Frederique Beroset MBA & M.S. in Biology

Why Your Protective Coastal Dune Needs a Separate Maintenance Program from Your Recreational Lawn

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Article Highlight: To achieve the highest level of sustainable resiliency, coastal homeowners must have separate, environment-specific maintenance plans for their dune system (white landscape) and recreational lawn (green landscape).

Key Takeaway: Traditional landscaping practices erode protective dunes and compromise coastal ecosystems. Do not attempt to manicure or alter your protective dune without the direction of a coastal restoration expert.

Fast Application: Have our coastal restoration experts work with your landscaping team to address the environment transition from your recreational lawn to your dune system.

1. Frequent Irrigation will Erode Your Protective Dune

Unlike lawns and gardens, dune vegetation does not need regular watering. In fact, installing an irrigation system on your dune will compromise it in the long run. Initially, the plants may appear lush and vibrant. However, the availability of water close to the surface will disrupt the vegetation’s capacity to anchor the sand in place. A shallow source of moisture dissuades the native plants from growing deep roots in search of water. With limited root growth, the plants and your dune will be easily washed away come the first storm.  Irrigation also encourages invasive species to colonize the dune and crowd out native plants. If a storm or disease doesn’t kill your plants first, their dependency on the irrigation will. If their water is ever cut, the plants will have no alternative source and will die.

To understand more about the negative impacts of irrigation, watch the video below.

2. Fertilizer Intended for Turf will Damage Native Coastal Plants

The sand along the eastern Gulf Coast is primarily composed of quartz crystal and is nutrient-poor soil. According to the University of Florida, these quartz particles do not “hold water or nutrients very well.” Frequent fertilization might seem like the solution to help your coastal plants develop. However, a publication by North Carolina State University warns against excess fertilization, stating that it may “damage the development” of the plants and “increase the occurrence of plant diseases.” Do not apply fertilizers that are intended for turf on your protective dune. Instead, strengthen your coastal systems by working with a coastal restoration expert to ensure your native vegetation obtains the necessary nutrients. Keep in mind, fertilizer is a powerful chemical, and its misuse will result in environmental damages.

3. All Coastal Restoration Efforts Require Permitting from Regulating Agencies

Dunes function as natural barriers that absorb the impact of storm surge and as sand reserves that can seasonally replenish the beach. Because of their critical role, dunes are protected by law. All coastal restoration efforts need to be approved by local, state, and federal regulating authorities. In the event that a lawn care provider attempts to work on a dune without first obtaining the necessary permits, the coastal property owner is responsible and will be heavily fined regardless of the kind of work that is implemented. As coastal stewards continue to educate themselves about the dune environment, they will report any activities perceived to jeopardize this fragile ecosystem. In 2020, three-dozen Newport Beach, California homeowners illegally landscaped lawns on the beach. The consequences amounted to roughly 1.7 million dollars in fines due to encroachment on public beaches and destruction of the protected dune environment. A manicured lawn is aesthetically pleasing. However, as easy as it may have become for these homeowners to walk to the beach without having to step through any dunes, they also created a smooth path for high tides and storm surges to flood their waterfront homes. With theNewport Beach fiasco in mind, before requesting a lawn care provider that does not specialize in coastal restoration to perform any work on your dunes, consider the high likelihood that they may damage the protected ecosystem, resulting in financial penalties for you.

4. Traditional Landscapers and Coastal Restoration Experts Prioritize the Development of Different Parts of their Plants

The primary factor that differentiates coastal dune maintenance from traditional lawn care is which part of the plant each practice focuses on. Landscapers introduce non-native plants to develop and enhance the aesthetics of a recreational, outdoor area. If tasked with caring for dune vegetation, a lawn care provider may measure the environment’s health by how robust the foliage looks. However, while frequent irrigation and fertilizer may quickly enhance the visible part of dune-building plants, the plants’ stems and leaves are not what stabilize dunes. The vast and complex root systems developed by sea oats (the primary dune-building plant) are what anchors dunes in place. The coastal ecosystem undergoes constant erosion, and native plants are the only force that stabilizes the sand. Therefore, to protect coastal ecosystems, Dune Doctors measures the health of the environment by root growth and not stem growth. According to Carrie Stevenson, the University of Florida’s coastal sustainability agent for Escambia County, sea oats’ roots can grow up to 40ft deep! Homeowners can encourage this tremendous growth by working with a coastal restoration expert to implement an environment-specific maintenance plan designed for their protective dune system.

Work with Dune Doctors to Address the Environment Transition from your Recreational Lawn to your Protective Dune

Both the maintenance of your recreational lawn and protective dune require corresponding experts who can meet the unique needs of these two different environments. Enlist our coastal restoration experts to evaluate the transition from your lawn to your protective dune. Have our team address any potential weak points or erosion-prone areas along your property. Many forces act daily to damage and reshape your protective dune, so identifying erosion threats within your control can help mitigate damages to your coastal property. Partner with Dune Doctors today to begin naturally fortifying your dune, so you can achieve the highest level of sustainable coastal resiliency.

How Sea Oats Build and Sustain Coastal Dunes

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  • Article Highlight: Sea oats build, sustain, and protect dune systems. Healthy coastal vegetation anchors dunes in place creating a natural barrier against storm surge.
  • Key Takeaway: One of the first steps towards building coastal resiliency is to invest in sea oats. Sea oats yield a high return-on-investment as the plants can quickly propagate when correctly installed and cared for.
  • Learn Fast: Watch the video below to understand how sea oats help protect against erosion.

How does Nature Protect Against Coastal Erosion?

Pounding waves, scorching sunlight, flooding, and high-speed winds impact all living things along the beach. This environment is under constant stress, resulting in the survival of a resilient few. At the center of these powerful coastal forces is a plant that protects the Eastern and Southern shorelines from erosion and stabilizes the dune habitat: sea oats. Nature protects against coastal erosion with the help of the sturdy, dune-building sea oats.

How do Sea Oats Anchor Sand Dunes in Place?

Sea oats may seem non-extraordinary and are often depicted in artwork, as feathered flowers bending with the ocean’s breeze. However, similar to how the tip of an iceberg cannot reveal its depth, the vast and complex root system developed by sea oats extends down through the dune’s core to reach the water basin. To survive, sea oats create an intricate web that captures scarce nutrients and water. According to Carrie Stevenson, the University of Florida’s coastal sustainability agent for Escambia County, sea oats’ roots can grow up to 40ft deep. The limited availability of fresh water in the dune environment encourages root growth, and the deep roots, in turn, help anchor the dune in place. 

How do Sea Oats Stabilize Sand Dunes?

Sea oats are self-spreading plants. In addition to a fibrous root ball, sea oats also have a unique stem called a rhizome. Instead of growing up, rhizomes spread horizontally and develop new plants from its nodes. Each new plant will, in time, also send out more rhizomes. The sea oats’ rhizomatous growth allows for the plants to spread and vegetate bare areas. Eventually, the rhizomes will overlap each other contributing to the complex web of interconnected plants and root systems that stabilize sand dunes.

How do Sea Oats Help Build Sand Dunes?

While a sea oats’ root system determines the dune’s structural integrity, the plant’s above-ground portion accelerates sand accretion. When coastal winds come into contact with sea oats, wind-borne particles drop and deposit around the base of the plant. By trapping wind-blown sand, sea oats help further build sand dunes. Unlike most plants, sea oats can survive and benefit from being buried as it encourages the plant to grow more stems and helps pin down their rhizomes.

Why are Sea Oats so Prevalent along the Coast?

Sea oats are so prevalent along the coast because, often, they are the first to colonize impacted dunes after a storm event. For this reason, sea oats are considered pioneer species, a classification for highly resilient plants and animals that are the first to repopulate an ecosystem after damage or disruption has occurred. If a storm event buries or displaces the plants, sea oats will often resurface or establish where they wash ashore.

How can I Help Protect Sea Oats?

While sea oats can survive in one of nature’s most challenging environments, the plants cannot survive being trampled. To help protect sea oats, avoid walking through coastal dunes. The plants’ stems will snap under the localized pressure of a footstep. If a footpath cuts through a dune, the sea oats growing along the path will die and not stabilize the sand. Wind will erode the trail, creating a depression in the dune. In the event of a storm, the pathway will, unfortunately, function as a channel for storm surge to breach the protective barrier. Often, on the other end of a footpath will be vulnerable structures like the ground-level entrance to a building, its pool or garage.

Why is Proper Installation Critical for Sea Oat Survival?

Besides foot traffic, the only other leading cause of sea oat death is improper installation, making proper installation critical for the plant’s survival. When selecting a company to install dune-building vegetation, make sure to ask what their average plant survival rate was for previous coastal restoration projects. The industry average for government-led projects is roughly 70% survival. Dune Doctors works with the highest quality of sea oats available and guarantees that our plants don’t just survive but thrive and reach a rate above 95% on all projects. Proper sea oat installation lays the foundation for achieving coastal resiliency. If the planting is successful, the sea oats will quickly establish, enhance the beauty of this environment, and offer robust protection for years to come.

 

Sand Fences: How to Examine Erosion Levels and Rebuild your Coastal Dunes

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Sand Fences are the Most Economical Solution to Limit Coastal Erosion

The coastal environment is incredibly dynamic as multiple forces combine to cause the continual reshaping and erosion of the dunes and the beaches. Natural dunes exist in disconnected mounds along the coastline. These rapid changes in the environment can sometimes affect the long-term vision coastal homeowners have for their property because disconnected dunes cannot offer significant protection. Therefore, sand fencing is the most economical and effective method of fortifying and sculpting dunes into a continuous berm that will retain its linear shape and build a line of defense against the impact storm surges can have.

Dune Doctors installs sand fences
Dune Doctors installs sand fences at the toe (where the slope of a dune meets the flat of the beach) of the dune at Sand Cliff Condominiums, Rosemary Beach, FL.

Examine the Type of Erosion Your Dunes are Undergoing

At the end of a hurricane season, identifying the type of erosion-based damage your dunes incurred is essential to designing an effective restoration plan. A dune suffers erosion through wave action, stormwater runoff, and foot traffic. These events can damage the dune, resulting in a blowout, a dune cliff, an unvegetated dune, or the complete elimination of the dune. In most cases, the strategic installation of sand fencing paired with healthy dune-building vegetation is sufficient to accelerate your dune’s recovery. If stormwater breached and caused significant damage to your dunes, the best course of action for the creation of a new berm will be to add sand, plant dune-building vegetation, and install sand fences.

1. Dune Blowout: A Wide Depression in Your Protective Dune

A blowout is an unvegetated depression or trough in your dunes. Conditions for a blowout are met when repeated disturbances to a section of the dune result in killing the vegetation meant to anchor the sand in place. Unvegetated sand enters a heightened state of erosion and cannot weather or protect against the impact of a powerful storm event. Eventually, storm surge will find the path of least resistance to breach the dune, push landward through the unvegetated depression, and erode the loose sand. The result is a massive gap in the dune’s formation that will continue to widen unless addressed. The best way to handle a blowout is by placing new sand to realign the dune and to stabilize the placement with dune building vegetation.  While the vegetation stabilizes the added sand, initiating a new protective berm at the dune’s toe (the place where the dune’s slope meets the flat of the beach) can provide an additional barrier that can absorb the impact of storm surge. Under ideal circumstances, coastal homeowners will invest in creating multiple rows of protective berms to capture as much free sand as possible and protect the established dune closest to their homes. The goal is to achieve the reassurance that if multiple major storm events happened with short intervals the different rows would provide a series of buffers.

2. Dune Cliff: A Vertical, Highly Collapsible Sand Wall

After 2020’s busy hurricane season, repeated storm surge impacts have carved away at dunes, leaving behind highly unstable sand cliffs. In the weeks following the storm, the soaked sand cliffs retained their shape because the sand was wet. Once it dried, they began to collapse into a more natural slope. After the collapse has occurred, Dune Doctors reccomends carefully installing dune-building vegetation to anchor the new slope in place. To further strengthen the dune, Dune Doctors then installs a new row of sand fences along the dune’s toe (the place where the dune’s slope meets the flat of the beach) to encourage the dune’s gradual incline.

3. Unvegetated Dune: Bare Areas Resulting from Dying Vegetation

Public beach access in Walton County experiencing erosion caused by storm water run off
Dothan Avenue beach access, 30A. Storm surge runoff heavily eroded the dune.

After storm surge tears away dune-stabilizing plants, the structural integrity of a dune is compromised. While the damage of a single storm event will be immediately apparent, two other forms of ongoing erosion will have a longterm impact as well. Foot traffic erosion and stormwater runoff are both year-round forces that can significantly weaken your dune by killing off the plants that anchor it in place. As stated earlier, conditions for a blowout are met when repeated disturbances to a dune result in a bare area that becomes a depression. Dune-building vegetation has evolved to survive drought, powerful winds, intense sunlight, and being temporarily submerged in water. However, the plants’ horizontal stems have not evolved to survive localized pressure and will snap  under foot traffic. Beachgoers need to be encouraged to stay off the dunes via signage or roping. To help minimize foot traffic damage to dunes that extend past your boardwalk, Dune Doctors recommends roping off a narrow walkway that is the boardwalk’s width to keep beachgoers from fanning out across the dune. Stormwater runoff often drains below and around the property’s boardwalk. Routine revegetation is necessary to protect the boardwalk’s foundation and strengthen that area of the dune.

 

Newly installed sea oats line the 200 tons of loose sand placed under a newly replaced boardwalk.
Dothan Avenue beach access, 30A. Restored dune to pre-erosion form and newly installed boardwalk. Taken by Colin O’Nowlin.

 

4. Complete Erosion: What to do when the Entire Dune has Washed Away

In cases where the dune has suffered complete erosion, sand placement becomes an urgent solution to protect the building’s structural base. Once placed, the sand by itself cannot offer significant protection. Therefore, sand placement must be paired with dune-building plants to help anchor the added sand in place. Otherwise, the next storm event will, yet again, quickly erode the costly investment.

Sand Fences Initiate Continuous Berms and Provide Strategic Protection

The dune’s elevation and shape are critical. Powerful waves can push their way through unvegetated grooves and foot paths that cut through the dune. When storm breaches the dune it causes damage landward. The end goal of sand fence installations by Dune Doctors is to create a continuous protective berm. The sand fencing can be used to initiate the accumulation (accretion) of sand in a strategic shape. The installation of sand fencing to accrete sand in a specific location helps to limit the natural tendency of dunes to form in irregular shapes while still providing beachgoers ample access to recreational beach areas.

Dune-building vegetation has colonized an emerging berm initiated by sand fences

Phase 4: Maintenance – 7 Ways Dune Maintenance Differs from Lawn Care

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Thriving landscapes are often the result of careful planning and consistent maintenance. Coastal property owners have stewardship over two outdoor areas: their recreational yard and their protective dune ecosystem. Even if there are a few similarities to how these environments are best cared for, the differences are numerous and need to be addressed in two separate environment-specific plans. Here, we compare seven major aspects of what we call the white landscape (dune ecosystem) to the green landscape (manicured yard planted in composite soil).

Dune Doctors installs sea oats to stabilize a sand placement.
After Hurricane Sally eroded the entire dune at Sandcliff Condominiums, Dune Doctors replenished the sand to construct a new berm. Above, our field team stabilizes the sand placement with sea oats.

1. Purpose: Resiliency vs. Leisure

White Landscape: Dunes are natural barriers that can help absorb the impact of storm surge and protect coastal properties from storm damage.

Green Landscape: Backyards offer space for leisure, beauty, exercise, and pet use.

2. Return-on-investment: Both are huge!

White Landscape: Every $1 invested in building hurricane protection reduces a property’s average loss exposure by an estimated $105.

Green Landscape: A well-manicured and maintained yard can increase property value by 28%, according to landscape economist John Harris.

3. Root Depth: Long vs. Shallow

White landscape: Dune-building vegetation has evolved to develop impressive root systems. Individual plants have 40 to 50 roots that can each grow upwards of 25ft long. The result is vast, interconnected root webs that grow deep into the core of the dune. This root mass allows the plants to capture the limited water and nutrients available in the coastal environment.

Green landscape: Most turf grasses can develop roots that are 6-12 inches long. Frequent irrigation does not encourage deep root growth.

4. Soil Composition: Sand vs. Composite Soil

White landscape: Coastal soil tends to have high salinity (salt count) and is nutrient-deprived. Only a few resilient plant species can grow in it.

Green Landscape: Yards typically comprise a composite, nutrient-rich soil that can foster a wide range of vegetation.

5. Irrigation: Drought Tolerance vs. Daily Water Dependence

White Landscape: Routine irrigation heightens dune erosion risk. Before killing the vegetation through rot or disease, the excess water causes the dune-building plants to develop shallow roots. Shallow roots cannot stabilize loose sand, compromising the integrity of the dune. Continue reading about dune irrigation. 

Green Landscape: Yards benefit from daily irrigation, especially during the extended periods of drought regularly experienced by the Gulf Coast.

6. Fertilization: Dune-specific vs. Basic

Any landscape that hosts a variety of plants and trees needs nutrient-rich soil. However, fertilizer is a chemical that, if applied incorrectly, will pollute the environment. Regardless of where the application is made, you should always seek the advice of an expert.

White Landscape: The snow-white sand of the Eastern Gulf Coast is made of quartz crystals. Quartz crystals are incredibly smooth and unable to hold on to nutrients, therefore, the application of coastal-specific, slow-release fertilizer is recommended twice a year. Using a basic fertilizer is insufficient because the nutrients will be washed away before the plants can absorb them. Continue reading about proper dune fertilization. 

Green Landscape: Fertilizing a yard may require a similar application frequency, however, it is the type of fertilizer used, not the frequency, that will result in the most notable difference between healthy and malnourished plants.

7. Pruning: Illegal vs. Legal

White Landscape: Unpermitted removal of native coastal plants may result in legal consequences and weaken or erode the dune. Dune Doctors promotes pruning and dethatching (removing dead plant material) to stimulate plant growth. However, to protect dune ecosystems from further erosion, governmental agencies from the local to federal levels regulate all efforts to clean or enhance the dune vegetation. Continue reading about dethatching. 

Green landscape: Mowing and pruning can stimulate growth while minimizing invasive species.

8. Permitting: Strong vs. Moderate Government Involvement

White Landscape: Because dunes provide coastal communities with protection from storm surge, the land south of the coastal construction line is protected. An individual must obtain permits and special qualifications before implementing any restoration.

Green Landscape: Government involvement in landscaping hinges on whether the project is seaward or landward of the coastal construction line. Anything seaward of the CCL requires a coastal restoration expert who understands the complexity of both the regulations and the fragile environment’s needs.

What does a Dune Maintenance Program Accomplish?

A sand fence installation accretes sand along a steep slope in Walton County, Florida

A successful dune restoration project in Walton County, Florida

A dune maintenance program should help protective berms stabilize and provide season-specific care for your coastal vegetation. Like lawn care, dune maintenance revolves around sustaining an environment that supports and nurtures plant growth. Dune Doctors’ maintenance program removes built-up dead plant material, invasive plants, and weeds to protect the dune-building plants from being suffocated or having to compete for food. Furthermore, our routine fertilization provides the plants with the nutrients necessary to sustain healthy root growth, thus accelerating the dune’s development. This ongoing care nurtures massive root systems that anchor your dunes in place and defend your coastal property from storm surge. For a success story about a property that managed to accumulate $180,000 in free sand in part due to the implementation of our maintenance program, click here.

Transforming a Dune into a Lawn may Lead to Hefty Fines

Earlier this year, nearly three-dozen Newport Beach, California homeowners illegally landscaped lawns on the beach. The consequences amounted to roughly 1.7 million dollars in fines due to encroachment on public beaches and destruction of the protected dune environment. A manicured lawn is aesthetically pleasing. However, as easy as it may have become for these homeowners to walk to the beach, they also created a smooth path for high tides and storm surges to flood their waterfront homes. With these Newport Beach homes in mind, before requesting a lawn care service that does not specialize in coastal restoration to perform any work on your dunes, consider the high likelihood that they may damage the protected ecosystem, resulting in financial penalties for you.

References:
https://newsroom.fmglobal.com/releases/fm-global-every-dollar-spent-on-hurricane-protection-can-prevent-us-105-in-business-property-loss-disruption
https://www.mountainviewlandscapewnc.com/does-landscaping-increase-home-value/
https://www.courthousenews.com/socal-homeowners-fined-1-7-million-for-blocking-beach/ 4.https://oceanservice.noaa.gov/news/dec15/california-flooding.html

Sand Collapse: Protecting Beachgoers from Eroded Dunes

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2020 brought record-breaking hurricanes and an onslaught of powerful storm surge that eroded hundreds of miles of protective sand dunes along the Gulf Coast. We would like to take this moment to highlight the dangers of the unstable sand cliffs carved by this ongoing erosion.

After storm surge tears away dune-stabilizing plants, the structural integrity of a sand dune is compromised. Currently, the sand cliffs are retaining their shape because the sand is wet but, over the following weeks, they will collapse into a more natural shape.

Sand Cliffs Are Highly Unstable

During a field visit to evaluate the level of damage caused by Hurricane Sally, Frederique Beroset, spotted beachgoers attempting to climb the eroded sand cliffs and sitting at the toe of the cliff. “While it may look small, a cubic yard of sand is upwards of 2,000lbs that can fall on you,” says Frederique Beroset.

Beachgoers sit at the toe of an eroded sand cliff.
Hurricane Sally and Hurricane Cristobal’s storm surge churned at the curved peat formation below the sand dune above. Now, the building’s foundational concrete slab is exposed to the gulf. Beachgoers sit at the toe of the cliff.

Sand Cliffs are as Dangerous as Sand Holes

Harvard medical researcher, Bradley Maron, who has been tracking sand hole collapses worldwide for the past decade says that 60% have been fatal due to the difficulty of retrieving buried victims. The same awareness applied to the potentially lethal consequence of beach holes needs to extend to the imminent collapse of these highly unstable sand cliffs.

Post-Hurricane Beach Safety Rules:

  • Do not attempt to climb an eroded sand cliff.
  • Do not pull on exposed vegetation protruding from an eroded sand cliff.
  • Do not sit at the toe of an eroded sand cliff.
  • Do not dig into the side of an eroded sand cliff.

Year-Round Beach Safety Rules:

  • Do not dig a hole that is deeper than knee height of the shortest person in sight.
  • Cover up holes to avoid creating a deadly trap for other beachgoers, pets, and wildlife.
  • Do not walk on sand dunes.

Phase 3: Optimization – Boardwalk Design with Backwoods Bridges

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Boardwalks are Intended to Lessen the Impact of Foot Erosion.

As of July 2020, certain areas of the Gulf Coast have gone nearly two decades without experiencing hurricane-related erosion. These coastal properties have accumulated substantial dunes and protective berms that have progressed seaward, often burying their boardwalks. We have observed this phenomenon and noted that many properties, when the time came to replace their aging boardwalk, opted to keep identical placement and design instead of altering their walkover to fit their dunes’ accumulation of new sand. A boardwalk is one of the core components of a successful hurricane resiliency plan. The upfront investment of obtaining the right permits and installing a dune walkover designed to protect your living coastal barriers can save thousands of dollars in the long run. The tradeoff of cutting costs and installing an inadequate boardwalk creates a safety hazard for pedestrians and accelerates dune erosion, thus resulting in a higher risk of hurricane damage. Boardwalks were introduced into the coastal environment to help lessen the erosion and damage caused by foot traffic to the dune ecosystem and provide safe passage to beachgoers. Boardwalks are not designed to last forever; but, within the guidelines provided by regulating authorities, building a boardwalk designed for an ever-evolving dune allows for practical, economical, and sustainable results.

What Happens when a Dune Progresses Past the Boardwalk

When a dune accumulates enough sand to evolve past or bury a boardwalk, the following 5 major issues arise. If sand is spilling onto the boardwalk, a concerning liability is created as loose sand is slippery. Shoveling loose sand off of a boardwalk to avoid accidents is labor-intensive, thus expensive, and nearly impossible to maintain. If the boardwalk is too close to the dune’s surface, native vegetation below the structure will die. Without healthy plants and their complex roots systems to hold the sand under the boardwalk in place, that area of the dune becomes more susceptible to erosion. If the boardwalk ends prematurely, beachgoers are forced to walk through developing dunes to reach the recreational beach area. This ongoing foot traffic kills the native vegetation and destabilizes these newly-created dunes. The section of dune below a boardwalk is often the weakest point because of a phenomenon we call the washing machine effect where surge churns against the poles of the boardwalk eroding sand at an accelerated rate.

Note: If your dune has already progressed past your boardwalk, there are other protective measures you can implement. For further information, read our article “4 Proactive Steps to Protect the Development of your New Berms.”

Interview with Andrew Kuehl from Backwoods Bridges

These observations prompted a conversation with the boardwalk experts at Backwoods Bridges, a custom timber construction company. We asked Andrew Kuehl their chief estimator to weigh in on our findings and discuss what kind of design-thinking may help maximize a boardwalk’s use while protecting the dune and protective berm evolving below and around it.

1. Dune Doctors: “Do you have any important design recommendations you would like property owners to know about?”

Andrew Kuehl: “We typically like to use 6x6s instead of 4x4s for posts. The use of 316 Stainless Steel hardware is best for corrosion resistance, but it does come at a significant cost.”

2. Dune Doctors: “In Florida, aside from following the boardwalk specifications from the Florida Department of Environmental Protection (FLDEP), are there other protective measures you take to minimize damage to the dune?”

Andrew Kuehl: “We try to stay within 24”-36” of the boardwalk footprint during construction to minimize damage to the dune system and vegetation.”

3. Dune Doctors: “Any boardwalk installation comes with a certain degree of disruption to the environment. When the disruption is significant is there a follow-up plan to help restore the damaged dune? Does the permit include mandatory restoration?”

Andrew Kuehl: “We don’t have a follow-up plan. We recommend they give you guys a call! The last DEP permit we pulled had a stipulation to restore the dune and vegetation to existing conditions. I recommend contacting the DEP for up-to-date information.”

4. Dune Doctors: If a storm erodes a dune and the boardwalk needs to be replaced, do you design a replacement boardwalk that fits the pre-storm dune or the eroded dune?

Andrew Kuehl: “Whether in Florida or Alabama, we would build to the eroded dune profile unless the client plans to replace the sand and replant the dune to pre-storm condition. We would work in tandem with you guys to coordinate where it would end… I’m sure FLDEP would also have a big say in the matter.”**

5. Dune Doctors: “Many coastal areas are susceptible to high levels of erosion. How do you strike a balance in the design of a boardwalk between planning for the dune’s seaward progression and the property’s regular loss of recreational beach area?”

Andrew Kuehl: “The dunes change so much that we build them to the dune profile at the time of construction. It is hard to predict what the dune is going to do. We’ve had some boardwalks that had to be elevated significantly because they were ‘buried’ in the dune. We’ve also had the opposite where we had to lower the boardwalk because the dune had moved and the structure was too high.”

6. Dune Doctors: “If you design a boardwalk for a dune that has a wide recreational beach area, do you consider dune evolution in the design?”

Andrew Kuehl: “It is hard to anticipate how a dune is going to move, so we don’t typically take that into account. The FLDEP typically requires you to end right around the toe of the dune, so that is usually where we will plan to end it. Another point I’d like to bring up is that the lifespan of these structures is typically not very long. The hot/cold, wet/dry cycles along with the salt and sun really take a toll on them, so 10 years is probably about the average lifecycle for a boardwalk. When the dune does its thing over 10 years then it is probably time to rebuild the beach access anyways.”

**NOTE: We confirmed with the FLDEP that dune restoration is mandated if damage occurs during the process of replacing the boardwalk. Marina Borries an Environmental Specialist with the FLDEP says “after installing a boardwalk, any vegetation damaged or destroyed must be restored or replaced. Since heavy equipment is not authorized for walkover construction, there is no reason any additional dune damage should occur, but if for some reason it does, additional restoration would have to be completed.”

Walton County Beach Access: A Joint Dune Rehabilitation Effort Between Backwoods Bridges and Dune Doctors

When dune rehabilitation and seaward progression are part of a property’s long-term vision of hurricane resiliency, the boardwalk design is a significant factor that can determine the property’s level of coastal protection. Several years ago, we worked alongside Backwoods Bridges on a project for Walton County. The area under the county’s public beach access on Dothan Avenue off of 30A had experienced erosion caused by stormwater run-off. To rehabilitate the dune, Backwoods Bridges brought in about 200 tons of beach sand and rebuilt their dune to the estimated pre-erosion form. To help curb the original cause of erosion, they also added a stormwater drain and pipe under the first part of the boardwalk. Dune Doctors installed native vegetation to stabilize the fresh sand. In the event of a storm, Andrew says they would most likely rebuild the dune and beach access in a similar way.

Wind Drift Condominiums, Orange Beach, AL: Achieving Sustainable Coastal Protection through Optimized Boardwalk Design

Dune Doctors also collaborated with Matt Gilley from MG Marine Construction in the replacement of Wind Drift Condominiums’ two boardwalks. Dune Doctors worked alongside boardwalk builders in a joint effort to protect and preserve Wind Drift’s dune ecosystem and initiate a new protective berm. Through proper design, the boardwalks were extended and elevated to provide breathing space for the dune to evolve. To strengthen the existing dune, Dune Doctors revitalized the vegetation and extracted dead organic material and debris. Dune Doctors also installed sand fencing to serve two purposes: initiate a new protective berm and stop foot traffic from damaging the dunes. The integration of both the boardwalk construction and Wind Drift’s enactment of the Dune Master Plan™ allowed Wind Drift to achieve the highest level of sustainable coastal protection. To read more about this project, click here to view our case study.

Boardwalk Design is a Key Factor in Dune Restoration

While the contour of the beach changes often, property owners that invest in sand fencing and coastal vegetation to initiate new protective barriers and accelerate their existing dune’s seaward progression benefit from designing a boardwalk that enhances these efforts. Certain properties do not have enough recreational beach area to extend their boardwalk 10ft past the seaward line of their dune’s vegetation (as regulated by the Florida Department of Environmental Protection), but if the environment is conducive – the boardwalk’s design should be centered on protecting the dune’s evolution. To mitigate storm-related damage, the integration of healthy vegetation, sand fencing, and strategic boardwalk design is key to the protection and growth protect of natural barriers to storm surge.