WIXLIB

xivPREFACE TO THE THIRD EDITIONChapter 16.Chapter 15 ‘Coastal engineering’Consequently the whole material has been reorganized. Thetreatment of forces on cylindrical bodies in waves and currents has been significantly extended in Chapter 14. Chapter15 now includes an extended treatment of wave overtoppingand stability of breakwaters as well as a brief discussion ofcoastal management.(formerly ch. 15). Extended discussion of computationalmodelling of hydraulic structures.P. Novak, A.I.B. Moffat, C. Nalluri and R. NarayananNewcastle upon Tyne, August 2000

Preface to the secondeditionThe main aim of the book, i.e. to provide a text for final year undergraduate and for postgraduate students, remains the same as for the first edition;equally we hope that researchers, designers and operators of the manytypes of hydraulic structures covered in the book will find the text of interest and a useful reference source.We took the opportunity of a new edition to correct all (known)errors and to thoroughly update the text and references throughout. Atthe same time as a response to received comments and reviews as well as areaction to some new developments in the field, certain parts of the textwere rewritten or enlarged. Readers of the first edition may wish to notethe following major changes.Chapter 1.Chapter 2.Chapter 3.Chapter 4.Chapter 5.Chapter 6.Chapter 7.Chapter 8.Chapter 9.Extended text on site assessment for dams.Expanded treatment of geotechnical aspects, e.g. a newparagraph (2.8.3) on performance indices for earthfill cores,and a new brief section (2.10) on geosynthetics.Extended coverage of RCC dams with a new paragraph(3.7.3) dealing with developments in RCC construction.Enlarged text dealing with design flood estimation, reservoirsedimentation, interference waves and aeration on spillwaysand a new paragraph (4.7.6) on stepped spillways.Enlarged section on scour below spillways.A new paragraph (6.2.8) on overspill fusegates.Enlarged text on reservoir downstream hazard assessment.Enlarged text on multistage channels, geotextiles, Crumpweir computation and a new section (8.6) on river floodrouting.Extended text on fish passes and a new paragraph (9.1.6)on the effect of the operation of barrages on river waterquality.

xviPREFACE TO THE SECOND EDITIONChapter 10.Chapter 13.Chapter 14.Chapter 15.Enlarged text on canal inlets and scour at bridges and belowculvert outlets.A new short section (13.7) on benching.Change of title (from Coastal engineering) to Coastal andoffshore engineering incorporating a substantial new section(14.7) on sea outfalls and the treatment of wave forces onpipelines in the shoaling region.Change of title (from Scale models in hydraulic engineering)to Models in hydraulic engineering to include in the generaldiscussion of hydraulic models (15.1.1) a typology of mathematical models; also included a short paragraph (15.2.4) onmodelling of seismic response.The authors would like to thank the reviewers for their constructive comments and the publisher for providing the opportunity for this secondedition.P. Novak, A.I.B. Moffat, C. Nalluri and R. NarayananNewcastle upon Tyne, December 1994

Preface to the firsteditionThis text is loosely based on a course on ‘Hydraulic Structures’ whichevolved over the years in the Department of Civil Engineering at the University of Newcastle upon Tyne. The final-year undergraduate andDiploma/MSc postgraduate courses in hydraulic structures assume a goodfoundation in hydraulics, soil mechanics, and engineering materials, andare given in parallel with the more advanced treatment of these subjects,and of hydrology, in separate courses.It soon became apparent that, although a number of good books maybe available on specific parts of the course, no text covered the requiredbreadth and depth of the subject, and thus the idea of a hydraulic structurestextbook based on the course lecture notes came about. The hydraulicstructures course has always been treated as the product of team-work.Although Professor Novak coordinated the course for many years, he andhis colleagues each covered those parts where they could make a personalinput based on their own professional experience. Mr Moffat, in particular,in his substantial part of the course, covered all geotechnical engineeringaspects. In the actual teaching some parts of the presented text may, ofcourse, have been omitted, while others, particularly case studies (includingthe discussion of their environmental, social, and economic impact), mayhave been enlarged, with the subject matter being continuously updated.We are fully aware that a project of this kind creates the danger ofpresenting the subject matter in too broad and shallow a fashion; we hopethat we have avoided this trap and got it ‘about right’, with workedexamples supplementing the main text and extensive lists of referencesconcluding each chapter of the book.This text is not meant to be a research monograph, nor a designmanual. The aim of the book is to provide a textbook for final-yearundergraduate and postgraduate students, although we hope thatresearchers, designers, and operators of the many types of hydraulic structures will also find it of interest and a useful reference source.

xviiiPREFACE TO THE FIRST EDITIONThe text is in two parts; Part One covers dam engineering, and PartTwo other hydraulic structures. Mr A.I.B. Moffat is the author of Chapters 1, 2, 3 and 7, and of section 15.2. Dr C. Nalluri wrote Chapters 9, 10,12 and 13, and sections 8.4 and 8.5. Dr R. Narayanan of UMIST wasinvited to lecture at Newcastle for two years, on coastal engineering, and isthe author of Chapter 14. The rest of the book was written by ProfessorP. Novak (Chapters 4, 5, 6 and 8, except for sections 8.4 and 8.5, Chapter11 and section 15.1), who also edited the whole text.P. Novak, A.I.B. Moffat, C. Nalluri and R. NarayananNewcastle upon Tyne, 1989

AcknowledgementsWe are grateful to the following individuals and organizations who havekindly given permission for the reproduction of copyright material (figurenumbers in parentheses):Thomas Telford Ltd (4.1, 4.2); US Bureau of Reclamation (4.3, 4.7,4.15, 4.16, 5.6, 5.7); Elsevier Science Publishers (4.5, 4.12, 4.13, 5.5, 5.8,5.10. 11.1, 11.2, 11.10, 11.11, 11.16, 11.17, 11.18, 12.17); British Hydromechanics Research Association (4.11, 13.6, 13.9); Institution of Waterand Environmental Management (4.18); ICOLD (4.19, 4.20); Figures 4.21,6.2, 6.3, 6.4 reproduced by permission of John Wiley & Sons Ltd, fromH.H. Thomas, The Engineering of Large Dams, 1976; C.D. Smith (6.6,6.7); MMG Civil Engineering Systems Ltd (8.20); E. Mosonyi (9.12, 9.13,12.17); International Institute for Land Reclamation and Improvement,the Netherlands (10.14, 10.15); Morgan-Grampian Book Publishing (11.1,11.5); Delft Hydraulics (11.7); Macmillan (14.12); C.A.M. King (14.13);C. Sharpe (11.2); J. Lewin (6.1, 6.2).Cover image courtesy of Ingetec S.A. Colombia (Dr A. Marulanda)

List of 83.13.23.33.43.53.63.73.83.93.103.114.17.1Large dams: World Register statisticsSummary of numbers of British, US and Chinese damsHighest damsLargest-volume damsDams with largest-capacity reservoirsNotional foundation stresses: dams 100 m in heightDam selection: type characteristicsRepresentative physical characteristics of soilsDescriptive consistency of clay soilsIllustrative engineering properties for selected soil typesEmbankment dam defect mechanisms and preventivemeasuresCharacteristics of core soilsIndicative engineering properties for compacted earthfillsGuideline factors of safety: effective stress stability analysisSeismic acceleration coefficients, h, and earthquakeintensity levelsSeismic pressure factors, CeNominated load combinationsRange of shearing resistance parametersFoundation rock shear strength characteristicsExamples of shear strength degradationRecommended shear friction factors, FSFComparative sliding stability factors: triangular gravity profilePermissible compressive stressesIllustrative values for coefficient, K0Characteristics of mass concrete for damsCharacteristics of RCCs for damsFlood, wind and wave standards by dam categorySelected major dam disasters 8141143147154173177194290

LIST OF 516.1Primary monitoring parameters and their relationship topossible defectsRepresentative monitoring frequenciesTypes of weirCorrection factors for submerged (non-modular) flowsValues of for parallel flowTypes of flow in the barrel of a culvertBridge loss coefficient, KBValues of K as a function of pier shapeValues of KN and KAPermissible velocities to withstand erosionRange of values of C for free flow over the embankmentCorrection factor, f (non-modular flows)Freight on inland waterways: annual throughput of shippingRange of values, specific speeds and headsQ–H–Ns dataRunaway speeds and acceptable head variationsCritical plant sigma values, cTypes of pumps and their applicationsSpecific speeds for rotodynamic pumpsSludge flow head lossesFactor r for various armour unitsValues of coefficients A and B for simple sea wallsValues of KD in Hudson’s formula (SPM): no damageand minor overtoppingLayer coefficient K D and porosity for various armour unitsVariation in damage number for failure conditionsScale 09510511550551568644646649650652680xxi

Main symbolsaAbBBcCCdCDCvdDEefFFDFrFSLgGWLh hHHsHFLiIconstant, gate opening, pressure wave celerity, wave amplitudecross-sectional areabreadth, channel width, constant, length of wave crestwater surface widthporewater pressure coefficientapparent cohesion, coefficient, constant, unit shearing strength,wave celerityChezy coefficient, coefficient, concentrationcoefficient of dischargedrag coefficientcoefficient of consolidation, coefficient of velocitydepth, diameter, sediment grain sizediameter, displacement of vesselscut-off (core) efficiency, energy, Young’s modulusenergy loss, pipe wall thicknesscorrection factor, frequency, function, Lacey’s silt factorfactor of safety, fetch, force, functiondrag forceFroude numberfull supply levelgravitational accelerationground water leveluplift pressure headhead, pump submergence, rise of water level above SWL, stagetotal energy (head), head (on spillway etc.), wave (embankment)heightseepage head, significant wave height, static lifthigh flood levelhydraulic gradientinflow, influence factor, moment of inertia

MAIN S0ShSWLtTuuwUU* VVcwwsWcoefficient (of permeability), effective pipe roughness, wavenumberbulk modulus, channel conveyance, coefficientKeulegan–Carpenter numberlengthlength, wavelengthmasscoefficient of volume compressibilitymomentManning roughness coefficienthydraulic exponent speed in rev/minnumber of increments of potential in flownetnumber of flow channels in flownetspecific speednormal water leveloutflownumber of poles, pressure intensityvapour pressureforce, power, wetted perimeterspecific dischargedischargedischarge of sedimentfactor, radiuspore pressure ratiohydraulic radius, resistance, resultant, radiusReynolds numberrégime scour depthmaximum shearing resistance, slopecritical slopefriction slopebed slopeStrouhal numberstill water levelthickness, timedraught, time, wave periodlocal velocity (x direction)porewater pressurewind speedshear velocityvelocity (general), velocity (y direction)mean cross-sectional velocity, storage, volumecritical velocitymoisture content, velocity (z direction)sediment fall velocityrégime width, weightxxiii

xxivMAIN SYMBOLSxyy y ycymysz µv s 1,2,3 c 0 distance, x coordinateflow depth, y coordinatestilling basin depthdepth of centroid of section Acritical depthmean depth ( A/B)maximum scour (local) depth, turbine settingdepth, elevation relative to datum, z coordinateangle, constant, energy (Coriolis) coefficient, (seismic)coefficient, wave crest angleangle, momentum (Boussinesq) coefficient, slope, anglespecific (unit) weight ( pg)boundary layer thickness, deflection settlementlaminar sublayer thickness)/ )relative density of sediment in water (( sstrainarea reduction coefficient, efficiencyangle, velocity coefficientDarcy–Weisbach friction factor, flownet scale transform factordynamic viscosity of waterkinematic viscosity of water, Poisson ratiocoefficient (head loss), parameterdensity of waterdensity of sediment particlecavitation number, conveyance ratio, safety coefficient, stress,surface tensionmajor, intermediate and minor principal stresseseffective stress, safety coefficientshear stress, time intervalcritical shear stressboundary shear stressangle of shearing resistance or internal friction, function,sediment transport parameter, speed factorflow parameterangular velocity (radians s 1)

Part OneDam engineering

Chapter 1Elements of damengineering1.1GeneralThe construction of dams ranks with the earliest and most fundamental ofcivil engineering activities. All great civilizations have been identified withthe construction of storage reservoirs appropriate to their needs, in theearliest instances to satisfy irrigation demands arising through the development and expansion of organized agriculture. Operating within constraints imposed by local circumstance, notably climate and terrain, theeconomic power of successive civilizations was related to proficiency inwater engineering. Prosperity, health and material progress becameincreasingly linked to the ability to store and direct water.In an international context, the proper and timely utilization of waterresources remains one of the most vital contributions made to society bythe civil engineer. Dam construction represents a major investment inbasic infrastructure within all nations. The annual completion rate fordams of all sizes continues at a very high level in many countries, e.g.China, Turkey and India, and to a lesser degree in some more heavilyindustrialized nations including the United States.Dams are individually unique structures. Irrespective of size andtype they demonstrate great complexity in their load response and in theirinteractive relationship with site hydrology and geology. In recognition ofthis, and reflecting the relatively indeterminate nature of many majordesign inputs, dam engineering is not a stylized and formal science. Aspractised, it is a highly specialist activity which draws upon many scientificdisciplines and balances them with a large element of engineering judgement; dam engineering is thus a uniquely challenging and stimulating fieldof endeavour.

4ELEMENTS OF DAM ENGINEERING1.2Introductory perspectives1.2.1Structural philosophy and generic types of damsThe primary purpose of a dam may be defined as to provide for the saferetention and storage of water. As a corollary to this every dam must represent a design solution specific to its site circumstances. The design therefore also represents an optimum balance of local technical and economicconsiderations at the time of construction.Reservoirs are readily classified in accordance with their primarypurpose, e.g. irrigation, water supply, hydroelectric power generation,river regulation, flood control, etc. Dams are of numerous types, and typeclassification is sometimes less clearly defined. An initial broad classification into two generic groups can be made in terms of the principal construction material employed.1.2.Embankment dams are constructed of earthfill and/or rockfill. Upstreamand downstream face slopes are similar and of moderate angle, giving awide section and a high construction volume relative to height.Concrete dams are constructed of mass concrete. Face slopes are dissimilar, generally steep downstream and near vertical upstream, anddams have relatively slender profiles dependent upon the type.The second group can be considered to include also older dams of appropriate structural type constructed in masonry. The principal types of damswithin the two generic groups are identified in Table 1.1. Essentialcharacteristics of each group and structural type are detailed further inSections 1.3 and 1.4.Embankment dams are numerically dominant for technical and economic reasons, and account for an estimated 85–90% of all dams built.Older and simpler in structural concept than the early masonry dam, theTable 1.1Large dams: World Register statistics (ICOLD, 1998)GroupTypeICOLD codeEmbankment iple archPGVACBMVConcrete dams(including masonrydams)Total large dams%冧82.911.34.41.00.441 413

INTRODUCTORY PERSPECTIVESembankment utilized locally available and untreated materials. As theembankment dam evolved it has proved to be increasingly adaptable to awide range of site circumstances. In contrast, concrete dams and theirmasonry predecessors are more demanding in relation to foundation conditions. Historically, they have also proved to be dependent upon relatively advanced and expensive construction skills and plant.1.2.2Statistical perspectiveStatistics are not available to confirm the total number of dams in serviceworldwide. Accurate statistical data are confined to ‘large’ dams enteredunder national listings in the World Register of Dams, published by theInternational Commission on Large Dams.ICOLD is a non-governmental but influential organization representative of some 80 major dam-building nations. It exists to promote theinterchange of ideas and experience in all areas of dam design, construction, and operation, including related environmental issues. La

Alternatively our books are available from all good bookshops. Hydraulic Structures Fourth Edition P. Novak, A.I.B. Moffat and C. Nalluri School of Civil Engineering and Geosciences, University of Newcastle upon Tyne, UK and R. Narayanan Formerly Department of Civil and Structural E