Fluvial Design Guide - Chapter 7 Background

Hydraulic analysis and design

Richard Crowder

Chapter 7 provides comprehensive coverage of both the theory and practice of hydraulic analysis and design as applied to works in rivers and streams. After brief introductory sections the rest of the chapter is divided into three main parts – basic hydraulic concepts, fundamental hydraulic principles, and the practical application of hydraulic modelling.

The basic concepts section covers water level control and flow in open channels, and includes guidance on hydrostatics as well as the various types of flow encountered in fluvial design.

The fundamental principles covered include conservation of energy, normal flow, subcritical and supercritical flow, Froude number, specific energy, and the Manning equation. There is also a section on the Conveyance estimation system (CES) including the Roughness adviser. Backwater analysis is also described, and there is guidance on the analysis of flow at structures (weirs, culverts, bridges and hydraulic gates).

The final section covers the practical application of hydraulic modelling, from developing the scope of work, through data collection, constructing the model, and on to verification, validation, calibration and sensitivity testing. The section on model construction covers both steady and unsteady models and 1-D, 2-D and 3-D options, with guidance of schematisation, boundary conditions, construction order and simulations.

The modelling guidance also covers good practice in model construction, identification of risks and their mitigation, and the use of models as part of the design process. The chapter ends with a summary of the key modelling tools available to a designer.

Chapter Structure

7.1 Overview

7.2 The main issues

7.3 Basic hydraulic concepts

7.4 Fundamental hydraulic principles

7.5 Practical application of hydraulic modelling

7.6 Modelling and the design process

7.7 Summary of key tools

Key references

Other references

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Graphical output from a 2-D model

Richard Crowder

R A Crowder
Director (Water)
Arndale House, Otley Road, Headingley, Leeds LS6 2UL

Richard Crowder is a specialist in the development and use of mathematical (hydraulic) models for integrated flooding, pollution and water quality studies. He has a PhD in computational hydraulics and has extensive experience in software benchmarking and software engineering.

He is also a specialist in flood risk management, water management, integrated urban and river flooding, and developing national guidelines and decision-making frameworks for flood risk management. He is the author or co-author of more than 25 technical publications.