The goal of this book is to draw a profile of the world behind the coastal engineers work. For a good understanding of this world, many other disciplines are needed. For example historical, geological, physical and economical information and activities are integrated into the terrain of the coastal engineer. Other disciplines, like biology and sociology, yield extremely important information for the coastal engineer, but as they are not integrated yet into the engineering approach, they are not worked out in this introduction. Apart irom that, a good approach cannot be made without a personal sense of what is going on. No book can give a complete picture of the coastal engineering practice, so in addition to studying this book, it is necessary to be curious and have a look at the coast. Not only in summer, but also during stormy weather; to sniff the spray and feel the sand blown by the wind.
CTwa4300 Coastal Engineering Volume T Faculty of Civil Engineering and Geosciences Subfaculty of Civil Engineering Hydraulic and Offshore Engineering Division Delft Delft University of Technology cTwa43oo Coastal Engineering Volume I Prof.ir K d'Angremond Ir C.M.G Somers 310222 cTwa43oo Coastal Engineering Volume I Prof.ir K d'Angremond Ir C.M.G Somers 310222 Contents List of Figxires List of Tables List of Symbols Preface Introduction 1.1 The coast 1.2 Coastal engineering 1.3 Structure of these lecture notes 3 The natural subsystem 2.1 Introduction 2.1.1 Dynamics of a coast 2.1.2 Genesis of the universe, earth, ocean, and atmosphere 2.1.3 Sea level change 2.2 Geology 2.2.1 Geologic time and definitions 2.2.2 Plate tectonics: the changing map of the earth 2.2.3 Tectonic classification of coasts 2.3 Climatology 2.3.1 Introduction 2.3.2 Meteorological system 2.3.3 From meteorology to climatology 2.3.4 The hydrological cycle 2.3.5 Solar radiation and temperature distributions 2.3.6 Atmospheric circulation and wind 2.4 Oceanography 2.4.1 Introduction 2.4.2 Variable density 2.4.3 Geostrophic currents 2.4.4 The tide 2.4.5 Seiches 2.4.6 Short waves 2.4.7 Wind wave statistics 2.4.8 Storm surges 2.4.9 Tsunamis 2.5 Morphology 2.5.1 Introduction 2.5.2 Surf zone processes 2.5.3 Sediment transport 2.5.4 Coastline changes 6 12 13 13 14 18 23 23 23 24 25 27 31 35 35 36 38 40 46 47 56 69 60 62 62 63 64 68 Coastal formations 3.1 Introduction 3.2 Transgressive coasts 3.2.1 Definition 3.2.2 Estuaries 3.2.3 Tidal 3.2.4 Lagoons 3.2.5 Beaches 3.2.6 Dunes 3.2.7 Barriers 3.2.8 Tidal inlets 3.3 Prograding coasts 3.3.1 Introduction 3.3.2 Classification of deltas 3.3.3 Young or old? 3.3.4 Delta shape 3.3.5 Human interest 3.4 Ecology-dominated coastal features 3.4.1 Salt marshes 3.4.2 Mangrove swamps 3.4.3 Coral reefs 3.5 Rocky coasts 3.5.1 Origin of rocky coasts 3.5.2 Rock erosion flats 70 70 73 73 73 78 78 80 81 82 85 86 86 86 87 89 94 96 96 98 99 104 104 105 Coast and culture 4.1 Introduction 4.2 Description of the socio-economic subsystem 4.2.1 Boundaries of the socio-economic subsystem 4.2.2 Structure of social and economic life 4.2.3 The necessity of management 4.3 Coastal Zone Management 4.3.1 Introduction 4.3.2 History of Coastal Zone Management 4.3.3 Pohcy analysis and its function 4.3.4 Management tools and strategies 4.3.5 Description of management practice 4.3.6 Where is the coastal engineer? 4.4 Global changes 4.4.1 The world doesn't stay still 4.4.2 Human-induced climate change 4.4.3 Global sea-level rise 4.4.4 Integrated Coastal Zone Management Ill Ill 112 112 112 113 116 116 119 119 121 122 124 126 126 127 127 130 The Netherlands, one specific coastal zone 133 5.1 5.2 5.3 5.4 5.5 Introduction Genesis of the Dutch coast 5.2.1 Geological time schedule 5.2.2 Geological overview 5.2.3 Sediment balance Dutch coastal engineering history 5.3.1 Old times 5.3.2 Modem times 5.3.3 Human influence on morphology Nature of the Dutch coast nowadays 5.4.1 Types of coast 5.4.2 Wadden coast 5.4.3 Delta coast 5.4.4 Dutch coast Social and economic environment of the coast in the Netherlands 5.5.1 Functions 5.5.2 Politics, interest groups 5.5.3 Economy 5.5.4 Infrastructure 5.5.5 Flexibility 133 133 133 136 143 145 145 151 154 156 156 158 158 159 161 161 162 163 164 166 Pollution and density problems 6.1 Introduction 6.2 Pollution 6.2.1 Types of pollution 6.2.2 Control measures 6.2.3 Density currents in harbors 6.3 Tidal inlets and estuaries 6.3.1 Introduction 6.3.2 Tidal inlets 6.3.3 Tidal curves in a river 6.3.4 Density problems 6.3.5 Tidal river morphology 171 171 171 171 173 174 185 185 185 187 187 192 7.1 Practical problems and common methods how to solve them Introduction 7.2 Design under wave load conditions 7.2.1 Introduction 7.2.2 Wave data 7.2.3 Wave load and optimum design techniques 7.3 Breakwaters 7.4 Shore protection 7.4.1 Introduction 7.4.2 Groynes 7.4.3 Dune protection 199 I99 200 200 200 201 205 207 207 209 211 7.5 7.6 7.4.4 Bad solutions 7.4.5 Artificial by-passing and beach nourishment 7.4.6 Coast-line dynamics Harbors and dredging 7.5.1 History 7.5.2 Soil type 7.5.3 Harbor dredging 7.5.4 Pipeline into trench 7.5.5 Artificial land winning 7.5.6 Polluted soil dredging Map reading 213 214 215 219 219 220 221 225 227 227 230 List of Figures Figure 2.1 Figure 2.2 Figure Figure Figure Figure Figure Figure Figure 2.3 2.4 2.5 2.6 2.7 2.8 2.9 Figure 2.10 Figure 2.11 Figure Figure Figure Figure Figure 2.12 2.13 2.14 2.15 2.16 Figure 2.17 Figure 2.18 Figure 2.19 Figure 2.20 Figure 2.21 Figure 2.22 Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure 2.23 2.24 2.25 2.26 2.27 2.28 2.29 2.30 2.31 2.32 2.33 Major factors influencing coastal environments (Martinez and Harbaugh [1993]) Model of the gravitational collapse theory of the origin of the solar system (Ingmanson and Wallace [1985]) Planetary orbits around the Sun (Spectrum Atlas [1973]) Geologic tune scale (Spectrum Atlas [1973]) Continental landmasses during the early Triassic Period (Davis [ 9 ] ) Continental drift (Wegener [1924]) Movements of the crust plates (Spectrum Atias [1973]) Movement in the asthenosphere (Tarbuck and Lutgens [1993]) Formation of leading and trailing edge coasts (from Inman and Nordstrom, [1971]) The coast near Antofagasta, Chile (Davis [1994]) Coarse gravel beach along a high-relief coast on the Sea of Cortez, Mexico (Davis [1994]) Namibian desert along the coast of southwest Africa (Davis [1994]) Coast near the mouth of the Amazon River in Brazil (Davis [1994]) The hydrological cycle (Harvey [1976]) Saturation vapour pressure as a function of temperature (Harvey [1976]) Distribution of radiation intensity with wave length for a black body, surface temperature 6000 K, representing the sun (Harvey [1976]) Reduction of solar radiation intensity as it is transmitted through the atmosphere (Harvey [1976]) Long-term mean values of incoming, short wave radiation and long wave, outgoing radiation for the earth atmosphere system, averaged over zones of latitude (Harvey [1976]) Air temperatures reduced to sea level in January and July, after Barry and Chorley (1971) Convection cell circulation on a non-rotating uniform earth Shnple Three-Cell Convection Schematic representation of zonal pressure belts and wind systems near the earth's surface (Harvey [1976]) Continental shelf The system of OTEC (Delta Marine Consultants) Global geostrophic current pattern (Stowe [1987]) Deviation of projectile path due to Coriolis Effect Rotating Earth-Moon system (van Urk and de Ronde [1980]) Equilibrium moon tide (van Urk and de Ronde [1980]) Daily inequality of the lunar tide (van Urk and de Ronde [1980]) Spring and neap tide (van Urk and de Ronde [1980]) Amphidromic system/tidal wave on the North Sea (RWS, TRl [1989]) Tidal bore on the Petitcodiac River, New Brunswick (Stowe [1987] Standing wave in a closed body of water 10 11 13 15 15 16 17 18 19 20 20 21 25 26 27 28 29 30 31 31 32 35 37 38 39 40 41 41 42 43 44 46 Figure Figure Figure Figure Figure 2.34 2.35 2.36 2.37 2.38 Figure 2.39 Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure 2.40 2.41 2.42 2.43 2.44 2.45 2.46 2.47 2.48 2.49 2.50 2.51 2.52 2.53 2.54 Figure 3.1 Figure 3.2 Figure 3.3 Figure 3.6 Figure 3.5 Figure Figure Figure Figure Figure Figure 3.4 3.7 3.8 3.9 3.10 3.11 Figure 3.12 Figure 3.13 Figure 3.14 Figure 3.15 Standing wave in a semi-closed body of water 47 Sinusoidal wave form 48 Orbital movement in short waves (linear theory) 49 Wave refraction 50 Waves approaching embayment and spreading into its shape due to refraction (Davis [1994]) 51 Various types of breakers may develop in the surf zone, each caused by a different combination of wave type and nearshore slope 54 Standing wave for = 1.0 (a) and reflection on slopes (b) 55 Wave diffraction 56 Different wave patterns forming a complicated sea surface (Davis [1994) 57 Irregular surface elevation resulting from waves 57 Rayleigh distribution of wave height in a given wave field 58 Wave energy spectrum and characteristic wave heights for a given wave field 58 WeibuU distribution for the B.^^^ at a specific North Sea site 59 The situation after the tsunami that struck near Minehaha, Japan 61 The morphological subsystem 62 Longshore current velocity profile 63 Circulation cell, rip currents 64 Circulation cell 64 Longshore and cross shore transport 65 Causes of a positive longshore-transport gradient 66 Sediment concentrations as a function of time (99 individual records) 67 Coastal forms for prograding and transgressive coasts (from Boyd et al [1992]) 70 Ternary shoreline classification diagram (Boyd et al, 1992, and Dalrymple et al, 1992) 71 Stratification in an estuary: density variations and velocity profiles 74 Time-averaged sediment transport paths 77 Schematic definition of estuary according to Dalrymple, Zaitlin and Boyd (1992) 77 Plan view of distribution of energy and physical processes in estuaries 77 Section through a barrier closing a lagoon (Bird [1984]) 78 Stages in the evolution of a barrier to enclose a lagoon (Bird, 1984) 79 Processes which control evolutionary processes in a lagoon 79 Sandy beach profile nomenclature (distorted scales) 80 Variety of dune types (adapted from Carter, 1988, Reading, 1986, and Flint, 1971) 81 Two-dmiensional and three-dimensional dunes (adapted from Reineck and Singh) 82 General barrier types: bay, spit, island 83 Drumstick model 84 Geological model of a tidal inlet with well-developed flood- and ebb-deltas (from Boothroyd, 1985, etal.) 85 Figure Figure Figure Figure 3.16 3.17 3.18 3.19 Figure 3.41 William Galloway's triangular delta classification diagram 86 Mississippi Delta 88 Niger Delta 89 Configurations of deltas; digitate (Mississippi), cuspate (Ebro), lobate (Niger) and blunt (Sao Francisco, Brazil) (after Wright and Coleman [1972]) 90 Historical stages in the growth of the Kilia lobe of the Danube Delta, Romani^>l Formation of a wave-dominated delta 92 Basic environments of a delta (from Wright, 1985) 93 Senegal River Delta 93 Sketch map showing the location of the Aswan High Dam, the flooded area, and Khasm el-Girba (H.M Fahim, 1972b) 94 A cross-section of a salt marsh 96 Common cordgrass (Spartina anglica) (Packham [1997]) 97 Mangrove roots and typical cross-section of mangal 98 The massive root systems of mangroves create dense sedhnent stabilizing mazes 99 Reef landform types (from Bird, 1983, and Verstappen, 1953) 100 Evolution of a coral island (adapted from Press and Siever, 1986) 101 Cross-sectional model of an individual coral 102 Fjord at Kenai Fjords National Park, Alaska 104 Gay Head, Martha's Vineyard, Massachusetts 105 Wave-erosion effects (adapted from de Blij and Muller [1993]) 106 This rock photographed near a beach in San Mateo County, California, is perforated by the spherical hollows called Tafoni 107 Drakes bay in Pt.Teyes National Seashore, California 107 Tasmanian coast of Australia 108 Rempton Cliffs in Yorkshire, England 108 Schooner Gulch, Mendicino State Park, California 109 The London Bridge arch along the Great Ocean Road in southwestern Victoria, Australia, July 1986 109 The London Bridge Arch in Februari 1989 110 Figure Figure Figure Figure Figure 3.20 3.21 3.23 3.22 3.24 Figure Figure Figure Figure 3.25 3.26 3.27 3.28 Figure Figure Figure Figure Figure Figure Figure 3.29 3.30 3.31 3.32 3.33 3.34 3.35 Figure Figure Figure Figure Figure 3.36 3.37 3.38 3.39 3.40 Figure 4.1 Figure 4.2 Figure 4.3 Fresh water coastal aquifer (Kamphuis, 1997) Divergent problem approaches Basis for scenarios regarding global sea level rise (Hoffman, 1983) 114 120 128 Figure 5.1 Figure 5.2 Figure 5.3 Geological time schedule, in C14 years and in sun years Holocene coastal plain sediment (Beets, v.d Spek e.a [1994]) Cross-section through the coastal sequence South from Haarlem (Beets v.d Spek e.a [1994]) Reconstruction of the Dutch coastal plain around 7000 BP, i.e around 5800 years A.D (Van der Spek, 1994) Qualitative view of the sand transport along the Dutch coast in the Atlanticum and early Subboreal (Beets, v.d.Spek et al, [1994]) Reconstruction of the Dutch coastal plain around 5300 BP, i.e around 4000 134 135 Figure 5.4 Figure 5.5 Figure 5.6 136 137 138 / Figure 7.22 i Plain suction dredger is more difficult to cut Then, a cutter suction (Figure 7.23) or a bucket dredger (Figure 7.24) is needed Under more severe wave conditions, a seagoing type must be used Often a hopper dredger (Figure 7.25) can the job A relatively new type of dredger is the water injection dredger (Figure 7.26) It makes use of the difference in density between a mixture of soh and water and water It injects a jet of water into the soil over a large width, which changes into a density current This density current moves into deeper places, for example out of the harbor 222 Figure 7.23 Cutter suction dredger barge warping winchi it -movabla side chute f o r w a r d port s i d e w i n c h • { -flxod Sid chute *^ VdtJdBr \ +^ y ' ^ " A, / starboard side w i n c h bowwinch l>arge w a r p i n g w i n c h Figure 7.24 Bucket dredger 223 ^ ^ forward starboard side winch "'""^ Figure 7.25 Hopper dredger Dredging a gully or the harbor hself is called capital dredging The soh often is consolidated Sometimes h is rock A cutter dredger is often seen Explosives can be used in combination with a hopper dredger, too 224 Figure 7.26 A Water injection dredger Figure 7.26 B Water injection beam in action Figure 7.26 C Principle of Water Injection Dredging 7.5.4 Pipeline into trench A pipeline going into a trench requires a combination of activities, often far offshore If the soil consists of sand, the flow-dredging method (Figure 7.27) can be used Trailing suction hopper dredgers or water injection dredgers can be used in such a way, that the seabed material is eroded from the work surface in a controlled manner by a large volume of water flow This water flow is generated several metres above the seabed, which enables accurate and safe excavation near pipelines or structures 225 Trailing suction hopper dredgei in Flo'/rtJredging' mode Water injection dredger in Ftowdfedging' mode Figure 7.27 Dredgers in flow-dredging mode Figure 7.28 Trencher A handy help can be a so-called trencher Such a thing is shown in Figure 7.28 In Figure 7.29, the special equipment of a trencher is clarified 226 UiTiijfiicai 4vcnlcaUhïUstcr3 Mass pump (cmüvessoil Buoyancy chambfir Figure 7.29 7.5.5 Special equipment of a trencher Artificial land winning Artificial land winning can be huge-sized Examples are: Maasvlakte in the Netherlands, airport Hongkong, Singapore harbor For such large projects, a fast, not to precise way of dredging is required A hopper dredger is often used 7.5.6 Polluted soil dredging Polluted soh dredging and storage puts strict requirements to the accuracy of the dredging process It should happen without any spills, the water should not get muddy, and there should not be put too much water into the pumped mixhire of polluted soil and water Suhable techniques can be: the use of wormwielzuiger (Figure 7.30) or bodemschijfcutter (Figure 7.31) Special attention must be paid to the transport of polluted soil The hydraulic method, using pipeline and pump, can be used only when the mixture of soh and water contains enough water Usually this is not the case when the soil is polluted The alternative is the use of barges or hopper dredgers In Figure 7.32, chemical processes during sediment discharge (possibly affecting the enviromnent) are shown 227 228 Figure 7.32 Chemical processes during sediment discharge 229 7.6 Map reading Did you ever loose your way? If you did, did you ask for it to someone else? Some people have enormous stamina against asking their way to someone It is commonly thought that especially men rather walk around the earth before asking where they are Women are generally supposed to be more flexible in that matter! In this paragraph, some example situations are given where orientation on a map plays an important role In Figure 7.33, part of a map shows of a coast section near Plymouth, England.The coast formation called "A" in the figure, can that be sph, and why? Such a map is an inexhaustile source of examination questions In Figure 7.34, another part of it is shown Take two different locations in river "B", one up- and one downstream What would be the main difference between the two? Here follow answers to the questions Map 7.33 shows no sph In case of sph, the longshore transport causing the coastal formation must be driven by waves incident under an angle In this case, and angle is not there This can be derived from the depth lines close to High Pine Ledge They would follow the same angle as the incident waves The main difference between two river locations is found in their tidal curves The farther upstream, the smaller the tidal prism, and therefore the horizontal tide whl be smaller, too In Figure 7.35, a Dutch map is shown which is used for shipping purposes What the numbers mean exactly? Which depths are meant, and what is the reference level? Note that the reference level is not die least of a horizontal plane! 230 Figure 7.33 Coast section near Plymouth (1) 231 Figure 7.34 Coast section near Plymoutli (2) 232 TO R O T T U M E R P L A A T UJ WADDENZEE S C H I E R M O N N I K O O G TOT R O T T U M E R O O G Ö : 50.000 {SA'H) I w DIEPTEN IN METERS SOUNDINBS IH METRES HOOGTEN IM METERS HEIGHTS IN METRES GFTIIGEgEVENS BOSCHPLAAT ft