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Coastal Engineering: Theory and Practice
6.3 Wave Overtopping
6.3.1 General
The overtopping of water over a Coastal structure dépends on its crest
élévation. As overtopping dictâtes the crest élévation, it also influences the
cost effect of a structure. Curiously, it is not something that has attracted a
significant amount of research until recently. However, the modern practice
of design involves the assessment of overtopping as a design criteria instead
of wave run-up, which does not quantify the discharge over a structure,
whereas, the run-up approach as design criteria was factually used due to
the lack of adéquate design data.
Conventional design practices require a structure to protect against critical wave climate that would damage the structure as well as spoils the
beach or land and also affects the future development that follows. The
latter will often make it necessary to consider good standards of design
practice for safety reasons and also to avoid the damage to a property
than would be required for protection of the structure along. Such features
could be other structures, such as buildings, roadways or working areas
as in the case of port facilities. It is necessary to consider the safety of
people or vehicles behind the structure. However, designing to meet these
criteria can lead to the development of tremendously huge érections. Consequently, it is only during the exceptional circumstances of critical conditions these criteria cornes into considération for example when a highway
présent immediately behind a sea wall, densely populated Coastal community. Although, the allowable discharge over a structure is small, it is worth
analyzing that it could resuit in localized flooding, and duration with level
of depth of flooding could be the governing factor in determining the appropriate level of overtopping discharge. Tolerable discharges over a structure
can be established through the knowledge of drainage capacity, and also fixing the spreading area of the flood thereby limiting the depth which would
in turn limit the allowable volume per unit meter of defense. Further, the
actual discharge can be calculated as a whole volume instead of a mean rate
and calculating the incrémental volume due the action of tidal variations.
These are the primary reasons for limiting overtopping discharge and it is
therefore important to establish the design criteria that relate to ail facets
of the structure and its intended performance.
Overtopping discharges are usually calculated and quoted as mean
discharges (litres/sec/m run) and can appear to be relatively small values. However, the actual discharge occurs as a random sériés of large
Coastal Engineering: Theory and Practice
6.3 Wave Overtopping
6.3.1 General
The overtopping of water over a Coastal structure dépends on its crest
élévation. As overtopping dictâtes the crest élévation, it also influences the
cost effect of a structure. Curiously, it is not something that has attracted a
significant amount of research until recently. However, the modern practice
of design involves the assessment of overtopping as a design criteria instead
of wave run-up, which does not quantify the discharge over a structure,
whereas, the run-up approach as design criteria was factually used due to
the lack of adéquate design data.
Conventional design practices require a structure to protect against critical wave climate that would damage the structure as well as spoils the
beach or land and also affects the future development that follows. The
latter will often make it necessary to consider good standards of design
practice for safety reasons and also to avoid the damage to a property
than would be required for protection of the structure along. Such features
could be other structures, such as buildings, roadways or working areas
as in the case of port facilities. It is necessary to consider the safety of
people or vehicles behind the structure. However, designing to meet these
criteria can lead to the development of tremendously huge érections. Consequently, it is only during the exceptional circumstances of critical conditions these criteria cornes into considération for example when a highway
présent immediately behind a sea wall, densely populated Coastal community. Although, the allowable discharge over a structure is small, it is worth
analyzing that it could resuit in localized flooding, and duration with level
of depth of flooding could be the governing factor in determining the appropriate level of overtopping discharge. Tolerable discharges over a structure
can be established through the knowledge of drainage capacity, and also fixing the spreading area of the flood thereby limiting the depth which would
in turn limit the allowable volume per unit meter of defense. Further, the
actual discharge can be calculated as a whole volume instead of a mean rate
and calculating the incrémental volume due the action of tidal variations.
These are the primary reasons for limiting overtopping discharge and it is
therefore important to establish the design criteria that relate to ail facets
of the structure and its intended performance.
Overtopping discharges are usually calculated and quoted as mean
discharges (litres/sec/m run) and can appear to be relatively small values. However, the actual discharge occurs as a random sériés of large