]

The Formal Water Garden
 Unesco World Heritage Listing (for Virtual Tours, click here [**])

Basic Fluid Dynamics

Gallery of photographs in fluid dynamics by Mark Kramer [**]

Numerical modelling : backwater calculations

Hydrochan (TM)  [**]  Gradually-varied flows (1D)
US Army Corps of Engineers HEC Softwares

Hydraulic structures

California 1997 Flood Images
Chicago Calumet waterway: sidestream aeration cascades
Petit-saut dam (French Guyana)
US Army Corps of Engineers, Walla Walla district  [Photographs are listed Here]
US Army Corps of Engineers, Portland district, Photofile [**]

Goulburn-Murray Water

 History of arch dams
 The Rideau Canal (Canada) incl. the 1831 Jones Falls arch dam [*]
 Steel dams

 Timber Crib Weirs in Queensland, Australia
 Air entrainment on chutes spillways
 Rubber dams
 Minimum Energy Loss (MEL) culverts and bridge waterways
 Embankment overflow stepped spillways: earth dam spillways with precast concrete blocks
 Spillway Aeration Devices to prevent Cavitation Damage in high-head chutes {}

Roman waterworks

 LacusCurtius - Roman Waterworks and Hydraulic Engineering [***]
 Roman Aqueducts and Water Systems (Rome aqueduct system)
 Ostia - Harbour of Ancient Rome (Italy)
 Gorze Aqueduct at Metz  (France) [**]
 The Aqueduct in Caesarea (Israel)
 Aqueduc de Cahors (in French)

 Hydraulics of Roman Aqueducts : Steep Chutes, Cascades and Dropshafts, AJA, 2000


 Dr Lockington's CIVL3110 home page
 El Niño Information in California

River engineering

The tidal bore of the Seine river

Water quality issues

Chicago Calumet waterway: sidestream aeration cascades
Petit-saut dam (French Guyana): aeration cascade
       Petit-Saut dam : photographs, dam details


Bureau of Meteorology
Goulburn-Murray Water
Hydro-Electric Corporation (Tasmania)
Murray-Darling Basin Commission
NSW Department of Land and Water Conservation
QLD Department of Natural Resources [Water, Storages]

Extreme reservoir siltation in Australia

Sediment transport

Mount St. Helens (USA), debris and mud flows, Photofile [**]

Extreme reservoir siltation

Coastal engineering

French Naval and Hydrographic Service SHOM [**]
Tidal bore (mascaret) of the Seine river
Photographs of tidal bores (incl. mascaret, pororoca)

Tide calculations worldwide (in French)

Coastal engineering web page of Dr Robert A. Dalrymple
Tsunami : Information - Photographs


 University of Queensland Library

 Measurement systems : SI Units and significant figures

 Reprints of Research Papers in Water enginering

 ICEnet: The Institution of Civil Engineers Homepage
 Japan Society of Civil Engineers
 ASCE - American Society of Civil Engineers Homepage
 ASME Meetings & Exhibits Frames Index

 Welcome to the IAHR homepage

 US Geological Survey
 Civil Engineering Resources on the Internet (

 Highlights in the History of Hydraulics by Hunter ROUSE

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Last update : 09/05/2001
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