232
R.H. Charlier and Chr. P. De Meyer
Grain size distribution varies daily due to wave climate, storms, water height, but
changes are less pronounced on lakes than on ocean beaches because of water
level variations on lakes with ensuing base level readjustments.
Dune nourishment and artificial building may provide additional beach
protection. The dune blocks wave attack and provides sand to the beach. Such an
approach is being tested at Mantoloking, NY, where a 6m. (19.5 r) high dune
has been erected.
Materials site areas must be examined vertically and horizontally and cores taken
several meters below the bottom. Such cores, compared with seismic data, will
provide information about sediment nature in each layer and layer extent.
Fill should resemble as much as possible the original material. Coarser fill will
erode slowlier but thinner fill will erode laster than the original beach material.
Sediment selected for beach nourishment must be at least as coarse texturally as
the original beach material. Beach nourishment using sand too fine leads to berm
material erosion with offshore redeposition.
The source area must be so selected that no significant deepening of nearshore
areas occurs, otherwise wave energy may be intensified and result in or speed up
coastal erosion.
When dredging material for beach nourishment, care must be taken to select
appropriate depths so as to avoid any beach damage. Somewhat coarser and
better sorted sand that the beach material is preferable. Dredging up to 60 m
(197 ft) poses no problem and piping it as far as 8 km (4.8 mi) is possible.
Shingle-beach nourishment schemes usually present fewer problems than sand
beach nourishment where careful selection of the particle size of material is used
is particularly important.
Related to "nourishment" in the broad concept is an effort by Erosion Technology
Systems Inc., the developer of "Sea Grid" to counter shoreline erosion by
fostering, using artificial reefs, the formation of energy-absorbing sand-bars
offshore. No report, so far, has attributed any sand-bar building to any artificial
seaweed action ~8d.
Unintentional beach nourishment has also yielded good results. Near Workington
(Cumbrian Coast, England) coast mining waste and industrial slag dumped there
are used as beach nourishment material. In Denmark, at Hoed (Hod), flint gravel
and limestone waste products are regularly dumped. Quarry wastes feed the
Cornwall beaches at Porthoustock and mine wastes and slag at Porthallow Coal
does fulfill the same role (table 2).
R.H. Charlier and Chr. P. De Meyer
Grain size distribution varies daily due to wave climate, storms, water height, but
changes are less pronounced on lakes than on ocean beaches because of water
level variations on lakes with ensuing base level readjustments.
Dune nourishment and artificial building may provide additional beach
protection. The dune blocks wave attack and provides sand to the beach. Such an
approach is being tested at Mantoloking, NY, where a 6m. (19.5 r) high dune
has been erected.
Materials site areas must be examined vertically and horizontally and cores taken
several meters below the bottom. Such cores, compared with seismic data, will
provide information about sediment nature in each layer and layer extent.
Fill should resemble as much as possible the original material. Coarser fill will
erode slowlier but thinner fill will erode laster than the original beach material.
Sediment selected for beach nourishment must be at least as coarse texturally as
the original beach material. Beach nourishment using sand too fine leads to berm
material erosion with offshore redeposition.
The source area must be so selected that no significant deepening of nearshore
areas occurs, otherwise wave energy may be intensified and result in or speed up
coastal erosion.
When dredging material for beach nourishment, care must be taken to select
appropriate depths so as to avoid any beach damage. Somewhat coarser and
better sorted sand that the beach material is preferable. Dredging up to 60 m
(197 ft) poses no problem and piping it as far as 8 km (4.8 mi) is possible.
Shingle-beach nourishment schemes usually present fewer problems than sand
beach nourishment where careful selection of the particle size of material is used
is particularly important.
Related to "nourishment" in the broad concept is an effort by Erosion Technology
Systems Inc., the developer of "Sea Grid" to counter shoreline erosion by
fostering, using artificial reefs, the formation of energy-absorbing sand-bars
offshore. No report, so far, has attributed any sand-bar building to any artificial
seaweed action ~8d.
Unintentional beach nourishment has also yielded good results. Near Workington
(Cumbrian Coast, England) coast mining waste and industrial slag dumped there
are used as beach nourishment material. In Denmark, at Hoed (Hod), flint gravel
and limestone waste products are regularly dumped. Quarry wastes feed the
Cornwall beaches at Porthoustock and mine wastes and slag at Porthallow Coal
does fulfill the same role (table 2).