3 . Beach Slope. The beach slope is usually chosen to match the slope of
the existing beach, based on the assumption that the native sand has
reached an equilibrium with existing forces.
Fill which is coarser than
native sand will tend to assume an angle steeper than the existing beach;
hence, fill may be placed slightly steeper than the existing slope to
reduce the volume of fill sand lost during initial adjustment to wave con-
d i t i o n s . It is noted though, that as the beach slope angle increases,
the potential for beach erosion is increased since steeper or more erosion-
producing waves can reach the beach fill.
4 . Beach Length. If fill is placed over a short stretch of shoreline, it
may create a bump on the shoreline which focuses waves on the newly-placed
fill, increasing its erosion.
Unless this phenomena is used to distribute
sand from a feeder beach, a protective beach must be transitioned into ad-
jacent beaches to prevent abrupt changes in the wave regime or placed
between hard points such as groins. In many cases, this requirement pre-
cludes use of a protective beach along a single private owner's shorefront
p r o p e r t y . Where the direction and volume of the longshore transport is
accurately known, however, short stretches of fill or even discrete piles
(stockpiles) may be placed at one end of an eroded beach, or at carefully
chosen, intervals along. the beach; for the purpose of supplying sand to ad-
jacent shores;. If the stockpiles are correctly spaced, the gaps between
them will be completely filled as waves and littoral currents distribute
the sand.
DESIGN
CONSIDERATIONS:
1 . In most cases, a restored beach must be renourished periodically in
order to maintain its protection.
The fill material should be the least
The design
erodible of the sands available and environmentally acceptable.
beach slope should be chosen to limit losses from wave action during adjust-
ment of the fill's shape, and the berm should be wide enough to keep an ade-
The fill
quate amount of sand on the beach between renourishment periods.
should be spread over a sufficient length of beach and should be transi-
tioned into adjacent beaches to prevent changing the wave regime which may
increase erosion.
2 . A-protective beach can provide sand for longshore transport to aid adja-
cent shorelines. Where this reduces erosion or promotes accretion of nearby
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