INTRODUCTION TO URBAN WATER DISTRIBUTION - CHAPTER 1 pdf

INTRODUCTION TO URBAN WATER DISTRIBUTION © 2006 Taylor & Francis Group, London, UK UNESCO-IHE LECTURE NOTE SERIES BALKEMA - Proceedings and Monographs in Engineering, Water and Earth Sciences © 2006 Taylor & Francis Group, London, UK Introduction to Urban Water Distribution NEMANJA TRIFUNOVI_ LONDON / LEIDEN / NEW YORK / PHILADELPHIA / SINGAPORE © 2006 Taylor & Francis Group, London, UK © 2006 Taylor & Francis Group, London, UK Typeset in Times New Roman by Newgen Imaging Systems (P) Ltd, Chennai, India Printed and bound in Great Britain by Cromwell Press Ltd, Trowbridge, Wiltshire All rights reserved. No part of this publication or the information contained herein may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, by photocopying, recording or otherwise, without written prior permission from the publishers. Although all care is taken to ensure integrity and the quality of this publication and the information herein, no responsibility is assumed by the publishers nor the author for any damage to the property or persons as a result of operation or use of this publication and/or the information contained herein. Published by: Taylor & Francis/Balkema P.O. Box 447, 2300 AK Leiden, The Netherlands www .balkema.nl, www.tandf.co.uk, www.crcpress.com British Library Cataloguing in Publication Data A catalogue record for this book is available from the British Library Library of Congress Cataloging in Publication Data Trifunovi-, N. Introduction to urban water / N. Trifunovi p.cm. – (IHE Delft lecture note series) 1. Municipal water supply. 2. Waterworks. I. Title. II. Series. TD346.T75 2006 628.1Ј4091732–dc22 2005035210 ISBN10 0–415–39517–8 ISBN13 9–78–0–415–39517–5 (hbk) ISBN10 0–415–39518–6 ISBN13 9–78–0–415–39518–2 (pbk) © 2006 Taylor & Francis Group, London, UK e-mail: Pub .NL@tandf.co.uk The more we learn, the less we know as we realise how much is yet to be discovered. © 2006 Taylor & Francis Group, London, UK Contents PREFACE XII INTRODUCTION XIV 1 WATER TRANSPORT AND DISTRIBUTION SYSTEMS 1 1.1 Introduction 1 1.2 Definitions and objectives 5 1.2.1 Transport and distribution 5 1.2.2 Piping 9 1.2.3 Storage 11 1.2.4 Pumping 15 1.3 Types of distribution schemes 16 1.4 Network configurations 18 2 WATER DEMAND 21 2.1 Terminology 21 2.2 Consumption categories 24 2.2.1 Water use by various sectors 24 2.2.2 Domestic consumption 25 2.2.3 Non-domestic consumption 28 2.3 Water demand patterns 31 2.3.1 Instantaneous demand 32 2.3.2 Diurnal patterns 38 2.3.3 Periodic variations 40 2.4 Demand calculation 44 2.5 Demand forecasting 48 2.6 Demand frequency distribution 52 3 STEADY FLOWS IN PRESSURISED NETWORKS 55 3.1 Main concepts and definitions 55 3.1.1 Conservation laws 56 3.1.2 Energy and hydraulic grade lines 60 3.2 Hydraulic losses 64 3.2.1 Friction losses 64 3.2.2 Minor losses 73 © 2006 Taylor & Francis Group, London, UK 3.3 Single pipe calculation 74 3.3.1 Pipe pressure 76 3.3.2 Maximum pipe capacity 78 3.3.3 Optimal diameter 81 3.3.4 Pipe charts and tables 82 3.3.5 Equivalent diameters 84 3.4 Serial and branched networks 87 3.4.1 Supply at one point 87 3.4.2 Supply at several points 88 3.5 Looped networks 91 3.5.1 Hardy Cross methods 92 3.5.2 Linear theory 98 3.6 Pressure-related demand 100 3.7 Hydraulics of storage and pumps 103 3.7.1 System characteristics 103 3.7.2 Gravity systems 105 3.7.3 Pumped systems 109 3.7.4 Combined systems 117 4 THE DESIGN OF WATER TRANSPORT AND DISTRIBUTION SYSTEMS 122 4.1 The planning phase 122 4.1.1 The design period 123 4.1.2 Economic aspects 125 4.2 Hydraulic design 130 4.2.1 Design criteria 130 4.2.2 Basic design principles 132 4.2.3 Storage design 136 4.2.4 Pumping station design 143 4.3 Computer models as design tools 148 4.3.1 Input data collection 150 4.3.2 Network schematisation 152 4.3.3 Model building 153 4.3.4 Nodal demands 155 4.3.5 Model testing 158 4.3.6 Problem analysis 159 4.4 Hydraulic design of small pipes 160 4.4.1 Equivalence Method 160 4.4.2 Statistical methods 162 4.5 Engineering design 163 4.5.1 Pipe materials 165 4.5.2 Joints 178 4.5.3 Fittings 181 4.5.4 Valves 182 4.5.5 Water meters 187 4.5.6 Fire hydrants 194 VIII Introduction to Urban Water Distribution © 2006 Taylor & Francis Group, London, UK 4.5.7 Service connections 196 4.5.8 Indoor installations 197 4.5.9 Engineering design of storage and pumping stations 197 4.5.10 Standardisation and quality assessment 203 5 NETWORK CONSTRUCTION 206 5.1 Site preparation 207 5.1.1 Excavation 208 5.1.2 Trench dewatering 212 5.2 Pipe laying 213 5.2.1 Laying in trenches 213 5.2.2 Casings 215 5.2.3 Laying above ground 215 5.3 Pipe jointing 220 5.3.1 Flanged joints 220 5.3.2 Gland joints 220 5.3.3 ‘Push-in’ joints 221 5.3.4 Anchorages and supports 221 5.3.5 Backfilling 223 5.3.6 Testing and disinfection 223 6 OPERATION AND MAINTENANCE 226 6.1 Network operation 226 6.1.1 Monitoring 228 6.1.2 Network reliability 230 6.1.3 Unaccounted-for water and leakage 235 6.1.4 Corrosion 248 6.2 Network maintenance 256 6.2.1 Planning of maintenance 257 6.2.2 Pipe cleaning 259 6.2.3 Animal disinfection 263 6.2.4 Pipe repairs 264 6.3 Organisation of water company 267 6.3.1 Tasks 267 6.3.2 Mapping 268 6.3.3 Structure and size 270 6.3.4 Example 272 APPENDIX 1 WORKSHOP PROBLEMS 277 A1.1 Water demand 277 A1.2 Single pipe calculation 280 A1.3 Branched systems 283 A1.4 Looped systems 288 A1.5 Hydraulics of storage and pumps 291 Contents IX © 2006 Taylor & Francis Group, London, UK APPENDIX 2 DESIGN EXERCISE 304 A2.1 Case introduction – the Town of Safi 305 A2.1.1 Topography 305 A2.1.2 Population distribution and future growth 305 A2.1.3 Supply source 305 A2.1.4 Distribution system 307 A2.1.5 Water demand and leakage 308 A2.1.6 Financial elements 308 A2.2 Questions 309 A2.2.1 Hydraulic design 309 A2.2.2 System operation 310 A2.3 Hydraulic design 312 A2.3.1 Preliminary concept 312 A2.3.2 Nodal consumptions 316 A2.3.3 Network layout 318 A2.3.4 Pumping heads and flows 339 A2.3.5 Storage volume 345 A2.3.6 Summary of the hydraulic design 348 A2.4 System operation 349 A2.4.1 Regular operation 349 A2.4.2 Factory supply under irregular conditions 364 A2.4.3 Reliability assessment 375 A2.5 Final layouts 380 A2.5.1 Alternative A – Direct pumping 380 A2.5.2 Alternative B – Pumping and balancing storage 384 A2.5.3 Phased development 389 A2.5.4 Cost analyses 390 A2.5.5 Summary and conclusions 394 APPENDIX 3 MINOR LOSS FACTORS 396 A3.1 Bends and elbows 396 A3.2 Enlargements and reducers 397 A3.3 Branches 398 A3.4 Inlets and outlets 399 A3.5 Flow meters 399 A3.6 Valves 400 APPENDIX 4 HYDRAULIC TABLES (DARCY–WEISBACH/ COLEBROOK–WHITE) 402 APPENDIX 5 SPREADSHEET HYDRAULIC LESSONS – OVERVIEW 426 A5.1 Single pipe calculation 426 A5.2 Pipes in parallel and series 434 A5.3 Branched network layouts 440 A5.4 Looped network layouts 442 X Introduction to Urban Water Distribution © 2006 Taylor & Francis Group, London, UK A5.5 Gravity supply 445 A5.6 Pumped supply 452 A5.7 Combined supply 457 A5.8 Water demand 461 APPENDIX 6 EPANET – VERSION 2 472 A6.1 Installation 472 A6.2 Using the programme 473 A6.3 Input data 479 A6.3.1 Data preparation 479 A6.3.2 Selecting objects 480 A6.3.3 Editing visual objects 480 A6.3.4 Editing non-visual objects 484 A6.3.5 Editing a group of objects 487 A6.4 Viewing results 488 A6.4.1 Viewing results on the map 488 A6.4.2 Viewing results with a graph 489 A6.4.3 Viewing results with a table 492 A6.5 Copying to the clipboard or to a file 494 A6.6 Error and warning messages 495 A6.7 Troubleshooting results 497 APPENDIX 7 UNIT CONVERSION TABLE 499 REFERENCES 500 Contents XI © 2006 Taylor & Francis Group, London, UK [...]... Water Transport and Distribution Systems 5 Table 1. 2 World urban population growth 19 75–2 015 (UN, 20 01) Areas Population (millions)/% of total 19 75 2000 2 015 Urban, above 5 million inhabitants Urban, 1 to 5 million inhabitants Urban, below 1 million inhabitants Rural 19 5/5 327/8 10 22/25 2530/62 418 /7 704 /12 17 23/28 3 210 /53 623/9 10 06 /14 218 9/ 31 3337/46 Total 4074 /10 0 6055 /10 0 715 4 /10 0 is over 70% more... 20 01) Region Total population (millions) /urban population (%) 19 50 North America Europe Oceania South and Central America Asia Africa Global © 2006 Taylor & Francis Group, London, UK 19 75 2000 2030 17 2/64 547/52 13 /62 16 7/ 41 1402 /17 2 21/ 15 2522/28 243/74 676/67 21/ 72 322/ 61 2406/25 406/25 4074/38 310 / 71 729/75 30/70 519 /75 3683/37 784/38 6055/47 372/84 6 91/ 83 41/ 74 726/83 4877/53 14 06/55 811 3/60 Water. .. in Figure 1. 13 shows a ground level tank with a volume of 1 2 m3, connected to the distribution network This reservoir receives the water in periods when the pressure in the distribution system is sufficient The © 2006 Taylor & Francis Group, London, UK 14 Introduction to Urban Water Distribution Pressure Pump Figure 1. 13 Individual storage in water scarce areas (Trifunovi-, 19 94) Figure 1. 14 Roof tanks... & Francis Group, London, UK 4 Introduction to Urban Water Distribution 5% 18 % 12 % 14 % 51% Extraction Connections Treatment Others Transport & Distribution Figure 1. 4 Structure of assets of the Dutch water supply works (VEWIN, 19 90) 10 % 6% 36% 48% Production ICT Distribution/ infrastructure Others Figure 1. 5 Annual investments in the Dutch water supply works (VEWIN, 20 01) recent data on annual investments... this pipe only needs to be sufficient to convey the average flow, while the maximum peak flow is going to be supplied by drawing the additional requirement from the balancing volume © 2006 Taylor & Francis Group, London, UK 12 Introduction to Urban Water Distribution Tokyo 23 Stockholm 50 Sophia 45 Rome 14 Moscow 36 London 86 Chicago 22 Budapest 24 Belgrade Figure 1. 11 Total storage volume in some... UK Water Transport and Distribution Systems 11 Stop cock Water meter Saddle Figure 1. 10 Schematic layout of a service connection Distribution pipe Pipe protection Watertight seal of the water supply company usually stops These can be different types of house or garden connections, as well as connections for non-domestic use One typical domestic service connection is shown in Figure 1. 10 1. 2.3 Storage... living without access to safe drinking water © 2006 Taylor & Francis Group, London, UK 2 Introduction to Urban Water Distribution North America Europe Oceania South and Central America Asia Africa Global Figure 1. 1 Water supply coverage in the world (WHO/UNICEF/WSSCC, 2000) 0 20 40 60 80 10 0 Percentage Urban Total Rural Asia in 2000 Asia in 19 90 Africa in 2000 Figure 1. 2 Growth of water supply coverage... where the focus has shifted towards environmental issues In many less developed countries, this is still a dream 1. 2 DEFINITIONS AND OBJECTIVES 1. 2 .1 Transport and distribution In general, a water supply system comprises the following processes (Figure 1. 6): 1 raw water extraction and transport, 2 water treatment and storage, 3 clear water transport and distribution Transport and distribution are technically... drinking water, these systems may be constructed for the conveyance of raw or partly treated water As a part of the drinking water system, the transport lines do not directly serve consumers They usually connect the clear water reservoir of a treatment 6 Introduction to Urban Water Distribution Transport raw water Transport clear water Source – water extraction Production – water treatment Distribution. .. performance of the network The main objectives of water transport and distribution systems are common: – supply of adequate water quantities, – maintaining the water quality achieved by the water treatment process © 2006 Taylor & Francis Group, London, UK 8 Introduction to Urban Water Distribution Figure 1. 8 Water distribution system in Zanzibar, Tanzania (Hemed, 19 96) Each of these objectives should be satisfied . 5 1. 2 .1 Transport and distribution 5 1. 2.2 Piping 9 1. 2.3 Storage 11 1. 2.4 Pumping 15 1. 3 Types of distribution schemes 16 1. 4 Network configurations 18 2 WATER DEMAND 21 2 .1 Terminology 21 2.2. 5 million inhabitants 327/8 704 /12 10 06 /14 Urban, below 1 million inhabitants 10 22/25 17 23/28 218 9/ 31 Rural 2530/62 3 210 /53 3337/46 Total 4074 /10 0 6055 /10 0 715 4 /10 0 © 2006 Taylor & Francis. 243/74 310 / 71 372/84 Europe 547/52 676/67 729/75 6 91/ 83 Oceania 13 /62 21/ 72 30/70 41/ 74 South and Central America 16 7/ 41 322/ 61 519 /75 726/83 Asia 14 02 /17 2406/25 3683/37 4877/53 Africa 2 21/ 15 406/25