Download guidelines for proper beach and dune management

Palm Beach County
Department of Environmental Resources Management
GUIDELINES FOR PROPER
BEACH AND DUNE MANAGEMENT
NATIVE DUNE-FORMING PLANTS
The beach and dune system is a dynamic environment subject to
extensive change as a result of wind, waves, tides and storms. Native
salt-resistant vegetation is essential to the beach and dune system as it
both accumulates and stabilizes sand. Vegetation traps wind blown
sand which collects around the plant and builds up the dune, a process
known as “accretion”. As the plants become buried, new roots develop
on the recently buried stems while new stems emerge from the sand. A
dense stand of sea oats, and other primary vegetation in the foredune
can significantly minimize erosion during high tides and storms. Sea
oats are “protected” under regulations of the Florida Department of
Environmental Protection (FDEP). Sea oats seeds can not be collected
without a permit and the plants can not be cut back or removed. Sea
grapes, which grow on the back dune and have large ping-pong paddleshaped leaves, act as a highly efficient barrier to blowing sand and
result in significant accretion of the backdune. Dunes are important
reservoirs for sand, replacing sand lost from the beach through erosion.
All native dune vegetation should be protected from pedestrian traffic,
pruned only as necessary and according to FDEP guidelines, and
replanted as necessary to maintain this delicate system.
DUNE SYSTEM
Sea oats roots
EXOTIC PLANTS
Invasive exotic vegetation (i.e., Australian pine,
Hawaiian half-flower, St. Augustine grass, wedelia,
Brazilian pepper) should be eradicated from dune areas
whenever possible. Invasive exotic species have a
tendency to overgrow native species and are less
effective in stabilizing the sand or maintaining the dune
ecosystem. One of the most common dune invasives is
the Hawaiian half-flower (Scaevola frutescens). The
shallow roots and fragile stems of this exotic are easily
destroyed in high winds or storms making it far less
effective in dune stabilization than sea oats and other
native species. It is important not to confuse this exotic
with its native counterpart, inkberry (Scaevola plumieri)
which is an endangered species protected by Federal
law. The native inkberry has thick, round, rubbery
leaves, and when fruit-bearing, the fruit is black in color
unlike the exotic species which has snow white berries.
EXOTIC: Hawaiian half-flower
Australian pines inhibit the growth of other plants as a
result of their shading effect and the acidic nature of
their pine needles. Australian pines eventually results in
a ‘weak spot’, making the dune vulnerable to storm
erosion. In all cases where exotics have been removed,
the area should be replanted with natives typical of that
portion of the dune. Where lawn grasses adjoin the
dune area, a distinct buffer zone should be maintained
by herbiciding, mulching, and edging to control the
ENDANGERED NATIVE: inkberry
encroachment of these grasses into the dune.
PRUNING NATIVE VEGETATION
Trimming or pruning native dune vegetation may seem desirable to a property owner in order to
provide a clear view. All trimming and pruning of sea grapes seaward of the Coastal
Construction Control Line is subject to the permitting requirements of the FDEP. No more than
one-third of the height of a sea grape and no more than one-third of the leaf area may be removed
in a single pruning event or a single year. The plants can not be reduced to an overall height of
less than six feet. All pruning should be in accordance with accepted horticultural practices
referred to as “Crown Reduction Pruning Standards”. Any pruning beyond this limit requires an
FDEP permit. A well-developed stand of seagrapes is essential to the stability of the beach and
dune, accretion of sand, and protection of upland buildings from storm-induced erosion and
blowing sand and salt spray. Sea grapes also block light from the beach where it could otherwise
interfere with sea turtle nesting and disorient emerging hatchlings. Marine turtle mortality
resulting from increased illumination is a violation of Florida Statutes and the Federal Endangered
Species Act of 1973 and is subject to fines up to $10,000. The best policy is to let a hard winter
freeze and salt spray control the height of dune seagrapes naturally.
BEACH RAKING
Beach raking can have negative effects on the beach and
dune. Beach raking too close to the dune can destroy new
seedlings establishing at the leading edge of the dune.
Although seedlings in this pioneer zone often become
buried by wind-blown or storm-deposited sand, they
usually grow through the new sand layer and continue to
stabilize the area. Beach rake operators should stay well
away from the toe of the dune. Seaweed is valuable to the
dune system as both a source of nutrients and a sand
stabilizer. Seaweed removed from the beach should be
deposited at the toe of the dune. Beach raking
also reduces compaction of the sand which results in
suspension of the sand in the water during high tides and
contributes to loss of sand and erosion of the beach.
Seaweed is a fertilizer and stabilizer
IRRIGATION AND FERTILIZATION
Healthy dune ecosystem
In contrast to ornamental plants, dune vegetation is
considered “xeric”, adapted to low water requirements.
Excessive watering of the dune usually results in the
establishment of undesirable, invasive exotics. It is
therefore important that all sprinklers near the dune be
adjusted to minimize overspray onto the dune. The
nutrient requirements of native dune plants are generally
low and fertilization can result in impacts similar to those
caused by excessive watering. The best method to
ensure an adequate nutrient supply is to leave all organic
material such as leaf litter and seaweed in place on the
dune. New plantings may require temporary watering
until the plants establish a well-developed root system.
RECREATIONAL ACTIVITIES
Foredune plants are vital to sand accretion and building the reservoir of sand available to
replenish the beach. These plants are also highly sensitive to disturbances. In order to protect
these valuable plants, all recreational activities should be kept at least 10 feet away from the
leading edge of the foredune. Recreational equipment such as boats, surfboards, beach chairs
and cabanas should never be stored on the dune or within 10 feet of the foredune. Repeated
disturbances to the vegetation will destroy the plants and weaken the dune system, leaving the
beach as well as upland buildings vulnerable to storm damage. Following storm events, the
change in beach profile should be noted. Has erosion occurred, or has sand simply been pushed
higher on the beach covering previously exposed vegetation? In the case of the latter,
recreational activities and cabanas should be kept far enough away from this location to allow the
buried vegetation to re-emerge through the sand.
PRESERVING YOUR BEACH
Preserving the beach and the value of beachfront property depends on our understanding the
significance of coastal sand dunes and our willingness to maintain the native vegetation critical to
the functioning of this system. The actions you can take are:
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Protect and replant native dune vegetation.
Eliminate invasive exotic vegetation.
Trim and prune sparingly and according to FDEP guidelines.
Avoid beach raking if possible or move seaweed to the toe of the dune.
Avoid irrigating or fertilizing dune plants.
Keep recreational activities and equipment well away from dune vegetation.
Participate in restoring and maintaining your dune system.
Call ERM with any questions you may have.
Palm Beach County Environmental Resources Management (ERM) sponsors beach restoration
projects throughout the County including dune restoration, beach nourishment, inlet sand
transfer operations and construction of groins, breakwaters and other erosion control structures.
Funding for these projects is obtained through County, State, Federal and local government.
County funds for beach restoration and enhancement projects are primarily obtained through
taxes paid by tourists on hotel and motel rooms in the County.
Never underestimate the power of a storm.
FOR MORE INFORMATION, CALL:
Palm Beach County
Department of Environmental Resources Management
Environmental Enhancement & Restoration Division
(561) 233-2400
OR VISIT OUR WEB SITE:
www.co.palm-beach.fl.us
Revised: September 2000