168
R.H. Charlier and Chr. P. De Meyer
Global warming taking its toll, some authors (V. Gornitz et aL, 1982, Global sea
level trend in the past century : Science 215, 1611) project a 40 to 60 cm (+ 14 in
to + 22 in) sea-level rise by 2050 ; it could even be 1 m (35 in) or more in areas
where subsidence is important. Some have cf.n Charleston NC under water by
2020.
3
Coastal Profiles
Profiles are two-dimensional vertical sections showing elevations-to-distance
variation. Coastal profiles, usually perpendicular to the shoreline, include shelf-,
nearshore, and beach profiles. The latter two are of major importance in coastal
protection schemes.
Profiles are needed from both zones because modalities are clearly different in
one and the other.
While hydrographic charts are adequate to make a profile for deeper offshore
zones, recent surveys are necessary for waters 20 m (66 ft), and less, deep.
Profiles are needed because of long-term stability of the swell profile and shortterm transposition from swell to storm beach profile.
The envelope of a profile defines fluctuations of sand level at a site, data that is
needed for beach nourishment as well as groin design.
The nearshore profile is usually measured aboard with an echo-sounder or a leadline. The beach profile is surveyed by leveling and taping techniques, the latter is
less affected by such errors as sounding, spacing, closure and sea bottom
temporal fluctuations, than the nearshore profile.
3.1
Beach Profile
Profiles are two-dimensional vertical sections showing elevations-to-distance
variation. Coastal profiles, usually perpendicular to the shoreline, include shelf-,
nearshore, and beach profiles. The latter two are of major importance in coastal
protection schemes.
R.H. Charlier and Chr. P. De Meyer
Global warming taking its toll, some authors (V. Gornitz et aL, 1982, Global sea
level trend in the past century : Science 215, 1611) project a 40 to 60 cm (+ 14 in
to + 22 in) sea-level rise by 2050 ; it could even be 1 m (35 in) or more in areas
where subsidence is important. Some have cf.n Charleston NC under water by
2020.
3
Coastal Profiles
Profiles are two-dimensional vertical sections showing elevations-to-distance
variation. Coastal profiles, usually perpendicular to the shoreline, include shelf-,
nearshore, and beach profiles. The latter two are of major importance in coastal
protection schemes.
Profiles are needed from both zones because modalities are clearly different in
one and the other.
While hydrographic charts are adequate to make a profile for deeper offshore
zones, recent surveys are necessary for waters 20 m (66 ft), and less, deep.
Profiles are needed because of long-term stability of the swell profile and shortterm transposition from swell to storm beach profile.
The envelope of a profile defines fluctuations of sand level at a site, data that is
needed for beach nourishment as well as groin design.
The nearshore profile is usually measured aboard with an echo-sounder or a leadline. The beach profile is surveyed by leveling and taping techniques, the latter is
less affected by such errors as sounding, spacing, closure and sea bottom
temporal fluctuations, than the nearshore profile.
3.1
Beach Profile
Profiles are two-dimensional vertical sections showing elevations-to-distance
variation. Coastal profiles, usually perpendicular to the shoreline, include shelf-,
nearshore, and beach profiles. The latter two are of major importance in coastal
protection schemes.