230
R.H. Charlier and Chr. P. De Meyer
Already in 1982, dredging equipment routinely used, was capable of constructing
significant mounds, even when the material is a mixture of fine sand and silt
particles. Mounds, near Norfolk VA, have remained stable in that area despite
three hurricanes which have struck the area.
3.1.3 Monitoring, bypassing
Monitoring techniques apply to both the feeder and the stable berms : in the case
of the feeder berm, material will move downdrift while a little stable berm is
expected to remain stable. An unacceptable movement would lead to a return to
conventional open-water disposal (id. op. cit.).
Fathometer surveys will be used to measure berm elevations and side-scan sonar
will help define the boundaries of the berms.
To track sediment movement, grab samples of surface sediments will be taken. In
addition, divers will take core samples to assess to consolidation of the berm
material. Waves and currents will be measured and bottom currents tracked,
using bed drifters, and wave climate in the vicinity of the berms will also be
measured. Aerial photography and satellite imagery will measure any large
movement of the berms and detect turbidity plumes that may develop in the stable
berm. Effects of the stable berm on fisheries will be evaluated.
An overfill ratio should not necessarily be applied to the entire fill volume when
reclamation as well as beach building is involved. The relative proportion will
depend on the rate of filling and the extent of the active beach zone.
If the profile formed during material placing is at substantial variance with the
natural equilibrium profile for the imported material, initial losses may be very
large.
Bypassing is one of the techniques of artificial beach nourishment : sand is
'bypassed" from one side of an inlet to the other, reestablishing natural
processes.
One advantage of the nourishment approach is that it can easily be adapted to
changes in coastal patterns. So-called permanent structures are not flexible and
may become harmful in a new situation, necessitating removal. In the long run
artificial accretion is less costly.
A beach nourishment program has several options, each with its own merits,
some placing an important part of rebuilding the strand to nature. The latter
provide far less immediate results. Some options may even be considered more of
a maintenance action.
R.H. Charlier and Chr. P. De Meyer
Already in 1982, dredging equipment routinely used, was capable of constructing
significant mounds, even when the material is a mixture of fine sand and silt
particles. Mounds, near Norfolk VA, have remained stable in that area despite
three hurricanes which have struck the area.
3.1.3 Monitoring, bypassing
Monitoring techniques apply to both the feeder and the stable berms : in the case
of the feeder berm, material will move downdrift while a little stable berm is
expected to remain stable. An unacceptable movement would lead to a return to
conventional open-water disposal (id. op. cit.).
Fathometer surveys will be used to measure berm elevations and side-scan sonar
will help define the boundaries of the berms.
To track sediment movement, grab samples of surface sediments will be taken. In
addition, divers will take core samples to assess to consolidation of the berm
material. Waves and currents will be measured and bottom currents tracked,
using bed drifters, and wave climate in the vicinity of the berms will also be
measured. Aerial photography and satellite imagery will measure any large
movement of the berms and detect turbidity plumes that may develop in the stable
berm. Effects of the stable berm on fisheries will be evaluated.
An overfill ratio should not necessarily be applied to the entire fill volume when
reclamation as well as beach building is involved. The relative proportion will
depend on the rate of filling and the extent of the active beach zone.
If the profile formed during material placing is at substantial variance with the
natural equilibrium profile for the imported material, initial losses may be very
large.
Bypassing is one of the techniques of artificial beach nourishment : sand is
'bypassed" from one side of an inlet to the other, reestablishing natural
processes.
One advantage of the nourishment approach is that it can easily be adapted to
changes in coastal patterns. So-called permanent structures are not flexible and
may become harmful in a new situation, necessitating removal. In the long run
artificial accretion is less costly.
A beach nourishment program has several options, each with its own merits,
some placing an important part of rebuilding the strand to nature. The latter
provide far less immediate results. Some options may even be considered more of
a maintenance action.