Handbook of Coastal and Ocean Engineering

The following sections are included:

• Preface
• The Editor
• Contributors
• Contents

A body of literature quantifying wave attenuation through vegetation has developed within the last few decades and serves as the foundation for growing interest in wetlands for engineering with nature applications. Wave dissipation is shown to be highly variable, influenced by hydrodynamics, plant structure, and the interaction between the two. The current method of predicting wave dissipation often makes use of an empirical drag coefficient, which is given as a function of nondimensional flow parameter. These empirical equations are shown to have limitations, particularly in the transition from the submerged to emergent regime, and are highly variable in nature and in magnitude. Vegetation is shown to preferentially dissipate energy at frequencies higher than the spectral peak for single- and double-peaked wave spectra. Idealized simulations of Jamaica Bay with STeady-state spectral WAVE (STWAVE) demonstrate the potential for vegetation to provide shoreline protection by reducing wave height under severe wind and water level conditions.

Wave setup is the increase of water level within the surf zone due to the transfer of wave-related momentum to the water column during wave-breaking. Wave setup has been investigated theoretically and under laboratory and field conditions, and it includes both static and dynamic components. Engineering applications include a significant flooding component due to severe storms and oscillating water levels that can increase hazards to recreational beach goers and can contribute to undesirable oscillations of both constructed and natural systems including harbors and moored ships. This chapter provides a review of the knowledge regarding wave setup and presents preliminary recommendations for design. It will be shown that wave setup is not adequately understood quantitatively for engineering design purposes.

The fundamental solutions to the wavemaker boundary value problem (WMBVP) are given for 2D channels, 3D basins, and circular basins. The solutions are given in algebraic equations that replace integral and differential calculus. The solutions are generic and apply to both full- and partial-draft piston and hinged wavemakers; to double-articulated wavemakers, and to directional wave basins. The WMBVP is solved by conformal mapping and by domain mapping. The loads on a wavemaker are connected to the radiation boundary value problem for semiimmersed bodies and demonstrate the connection of these loads to the added mass and radiation damping coefficients required to compute the dynamic response of large Lagrangian solid bodies.

The Wiggins–Holmes extension of the generalized Melnikov method (GMM) to higher dimensions and the extension of the Generalized Herglotz Algorithm (GHA) to nonautonomous systems are applied to weakly damped parametrically excited cross waves with surface tension in order to demonstrate that cross waves are chaotic. The GMM is a global perturbation analysis about a manifold of fixed points that are connected by separatrices for higher dimensional nonlinear dynamical systems. The Luke Lagrangian, density function for surface gravity waves with surface tension and dissipation is expressed in three generalized coordinates that are the time-dependent components of three velocity potentials that represent three standing waves. The Hamiltonian for these cross waves is homomorphic to the Hamiltonian for a parametrically excited pendulum that is an example of a Floquet oscillator that may be approximated by the Mathieu equation. Neutral stability curves measured from wave tank data motivated the inclusion of dissipation in the Luke Lagrangian density function for cross waves. An integral containing a generalized dissipation function that is proportional to the Stokes material derivative of the free surface is added to the Luke Lagrangian integral so that dissipation is correctly incorporated into the dynamic free surface boundary condition. The generalized momenta are computed from the Lagrangian; and the Hamiltonian is computed from a Legendre transform of the Lagrangian. This Hamiltonian contains nonautonomous components and is transformed by three canonical transformations in order to obtain a suspended system for the application of the Kolmogorov–Arnold–Moser (KAM) averaging operation and the GMM. The system of nonlinear nonautonomous evolution equations determined from Hamilton’s equations of motion of the second kind must be averaged in order to obtain an autonomous system that may be analyzed by the GMM. Hyperbolic saddle points that are connected by heteroclinic orbits are computed from the unperturbed autonomous system. The nondissipative perturbed Hamiltonian system with surface tension satisfies the KAM nondegeneracy requirements; and the Melnikov integral is calculated to demonstrate that the motion is chaotic. For the perturbed dissipative system with surface tension, the only hyperbolic fixed point that survives the averaged equations is a fixed point of weak chaos that is not connected by a homoclinic orbit; and, consequently, the Melnikov integral is identically zero. The chaotic motion for the perturbed dissipative system with surface tension is demonstrated by numerical computation of positive Liapunov characteristic exponents. A chaos diagram of the largest Liapunov exponent demonstrates regions in the Floquet forcing parameter space of possible chaotic motions; and the range of values of the Floquet parametric forcing parameter ∊ and of the wavemaker dissipation parameter α in the α−∊ space where chaotic motions may exist.

A review is made on the statistical features of breaking waves in the nearshore waters. Inherent variability of the breaker index for regular waves is examined with the revised Goda’s formula. The incipient breaking height of significant wave is about 30% lower than that of regular waves. Nonlinearity of random waves is strongest at the outer edge of surf zone, but it is destroyed by wave-breaking process inside the surf zone. The wave height distribution is the narrowest in the middle of the surf zone, but it returns to the Rayleigh near the shoreline. Large differences among various wave models are noted for prediction of wave heights in the surf zone.

This chapter presents a brief summary of aeration in the surf zone, beginning with a review of air–water characteristics in surf zone waves. Second, measurements techniques of the bulk of air and bubbles induced by breaking waves in the surf zone are described, and third, the bulk of air and bubble characteristics are summarized based on the in situ and visualization laboratory measurements. Finally, the gas transfer in the surf zone is described and related to the wave characteristics.

In this chapter, we describe mechanisms that lead to the occurrence of freak waves in the ocean. It is now generally recognized that freak waves can be generated by any one of four possible mechanisms. The traditional mechanism is a simple linear superposition of waves, the theory of which is reviewed here. The newest mechanism attempts to include the third-order nonlinearities that depart from linear wave theory. Therefore, we present here a state-of-the-art review that is based on nonlinear wave dynamics.

This chapter deals with the short-term statistical properties of irregular sea waves. It begins with a description of an early study by Rice [Bell Syst. Tech. J. 23, 282–332; 24, 46–156 (1944, 1945)] about the relation between wave spectra and statistics of wave amplitudes. Next, an explanation is given of studies which deal with the effect of spectrum width and wave nonlinearity on wave statistics as well as with joint statistical properties between wave heights and periods. Finally, the chapter closes with a look at the statistics of wave direction, length of wave crest, and spatial maximum amplitude (which are the 3D wave’s properties) as well as the time series of wave height.

The integrally coupled wave–tide–surge model based on hydrodynamic and spectral wave models with an unstructured mesh system was tested during the typhoon Bolaven, which hit the Korean Peninsula in 2012, killing 19 people. The identical and homogeneous mesh allows the physics of wave circulation interactions to be correctly resolved in the coupled model. The unstructured mesh can be applied to a large domain, allowing all energy from deep to shallow waters to be seamlessly followed. The model results were compared with the observations, and the performance of the model was evaluated. The results show that incorporating the wave–current interaction effect into coastal areas in the wave–tide–surge coupled model is important. The model should consider effects of depth-induced wave breaking, wind field, currents, and sea surface elevation in the prediction of waves. The resulting modeling system can be used for hindcasting (prediction) and forecasting the wave–tide–surge coupled environments at complex coastlines, shallow water and fine sediment areas, such as around the Korean Peninsula.

A resume is presented of recent work that has identified the mechanism through which the seiches are generated that occasionally occur in Rotterdam Harbor basins, and that has led to the development and implementation of an operational warning system for the occurrence of significant seiche events. The generation is due to moving systems of atmospheric convection cells that can arise over the relatively warm water of the North Sea, behind a cold front. These cause fluctuations in wind speed and atmospheric pressure that can generate long waves at sea, as these cells move toward the coast. The average variance spectrum of these long-wave surface elevations is found to have an approximately f^−1.5 tail. As these long waves at sea approach the harbor mouth, they can be resonantly amplified inside certain semi-closed basins. The ratio of seiche amplitudes in two different basins, derived through numerical simulations based on a 2DH mildslope model and an incident f^−1.5 long-wave elevation spectrum, is in excellent agreement with the mean ratio derived from observations for the same locations. Finally, the principle of a possible system of prediction of the occurrence of seiche events is described. Its predictive potential is proven through a series of hindcasts. Based on these promising results, an operational forecasting system has been developed and implemented by the authorities involved.

This chapter presents an overview of seiches and harbor oscillations. Seiches are long-period standing oscillations in an enclosed basin or in a locally isolated part of a basin. They have physical characteristics similar to the vibrations of a guitar string or an elastic membrane. The resonant (eigen) periods of seiches are determined by basin geometry and depth and in natural basins may range from tens of seconds to several hours. The set of seiche eigen frequencies (periods) and associated modal structures are a fundamental property of a particular basin and are independent of the external forcing mechanism. Harbor oscillations (coastal seiches) are a specific type of seiche motion that occur in partially enclosed basins (bays, fjords, inlets, and harbors) that are connected through one or more openings to the sea. In contrast to seiches, which are generated by direct external forcing (e.g., atmospheric pressure, wind, and seismic activity), harbor oscillations are mainly generated by long waves entering through the open boundary (harbor entrance) from the open sea. Energy losses of seiches in enclosed basins are mostly due to dissipative processes, while the decay of harbor oscillations is primarily due to radiation through the mouth of the harbor. An important property of harbor oscillations is the Helmholtz mode (pumping mode), similar to the fundamental tone of an acoustic resonator. This mode is absent in a closed basin…

A practical numerical model based on the dispersion-correction finite difference scheme of Yoon et al. [Terres. Atmos. Oceanic Sci. 18(1), 31–53 (2007)] equipped with the grid nesting scheme of Lim et al. [Natural Hazards 47(1), 95–118 (2008)] is introduced. The model is applied to simulate the propagation of a historical tsunami event that attacked the east coast of Korea. The calculated free surface displacements are compared with the observations at two tidal stations along the east coast of Korea. The comparison shows that the results agree well with the observations. The analyses of the simulated results show that the underwater topography such as submerged rises and ridges plays an important role in the propagation of tsunamis in this region.

Optimum safety levels for breakwaters corresponding to minimum lifetime costs are identified by life cycle cost optimization simulations. Safety levels for rock and cube armored rubble mound breakwaters, berm breakwaters, breakwaters armored with single-layer complex types of armor unit, and caisson breakwaters on rock and sand seabeds are presented corresponding to serviceability limit state, repairable limit state, and ultimate limit state. Methods of probabilistic design to target safety levels and design based on application of partial safety factors are discussed. Example application of partial safety factors for design of a breakwater is presented.

Berm breakwaters may be a good alternative for rock armored slopes and even concrete armored slopes or breakwaters. Guidance on berm breakwater design, including large rock quarrying, was lacking as this type of breakwater does not belong to the conventional designs of rock and concrete armor. Some guidance by the authors became available in recent years in conference papers and that all has resulted in a book on berm breakwaters. This chapter considers the actual geometrical design of three cross-sections of berm breakwaters, depending on available rock sizes as well as on the design wave climate. Three wave climates are taken: 3, 5, and 7 m. For each wave climate, various maximum rock classes are considered, which in reality will depend on availability of such rock. One design has been presented for each wave climate and one is referred to the book for a number of other possibilities. For the 3 and 5 m wave climate, the designs have been compared with a conventional two-layer design. All the designs together give a good impression of what can be achieved by a proper berm breakwater design.

In the life cycle of port structures that represent a large economic investment for society, devastation by an earthquake might be a rare event. However, once it occurs, they can suffer extensive damage due to earthquake. As ports play a key role in the economy of many countries, in most cases, the damage to quay walls manifested as limited deformations, as opposed to catastrophic failures or the collapse of structures. Although these permanent deformations are often repairable, the economic loss is sustained by ports due to trade interruption during repair and reconstruction. In this study, a review of seismic induced soil–structure–water interaction (SSWI) of port structures is given. Earthquakes may also be a threat to coastal areas, and their hazards are summarized in this chapter. Consequently, primary recommendations for the design of port structures against seismic effects are presented.

The artificial reef with wide crown width does not cause an extreme shoreline change, while the other beach erosion countermeasures such as groin, headland, and detached breakwater affect the shoreline from behind the structures. The artificial reef also can provide better environmental condition for the growth of seaweed and function as a fish shelter. Therefore, they are mainly selected as a beach erosion countermeasure on the coasts where environmental preservation is required. The artificial reefs are mostly composed of rubble mound or armor block. In these days, however, connected type blocks can be a maximize the various effects including environmental are often used. In this chapter, design elements and hydraulic characteristics of an artificial reef are reviewed by field observation data and empirical formula based on hydraulic model test. In addition, various examples of artificial reefs that practically applied on eroded beach are introduced.

The entrainment of debris within inundating flows in extreme hydrodynamic events results in impact loads and other effects that need to be considered in the design of at-risk structures. The analysis of debris impact loads has been performed following field investigations as well as in an experimental setting. The emphasis of this research has primarily been focused on determining the debris impact loads. Additionally, some work has been performed for assessing the risk of debris impact and entrainment characteristics of the debris. This chapter provides a review of the current research on debris motion, impacts and loads, and analyzes existing design guidelines related to debris loads. The chapter presents the current stateoftheart in the field and also provides recommendations for future research.

This chapter deals with the estimation of tsunami-induced hydrodynamic forces on infrastructure located in the vicinity of the shoreline. While extensive research has been conducted on the impact of hydrodynamic forces on classical coastal protection works (breakwaters, seawalls, reefs, etc.), there is limited research on their impact on structures such as buildings and bridges located inland. The devastation brought by the 26 December 2004 Indian Ocean Tsunami on coastal communities in Indonesia, India, Sri Lanka, Thailand, and other countries outlined the urgent need for research on the evaluation of structural resilience of infrastructure located in tsunami-prone areas. This chapter summarizes the state-of-the- art knowledge with respect to forces generated by tsunami-induced hydraulic bores, including debris impact. Further, sample calculations of tsunami loading on a prototype structure are presented.

After a brief discussion of the necessity (i) to consider in addition to the reduction of wave heights in the sheltered area further aspects of the hydraulic performance when developing and designing new coastal structures for the protection against wave action and (ii) to develop a systematic “roadmap” of the existing concepts and types of structures together with their hydraulic performance characteristics as an important tool for practicing engineers and decision-makers, five examples from selected research studies performed in the last years by the Leichtweiss-Institute are presented in order to illustrate the development of nonconventional structures with substantially improved performance as compared to their conventional counterparts. These examples include (i) a multi-chamber structure to overcome the drawbacks of the perforated JARLAN-type breakwater concept, (ii) an artificial reef made of successive submerged permeable screens to increase the wave damping performance and to better control both wave reflection and wave transmission, (iii) a “High Mound Composite Breakwater” (HMCB) concept to decrease breaking wave loads, wave reflection, overtopping, and spray generation at the structure, (iv) an onshore wave damping barrier made of staggered walls, and (v) a rubble mound breakwater with a coremade of geotextile sand containers.

During the past several decades, breakwaters including perforated walls have been introduced to resolve various problems associated with gravity-type breakwaters. In this chapter, firstly the mathematical models are described that predict various hydrodynamic characteristics of single- or multiple-row curtain-wall-pile breakwaters, the upper part of which is a curtain wall and the lower part consisting of an array of vertical piles. Their extension to irregular waves is also described. These models can also be used for curtain-wall breakwaters by just removing the piles or for pile breakwaters by removing the curtain wall and extending the piles to the water surface. Secondly the mathematical model to predict wave reflection from a fully-perforated-wall caisson mounted on a rubble foundation is described, and its applicability to a partially-perforated-wall caisson and irregular waves is described. Thirdly a discussion is given for the calculation of the so-called permeability parameter, which represents the energy dissipation and phase shift of flows passing across a perforated wall.

This chapter describes the processes of wave overtopping at sea defense and related coastal or shoreline structures. It introduces a range of methods to calculate mean overtopping discharges, individual and maximum overtopping volumes, and the proportion of waves overtopping a seawall. It describes the principal hazards from wave overtopping and will help engineers by suggesting limiting tolerable discharges for frequent, design, and extreme wave conditions. This chapter is supported by more detailed material in Chaps. 15 and 16 which focus on the methods to predict overtopping for rubble mound structures (with partly sloping embankments), and on vertical structures and battered walls. All of these three chapters have been based closely on the new EurOtop Overtopping Manual.

Wave overtopping and to a lesser extent wave run-up for armored rubble slopes and mounds have been subject to a number of investigations in the past. The objective of the present chapter is to summarize existing information to be present as a closed guidance on the use of wave run-up and wave overtopping formulae for a wide range of possible applications in practice. Therefore, guidance is given first on the use of wave run-up and wave overtopping formulae for simple slopes, excluding the effects of composite slopes, direction of wave attack, roughness, wave walls, etc. Then, formulae are presented to include these parameters in the calculation procedure. Guidance is also given on wave overtopping volumes, overtopping velocities, and the spatial distribution as well as for wave overtopping for shingle beaches. Finally, the effect of model and scale effects on the calculation of average overtopping rates are discussed. This chapter has mainly been composed from Chap. 6 of the EurOtop Overtopping Manual (2007), with some additions from Chap. 5. The present chapter is related to the previous Chap. 14 and the next Chap. 16 of this manual.

Wave overtopping prediction at vertical structures in earlier days was mainly based on caisson-type structures in relatively deep water. Recent research in many EU-projects has been concentrated on shallower water with waves breaking onto the structure as well. It has led to the definition of two situations: nonimpulsive and the most severe impulsive condition. This chapter relies on the EurOtop Overtopping Manual, as well as the two previous chapters, 14 and 15, in this handbook. It first describes the mean overtopping discharges for many configurations of vertical and composite vertical structures. Later sections quantify influences such as oblique wave attack, wind effects, model, scale effects, etc. Individual overtopping volumes are then described. Finally, post-overtopping processes and parameters — landward distribution of discharge; velocities and downfall pressures — are described.

Iribarren number is widely used by coastal engineers for classifying the type of breaking waves and for estimating armor weight, run-up height, and even for estimating wave overtopping. Iribarren number is the ratio of breakwater slope or beach slope to the square root of wave steepness. Another existing surf parameter is the ratio of breakwater slope to the wave steepness. In the present chapter new surf parameters, which are called “first order wave action slope” and “second order wave action slope,” are introduced for representing the local wave conditions in shallow waters by employing local values of wavelength as well as wave height. The use of linear wave theory on a flat bed of the depth at the front of breakwater might be considered far better than the simple adoption of the deep-water wavelength for characterizing surfing waves at a shoaling depth. The wave action slopes are formed by the product of the breakwater slope and the celerity ratio to the wave height. The run-up height is related to the first order wave action slope, and the optimum or minimum weight of armor unit is related to the second order wave action slope.

The experiences of caisson breakwater failures are explained and the current design of caisson breakwaters is described to prevent such failures. The design method of conventional caisson against wave forces is especially explained in this chapter. The design method of caisson breakwaters is still under development including a new design method of performance design. The future direction will be discussed in the final section.

Revetments are most common structures in coastal engineering. The design of revetments is a complex process and needs proper understanding of loads and structural interactions. The basic information on composition and dimensioning of various types of revetments under wave and current attack are provided. Special attention is given to filter structures using geotextiles and transitions into splash areas and toe protection. Reference to actual developments and manuals is also provided.

Erosion control and coastal stabilization are common problems in coastal engineering. A brief overview of some available alternative systems for shore stabilization and beach erosion control is presented. Special attention is paid to artificial reefs and geosystems. Geosystems (geotubes, geocontainers, etc.) have gained popularity in recent years because of their simplicity in placement, cost effectiveness, and environmental aspects. However, all these systems have some advantages and disadvantages, which have to be recognized before application.

This chapter aims at providing a brief overview on geotextile sand containers (GSCs) applied in coastal engineering for shore protection. First, the engineering properties required for the geotextile used for sand containers as well as the durability and the lifetime prediction issue are discussed. Second, some example applications are provided to illustrate the versatility of GSCs as an appropriate soft shore prediction alternative to conventional hard coastal structures made of rock and concrete units. However, the major part of the chapter is aimed to address the hydraulic stability of the containers constituting a shore protection structure subject to wave attack. For this purpose, simple formulae are first proposed for the stability of the slope and crest containers. The processes which may affect the hydraulic stability are then discussed to highlight the necessity of developing more process-based stability formulae. New stability formulae are finally proposed which can also account explicitly for the effect of deformation of the containers. Finally, a discussion is provided on the comparative analysis of the stability of the slope and crest containers with and without consideration of the deformation effect.

The chapter describes typical features of low crested breakwaters, their hydraulic stability, effects on waves, induced circulation, erosion, and problems related to construction and maintenance, providing basic tools for design.

Knowledge of the hydrodynamic behavior of net cage under the action of waves and currents is the basis of the design and management of net cages in the open sea. Techniques used to investigate the net cage have typically included the use of scaled physical and numerical models, and, where possible, field measurements. In this chapter, information on the hydrodynamic behavior of net cages in the open sea is focused on gravity cages. The main methods used for research into hydrodynamic behavior are introduced: physical tests and numerical computation.

This chapter will review and highlight the research being carried out today to meet the challenges in the design, and operation of offshore structures. The subject matter, while general in nature, will focus on one of the most unique areas in the offshore structure design, namely, the fluid-induced responses of offshore structures and the associated structural design consequences. Due to the rapid growth in the offshore field, particularly in deepwaters, this area is seeing a phenomenological advancement. The chapter will begin with an overview of the historical development of fixed and floating structures. It will state the design status for these systems. The fixed structure design is more mature today, even though many aspects of it still remain empirical. For floating structures the design procedure is still advancing and more research is ongoing in this area. These will be highlighted. The treatment of the individual components of the floating structure, namely, the floater, the mooring system, and the riser system including their interactive coupling effects with fluid will be discussed. The state-of-the-art in the treatment of the individual components of the floating structure, namely, the floater, the mooring system, and the riser system will be briefly described. The design methods for these offshore components will be included. The basic differences between the coupled and uncoupled systems and the complexity of the later method will be discussed. The chapter will conclude with a discussion of the present-day deepwater design challenges that remain and the research that is needed to meet these challenges.

The following sections are included:

• Introduction
• Brief State of the Art
• Mathematical Framework
• Requirements for the Use of Navier-Stokes Models
• Applications: Examples
• Summary and Discussion
• References

The morphological variations in seabed due to sediment motion in the marine environment pose one of the challenging tasks in coastal engineering because of the need to avoid their negative effects. The flow and scour process around the nearshore structures due to steady current and/or waves is a very complex issue. In this chapter, the evolution and the equilibrium stages of the scour process, especially around cylindrical nearshore structures like submarine pipelines and marine piles, are summarized. Basic relations and nomograms are provided for practical usage.

The following sections are included:

• Introduction
• Wave Models
• Seabed Models: Oscillatory Mechanism
• Seabed Models: Residual Mechanism
• Solitary Waves Over a Sloping Seabed
• Conclusion and Remarks
• References

Harbors are built to provide a sheltered environment for the mooring of ships and vessels. For some wave periods the semi-enclosed harbor basin acts as a resonator to amplify the wave motions in the harbor due to the combined effects of wave diffractions, refractions, and multiple reflections from the boundaries. This undesirable wave motion could induce significant ship motions, damage ships and dock facilities, and delay loading and unloading activities if the resonant wave periods are close to that of the ship mooring system. Harbor planners and engineers need to model the wave induced oscillations as new harbor layouts are contemplated…

This chapter presents a summary of ship squat and its effect on vessel underkeel clearance. An overview of squat research and its importance in safe and efficient design of entrance channels is presented. Representative PIANC empirical formulas for predicting squat in canals and in restricted and open channels are discussed and illustrated with examples. Most of these formulas are based on hard bottoms and single ships. Ongoing research on passing and overtaking ships in confined channels, and offset distances and drift angles is presented. The effect of fluid bottoms or mud is described. Numerical modeling of squat is an area of future research and some comparisons are presented and discussed.

This paper proposes a computational method for estimating the motion of a moored ship, taking into consideration a harbor resonance. Additionally, a method is provided to estimate the allowable wave height for ship loading and unloading as well as for evaluating the effective working days in a harbor. The harbor resonance was determined using the CGWAVE model, while the motion of a moored ship was determined using the three-dimensional Green’s function method. This method was verified with field measurement data from actual moored ships, and wave field and downtime records in Pohang New Harbor in the Republic of Korea. This study investigated whether harbor resonance affects the motion of a moored ship using simulated results of ship motion both with and without harbor resonance. In the case where harbor resonance was included, the moored ship motion increased by 10–30% compared with the results for the case without harbor resonance. The wave field data, obtained during downtime, indicated wave heights of 0.10–0.75 m and wave periods of 7–13 s for ship weights between 800 and 35,000 tons. Alternately, the estimated results for allowable wave heights for ship loading and unloading activities using this method were wave heights of 0.19–0.50 m and wave periods of 8–12 s for ships weights of 5,000, 10,000, and 30,000 tons. Thus, this method reproduced field data responses for ships of various sizes and at different wave periods. The results of this method tended to decrease by 16–62% when considering long waves. In addition, the percentage rate of effective working days accounting for ship motion at pier 8th in Pohang New Harbor was 6.5% less compared to the corresponding results for the case when ship motion was not considered.

Beach nourishment is increasingly chosen as the preferred method for maintaining recreational beaches while protecting upland property. This chapter outlines five key elements (building blocks) for a sustainable nourishment program: (1) rigorous shoreline inventory of coastal processes and geology; (2) development of a volumetric erosion database; (3) preparation of geomorphic models of the principal sand transport pathways, sources, and sinks; (4) determination of a target beach condition consistent with the financial resources of the community with possible phasing at graduated restoration levels until a robust database is available; and (5) availability of quality borrow sediments within economical distances. The authors draw on the experience of one state — South Carolina (USA) — to illustrate how a sustained nourishment effort over 30 years, at costs well under 1% of oceanfront property values per year, has led to expanded beach area and greater setback distances for existing buildings. The mixed-energy setting of South Carolina is representative of numerous barrier-island coasts around the world.

There are runoff, tides, waves, and storm surges in estuaries, where the sediment transport is complicated. In this chapter, basic formulas of sediment transport in estuary covering incipient motion and carrying-capacity are derived. Numerical models of total sediment transport under joint action of tidal currents and wind waves are established. The similarity of physical models considering both tidal currents and waves is given.

Prediction of turbidity due to fine sediment resuspension in wave-driven environments is a subject of considerable interest. In that regard, experience from shallow lakes, in which forcing is mainly by waves, has been used extensively in this presentation. Turbidity prediction is contingent upon an understanding of two processes, namely the effect of the bottom on wave height and period, and also the rate at which bottom sediment is locally entrained by the wave. Simple approaches pertinent to these processes have been reviewed. Attention is devoted to the role of rheological models in the determination of wave attenuation. This is followed by a brief description of simple modeling of suspended sediment profiles subject to sediment erosion, settling, and deposition. The role of sediment-induced stratification in governing resuspension is highlighted. Overall, the mainly analytic treatment is meant to help the engineer in developing first-order estimates of turbidity levels in wave-driven environments.

Simple formulas for the cross-shore and longshore transport rates of suspended sand and bedload on beaches are proposed by synthesizing available data and formulas. A combined wave and current model based on the time-averaged continuity, momentum, and energy equations for water is improved and used to provide hydrodynamic input to the proposed sand transport model. The model is compared with spilling and plunging wave tests conducted in a large wave basin using fine sand. The numeric model predicts the measured longshore suspended sand and total transport rates within a factor of about 2. The longshore bedload transport rate is predicted to be small. The predicted cross-shore sand transport rates are relatively small on the quasi-equilibrium beaches in these tests. The computed beach profile change under 10-h wave action is less than about 5 cm. The proposed sediment transport model will need to be verified using additional data but no bedload data is available in surf zones and reliable suspended load data is scarce.

Headlands and bays behave like a pair of twin on the coast. Field evidence and scaled model experiments have proven that long term stability of a bay beach without external littoral supply can be maintained, when the beach is in static equilibrium for a particular persistent swell direction. Therefore, no sea defense works would be necessary. But for location with storm-cycles or shortterm reversal of drift, a sufficient beach buffer width should be allowed as working capital on which the sea can operate. This chapter introduces the static bay beach concept (SBBC) that applies an empirical parabolic bay shape equation and software MEPBAY and SMC which apply this equation, as well as its preliminary engineering applications for stability verification of natural and artificial bay beaches, mitigation of beach erosion by headland control aided by adequate artificial headlands with beach nourishment, bay beach design for recreation, and EIA for coastal management.

Beach nourishment comprises the placement of sediment in the nearshore to advance the shoreline seaward and is usually placed in response to beach erosion which may be naturally or anthropogenically induced. Nourishment with compatible sediment has the advantage of maintaining the beach system in a nearnatural condition and can provide benefits to biota and upland property, the latter by buffering storm erosion and damage. The processes associated with beach nourishment are becoming better understood such that project design can be accomplished with simple or more complex models. The more simple models, called one-line models, represent the changes in the entire active beach profile by a single contour and consider the profile to be displaced without change in form in response to a change in volume. The transport equation completes the governing equations. Pelnard–Considère (PC) combined these two equations into a linearized second-order differential equation. Although the PC equation generally is not useful directly for design, it provides the basis for the derivation of a number of fundamental results. This chapter considers beach nourishment evolution to be represented as planform evolution and profile adjustment.

Tidal inlets are part of the coastal sediment-sharing system, and an inlet will modify the nearshore and estuary morphology, as well as the up-drift and down-drift beaches. Morphologic response to an inlet varies over several time and spatial scales. This chapter discusses the inlet morphology and its related functional design considerations that must balance navigation and shore-protection requirements. The first half of this chapter reviews the selected material on the morphology of inlets and introduces empiric predictive expressions found useful for engineering. The second half of the chapter concerns aspects of engineering of tidal inlets.

Enclosed bays are one of the most productive areas of seas, and they have long provided humans with uncountable benefits. Because enclosed bays are the boundary between land and open sea, they are also significant for global material cycles. However, eutrophication has been occurring in many enclosed bays around the world. In order to maintain sustainable utilization of the ecosystems of bays such as these, advanced inter-disciplinary research is needed. This chapter describes the mechanisms of water quality variation under typical currents and introduces an ecosystem model as a tool for the integrated management of enclosed bays.

The following sections are included:

• Introduction
• Concept Generation
• Tamilnadu (Groin Field)
• Kerala Coast
• Summary
• Acknowledgments
• References

It is broadly admitted socioeconomic progress is exhausting the energy, water, and coastal zone resources. To overcome this trend, a more serious and rigorous slogan must drive the progress today: (1) socioeconomic and environmental progress must be concomitant, (2) use of basic resources must be minimized, and (3) operationality and safety of the human works must be maximized. These new demands ask for a new coastal and ocean engineering philosophy, regarding the socioeconomic and environmental impact of the human intervention during its useful life. However, coastal and ocean engineering must deal with the environmental events and their random nature. Thus, the response to the problem has to include the associated uncertainty, among others, to the occurrence of the atmospheric and maritime agents and to the response of the systems.

In this chapter, a summary of some of the new design principles and tools that can help to match the society demands are presented. Based on risk analysis and decision theory, the problem of an integrated coastal and harbor management is formulated. The new approach is applied to evaluate the probability distribution of the coastline in V years in a stretch of coast in the south of Spain. Next, the evaluation of the risk during the ship passage in the harbor entrance channel is considered. Again, based on risk analysis and decision theory, the problem is formulated and solved to evaluate the stoppage probability along the entrance channel to the harbor of Motril of a bulkcarrier during a storm.

The history of human utilization of the coastal area can be traced to hundreds years ago, when they consumed the natural resources through fishing and pasturing. In the previous century, human beings built harbors and dikes to prevent storms and waves. When it came to the past decades, large-scaled reclamation lands were developed for the purposes of relaxation, aquaculture, and industry. Consequently, a large part of ecologic environment in the coastal area was seriously sabotaged. Therefore, this chapter attempts to categorize and explain different types of utilization around the world, to thoroughly review the impacts caused by local constructions and other factors, and to scheme applicable programs for response and reparation. Last, the monitoring data of land subsidence and ecologic transformation in the newly developed industrial area in western Taiwan serves as good lessons to the ocean engineers that they should work with other specialists of environment, ecology landscape, and management to solve the related problems. Only by doing this, the abundant resources in the coastal area could be preserved and utilized in a sustainable way.

Tropical cyclone storm surge represents a significant threat to communities around the world. These surge characteristics vary spatially and temporally over a range of scales; therefore, conceptual frameworks for understanding and mitigating them must be cast within a context of risk that covers the complete range of hazards, their consequences, and methods for mitigation. A review of primary overlapping time scales and associated spatial scales for tropical cyclone surge hazards covers two scales of particular interest: (1) synoptic-scale predictions used for warnings and evacuation decisions and (2) long-term estimation of hazards and related risks needed for coastal planning and decision making. Factors that can affect these estimates, such as episodic variations in tropical cyclone characteristics and longer-term climate change and sea-level rise are then examined in the context of their potential impacts on hazards and risks related to tropical cyclone surges.

In the United States, the Saffir–Simpson (S–S) wind-speed scale for hurricanes is misleading the public regarding the strength of a coastal storm for flooding events. In the spring of 2010, the National Hurricane Center removed the estimates for storm surge as previously published for the five-category, wind-speed system to avoid confusion over storm surge and flooding predictions that failed to match with what actually occurred as a hurricane made landfall. A coastal storm severity index is needed that takes into account the hydrodynamic variables (elevated water levels, higher wave conditions, and stronger currents over the duration of the storm) to supplement the wind-based S–S scale. This chapter describes the coastal storm impulse (COSI) parameter based on conservation of momentum principles that combines these hydrodynamic variables over the storm duration into one number for a specific location and storm event. The COSI parameter is not driven by the “consequences” of the storm (e.g., amount of property damage, beach erosion, etc.) but simply by the nearshore physics. This chapter then summarizes 10 years (1994–2003) of data analysis from measurements at the Corps of Engineers, Field Research Facility in Duck, North Carolina. The hydrodynamic strength of a coastal storm is readily measured by the COSI parameter. A regional definition of a base parameter will permit determination of a COSI index for coastal storm severity to complement the S–S scale for winds.

Storm intensities and the heights of ocean waves are being affected by Earth’s changing climate, including the extreme waves generated by both hurricanes and extratropical storms, attributed to global warming. The increases in wave heights have been documented by buoy data collected in the North Atlantic and North Pacific, with the rates of increase being important to engineering design and in the development of coastal-hazard zones. Reviews are presented about the climate controls and investigations that have documented the wave-height increases. The evidence is variously presented as progressive increases in the annual averages of the measured significant wave heights, and decadal shifts in histograms for the full ranges of measured waves. A review is also provided of the statistical techniques available that account for these climate-induced changes in the extreme-value projections used in engineering and management applications.

Water level variability has been one of the most significant aspects of coastal factors for coastal engineering and coastal management. Current factors influencing local water level include tides, wind waves, tsunamis, atmospheric forcing, seiching, storm surge, and local uplift and subsidence. Changes in global sea level have influenced coastal conditions over geologic time. Changes in eustatic sea level have been relatively small for the past several thousand years, but there is evidence from global records, trends in sea level and atmospheric-ocean models that sea level is now rising more quickly that has been experienced in the recent past, and this trend will continue or increase during the next 100 years. Coastal engineering and coastal management efforts will need to adjust to these changing sea level trends. Certain situations may be best addressed by individual responses, such as armoring, beach nourishment, or retreat. In most cases, the use of several complementary approaches and the application of the major principles of sustainability may be more appropriate.

IPCC projections indicate that the rate of sea level rise (SLR) during the 21st century may be about an order of magnitude greater than the 20th century rate of 1–2 mm/year. This accelerated SLR will in turn result in much faster coastline retreat with particularly severe impacts on low-lying areas. The socioeconomic impact of such accelerated coastline retreat could be massive due to the rapid growth of coastal communities and infrastructure over the past five or six decades. The method most commonly used to estimate coastline retreat due to SLR is the simple two-dimensional mass conservation principle known as the Bruun rule. However, in view of the high level of predictive accuracy that is clearly needed to facilitate informed planning decisions for the future, can we continue to depend on the Bruun rule? This chapter discusses the evidence for and against the Bruun rule and suggests alternative methods that may be more suitable for the 21st century.

This chapter deals with flood risk analysis and assessment within the general framework of flood risk management. Flood risk is defined as the product of the predicted probability of flooding and associated expected damages. The conceptual model Source-Pathway-Receptor-Consequence (SPRC) for flood risk analysis is presented and its components are analyzed. Methods and techniques of the univariate and multivariate Extreme Value Theory (EVT) to analyze the sources of coastal flooding are discussed. The methodology to extract the predicted probability of coastal flooding from risk sources and pathways (flood hazard) in the presence or absence of coastal defences is introduced. Tangible and intangible expected damages to risk receptors are examined and different techniques are presented to assess them and to integrate them within the framework of flood risk analysis. Quantitative methods to define acceptable flooding probabilities at the level of the protected area are presented. Tools such as cost benefit analysis, multi-criteria analysis, utility models and the life quality index are introduced to define the “tolerable” risk of flooding. Methodologies used in three European research projects (FLOODsite, THESEUS, XtremRisk) to analyse, assess and mitigate coastal flood risk are also presented and discussed.

Details are given of the growing worldwide interest in tidal renewable energy projects, including tidal stream devices and tidal range structures (i.e. barrages and lagoons), but the main emphasis in this chapter is on tidal range renewable energy structures. In investigating the hydro-environmental impacts of such tidal energy schemes, both for regional and far field effects, a 2D numerical model has been refined to predict the hydrodynamic impacts, including wake effects and flood risk and hazard impacts, and changes in the concentration distribution of conservative and nonconservative solutes, including primarily salinity, turbidity, fecal indicator organisms, and phosphorous and nitrogen levels. The model has been applied to a number of key sites and particularly in the Severn Estuary, UK, which has the second highest tidal range worldwide. The key schemes considered and reported herein include: (i) a series of lagoons along the North Wales coast and (ii) a barrage across the mouth of the Severn Estuary. The main findings are that: (i) two-way generation offers the best options for maintaining the current conditions in the region as closely as possible, (ii) boundary conditions need to be generated from the Continental Shelf, (iii) momentum conservation is crucial for turbine representation, (iv)lagoons interact with one another, reducing efficiency, (v) the design of turbine distribution is critical for optimum efficiency and minimal environmental change.

This chapter summarizes the physical modeling of tsunami waves. The first section contains an overview of historic studies. The next section describes equipment and procedures used in laboratory studies for generating, measuring, and analyzing tsunami waves. The third section summarizes some early National Science Foundation-funded laboratory studies of runup on vertical walls, plane beaches, and circular islands that were conducted at the Coastal and Hydraulics Laboratory. The next section describes the latest Network for Earthquake Engineering Simulation-funded, the state-of-the-art tsunami wave-making facility at Oregon State University, and several recent studies. Finally, the last section is a summary and conclusion of laboratory modeling of tsunami waves.

During the past two decades, a large number of multidirectional wave facilities had been built around the world. In parallel, wave generation and analysis techniques have also advanced so that it is now possible to ensure realistic wave conditions that mimic the nature in laboratory basins and flumes. With these capabilities, testing of coastal and offshore structures can be carried out with greater accuracy ensuring thereby optimal designs for structures in terms of cost and safety. This chapter provides a brief review of the wave generation and analysis techniques that are commonly used for simulating uni- and multidirectional waves and also shares the experience gained at the Canadian Hydraulics Centre of the National Research Council Canada, in this field.

The quality of morphodynamic predictions is often indicated by a skill score that weighs the mean-squared error of the prediction by that of the initial bed as the reference prediction. As simple as this Brier skill score (BSS) or meansquared- error skill score (MSESS) may seem, it is not well understood and, hence, sometimes misinterpreted. This chapter aims at improving the understanding of the MSESS. We review existing MSESS formulations and classifications, with and without an account of the measurement error. Using simple examples, we illuminate which aspects of prediction quality the MSESS actually measures. It is shown that the MSESS tends to favor model results that underestimate the variance of cumulative bed changes. We further demonstrate that the normalization by the observed cumulative change, which follows from the choice of the initial bed as the reference, is not effective in creating a level playing field over a wide range of prediction situations (trend, episodic event, different seasons). Also, it is shown that the combined presence of larger, persistent scales and smaller, intermittent scales in the cumulative bed changes may lead to an apparent increase of skill with time, although the prediction of neither of these scales becomes more skilful with time. Finally, in order to obtain a balanced appreciation of model performance, the use and development of a more extensive suite of validation measures is advocated.

This perspective traces developments in coastal and civil engineering practice and in coastal engineering education. It notes that engineering has changed substantially and that engineers are not educated for the contemporary tasks they face. It states that changes should be made urgently, but that they must be made within the confines of a global market. It then offers a number of examples of misconceptions and alternatives to bring about closer cooperation between practice and education in order to provide better engineering education and produce up-to-date engineering graduates that are more relevant to the present needs of engineering practice.