This page intentionally left blank P1: FCH/FYX P2: FCH/FYX QC: FCH/UKS T1: FCH CB373-FM CB373 July 18, 2001 11:7 Char Count= 0 COASTAL PROCESSES The world’s coastlines, dividing land from sea, are geological environ- ments unique in their composition and the physical processes affecting them. Humans have been building structures throughout history at these dynamically active intersections of land and the oceans. Although coast- lines were initially used for naval and commercial purposes, more recently recreation and tourism have increased activity in the coastal zones dra- matically. Shoreline development is now causing a significant conflict with natural coastal processes. This text on coastal engineering will help the reader understand these coastal processes and develop strategies to cope effectively with shoreline erosion. The book is organized into four parts: (1) an overview of coastal engineering using case studies to illustrate problems; (2) a consideration of the hydrodynamics of the coastal zone reviewing storm surges, water waves, and low-frequency motions within the nearshore and surf zone; (3) a discussion of coastal responses, including equilibrium beach profiles and sediment transport; and (4) a presentation of applications such as erosion mitigation, beach nourishment, coastal armoring, tidal inlets, and shoreline management. Students, practicing engineers, and researchers in coastal engineer- ing and coastal oceanography will find this book an invaluable resource for understanding the mechanisms of erosion and designing shoreline structures. Robert G. Dean is Graduate Research Professor, Department of Civil and Coastal Engineering, University of Florida. Professor Dean is a member of the National Academy of Engineering and serves as President of the Coastal Engineering Research Council. Robert A. Dalrymple is E. C. Davis Professor of Civil and Environmen- tal Engineering and founding director of the Center for Applied Coastal Research at the University of Delaware. Professors Dean and Dalrymple are also authors of the well-known Water Wave Mechanics for Engineers and Scientists. P1: FCH/FYX P2: FCH/FYX QC: FCH/UKS T1: FCH CB373-FM CB373 July 18, 2001 11:7 Char Count= 0 P1: FCH/FYX P2: FCH/FYX QC: FCH/UKS T1: FCH CB373-FM CB373 July 18, 2001 11:7 Char Count= 0 COASTAL PROCESSES with Engineering Applications ROBERT G. DEAN University of Florida ROBERT A. DALRYMPLE University of Delaware P1: FCH/FYX P2: FCH/FYX QC: FCH/UKS T1: FCH CB373-FM CB373 July 18, 2001 11:7 Char Count= 0 The Pitt Building, Trumpington Street, Cambridge, United Kingdom The Edinburgh Building, Cambridge CB2 2RU, UK 40 West 20th Street, New York, NY 10011-4211, USA 477 Williamstown Road, Port Melbourne, VIC 3207, Australia Ruiz de Alarcón 13, 28014 Madrid, Spain Dock House, The Waterfront, Cape Town 8001, South Africa http://www.cambridge.org © Cambridge University Press 2004 First published in printed format 2001 ISBN 0-511-03791-0 eBook (Adobe Reader) ISBN 0-521-49535-0 hardback P1: FCH/FYX P2: FCH/FYX QC: FCH/UKS T1: FCH CB373-FM CB373 July 18, 2001 11:7 Char Count= 0 Contents Prefacepageix Acknowledgmentsxi PART ONE. INTRODUCTION TO COASTAL PROCESSES 1Overview3 1.1Introduction3 1.2SomeTerminologyoftheCoasts6 1.3ExamplesofCoastalEngineeringProjects9 REFERENCES19 EXERCISES19 APPENDIX:USEFULUNITS20 2SedimentCharacteristics21 2.1Introduction21 2.2SandComposition21 2.3GrainSize s22 2.4Shape29 2.5Porosity29 2.6FallVelocity30 REFERENCES32 EXERCISES33 3Long-TermProcesses35 3.1Introduction35 3.2RelativeSeaLevelChange36 3.3EquilibriumBeachProfile42 3.4Classificationo fShorelin es45 REFERENCES65 EXERCISES66 PART TWO. HYDRODYNAMICS OF THE COASTAL ZONE 4TidesandStormSurges73 4.1Introduction74 4.2AstronomicalTides74 4.3StormSurges78 v P1: FCH/FYX P2: FCH/FYX QC: FCH/UKS T1: FCH CB373-FM CB373 July 18, 2001 11:7 Char Count= 0 vi CONTENTS REFERENCES86 EXERCISES87 5WavesandWave-InducedHydrodynamics88 5.1Introduction88 5.2WaterWaveMechanics89 5.3Cross-ShoreandLongshoreCurrents103 5.4Low-FrequencyMotionsattheShoreline105 5.5NearshoreCirculationandRipCurrents111 5.6SwashZoneDynamics114 REFERENCES121 EXERCISES125 PART THREE. COASTAL RESPONSE 6FieldMeasurementTechniquesandAnalysis133 6.1Introduction133 6.2BeachProfileMeasurements134 6.3AnalysisofBeachProfileData138 6.4HistoricalShorelineChange149 6.5MajorFieldCampaigns152 6.6InnovativeFieldTechniques154 REFERENCES158 EXERCISES160 7EquilibriumBeachProfiles162 7.1Introduction162 7.2MethodsofDerivingEquilibriumBeachProfiles163 7.3 Constructive and Destructive Forces Acting on Beach Profiles164 7.4DevelopmentofEquilibriumBeachProfileTheories166 7.5ApplicationsoftheEquilibriumProfile186 REFERENCES202 EXERCISES203 8SedimentTransport210 8.1Introduction210 8.2IncipientSandMotionandDepthofClosure212 8.3LongshoreSedimentTransport218 8.4Cross-ShoreSedimentTransport232 8.5LittoralDriftApplications241 8.6OverwashandWashover248 8.7AeolianSedimentTransport250 8.8IllustrationsofSandTransportandDuneAccumulation254 8.9CohesiveSediments254 REFERENCES261 EXERCISES266 9MiscellaneousCoastalFeatures275 9.1Introduction275 9.2NearshoreMorphology276 P1: FCH/FYX P2: FCH/FYX QC: FCH/UKS T1: FCH CB373-FM CB373 July 18, 2001 11:7 Char Count= 0 CONTENTS vii 9.3CrenulateBays278 9.4SandWaves281 9.5MultipleOffshoreSandbars282 9.6BeachCusps285 9.7Summary296 REFERENCES297 EXERCISES299 10ModelingofBeachesandShorelines301 10.1Introduction301 10.2PhysicalModelingofCoastalProcesses302 10.3AnalyticalModeling313 10.4NumericalModeling328 REFERENCES336 EXERCISES338 PART FOUR. SHORELINE MODIFICATION AND ANALYSIS 11BeachFillandSoftEngineeringStructures343 11.1Introduction343 11.2BeachNourishment(BeachFill)344 11.3SubmergedBerms374 11.4BeachDrains379 REFERENCES382 EXERCISES384 12HardEngineeringStructures387 12.1Introduction387 12.2PerchedBeach388 12.3Groins389 12.4OffshoreBreakwaters394 12.5ArtificialHeadlands400 12.6Revetments402 12.7Seawalls404 12.8OtherCoastalProtectionDevice s406 12.9JettiesandInlets407 12.10 Monitoring and Mitigation for All Coastal Structures409 REFERENCES410 EXERCISES411 13TidalInlets413 13.1Introduction413 13.2TidalHydrodynamics414 13.3InletStability433 13.4SedimentaryRelationshipsatInlets437 13.5SandBypassingatInlets441 13.6InletDesignConsiderations447 13.7AnExampl e448 REFERENCES449 EXERCISES450 P1: FCH/FYX P2: FCH/FYX QC: FCH/UKS T1: FCH CB373-FM CB373 July 18, 2001 11:7 Char Count= 0 viii CONTENTS 14ShorelineManagement452 14.1Introduction452 14.2OptionsandFactors453 14.3TheRoleofSetbacksandConstructionStandards457 14.4ProtectiveValueofaWideBeach461 14.5SandRights463 REFERENCES464 AuthorIndex465 SubjectIndex471 P1: FCH/FYX P2: FCH/FYX QC: FCH/UKS T1: FCH CB373-FM CB373 July 18, 2001 11:7 Char Count= 0 Preface This book is written for graduate students, researchers, and practitioners in the fields of coastal engineering, nearshore oceanography, and marine geology. Although the treatment in many chapters is rather mathematical, it is hoped that our message does not get swamped by the delivery. The book, which deals primarily with sandy coastlines, is divided into four parts. The first, Introduction to Coastal Processes, provides an overview of the problems of coastal engineering based on examples and a geological perspective of the field. Part 2, Hydrodynamics of the Coastal Zone, reviews storm surges, water waves, and low-frequency motions within the nearshore and surf zone. The third part, Coastal Response, discusses the equilibrium beach profile and sediment transport. Finally, the last section, Shoreline Modification and Analysis, covers aspects of erosion mit- igation such as beach nourishment and coastal armoring, tidal inlets, and shoreline management. We have attempted to include much of the important work in the field, but, given a book with such a broad scope, we have beenforced to omit (or overlook) a con- siderable amount of the literature. An attempt has been made to reference those contributions that clarified the physics of the processes or provided a model for engi- neering applications. Nevertheless, the book is biased toward our own experiences, which means that much of our work and many U.S. examples are presented. To our colleagues and friends whose work we have used, thanks, and to those whom we have egregiously omitted, our apologies. The field of coastal engineering is changing rapidly. Perforce, this book is a snap- shot of the field (albeit with a long exposure, when one considers how long it took us to write the book!), and many parts of it are subject to becoming outmoded soon. The reader is cautioned to review the recent literature before drawing conclu- sions. The bulk of the literature in the field of coastal engineering appears in such journals as Coastal Engineering; Journal of Waterway, Port, Coastal and Ocean En- gineering; Coastal Engineering Journal; and the Journal of Geophysical Research, as well as a variety of conference proceedings. Chief among these conferences is the biennial International Conference on Coastal Engineering, which is hosted by ix P1: FCH/FYX P2: FCH/FYX QC: FCH/UKS T1: FCH CB373-FM CB373 July 18, 2001 11:7 Char Count= 0 x PREFACE different countries around the world. The reader is referred to these original sources to provide a fuller explicationof the field. Robert G. Dean Department of Civil and Coastal Engineering University of Florida Robert A. Dalrymple Center for Applied Coastal Research Department of Civil and Environmental Engineering University of Delaware P1: FCH/FYX P2: FCH/FYX QC: FCH/UKS T1: FCH CB373-FM CB373 July 18, 2001 11:7 Char Count= 0 Acknowledgments We are