Urban Drainage, 2nd Edition

Urban Drainage

Urban Drainage2nd EditionDavid Butler† and John W. Davies†††Professor of Water EngineeringDepartment of Civil and Environmental EngineeringImperial College London††Head of Civil EngineeringSchool of Science and the EnvironmentCoventry University

First published 2000 by E & FN Spon11 New Fetter Lane, London EC4P 4EESimultaneously published in the USA and Canadaby E & FN Spon29 West 35th Street, New York, NY 10001Second Edition published 2004 by Spon Press11 New Fetter Lane, London EC4P 4EESimultaneously published in the USA and Canadaby Spon Press29 West 35th Street, New York, NY 10001This edition published in the Taylor & Francis e-Library, 2004.Spon Press is an imprint of the Taylor & Francis Group 2000, 2004 David Butler and John W. DaviesAll rights reserved. No part of this book may be reprinted orreproduced or utilised in any form or by any electronic, mechanical,or other means, now known or hereafter invented, includingphotocopying and recording, or in any information storage orretrieval system, without permission in writing from the publishers.British Library Cataloguing in Publication DataA catalogue record for this book is available from the British LibraryLibrary of Congress Cataloging in Publication DataButler, David.Urban drainage / David Butler and John W. Davies. – 2nd ed.p. cm.1. Urban runoff. I. Davies, John W. II. TitleTD657. B88 2004628 .21––dc222003025636ISBN 0-203-14969-6 Master e-book ISBNISBN 0-203-34190-2 (Adobe eReader Format)ISBN 0–415–30607–8 (pbk)ISBN 0–415–30606–X (hbk)

ContentsReadershipAcknowledgementsNotation ypes of system: piped or natural 17Types of piped system: combined or separate 18Combined system 18Separate system 20Which sewer system is better? 22Urban water system 23Water quality3.13.23.33.43.53.61What is urban drainage? 1Effects of urbanisation on drainage 2Urban drainage and public health 5History of urban drainage engineering 5Geography of urban drainage 13Approaches to urban drainage2.12.22.32.42.52.6xxiixiiixxIntroduction 29Basics 29Parameters 31Processes 42Receiving water impacts 44Receiving water standards 4929

ction 134Basic principles 135Pipe flow 139Part-full pipe flow 149Open-channel flow 159Hydraulic features9.19.29.39.4119Introduction 119Building drainage 119System components 121Design 129Hydraulics8.18.28.38.48.596Introduction 96Runoff generation 96Overland flow 103Stormwater quality 110System components and layout7.17.27.37.473Introduction 73Measurement 73Analysis 76Single events 85Multiple events 87Climate change 90Stormwater6.16.26.36.47Introduction 57Domestic 58Non-domestic 64Infiltration and inflow 65Wastewater quality 67Rainfall5.15.25.35.45.55.657Flow controls 168Weirs 177Inverted siphons 182Gully spacing 185168

Contents vii10Foul sewers10.110.210.310.410.5111214290Function of storage 290Overall design 291Sizing 294Level pool (or reservoir) routing 295Alternative routing procedure 297Storage in context 303Pumped systems14.114.214.314.414.514.614.7254Background 254System flows 254The role of CSOs 257Control of pollution from combined sewer systems 260Approaches to CSO design 265Effectiveness of CSOs 280CSO design details 283Storage13.113.213.313.413.513.6222Introduction 222Design 222Contributing area 226Rational Method 230Time–area Method 237Hydrograph methods 242Combined sewers and combined sewer on 192Design 192Large sewers 195Small sewers 204Solids transport 213Storm sewers11.111.211.311.411.511.6192Why use a pumping system? 305General arrangement of a pumping system 305Hydraulic design 307Rising mains 313Types of pump 315Pumping station design 318Vacuum systems 325305

viiiContents15Structural design and ntroduction 401Preparing for sewer rehabilitation 404Methods of structural repair and renovation 408Hydraulic rehabilitation 417Flow models19.119.219.319.419.519.619.7380Introduction 380Maintenance strategies 380Sewer location and inspection 383Sewer cleaning techniques 388Health and safety 391Pipe corrosion 393Performance 398Rehabilitation18.118.218.318.4351Introduction 351Origins 353Effects 354Transport 357Characteristics 360Self-cleansing design 365Load estimation and application 370Operation, maintenance and performance17.117.217.317.417.517.617.718Types of construction 328Pipes 330Structural design 333Site investigation 340Open-trench construction 343Tunnelling 345Trenchless methods 347Sediments16.116.216.316.416.516.616.7328Models and urban drainage engineering 420Deterministic models 421Elements of a flow model 422Modelling unsteady flow 424Computer packages 431Setting up and using a system model 434Flow models in context 439420

Contents ix20Quality n 503Health 504Option selection 506On-site sanitation 507Off-site sanitation 511Storm drainage 513Towards sustainability24.124.224.324.4486Introduction 486Urban Pollution Management 486Real-time control 488Integrated modelling 494In-sewer treatment 497Low-income communities23.123.223.323.423.523.6460Introduction 460Devices 462SUDS applications 471Elements of design 472Water quality 478Issues 479Other stormwater management measures 481Integrated management and control22.122.222.322.422.523Development of quality models 442The processes to be modelled 444Modelling pollutant transport 446Modelling pollutant transformation 450Use of quality models 454Alternative approaches to modelling 456Stormwater uction 521Sustainability in urban drainage 522Steps in the right direction 527Assessing sustainability 530Useful websites535Index536

ReadershipIn this book, we cover engineering and environmental aspects of thedrainage of rainwater and wastewater from areas of human development.We present basic principles and engineering best practice. The principlesare essentially universal but, in this book, are mainly illustrated by UKpractice. We have also included introductions to current developments andrecent research.The book is primarily intended as a text for students on undergraduateand postgraduate courses in Civil or Environmental Engineering andresearchers in related fields. We hope engineering aspects are treated withsufficient rigour and thoroughness to be of value to practising engineers aswell as students, though the book does not take the place of an engineeringmanual.The basic principles of drainage include wider environmental issues,and these are of significance not only to engineers, but to all with a seriousinterest in the urban environment, such as students, researchers and practitioners in environmental science, technology, policy and planning,geography and health studies. These wider issues are covered in particularparts of the book, deliberately written for a wide readership (indicated inthe table opposite). The material makes up a significant portion of thebook, and if these sections are read together, they should provide a coherent and substantial insight into a fascinating and important environmentaltopic.The book is divided into twenty-four chapters, with numerical examplesthroughout, and problems at the end of each chapter. Comprehensive reference lists that point the way to further, more detailed information,support the text. Our aim has been to produce a book that is both comprehensive and accessible, and to share our conviction with all our readersthat urban drainage is a subject of extraordinary variety and interest.

Readership xiChapterCoverage of wider issues12312161718192021222324AllAll3.5, 3.612.1, 12.2, 12.316.1, 16.217.1, 17.218.119.1, 19.2, 19.320.1, 20.221.1, 21.2, 21.3, 21.6, 21.722.1, 22.2AllAll

AcknowledgementsMany colleagues and friends have helped in the writing of this book. Weare particularly grateful to Dr Dick Fenner of University of Cambridge forhis encouragement and many useful comments. We would also like toacknowledge the helpful comments of John Ackers, Black & Veatch; Professor Bob Andoh, Hydro International; Emeritus Professor Bryan Ellis,Middlesex University; Andrew Hagger, Thames Water; Brian Hughes; DrPete Kolsky, Water and Sanitation Programme, World Bank; ProfessorDuncan Mara, University of Leeds; Nick Orman, WRc; Martin Osborne,BGP Reid Crowther; Sandra Rolfe and Professor David Balmforth, MWHEurope. We thank colleagues at Imperial College: Professor Nigel Graham,Professor Ĉedo Maksimović, Professor Howard Wheater, and current andformer researchers Dr Maria do Céu Almeida, David Brown, Dr EranFriedler, Dr Kim Littlewood, Dr Fayyaz Memon, Dr Jonathan Parkinsonand Dr Manfred Schütze. At Coventry University, we thank ProfessorChris Pratt.Clearly, many people have helped with the preparation of this book,but the opinions expressed, statements made and any inadvertent errorsare our sole responsibility.Thanks most of all to:Tricia, Claire, Simon, AmyRuth, Molly, Jack

Notation vCCdCvconstanteffective surface area for infiltrationcatchment areacross-sectional areaplan areaarea of baseimpermeable area from which runoff receivedsediment mobility parameterimpervious areaarea of orificegully pot cross-sectional areaFSR 5-day antecedent precipitation indexFSR rainfall areal reduction factorwidth of weirsediment removal constantconstantwidth of Preissman slotsediment removal constant (runoff)sediment removal constant (sweeping)flow widthoutside diameter of pipedownstream chamber width (high side weir)width of trench at top of pipeupstream chamber width (high side weir)concentrationchannel criteriondesign number of applianceswave speeddissolved oxygen concentrationsaturation dissolved oxygen concentrationvolumetric sediment concentrationrunoff coefficientcoefficient of dischargevolumetric runoff coefficient

xivNotation FsegGG'hhahfhLhlocalhmaxHdimensionless routing coefficientdepth of flowsediment particle sizecritical depthhydraulic mean depthdepth upstream of hydraulic jumpdepth downstream of hydraulic jumpsediment particle size larger than 50% of all particlesinternal pipe diameterrainfall durationwave diffusion coefficientlongitudinal dispersion coefficientorifice diametersediment dimensionless grain sizegully pot diameterdry weather flowvoids ratiosediment accumulation rate in gullyspecific energygully hydraulic capture efficiencyindustrial effluent flow-rateEffective BOD5soil infiltration ratepotency factorsoil infiltration capacitysoil initial infiltration ratenumber of sweeps per weeksoil infiltration rate at time tbedding factorFroude numberfactor of safetyacceleration due to gravitywater consumption per personwastewater generated per personheadacceleration headhead loss due to frictiontotal head losslocal head lossdepth of watergully pot trap depthtotal headdifference in water levelheight of water surface above weir crestdepth of cover to crown of pipe

Notation mMMsMT-DnnDUNminimum difference in water level for non-drowned orificerainfall intensityeffective rainfall intensitynet rainfall intensityinflow ratepipe infiltration raterainfall depthtimehousing densitycriterion of satisfactory serviceempirical coefficientconstanteffective roughness value of sediment dunesdimensionless frequency factorlocal head loss constantpipe roughnessconstant at T Cdepression storage constantHorton’s decay constantunit hydrograph exponential decay constantpollutant washoff constantamended pollutant washoff constantconstant at 20 Crouting constantconstant in CSO design (Table 12.6)Rankine’s coefficientempirical coefficientvolumetric reaeration coefficientlengthload-rategully spacingequivalent pipe length for local lossesinitial gully spacingWeibull’s event rank numberreservoir outflow exponentmassempirical coefficientmass of pollutant on surfaceFSR rainfall depth of duration D with a return period TnumberManning’s roughness coefficientporositynumber of discharge unitstotal numberBilham’s number of rainfall events in 10 yearsxv