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Introduction

1.1 Scope of Coastal Engineering

Coastal engineering relates to the solution of engineering problems in the coastal environment. It concerns, for example: the design of coastal structures such as breakwaters and seawalls, the design of harbors and marinas, understanding and addressing the consequences of sea level rise and coastal flooding, the assessment and control of sediment erosion and accretion, the design of shoreline protection schemes, and the assessment and controlled discharge of pollutants in the ocean environment.

Coastal engineering is a branch of civil engineering. Neighboring civil engineering subdisciplines that may be relevant to a coastal engineering project include hydraulic engineering, geotechnical engineering, structural engineering, and earthquake engineering. Neighboring disciplines include ocean engineering that relates to engineering projects in the ocean, uninfluenced by proximity to a coastline and often associated with offshore oil and gas recovery; naval architecture that relates to the design and operation of ships and marine vessels; and oceanography that relates to the scientific study of the oceans. Some subdisciplines of the sciences, such as nearshore oceanography and coastal geology, overlap with aspects of coastal engineering.

Several decades ago, Weigel (1964) and Ippen (1966) developed what may be regarded as foundational texts in coastal engineering. Subsequently, several texts on coastal engineering that have been available and widely used include Sorensen (2006), Sawaragi (2011), Reeve et al. (2018), and Kamphuis (2020), with each one providing different areas of emphasis. Many other texts focus on particular aspects of coastal engineering, such as marina design, port engineering, and coastal processes, or on topics within related disciplines such as ocean engineering and hydraulic engineering. In addition, various design manuals and guides that are relied upon in coastal engineering practice include the Coastal Engineering Manual (2002) and its predecessor the Shore Protection Manual (1984), the Rock Manual (2007), the Federal Emergency Management Agency’s (FEMA) Coastal Construction Manual (2011), and the EurOtop Manual (2018).

1.2 Outline of Book

Since ocean waves are usually the primary environmental consideration in coastal engineering, it is customary that a major part of a coastal engineering text relates to a description of waves. In this context, the chapter titles of the book are as follows:

1. Introduction
2. Regular Waves
3. Wave Transformations
4. Random Waves
5. Winds
6. Wave Predictions
7. Long Waves, Water Levels, and Currents
8. Coastal Structures
9. Coastal Processes
10. Mixing Processes
11. Design of Coastal Infrastructure
12. Coastal Modeling

More specifically, summaries of these chapters are given below.

Chapter 2, Regular Waves, describes the treatment of regular waves – that is, periodic waves that propagate over a horizontal seabed without a change in form. This chapter focuses on the development and application of linear wave theory.

Chapter 3, Wave Transformations, considers the transformation of waves associated with changes in water depth and with obstacles in the flow. Thus, the chapter treats wave shoaling, wave refraction, wave diffraction, wave reflection including standing waves, wave transmission, wave attenuation, wave breaking, and wave runup at a shoreline.

Chapter 4, Random Waves, recognizes the random nature of waves and distinguishes between the short-term variability of individual waves over a few hours and the long-term variability of different storms over several years, typically leading to design wave conditions with a specified return period.

Chapter 5, Winds, which serves as a prelude to Chapter 6, gives attention to descriptions of a wind climate, approaches to accessing and analyzing wind data needed for wave hindcasting, and a description of the wind field in a hurricane.

Chapter 6, Wave Predictions, describes the prediction of waves, with a focus on a simplified approach to wave hindcasting that provides estimates of wave conditions on the basis of available wind data. Other forms of wave prediction that are mentioned include ship waves and laboratory-generated waves.

Chapter 7, Long Waves, Water Levels, and Currents, outlines long waves, which include tides and tsunamis, and coastal flooding water levels and their components, which include storm surge and sea level rise. This chapter also indicates the impacts of climate change on coastal engineering practice and concludes with a summary of the kinds of currents that may be encountered.

Chapter 8, Coastal Structures, summarizes various categories of coastal structure and approaches to estimating wave loads on structures and wave interactions with structures. The kinds of structures considered include seawalls, rubble-mound structures, slender-member structures, large structures, and floating structures. This chapter also provides descriptions of the analysis of floating breakwaters and floating bridges and an outline of loads other than wave loads that may act on a coastal structure. The chapter concludes with a description of ocean-related renewable energy infrastructure.

Chapter 9, Coastal Processes, begins with an outline of the variety of coastal forms that may be encountered. It then describes in turn coastal sediments, the conditions for the onset of sediment movement under currents and waves, the movement of sediments near shorelines including sediment transport along beaches, bluff erosion, and scour, mitigation measures for addressing unwanted sediment erosion or accretion, approaches to shoreline protection, including reliance on nature-based methods, coastal restoration, and, finally, an introduction to coastal management.

Chapter 10, Mixing Processes, which is a primary topic of environmental fluid mechanics, describes fundamental solutions to the advection–diffusion equation and summarizes related topics that include stratified flows, mixing in estuaries, and jets and plumes.

Chapter 11, Design of Coastal Infrastructure, provides an introduction to the design process and approaches to accounting for uncertainty and outlines selected design tools including probability of failure analyses, risk assessment and management, permitting and approval requirements, and decision-making in design. It then summarizes selected design considerations with respect to coastal structures, including their modes of failure, design criteria, and aspects of detailed design. Finally, the chapter discusses the design of harbors and marinas, with attention given to available criteria for acceptable wave climate in marinas and to navigational considerations.

Chapter 12, Coastal Modeling, summarizes in a general way numerical modeling associated with various coastal engineering phenomena. It then outlines the underlying principles of model laws, describes different kinds of laboratory models used in coastal engineering, and provides descriptions of laboratory facilities, instrumentation, and measurements. The chapter concludes with a summary of field measurements relevant to coastal engineering.

1.3 Example Projects

In order to provide an appreciation of the breadth of coastal engineering practice, four generic example projects are now presented, along with an indication of the range of issues that may require consideration within each of these. (Any specific terminology that is used here is defined subsequently within the text.)

1.3.1 Coastal Flooding

The first generic project relates to an assessment of coastal flooding along a shoreline and the design of flood protection infrastructure. Figure 1.1 shows a coastal dike in Richmond, BC, used here as a basis for identifying key design parameters and associated issues.

The dike design entails the selection of the dike’s crest elevation and its sectional properties (e.g. crest width, seaward and landward slopes, rock size, vegetation, …) and a consideration of drainage and pump systems. The design is influenced by maximum water levels due to a combination of tides, sea level rise, storm surge and waves, and/or, if relevant, river flooding or tsunami flooding; a consideration of the probability and extent of any flooding in the context of uncertainty, risk, return period, and design life; wave runup and overtopping; and, finally, potential habitat enhancements, climate change impacts, permitting and approval requirements, and land use requirements. While Figure 1.1 indicates the case of a coastal dike, related coastal flooding projects may involve a seawall or other coastal defense along a shoreline, and a consideration of hurricane-prone areas for which storm surge is a major issue.

Figure 1.1 Coastal dike example project.

1.3.2 Coastal Structure Design

A second generic example relates to the design of different types of coastal structure. Figure 1.2 illustrates four types of structure: a seawall, rubble-mound shoreline protection, a piled pier, and a floating structure, with the figure used as a basis for identifying key design parameters and associated issues.

Common to all these are assessments of tides, water levels...