258
R.H. Charlier and Chr. P. De Meyer
Equipment and execution
The loading of the barges can be done with a stationary suction dredger, a
cutter, or even a trailing suction hopper dredger. The first dredger will,
most of the time, be equipped with barge loading facilities, e.g. spray-arms.
Cutter dredgers will need a flexible floating pipeline and a separate spider
barge, alongside which the barges can be loaded. The last-mentioned
loading method, using a trailing suction hopper dredger to fill the barges, is
feasible only under very calm weather conditions, while only one barge at a
time can be loaded.
For each of these loading systems, a different rate of washing out of the fine
particles will result. This is dependent upon the type of loading system, the
dimensions of the barge, the discharge flow rate and the concentration.
If no rehandle pit is available or permitted, the unloading is to be done by a
barge unloading dredger moored in a sheltered area.
By using this system, the fine fractions from the barges will automatically
be deposited on the beach. Therefore, a proper washing out of the '~nes"
will have to be achieved during barge loading operations. Because only one
barge at time can be emptied by the reclamation dredger, an irregular
pumping process takes place, which means more water at the reclamation
site and thus flatter reclamation slopes. The pumping irregularity makes it
impossible to maintain a constant high concentration flow, resulting in a
lower weekly production level compared with the rehandle pit method.
3.2
Beach Nourishment Schemes
Several schemes have been undertaken in sites spread over the entire world (table
8). In the United States, it took $ 65 million to restore 25 km m 3 of beach in
Miami Beach, FL.; at Redondo Beach 1,100,000 m 3 (+ 39 million fP) of
materials were used to rebuild the beach 2°' 21
Other areas in the U.S.A. where beach nourishment was selected as a means of
remedying coastal erosion, include the coast of Washington State (Ediz Hook),
Coronado Strand (San Diego) and downcoast from the Channel Islands Harbor in
California, Sandy Hook (New Jersey), Presque Isle peninsula (on Lake Erie),
famed Waikiki Beach (Hawaii) and Cape Hatteras.
R.H. Charlier and Chr. P. De Meyer
Equipment and execution
The loading of the barges can be done with a stationary suction dredger, a
cutter, or even a trailing suction hopper dredger. The first dredger will,
most of the time, be equipped with barge loading facilities, e.g. spray-arms.
Cutter dredgers will need a flexible floating pipeline and a separate spider
barge, alongside which the barges can be loaded. The last-mentioned
loading method, using a trailing suction hopper dredger to fill the barges, is
feasible only under very calm weather conditions, while only one barge at a
time can be loaded.
For each of these loading systems, a different rate of washing out of the fine
particles will result. This is dependent upon the type of loading system, the
dimensions of the barge, the discharge flow rate and the concentration.
If no rehandle pit is available or permitted, the unloading is to be done by a
barge unloading dredger moored in a sheltered area.
By using this system, the fine fractions from the barges will automatically
be deposited on the beach. Therefore, a proper washing out of the '~nes"
will have to be achieved during barge loading operations. Because only one
barge at time can be emptied by the reclamation dredger, an irregular
pumping process takes place, which means more water at the reclamation
site and thus flatter reclamation slopes. The pumping irregularity makes it
impossible to maintain a constant high concentration flow, resulting in a
lower weekly production level compared with the rehandle pit method.
3.2
Beach Nourishment Schemes
Several schemes have been undertaken in sites spread over the entire world (table
8). In the United States, it took $ 65 million to restore 25 km m 3 of beach in
Miami Beach, FL.; at Redondo Beach 1,100,000 m 3 (+ 39 million fP) of
materials were used to rebuild the beach 2°' 21
Other areas in the U.S.A. where beach nourishment was selected as a means of
remedying coastal erosion, include the coast of Washington State (Ediz Hook),
Coronado Strand (San Diego) and downcoast from the Channel Islands Harbor in
California, Sandy Hook (New Jersey), Presque Isle peninsula (on Lake Erie),
famed Waikiki Beach (Hawaii) and Cape Hatteras.