Practical Channel Hydraulics is a technical guide for estimating flood water levels in rivers using the innovative software known as the Conveyance and Afflux Estimation System (CES-AES). The stand alone software is freely available at HR Wallingford’s website www.river-conveyance.net. The conveyance engine has also been embedded within industry standard river modelling software such as InfoWorks RS and Flood Modeller Pro. This 2nd Edition has been greatly expanded through the addition of Chapters 6-8, which now supply the background to the Shiono and Knight Method (SKM), upon which the CES-AES is largely based.
With the need to estimate river levels more accurately, computational methods are now frequently embedded in flood risk management procedures, as for example in ISO 18320 (‘Determination of the stage-discharge relationship’), in which both the SKM and CES feature. The CES-AES incorporates five main components: A Roughness Adviser, A Conveyance Generator, an Uncertainty Estimator, a Backwater Module and an Afflux Estimator. The SKM provides an alternative approach, solving the governing equation analytically or numerically using Excel, or with the short FORTRAN program provided.
Special attention is paid to calculating the distributions of boundary shear stress distributions in channels of different shape, and to appropriate formulations for resistance and drag forces, including those on trees in floodplains. Worked examples are given for flows in a wide range of channel types (size, shape, cover, sinuosity), ranging from small scale laboratory flumes (Q = 2.0 1s-1) to European rivers (~2,000 m3s-1), and large-scale world rivers (> 23,000 m3s-1), a ~ 107 range in discharge. Sites from rivers in the UK, France, China, New Zealand and Ecuador are considered.
Topics are introduced initially at a simplified level, and get progressively more complex in later chapters. This book is intended for post graduate level students and practising engineers or hydrologists engaged in flood risk management, as well as those who may simply just wish to learn more about modelling flows in rivers.
Table of Contents
1.1 Context and motivation for book
1.2 Scope of book and introduction to the CES-AES
1.3 Limitations of the CES-AES
1.4 Outline of book
1.5 Origin of the CES-AES
2 Practical and theoretical issues in channel hydraulics
2.1 Getting started with some practical examples on calculating flows in watercourses
2.2 Common difficulties in modelling flow in rivers and watercourses
2.3 Flow in simple engineered channels
2.4 Inbank flow in natural rivers
2.5 Overbank flow in natural and engineered rivers
2.6 Flows through bridges and culverts
2.7 Data sources used in this book
3 Understanding roughness, conveyance and afflux
3.1 Flow structures in open channel flow
3.2 Governing equations
3.3 Dealing with uncertainty
3.4 Introduction to the CES-AES software
4 Practical issues – roughness, conveyance and afflux
4.1 An overview of the CES-AES use in practice
4.2 Estimating and using stage-discharge relationships and spatial velocities
4.3 Use of backwater module for estimating water levels along the River Main
4.4 Estimating afflux at bridges
4.5 Estimating afflux at culverts
4.6 Dealing with vegetation and maintenance of weedy rivers
5 Further issues on flows in rivers
5.1 Ecological issues
5.2 Sediment and geomorphological issues
5.3 Trash screen and blockage issues
5.4 Wider modelling issues
5.5 Software architecture and calculation engines
6 The Shiono & Knight Method (SKM) for analyzing open channel flows
6.1 Theoretical background to the governing equation used in the SKM
6.2 Physical background to the governing equation used in the SKM
6.3 Boundary conditions
6.4 Analytical solutions using the SKM
6.5 Boundary shear stress distributions in channel flow and shear forces on boundary elements
6.6 Resistance equations for surfaces, shape effects and trees
6.7 Flow dependent resistance issues
7 Worked examples using the Shiono & Knight Method (SKM)
7.1 Using Excel to solve the SKM equations together with analytical expressions for the Ai coefficients
7.2 Using Excel to solve the SKM equations numerically
8 Further examples – estimating flow, level and velocity in practice
8.1 Estimating and using stage-discharge relationships
8.2 Estimating and using spatial velocities
9 Concluding remarks
9.1 Concluding remarks
9.2 CES and SKM: Differences and Similarities
9.3 Future developments
Appendix 1 The finite element approximations for the CES equations
Appendix 2 Summary of hydraulic equations used in the AES
Appendix 3 Cross-section survey data
Appendix 4 Derivation of the governing depth-averaged equation used in the SKM
Appendix 5 Analytical solutions to the governing equation used in the SKM
Appendix 6 Fortran program for solving the governing depth-averaged equation used in the SKM
Professor Donald Knight retired from the University of Birmingham in December 2007, after teaching and undertaking research in the Department of Civil Engineering for just over 39 years. He continues research as an Emeritus Professor at Birmingham. He has co-authored several books and published over 160 refereed journal and conference papers on open channel flow, modelling, boundary shear stress, sediment mechanics and flooding, including several review articles. Donald is assistant Editor of the Journal of Disaster Research (Tokyo University) and of Water and Sediment Erosion Research (Beijing & Tsinghua Universities).
Caroline Hazlewood is Group Manager at HR Wallingford. She has a PhD and MSc in Hydraulic Engineering and a BSc in Civil Engineering. She is a member of International Association for Hydro-Environment Engineering and Research (IAHR) and member of the Journal of Flood Risk Management (JFRM) Editorial Board.
Rob Lamb is Managing Director of the JBA Trust, a research and educational charity funded by the JBA Group. His background is in hydrology and numerical modelling, with research interests in flooding and risk analysis in environmental and engineered systems. He has worked at the Centre for Ecology and Hydrology in Wallingford, and, from 2002, at JBA Consulting. Since 2013, he has been an Honorary Professor at Lancaster University’s Environment Centre. In 2016 he was part of the British government’s scientific advisory group on flooding.
Professor Paul Samuels is a Technical Director at HR Wallingford and a Visiting Industrial Professor at the University of Bristol, UK.
Shiono Koji is Emeritus Professor at Loughborough University since 2017. He studied his PhD on vertical turbulent exchange in stratified flow at the Department of Civil Engineering, Birmingham University 1978-1981 and was appointed as a research follow at Birmingham University from 1981-1986, specialising on estuarine flows. In 1989 he took up a lectureship at the Department of Civil Engineering, Bradford University. In 1994 he was appointed as a Senior Lecture at Department of Civil and Building, Loughborough University, and promoted to Professor of Environmental Hydrodynamics in 1999. Hiono was awarded Emeritus Professor at Loughborough University in 2017.