12 December 2001
METEOROLOGY AND WAVE CLIMATE. A basic understanding of
marine and coastal meteorology and the relationship between meteorological
processes and wave generation is important to coastal design and planning. Section II-
2 of the CEM contains an analysis of this subject.
ESTIMATION OF NEARSHORE WAVES. The size and directions of
nearshore waves that impact coastal design are strongly influenced by underlying
seafloor geometry and currents. While overestimating wave height can inflate the price
of a project, underestimating can result in catastrophic loss. Section II-3 of the CEM
evaluates wave transformation analyses methods and provides guidance for selecting a
reasonable approach for making wave transformation calculations.
SURF ZONE HYDRODYNAMICS. Breaking waves, and the resulting
that make the surf zone the most dynamic coastal region. Section II-4 of the CEM
describes shallow-water wave breaking and associated hydrodynamic processes that
affect shoreline and beach profile, which impact the design of coastal structures and
Coastal Bottom Boundary Layers. The severe interaction between the
slowly varying current boundary layer and the turbulent wave bottom boundary layer
during severe storm events plays a significant role in sediment transport. This
interaction, which occurs primarily in the area just outside the surf zone, in water depth
ranging between 2 or 3 m (6.6 to 9.8 ft) up to 20 to 30 m (65.6 to 98.4 ft), affects
sediment that is not usually suspended under normal wave conditions. The fate of the
sediments in this zone is a complex question for coastal engineers. The factors and
complexities that make analysis of this activity so difficult are discussed in Section III-6
of the CEM. An extensive analysis of this process is contained in Coastal Bottom
Boundary Layers and Sediment Transport by Peter Nielsen.
WATER LEVELS AND LONG WAVES. A significant component of
coastal design is protection of structures from some predefined water surface elevation.
The following sections, the scope of which is summarized in Section II-5, of the CEM,
classify the various types of surface elevation variation generated by long waves and
guidance for developing a preliminary study approach and applicable design procedure.
A discussion of the geological effects of wave action is contained in Section IV-2 of the
Water Wave Classification. Section II-5-2 of the CEM gives a brief
review of wave classification criteria and a summary of long wave properties.
Astronomical Tides. Astronomical tides represent an important example
of long waves. Section II-5-3 of the CEM describes tidal processes and effects.
Water Surface Elevation Datums. Section II-5-4 of the CEM describes
the various means of defining water surface elevation datums and the relationship
between tidal observation-based datums, which account for spatial variability of sea