ANALYSIS AND
RECOMMENDATIONS
FOR
MANAGEMENT OF THE COASTAL
DUNE
AT
DELRAY BEACH, FLORIDA
Prepared by
Robert H. Barron
Coastal Management and Consulting
7611 Lawrence Rd.
Boynton Beach fl. 33436
<[email protected]>
with assistance from
The Institute for Regional Conservation
<regionalconservation.org>
December 2015
INTRODUCTION
The coastal dune, at the Delray Public Beach, is almost entirely man-made, installed and
enhanced during several projects which began as an effort to solve the problem of sand blowing
into the street, after the first major beach nourishment in 1973. The investment, by the City, in
dune revegetation has paid off with an accumulation of more than 185,000 cubic yards of wind
transported sand, in a storm protective dune buffer that averages 160 feet wide. The character of
the Beach has been dramatically altered and most Delray Beach residents feel improved, by the
separation of the recreational beach from the traffic and business of A1A, which has resulted
from the growth of the dune.
Coastal dunes serve a number of functions. The dune vegetation traps and stabilizes wild
blowing sand, slowly growing an elevated dike which can reduce flooding and wave damage
during heavy storms. The sand mass then erodes, under wave attack, into the near shore where
wave energy is absorbed. The sandy dune also provides a habitat for over two hundred plant and
animal species.
The dune system at Delray Beach, which was actively created by the City, must be actively
managed as well, to balance engineering, recreational, aesthetic, and maintenance needs. This
report seeks to provide information, and advice toward optimizing management of the dune, with
special focus on the upcoming project to reduce the seagrape tree canopy and renovate the
dunescape in the area of Atlantic Avenue.
AUTHORIZATION
This review and report was authorized by the City of Delray Beach as Project # 15-072,
contracted to us on August 15, 2105.
FIELD INPECTIONS AND SURVEY
Thorough inspections of the dune were conducted between August 23 and September 10 to
identify exotic plant contamination on the public beach and generate maps to provide to the City
Contractor for removal. Inspections and mapping of the private areas seaward of the Erosion
Control Line were conducted thru October, and maps provided. Nighttime lighting surveys were
conducted on September 5 and 6th to confirm that exotic removal would not result in additional
light reaching the sea turtle nesting beach.
Floristic and Faunistic inventories were conducted by the Institute for Regional Conservation
from September thru December. Lists of plant species observed on the Delray Public Beach, at
Atlantic Dunes Park, and in the private beach areas of the City are included as Appendix A, and
animal species observed as Appendix B.
1
NARRATIVE DESCRIPTION
The man made dune measures the entire 6840 shore parallel length of the Public Beach, with the
shore normal width averaging 160 feet from the seaward edge of the turfgrass along A1A east to
the limit of native dune grass on the nourished beach. Width of the dune varies along the private
shoreline from 140 shore normal feet to the north of the public beach, to 200 feet between
Casuarina and Atlantic Dunes Park, and 125 feet south of Linton.
Windblown sand has accumulated in the vegetation, throughout this area, with as much as eleven
vertical feet of accretion above the nourished beach elevation of +9 feet NGVD, in some places.
This increased elevation has created a foredune ridge and left one or two low troughs, or swales,
between the grassy foredune and the scrub plants along the sidewalk . Short term growth of the
profile can be rapid, in the exposed seaward area, especially during a strong, dry, onshore wind
event, while sand trapping and the general microclimate farther upland in the swale is buffered.
The development of this foredune/backdune zonation is allowing species succession to proceed
on a compressed scale, and providing an environment for a broader palette of plant choice for
continued City replanting efforts to restore a more complete strand zone habitat.
The seagrape near the roadway is pruned semi-annually to maintain height at about three feet
above grade, and the sea oats dominated foredune grows without management, expanding
seaward at five to eight feet yearly, controlled by active beach use.
Eight species had been planted, and about 25 native and ruderal species had voluntarily recruited
to the renourished Delray Beach, prior to 1995, when the City conducted the first of several
projects to remove the invasive exotic scaevola hedge , prune seagrape trees, and revegetate the
hedge zone with native dune species.
A total of fifty native species have been added to date, including several listed as endangered or
threatened by the State of Florida or the U. S. Fish and Wildlife service. Another 73 native plant
species have recruited as volunteers into the system. Our Floristic Inventory, (Appendix A)
identifies an additional forty non native species of a few individuals or small populations, which
should be targeted for eradication
Atlantic Dunes Park, which has been managed by the City since the Nineteen Seventies, is one of
the few remaining coastal ecosystems in South Florida with a full transverse section of
Beach/Dune, Coastal Strand and Maritime Hammock communities. The species diversity of the
Park has suffered, in the past thirty years from overshadowing by exotic plants, and more than a
dozen of the native species, which used to exist there, have been lost.
2
ELEMENTS OF A COMPREHENSIVE DUNE MANAGEMENT
PLAN
1. Removal of invasive exotic pest plant species.
Exotic species compete with and overwhelm more stable native dune plants but are often
weaker and more likely to suffer damage during a storm, or to break up and deliver missiles
which may damage nearby property. These should be carefully removed as the first step in dune
landscape management, but not until a program is in place to replant cleared areas with more
appropriate native species.
2. Cultivation and support of a dense grassy pioneer zone dune.
The foredune is the first line of defense against erosion. Sea oats and fast growing deep
rooted grasses help to hold sand against wave attack. Regular care may be necessary, in some
areas, to promote dense growth, especially in critically eroding areas, or spots which conflict
with recreation activity. All areas cleared of invasive exotic plants should be quickly replanted
with pioneer zone grasses.
3. Remedial and maintenance pruning of native strand/scrub zone species.
In the stable natural condition, the nearshore dunescape immediately upland of the grassy
pioneer zone had no trees. This wind resistant Coastal Strand Zone, populated by saw palmettos
and low shrubs should be maintained at knee to hip high to reduce uprooting and toppling forces
during a blow. Where shrubs have been allowed to grow taller, initial pruning should be 24 to 30
inches below the desired maintenance height to allow for growth of branching sub structure ( an
arboricultural process called coppicing). Long term maintenance pruning should be at hip height,
balancing wind resistance with ease of maintenance.
4. Supplemental planting of the Strand Zone with a diversity of native species,
dominated by saw palmettos.
Areas cleared of exotics and exposed by reduction of tall native plant canopies should be
replanted with a mix of the native species which existed in the dune before development. Initially
this should be the pioneer zone community dominated by sea oats and dune panic grass, then
followed with saw palmettos and a mix of low growing shrubby species. The species mix will
vary with microclimates within the dune and should be chosen respecting the habits of the
species. Rare and listed species may be included, to restore a complex, historically correct
population. Once established, these should be pruned to maintain low shrub height. Pre-existing
native trees may, in limited areas, be maintained in tree form to provide shade.
3
5. Active, aggressive enforcement of ordinances to eliminate light pollution.
Execution of any Dune Management Plan of this scope requires permitting by the Florida
Department of Environmental Protection. Such permits are contingent upon demonstrating that
no additional light from upland development will reach the marine turtle nesting beach as a result
of implementation of the plan. Problems with marine turtle misorientation will be prevented by
considerate project design and by active nighttime inspection and concerted enforcement of
Local, County, and State Laws.
What follows is a topical review of our observations, with recommendation for future
management.
EXOTIC PLANT SPECIES CONTROL
The Florida Exotic Pest Plant Council designates certain plant species as Category I and II
Invasive Exotic Pest Plants, generally when the species is known to crowd out native plants and
produce a profusion of seeds which are spread by wildlife and wind, contaminating other areas.
The problem exotics on Delray Beach are also shallow rooted, compared to native dune species,
and more likely to uproot or wash out in a blow.
The City has recently completed a program of contracted removal of the six most common
invasive exotic species at the Municipal Beach. We have mapped populations of those for
Atlantic Dunes Park and the private areas within the City limits to facilitate control efforts by
homeowners. (provided as Appendix C ). Exotic contamination at Atlantic Dunes Park has not
been adequately addressed for years, with resultant loss of large areas of previously wild habitat.
There remain a number of more obscure but potentially problematic exotic species in the system
identified by our plant survey, some with only a single or few individuals. Eradication of these
should be under the supervision of an experienced botanist to ensure accurate identification.
MANAGEMENT RECOMMENDATION:
Develop a plan for the removal of exotics and restoration of strand and maritime hammock
habitats of Atlantic Dunes Park.
Develop a training outline for Parks staff with information on identification and control of exotic
species. and train Parks staff to inspect for and remove exotic seedlings on a regular basis, once
contractor obligations expire. This can be done during seagrape pruning events.
Inform oceanfront homeowners of the problems associated with exotic contamination, provide
maps and encourage their participation to eradicate.
Engage IRC to identify and supervise removal of less common but more threatening exotic
plants, while populations are small and inexpensive to control.
4
PIONEER ZONE SUPPORT
Recent exotic removal has exposed some areas within the existing dune which are too large to
recover from natural recruitment. These should be mapped and replanted with sea oats to
stabilize, according to specifications in Appendix E
MANAGEMENT RECOMMENDATION:
Map and r`eplant barren areas greater than 100 square feet with sea oats and dune panic grass.
DUNE SHRUB PRUNING
Natural coastal strand dunes, as observed in undeveloped areas of the Florida shoreline, and in
historical photographs, are dominated by saw palmettos, with a subordinate mix of herbaceous
and shrubs species, generally limited in height to about five or six feet. The coastal scrub
complex is shaped over long periods of time by intermittent freezes, wildfires, and hurricane
winds. Hurricanes disintegrate and uproot taller seagrapes along the shoreline. Freezing weather
and wildfires burn seagrapes and other perennials to the root collar, near the ground, but
palmettos and strand shrubs survive these insults with little damage. Palmettos are more deeply
rooted than other species, and were observed to have survived the worst of Hurricane Andrew,
with little long term damage..
Regular maintenance pruning replicates natural process and develops a dense scrub or strand
zone which is best suited to hold up through the high winds and overwash of a major storm.
The City's FDEP permits authorize control of the height of the seagrape and other strand zone species
in the dune as described in the permit plans.
Dune hedges and individual shrubs should be pruned two or more times per year, and maintained
in height at between two and four feet above grade. Initial pruning should be between ankle and
knee high, with the next cut about a foot higher, and some branches should be left, which orient
toward open areas. The effort should be to establish a branching sub structure a foot or so below
the objective maintenance height, so that long term pruning can be done with hand tools, cutting
through more succulent new growth, and allowing the trimmed leaves and stems to fall and
mulch into the dune. The necessary tools are safer and less fatiguing. The visual impact of each
pruning cycle is reduced. There is less stress to the plants.
This work has been done effectively by the Parks Department for fifteen years, but the regular
pruning program has failed to carry out the other important pruning task called out in the
permits; that is controlling the lateral expansion of the shrubs. As a result the footprint of the
seagrapes gets larger each year, increasing the workload cost of pruning, crowding out more of
the protective pioneer zone, and replacing it with a high maintenance and unnatural seagrape
monoculture.
Analysis of historical aerial photos at Section 17, for example, demonstrates that the 2015
seagrape covers 2.3 times the area as when pruning began in 2001, and has spread to 35 times
the area of the original planting. Expanding at about 7 percent per year, and continuing to be
left unmanaged, the hedged seagrape may cover the entire dune area in as little as fifteen years.
5
FDEP has indicated that remedial removal of seagrape to the approximate areas in the original
section by section permit plans is approvable, so long as those areas are replanted with native
pioneer zone species.
We observed areas where maintenance pruning has damaged some of the rare and lesser known
species which have been introduced with the dune renovation.
MANAGEMENT RECOMMENDATIONS;
Coordinate with FDEP to develop and carry out a plan for remedial reduction of the seagrape
footprint to predefined permit limits and replant with pioneer zone species.
Develop a protocol for lateral control during regular pruning events and train Parks staff to
incorporate lateral control into the regular maintenance program.
Review pruning methods and train Parks Staff in recognition and appropriate care of special
dune areas, and rare species.
SCRUB/STRAND ZONE RENOVATION
Permits from the Florida Department of Environmental Protection have been received to
renovate the remaining sections of the dune in the near Atlantic Avenue, including sections 12,
13, 14, 15, and 16. These projects will prune the seagrape tree canopy to low shrub height and
reduce the seaward footprint of the trees, followed by replanting with strand and pioneer zone
plants.
Generic specifications for soliciting bids for this work are included as Appendix E
Plant species and size selection, or more broadly the design of each section to be restored, should
consider the growth habit of each of the many plant species being installed. Certain native
species have growth habits which change, as the individual plant matures. The pioneer zone
grasses and vines will thrive over the long term only when there is a regular supply of
windlblown sand to stimulate new growth. These species die off after the second or third year, if
no new sand is available, and should be used sparingly to provide temporary infill with the new
shrubs and palmettos installed along the sidewalk.
Appropriate design selects plants which will require supplemental irrigation only for a few
months period of establishment, and will thereafter thrive with only natural rainfall, grow at a
manageable rate, and still grow dense enough to discourage traffic except at controlled
accessways. These requirements limit the choices, for species to be used along the sidewalk side
of the dune, to only a dozen or so of the one hundred fifty native dune species. Improper choices
will commit the City to renovation of the renovation in a short time.
Species which are well suited to development of a dense, manageable shrub thicket transition
zone, between the sidewalk and the grassy pioneer dune are ; Argusia gnaphalodes, (sea
lavendar), Baccharis halimifolia (saltbush), Chrysobalanus icaco (cocoplum. horizontal
variety), Ernodea litoralis (golden beach creeper), Eugenia foetida (Spanish stopper), Guapira
discolor (blolly), Pithecellobium guadelupense ( black bead), Randia aculeata (white
indigoberry), Serenoa repens (saw palmetto), and Suriana maritima (bay cedar).
Minor localized alteration of the existing grades, to reduce the cresting of the planting areas
after removal of the exotic species or reduction of seagrape canopy, will improve the resistance
of the shrub zone to wind stress. The street side of the dune will look better over time. This can
be done with minimal handwork, using only shovels and rakes.
Specimen bid specifications for contracting pruning and renovation plantings are included as
Appendix E. The actual bid documents will include detailed planting lists and section plans
generated at the time of the bids.
MANAGEMENT RECOMMENDATIONS
Proceed with the permitted dune section renovations as soon as funding can be secured.
RARE PLANT CONSERVATION
An important component of the Dune program at Delray Beach has been the rescue and
relocation of a number of plants listed as endangered or threatened by the State and Federal
governments. Some of these had been reduced by human activities to only a handful of
remaining examples. Plants such as Sea Lavender, Golden creeper, Silver Palm, and Beach
Clustervine have been grown from seed or transplanted from development sites or areas
of
neglected management,.and reintroduced to the Municipal Beach to establish functioning
populations, and preserve a genetic storehouse for future restoration efforts. This work has been
conducted and supported by high school and college students, local native plant nurseries, and a
Federal grant program.
MANAGEMENT RECOMMENDATION
Continue to support rare plant conservation by working with academic and conservation
organizations.
Authorize responsible collection of seed and cuttings for off site restoration programs.
LIGHT POLLUTION CONTROL
FDEP permits which allow the City to prune and maintain the dune vegetation in a low wind
resistant form are conditioned that no light from upland of the dune illuminate the sea turtle
nesting beach as a result of the work. The City must carry out an aggressive education,
homeowner outreach, and Code Enforcement program to address any lights visible from the
beach. The program should be proactive to prevent misorientations rather than documenting
when they occur. Though the entire shoreline of Delray Beach is darker than when we did the
surveys in years past, our late season inspections identified bright lights which should have been
eliminated before hatchling emergence.
7
MANAGEMENT RECOMMENDATIONS:
Conduct pre turtle nesting season nighttime surveys, taking geotagged photographs of all point
source illuminants visible from the nesting beach, allowing Code Enforcement time to
proactively engage property owners and suggest resolutions before nesting begins. These should
be independent of regular sea turtle monitoring since the light surveys are best conducted in the
middle of the night, rather than at sunrise during nest surveying.
Conduct regular mid season lighting surveys to identify occasional or temporary illuminants.
Recognize that this program impacts not just the turtles but the health of the entire beach/dune
system
SAND FENCES
Sand fencing should not be used as a means to collect sand, which is done better by vegetation,
but only to control pedestrian traffic. When necessary, plastic roll fence, available in black and
green, should be used, since the older wood and wire type can create hazards as it deteriorates.
The fences should be lifted from time to time, before sand covers the bottom half, and replaced,
if necessary so that the fence is not buried or integrated into the vegetated dune, since hand labor
to remove the buried fence can be more costly than the original installation.
We advise use only of geotechnical barrier fencing made of high density polyethylene. There are
several brands available in black, green, brown, and high visibility colors, which are usually
supplied in four or five foot widths, on fifty or one hundred foot rolls.
The roll should be cut into two half width rolls, two feet by one hundred, and hung on four by
four inch by six foot wood posts set into the sand leaving forty two inches above grade. The
fence is nailed to the post, hanging from the top on the windward side, leaving a one and a half
foot gap below, which allows windblown sand (and nesting marine turtles) to pass underneath.
The fence can also be secured to two inch metal posts using galvanized wire. This configuration
will control traffic, without interfering with sand transport into the vegetated dune. The fences
should only be used where there is clear and repeated evidence of long term pedestrian traffic
damage to the vegetation, for example, at the volleyball courts. Temporary, event related,
fencing can be suspended on half inch diameter electrical mechanical tubing ( EMT), woven
through the fencing during installation, and secured to the posts with twisted wire or cable ties.
In many cases, low load traffic control can be accomplished with light yellow poly line on two
by two inch posts.
Suppliers of HDPE roll barrier fencing are:
Tenaxfence.com, ph 800-878-7829
or
Forestry Suppliers Inc. ph 800-647-5368
8
THE OCEAN VISTA
The ocean view along SR A1A defines the character of Delray Beach. Managing the dune to
preserve that vista benefits the quality of life and economy of the City, and is a reasonable
consideration of dune management practice in balance with storm protection, recreation and
habitat concerns. Planning and construction of this man made dune seeks to replicate the low
scrubby natural ecosystem which existed at this location prior to settling and development of the
City.
The organic nature of dune growth creates low and higher spots. It may be possible, within certain FDEP
constraints, to grade areas of higher elevation into more upland swales, in combination with seagrape
reduction and local enhancement plantings. Sand should only be moved upland to increase volume of the
backdune profile, and only when this can be done with no increase of light pollution to the beach.
The dune at Delray Beach has been developed over the years as a series of efforts, most of which
were responding to a problem such as sand blowing into the street, or reduction of the ocean
view by overgrowing vegetation. As a living entity, the system will continue to grow seaward
and in elevation as sand continues to be provided by renourishments. The dune program has been
working with a set of habitat management goals, but there has never been a defined engineering
goal regarding sediment capture and storm protective dune dike development. In time there will
be conflicts between dune growth and recreation space, especially if outside funding sources
wane and reduce the frequency and volume of renourishment. There may be a point when the
City has enough dune, and I suggest that it is time to evaluate dune function from an engineering
standpoint. Comparative storm protection value can probably be assessed by study of existing
topographic data.
MANAGEMENT RECOMMENDATION
Seek a coastal engineering review and opinion to guide dune management decisions.
SAILBOAT STORAGE
Beachside storage of sailboats has clear impacts to the beach/dune system, at both the North end
Municipal Beach and the Seagate Beach Club Concession site. The frontal dune line at sections
25, 26, and 27, has migrated seaward to a lesser extent due to boating activity, but development
of the dune ridge by aeolian transport does not appear to be impacted. We observed a number of
boats that were clearly not in navigable condition, a few which appeared to have been so for
some time. There is a variety of owner installed locking systems. In general, the boat owners
police themselves, respecting the importance of the dune system, and only rarely push boats or
activities into the vegetation, except for two footpaths which have been trod through the dune
between the City access points.
A review of the Parks and Recreation Department's Boat Storage Permit application and the
Sailboat Storage Area Rules and Regulations, raises some questions.
The fee for one year of storage on the beach with full 24 hour access and minimal mobilization
time to use the boats is $265.00. By comparison, the average monthly cost for the five nearest
inland boat storage facilities is $146.00, or an annual cost of $1,750.00. six times more expensive
than keeping the boat at the beach. The city may be able to reasonably increase the fee, while
still providing a bargain cost to the users. More to the point is that it is cheaper to leave a junk
boat on the beach than to dispose of it, which may explain why some boats remain unusable for
long periods.
The Regulations twice require the boats to be "safely secured" or "tied down" but leaves it up to
the owner to determine what that means. The result is a variety of securing devices some of
questionable function and location. The Regulations also state that in the event of a storm,
"sailboats may not be moved westward of the sand fence", and "must be safely secured east of
the snow fence". Yet there is no snow fence in the area.
The Seagate Boat Rental Concession at Causarina St. and A1A, has caused greater impact. The
frontal vegetation line in this area is approximately ninety feet upland of the north and south
adjacent dunes. In addition to the effects of the equipment storage structures, there may be active
efforts to discourage vegetation growth and inhibit sand transport upland from the beach. The
result is an area where the roadway is more vulnerable than the adjacent shoreline to overwash
and erosion in a major blow. While there is certainly a valuable public recreational benefit from
this facility, we are concerned that half of the 16 catamarans parked in the concession area are
not maintained as navigable, and we have seen no investment in their repair during two months
of inspections. There is no public benefit to permitting what is essentially junk storage on the
beach to justify the risk of damage to upland areas in a storm.
MANAGEMENT RECOMMENDATIONS:
Install a cable, similar to that which was used in years past, seaward of the desired dune line, so
that the City controls the location and method of securing the boats.
Review the fee structure and apply user fees to the cost of the securing system..
Rewrite the Rules to more accurately represent the situation.
Install temporary pedestrian obstructing fence in the pathways between the City access points.
Engage the Seagate Concessionaire and insist that consideration be given to minimize impacts to
the dune system.
BEACH RAKING
Mechanical beach cleaning causes no harm to the beach dune system so long as the seaweed
biomass is not removed from the beach. During periods of extreme seaweed deposit, excess
material can be deposited into low areas in the dune with no harm and will break down to be a
beneficial nutrient. When necessary, this should be coordinated with FD
10
DESIGNATED DOG AREA
We have found no evidence of damage to the dune system from dogs on the beach, since most
activity is at or near the water line.
There have been incidents reported by the City's marine turtle surveying contractor, of dogs
digging into and destroying sea turtle nests.
The enforcement issues surrounding the existing dogs on the beach problem seem to have not
changed since I was Beach Supervisor between 1980 and 1987. What has changed is the
perception, probably promoted by social media, that existing ordinances are not enforced with
resolve, and that it is legal to take dogs to certain areas of the beach.
If the City does not, in fact, want dogs on the beach, then a short period of aggressive ticketing
would likely reduce the size of the de facto floating weekend kennel.
From a safety and recreation management viewpoint, my opinion as former Beach Supervisor for
the City, is that the limited public benefit makes it difficult to justify the risks or disturbances to
the general beachgoing public which are associated with having dogs, even on leashes, in close
proximity to bathers. Since I did have a personal experience as an ocean lifeguard in which it
was necessary to corral a loose and aggressive dog which had escaped the control of its owner, it
is my professional opinion that the risks outweigh the benefits of providing a dog area on the
Municipal Beach.
MANAGEMENT RECOMMENDATIONS:
Maintain a dog free beach policy and enforce as necessary.
Should the City decide to provide a dog area, it should be on fixed length leash only, at clearly
designated location and limited times, distanced as possible from concentrated parking areas, and
with a registration permit fee adequate to cover the costs of active Park Ranger supervision.
BEACH ACCESSWAY DESIGN
The City's decision, years ago to allow access pathways to evolve naturally, rather than to build
elevated structures, has proven prudent. The only evidence of harm from pedestrian load even at
the access points nearest the most concentrated parking, is the fanning of the sea side of a few
paths, such as at S-3/Sandoway, which allows sand to blow and accumulate farther into the
backdune.
MANAGEMENT RECOMMENDATION:
Install temporary pedestrian control fence to narrow and redirect selected paths to the south and
revegetate to reestablish the sand trapping foredune plants.
11
RECREATION AMENITIES
It is FDEP policy that movable, temporary storage structures, such as the boxes used for beach
cabana storage are not regulated and do not require a permit from the State. A permit is required
for any such structure which is proposed to be built on posts or pilings dug into the sand. Since
these storage structures alter and prevent the natural accretion of sand in the dune, an∂ cause
localized erosion during even moderate winds, they should be mobile and relocated as needed to
allow unimpeded dune function.
When trashcans were first placed on the beach, in the eighties, it was decided to not construct
fixed trash stations so that impacts could be spread out and cans could be removed before a
storm.
BEACH AND DUNE MANAGEMENT OVERSIGHT
Engineering and maintenance aspects of beach management have been split or shared in years
past, by Planning and Zoning, and Parks and Recreation, with neither having designated
responsibility for ensuring that all necessary work is on track . The result is that some bases went
uncovered. I suggest that one individual be tasked with keeping track of the entire beach
management program and coordinating efforts of all involved staff.
MANAGEMENT RECOMMENDATION
Designate the Public Work Director or other Staffer as Beach Management Coordinator
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APPENDIX A FLORISTIC INVENTORIES
APPENDIX B FAUNISTIC INVENTORY
APPENDIX C EXOTIC SPECIES MAPS
APPENDIX D DUNE MANAGEMENT HISTORY
Plant Events in green, Political events in blue., Engineering events In Black
1950-1970
1970-1973
1973
1974
1975
1978
1979-1980
1983
1984
1986
grow.
1987-1995
Beach
1992
1985-1998
1997
2000
2001
2002
2001-2004
2005-2007
2013
2013
2014
2015
2015
2016
critical erosion on East Coast due to cumulative inlet impacts. Sand starvation.
A1A falling into water at Delray Beach.
“Hard Solutions” (rock and concrete revetments) implemented and fail.
First Nourishment event
“NO HAYFIELD ON DB” Council rejects CPE recommendation to install
30 foot sea oats dune to control sand blowing into street.
Council approves installation of non native Beach Napauka which
immediately begins to trap sand and block view, but reduces blowing sand.
First Renourishment
Seagrape clusters ( 30foot triangles) added to angle access paths, but they
do not grow due to frontal winds. 2 miles of sand fence added. CPE Dune Report
written.
six foot sea oats zone planted seaward of Beach Napauka. Cost $22K.
Thanksgiving Nor’easter erodes, Second Renourishment restores beach width.
Sea oat foredune begins to spread with high volume of blowing sand, seagrapes
Extensive private investment in dune restoration to North and South of Public
Third Nourishment
Dunes form as sea oats spread, Seagrapes grow into 25 foot trees, block views.
Robert H. Barron Dune Management Plan written.
City does first exotic removal and pruning at N end. Cost $60K PB Cty and
FDEP object.
City secures FDEP field permits, continues dune projects. FDEP objects.
Fourth Renourishment
Regulatory turmoil as FDEP and local governments are forced to review policies
and base management on science. Objective reviews vindicate all elements of
CDB Dune Management Program. FDEP reverses position, approves plan.
City secures FDEP permits and funding, and resumes exotic removal, pruning and
strand zone enhancement planting. Fish and Wildlife Commission, P. B Cty.
object and predict marine turtle problems. CDB lighting enforcement program
eliminates light pollution. No problems with turtle disorientation
Delray Beach dune referred to as “model for projects moving forward” at
National Conference on Beach Preservation Technology.
Post Sandy Nourishment
Partial contract exotic plant removal. Miami Beach and others adopt Delray
model.
Contract for revised Dune Management Plan,
Exotic removal completed at Municipal Beach
FDEP permits for completion of dune renovations secured.
APPENDIX E SPECIMEN BID SPECIFICATIONS
DELRAY BEACH
COASTAL DUNE MANAGEMENT WORKPLAN DRAFT
This document is intended to be a preliminary framework for
requests for proposals or bid for dune restoration work and will
be updated when project objectives are defined.
STATEMENT OF PURPOSE
The 6840 foot Municipal Beach property on the Atlantic Ocean shoreline of the City of Delray
Beach is one the most valuable assets owned by its Citizens. The beach, and the vegetated dune
provide valuable benefits of storm protection, economic stimulus, and recreation, and have a
dynamic impact on the value of the upland private properties, and the quality of life in the City.
This DUNE MANAGEMENT WORKPLAN has been developed to outline a framework and
specifications for maintenance and husbandry of the vegetation of the dune ecosystem.
The Primary Goal of dune maintenance is to support and enhance the storm protection value of
the system. Coastal dunes are well known to capture windblown sand, consolidate and stabilize
the sand with roots and vegetative growth between storm events, and then to resist wave scour
and reduce flooding during storms.
Secondary goals include providing a biologically rich natural habitat buffer between the
recreation beach and the upland residential development, and doing so in a fashion which is
aesthetically pleasing, while maintaining the ocean vista, and minimizing the long term
maintenance burden. This Plan will incorporate the following:
FIVE OBJECTIVE ELEMENTS OF A SYSTEMATIC COASTAL DUNE
MANAGEMENT PROGRAM
1. Removal of invasive exotic pest plant species.
Exotic species compete with and overwhelm more stable native dune plants but are often
weaker and more likely to suffer damage during a storm, or to break up and deliver missiles
which may damage nearby property. These should be carefully removed as the first step in dune
landscape management, but not until a program is in place to replant cleared areas with more
appropriate native species.
2. Cultivation and support of a dense grassy pioneer zone dune.
The foredune is the first line of defense against erosion. Sea oats and fast growing, deep
rooted grasses help to hold sand against wave attack. Regular care may be necessary, in some
areas, to promote dense growth, especially in critically eroding areas, or spots which conflict
with recreation activity. All are+as cleared of invasive exotic plants should be quickly replanted
with pioneer zone grasses.
3. Remedial and maintenance pruning of native strand/scrub zone species.
In the stable natural condition, the nearshore dunescape immediately upland of the grassy
pioneer zone had no trees. This wind resistant Coastal Strand Zone, populated by saw palmettos
and low shrubs should be maintained at knee to hip high to reduce uprooting and toppling forces
during a blow. Where shrubs have been allowed to grow taller, initial pruning should be 24 to 30
inches below the desired maintenance height to allow for growth of branching sub structure ( an
arboricultural process called coppicing). Long term maintenance pruning should be at hip
height, balancing wind resistance with ease of maintenance.
4. Supplemental planting of the Strand Zone with a diversity of native species,
dominated by saw palmettos.
Areas cleared of exotics and exposed by reduction of tall native plant canopies should be
replanted with a mix of the native species which existed in the dune before development. Initially
this should be the pioneer zone community dominated by sea oats and dune panic grass. Rare
and listed species may be included, to restore a complex, historically correct population. Once
established, these should be pruned to maintain low shrub height. Pre-existing native trees may,
in limited areas, be maintained in tree form to provide shade.
5. Active, aggressive enforcement of ordinances to eliminate light pollution.
Execution of any Dune Management Plan of this scope requires permitting by the Florida
Department of Environmental Protection. Such permits are contingent upon demonstrating that
no additional light from upland development will reach the marine turtle nesting beach, as a
result of implementation of the plan. Problems with marine turtle misorientation will be
prevented by considerate project design and by active nighttime inspection and concerted
enforcement of Local, County, and State Laws.
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DUNE MANAGEMENT SPECIFICATIONS
I.
PURPOSE AND INTENT
The City of Delray seeks to enter into contracts with experienced landscape and/or dune
restoration contractors for a project to renovate the coastal dune at the Delray Municipal Beach.
II.
LOCATION
This plan applies to all areas of the dune seaward of the improved sidewalk and State Road A1A,
between the North limit of the Public Beach and Casaurina St. to the South.. From 450 feet N of
FDEP monument R-177 then S along the shore to 500 feet N of R-183. (
III.
SCOPE OF THIS MANAGEMENT PLAN
This plan encompasses elements 1, 2, 3 and 4, as defined above. The City of Delray Beach will
secure all required environmental permits. The Contractor will secure other permits as required
by the City. Contractors are to bid on the following activities:
1. Remove and dispose of non-native and invasive native plant species. Maintain cleared
areas free of seedling recruitment for one year from completion of clearing.
2. Provide, install, maintain, and warrant survival of Florida native coastal dune plants.
All associated work is to be complete before ____________________.
It is incumbent upon the Contractor to visit and thoroughly inspect the sites of proposed
work. Aerial photographs may not be current and cannot be relied upon. Bid prices
should be based on best estimates of total area occupied by invasive plants, and square
footage of area to be replanted.
Contractors may form Primary Contractor/Subcontractor teams to bid on this work. The
Primary Contractor will be responsible for oversight of all work and all survival
guarantees. The CDB may at its discretion divide the project among two or more
Contractors, to ensure timely completion.
Conditions on site at the time of planting may necessitate modification of the planting
design and number of planting units required.
IV.
INVASIVE EXOTIC REMOVAL SPECIFICATIONS
A. TARGETED SPECIES
The Contractor shall be responsible for the physical removal of all vegetative mass,
including leaves, stems, and trunks, plus all gross roots of Category I and II Invasive
exotic Pest Plants, as identified by the Florida Exotic Pest Plant Council (FLEPPC),
including Scaevola taccada (Hawaiian seagrape), Shinus terebinthifolis (Brazillian
Pepper), Casaurina equisetifolia (Australian pine), Sanseveria trifasciata (bowstring
hemp).
Native Dalberghia ecastophylum ( coin vine), and Ceasalpinia bonduc (gray
nickerbean) will be removed as well.
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The Contractor shall additionally remove unclassified cultivated exotics as listed in
APPENDIX B of the attached BIOPHYSICAL SURVEY OF THE COASTAL DUNE
AT DELRAY BEACH.
B. PLANT DISPOSAL
All removed invasive exotic plant mass shall be legally disposed of off site; no shredding
or chipping will be allowed.
C. NATIVE SPECIES TO BE PROTECTED
The worksites include a mixture of native dune species and targeted non-native pest
species. SPECIAL ATTENTION IS REQUIRED TO ENSURE THAT THE EXISTING
DUNE IS IMPACTED BY THE EXOTIC REMOVAL EFFORTS TO THE
ABSOLUTE MINIMUM DEGREE. Use of herbicides, except as approved by the CDB
is prohibited.
D. REMOVAL METHODS
Removal of smaller and medium sized exotic clusters should be done by hand cutting and
digging to remove roots. Mechanized equipment may be used when it is possible to gain
access from the upland side without impact to the existing native dune vegetation.
Mechanized equipment may also be permitted on the soft sands of the beach, or
unimproved beach access pathways. All proposed methods for use of mechanized
equipment must first be submitted in writing and approved by the City. Fencing may be
temporarily removed for access, but must be restored upon completion of each section.
The Contractors shall replace fencing damaged during exotic removal or pruning efforts
in kind at no cost to the City
E. EXOTIC REMOVAL MAINTENANCE INTERVALS. The contractor shall be
responsible for maintaining cleared and pruned areas free of seedlings and resprouts for
the one year warranty period. Maintenance events shall be conducted at quarterly
intervals to hand remove seedlings or root sprouts.
V.
STRAND ZONE SPECIES PRUNING
All existing strand shrub species, including Coccoloba uvifera (seagrape), chrysobalanos
icaco (cocoplum), Conocarpus erectus ( buttonwood), which are greater than 4 feet in
height above grade will be initially crown reduction pruned (coppiced ) to eighteen
inches above grade. As new shoots from the root crown reach 36 inches in height (
growth rate will vary with species and season ), a second pruning to 24 inches in height
above grade will be done, to further establish a branching sub structure. Long term height
will then be maintained at between 36 inches and no greater than 42 inches above grade.
Heights are approximate and should follow the logical growth habit of the recovering
plant. Plants are to be pruned to natural organic shape, rather than box hedged.
Biomass removed from native species, during the initial coppice pruning, will be either
hauled and disposed off site, or may be chipped and deposited on site within the original
drip line of the pruned plant. No areas of pioneer dune vegetation shall be covered by
chipping.
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The City may, at its sole discretion, choose to maintain certain areas of existing native
seagrape trees as Coastal Hammock Zones. This will be accomplished by selective
pruning of specified trees and shall be done under the Supervision of a Certified
Professional Arborist. ( or CDB designate)
VI.
PLANTING SPECIFICATIONS
A. PIONEER ZONE SPECIES
Species approved for use in the pioneer zone: Uniola paniculata ( sea oats), 75 to 80 per
cent of total), and mix of Panicum amarum ( dune panic grass), Sporobolus virginicus
(Virginia dropseed grass), Paspalum vaginatum (shore paspalum), Spartina patens (
cordgrass), Canavalia maritima (beach bean), Ipomea pes caprea (railroad vine), Ipomea
imperati (beach morninglory ), remaining 20 to 25 per cent of mix. Additional native
Pioneer Zone species may be included at the sole discretion of the City from the Beach
Dune database of the Institute of Regional Conservation (<regionalconservation.org>)
Contractors are requested to bid on the following plant quantities:
Pioneer zone species..Sea Oats, (Uniola paniculata) in 96 cell liner size with 6 inch
planted height ( minimum 12 inch tall plants). Estimated quantity _____________plant
units.
Pioneer zone diversity species.. Dune Panic Grass ( Panicum amarum), Shore Paspalum
(Paspalum vaginatum), Virginia dropseed ( Sporbolus Virginicus), Beach bean
(Canavalia maritima), Railroad vine ( Ipomea pes caprea), Beach morninglory (Ipomea
imperati) in 72 cell liner size. Estimated quantity ________units.
B. STRAND ZONE SPECIES
Species approved for use in the strand zone: Serenoa repens ( saw palmetto ),
Chrysabalanos icaco ( horizontal or coastal cocoplum), Randia aculeata ( white
indigoberry ), Eugenia foetida ( Spanish stopper ), Ernodea litorallis ( golden creeper ),
Bacharis halimifolia ( saltbush ), Pithecellobium keyensis (blackbead ), in 3 gallon
containers. Estimated quantity_____________plant units. Additional native Strand Zone
species may be included at the sole discretion of the City from the Strand Dune Palm
Beach County database of the Institute for Regional Conservation
(<regionalconservation.org>)
C. PLANT QUALITY
The Contractor shall provide nursery grown plants that are of Florida #1, or superior
quality. All plants shall be true to the growth habit of the species, and are to be fully
rooted in the container, healthy, vigorous, well branched, and densely foliated. Plants
shall be free from physical damage, or conditions that would interfere with thriving
growth, and free of disease, insects, or insect eggs and larvae. The CDB shall inspect all
plants supplied by the City and private Contractors prior to installation and may reject
plants that do not meet these specifications.
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D. PLANT SIZES
Three (3) gallon Strand species and Palmettos shall me minimum 12 inches in height and
12 inches spread., except Cocoplum which shall be minimum 12 inches height and 18
inches spread.
Sea oats shall be supplied in 96 cell or larger. All other pioneer zone species shall be
supplied in 60 cell liners or larger.
E. PLANT SPACING PIONEER ZONE
Sea oats and pioneer zone species shall be installed to cover all barren areas and all areas
cleared of exotics greater than 100 square feet, at an average spacing of 18 inches on
center, to within 18 inches of the perimeter of undisturbed native vegetation. Sea oats
shall comprise 75 per cent of the species mix with the remainder comprised of
approximately two thirds grasses and one third vines.
F. PLANTING METHODS
Pioneer zone species will be installed with the top of the rootball no less than six inches
below finished grade. Fertilizer must be placed into the hole before the plant is
introduced Strand species shall be installed at no less than four inches below finished
garde. Plants must be watered in immediately to set the roots before backfilling the hole
to grade. No further irrigation will be required. No hydrophilic gels may be used.
VII.
FERTILIZATION
All plants shall be fertilized at the time of planting with Everris Suncoat 16-9-12 w
minors 90 day release or a proposed equivalent if approved by the CDB. 7 grams ( 1
teaspoon) shall be placed into the planting hole of Pioneer zone species before initial
watering. Strand zone species shall be fertilized at the time of planting by inclusion of
210 grams (one half cup), one half into the planting hole before installation of the plant
and one half distributed in a ring around the nursery rootball after backfilling the hole to
cover two thirds of the rootball height.
VIII.
IRRIGATION
A. Water Supply
Regularly dispersed water connections are not located in all the project areas. The City
will provide hose connections if available or a metered source for filling water tank
trucks.
Or
The Contractor will be solely responsible for providing a water source for irrigation.
B. Initial Watering
Pioneer zone plants shall be watered in at the time of planting to set the roots. No further
irrigation will be required except when it is determined by the contactor to be necessary
to ensure survival of the plants to meet the survival criteria below. Strand zone plants
and palmettos shall be watered initially using a jetting wand to consolidate the backfill
soil and ensure that there are no air pockets surrounding the nursery rootball.
C. Maintenance watering
The goal of supplemental irrigation is to promote the establishment of a self sustaining
root system, rather than to wet the nursery rootball. The Contractor(s) shall determine the
need for the additional irrigation to meet the required plant survival criteria, and include a
proposed irrigation plan with the bid. The proposed irrigation plan must include a
detailed description of the anticipated number of irrigation events, the equipment, labor
and irrigation methodology proposed for the maintenance irrigation. If the CDB, as part
of the Contract, approves the plan, The Contractor will be responsible for all aspects of
the maintenance irrigation, including compliance with all environmental permitting
regulations, requirements, and conditions stated in the permits. The cost of all anticipated
maintenance irrigation shall be included in the installation unit cost pricing schedule with
the Bid.
The CDB suggests a minimum watering schedule for Strand species of every four days
for three weeks then once per week for five weeks, then as needed as determined by
observation to achieve survival criteria.
IX.
D. Antitranspirant
Strand species and Palmettos shall be treated after delivery and prior to installation
with application of Vapor Guard antitranspirant or approved equivalent, at
manufacturers recommended application rate.
SURVIVAL CRITERIA AND REPLANTING
A. Initial Planting Survival
Plants not living at the end of 30 days will be rejected, and shall be replaced.
B One Year Survival Warranty.
The Contractor shall guarantee that at least 90% of all pioneer zone, and separately 90 %
of all palmettos and strand zone species survive and are in healthy condition for a period
of one (1) year from the time of planting.
Plants shall be deemed surviving if they present vigorous new leaf growth and inspection
of the root zone demonstrates that new roots have migrated into the surrounding soil by
no less than four inches.
The Contractor will not be responsible for any loss of plants resulting from erosion or
vandalism.
The CDB shall periodically inspect all installed plants and notify the Contractor if it is
determined that the survival rate is not acceptable. Minimally, inspections will be
conducted approximately one month, three months, and ten months after planting. Within
thirty days of receipt of notification by the CDB, the Contractor shall install additional
plants , to achieve the acceptable level of plant survival.
X.
MOBILIZATION AND ACCESS
CDB to provide_____________________.
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APPENDIX F
THRU 17
FDEP PERMIT DRAWINGS FOR SECTIONS 12
These drawings were submitted to the Florida Department of Environmental Protection and
approved for construction in early January 1016. They cover dune renovations proposed for the
sections near Atlantic Avenue and A1A, where tall seagrape trees have not been reduce.