There are places where the beach has been graduaily widened, as well
as narrowed, by natural processes over the years. This is evidenced by
lighthouses and other structures that once stood on the beach, but now
stand hundreds of feet in1and.
In their eagerness to be as close as possible to the water, developers
and property owners often forget that land contes and goes, and that land
which nature provides at one tinte may later be reclaimed by the sea. Yet
once the seaward lirait of a development is established, this line must be
held if large investments are to be preserved. This type of encroachment
has resulted in great monetary losses due to storm damage, and in everincreasing costs of shore protection.
1.52 NATURAL PROTECTION
While the sloping beach and beach berm are the outer line of defense
to absorb most of the wave energy, dunes are the last zone of defense in
absorbing the energy of storm waves that overtop the berm. Although dunes
erode during severe storms, they are often substantial enough to afford
complété protection to the land behind them. Even when breached by waves
of a severe storm, dunes may graduaily rebuild naturally to provide protection during future storms. Continuing encroachment on the sea with
manmade development has often taken place without proper regard for the
protection provided by dunes. Large dune areas hâve been leveled to make
way for real estate development s, or hâve been lowered to permit easy
access to the beach. Where there is inadéquate dune or similar protection
against storm waves, the storm waters may wash over low-lying land, moving or destroying everything in their path, as illustrated by Figure 1-8.
1.53 SHORE PROTECTION METHODS
Where beaches and dunes protect shore developments, additional protective Works may not be required. However, when natural forces do
create érosion, storm waves may overtop the beach and damage backshore
structures. Manmade structures must then provide protection. In general, measures designed to stabilize the shore fall into two classes:
structures to prevent waves from reaching erodible material (seawalls,
bulkheads, revetments); and an artificial supply of beach sand to make
up for a deficiency in sand supply through natural processes. Other
manmade structures, such as groins and jetties, are used to retard the
longshore transport of littoral drift. These may be used in conjunction
with seawalls or beachfills or both.
Separate protection for short reaches of eroding shores (as an individual lot frontage) within a larger zone of eroding shore, is difficult
and costly. Such protection often fails at its flanks as the adjacent
unprotected shores continue to recede. Partial or inadéquate protective
measures may even accelerate érosion of adjacent shores. Coordinated
action under a comprehensive plan that considers érosion processes over
the full length of the régional shore compartment is much more effective
and economical.
1-14
as narrowed, by natural processes over the years. This is evidenced by
lighthouses and other structures that once stood on the beach, but now
stand hundreds of feet in1and.
In their eagerness to be as close as possible to the water, developers
and property owners often forget that land contes and goes, and that land
which nature provides at one tinte may later be reclaimed by the sea. Yet
once the seaward lirait of a development is established, this line must be
held if large investments are to be preserved. This type of encroachment
has resulted in great monetary losses due to storm damage, and in everincreasing costs of shore protection.
1.52 NATURAL PROTECTION
While the sloping beach and beach berm are the outer line of defense
to absorb most of the wave energy, dunes are the last zone of defense in
absorbing the energy of storm waves that overtop the berm. Although dunes
erode during severe storms, they are often substantial enough to afford
complété protection to the land behind them. Even when breached by waves
of a severe storm, dunes may graduaily rebuild naturally to provide protection during future storms. Continuing encroachment on the sea with
manmade development has often taken place without proper regard for the
protection provided by dunes. Large dune areas hâve been leveled to make
way for real estate development s, or hâve been lowered to permit easy
access to the beach. Where there is inadéquate dune or similar protection
against storm waves, the storm waters may wash over low-lying land, moving or destroying everything in their path, as illustrated by Figure 1-8.
1.53 SHORE PROTECTION METHODS
Where beaches and dunes protect shore developments, additional protective Works may not be required. However, when natural forces do
create érosion, storm waves may overtop the beach and damage backshore
structures. Manmade structures must then provide protection. In general, measures designed to stabilize the shore fall into two classes:
structures to prevent waves from reaching erodible material (seawalls,
bulkheads, revetments); and an artificial supply of beach sand to make
up for a deficiency in sand supply through natural processes. Other
manmade structures, such as groins and jetties, are used to retard the
longshore transport of littoral drift. These may be used in conjunction
with seawalls or beachfills or both.
Separate protection for short reaches of eroding shores (as an individual lot frontage) within a larger zone of eroding shore, is difficult
and costly. Such protection often fails at its flanks as the adjacent
unprotected shores continue to recede. Partial or inadéquate protective
measures may even accelerate érosion of adjacent shores. Coordinated
action under a comprehensive plan that considers érosion processes over
the full length of the régional shore compartment is much more effective
and economical.
1-14