Current through Register Vol. 46, No. 39, September 25, 2024
(a) Natural features such as beaches, bluffs,
dunes and nearshore areas, and the vegetation thereon, protect coastal areas
and human lives from wind and water erosion and storm-induced high water.
Inappropriate activities of man may diminish or eliminate entirely the
erosion-buffering function of natural protective features.
(b) The specific functions and protective
values of different types of natural protective features may vary. Certain
types of natural protective features are intrinsically better suited for
certain types of uses, activities, or development than others. The standards
and development restrictions of this Part that apply to regulated activities
within specific types of natural protective features are based on:
(1) the protective functions that specific
types of natural protective features provide; and
(2) the interaction between specific types of
natural protective features and physical coastal processes.
(c) Described below are the
erosion protection functions of various types of natural protective features
and their relationship to physical coastal processes. These descriptions are to
be used to guide the review of coastal erosion management permit applications
as required in sections
505.5
-505.9 of this Part, and in the review of variance requests as required in
section
505.13 of this Part.
(1) Beaches buffer shorelands from erosion by
absorbing wave energy that otherwise would be expended on the toes of bluffs or
dunes. Beaches that are high and wide protect shorelands from erosion more
effectively than beaches that are low or narrow. Beaches also act as a
reservoir of sand or other unconsolidated material for longshore littoral
transport and offshore sandbar and shoal formation.
(2) Bluffs protect shorelands and coastal
development by absorbing the often destructive energy of open water. Bluffs are
of greatest protective value during times of storm-induced high water. Bluffs
are a source of depositional material for beaches and other unconsolidated
natural protective features.
(3)
Dunes, along with bluffs and beaches, buffer shorelands from the energy of open
water. Like bluffs, dunes are of greatest protective value during conditions of
storm-induced high water. Because dunes often protect some of the most
biologically productive as well as developed coastal areas, their value as
protective features is especially great. The two primary functions of dunes are
prevention of wave overtopping and storage of sand for coastal processes. High,
vegetated dunes provide a greater degree of protection than low, unvegetated
ones. The keys to maintaining a stable dune system are the establishment and
maintenance of beachgrass or other vegetation on the dunes and assurance of a
supply of nourishment sand to the dunes.
(4) Nearshore areas dissipate a substantial
amount of wave energy before it is expended on beaches, bluffs or dunes by
causing waves to collapse or break. Nearshore areas also function as reservoirs
of sand, gravel and other unconsolidated material that is returned to beaches.
Sandbars, which are located in nearshore areas, control the orientation of
incoming waves and promote the development of ice-cap formations which help to
protect shorelines during winter storms. The roots of aquatic vegetation in
nearshore areas bind fine-grained silts, clays and organic matter to form a
fairly cohesive bottom that resists erosion. Such vegetation also assists in
trapping sediments.
