Living Shorelines as an Erosion Mitigation...

Living Shorelines as an Erosion Mitigation Strategy

Living Shorelines as an

Erosion Mitigation Strategy

Evidence from the Guana Tolomato Matanzas

National Estuarine Research Reserve

Monica Quintiliani


Page | ii

Table of Contents

Tables ................................................................................................................................................... ii

Figures ................................................................................................................................................. iii

Abstract ................................................................................................................................................ 1

Introduction .......................................................................................................................................... 2

Case Studies ......................................................................................................................................... 7

Grand Isle and St. Bernard Oyster Reef, Louisiana ......................................................................... 8

Saw Grass Point Salt Marsh, Dauphin Island, Alabama ................................................................ 10

Winyah Bay South Island Living Shoreline, Yawkey Wildlife Preserve, South Carolina ............ 12

Johns Point Landing, Virginia ........................................................................................................ 14

Gandy’s Beach/Money Island, Downe, New Jersey ...................................................................... 16

Summary ......................................................................................................................................... 18

Study Site ........................................................................................................................................... 20

Methods .............................................................................................................................................. 23

Results ................................................................................................................................................ 25

Beach Width ................................................................................................................................... 25

Marsh Area ..................................................................................................................................... 26

Discussion .......................................................................................................................................... 28

Conclusions ........................................................................................................................................ 33

Project Limitations ......................................................................................................................... 33

Future Research Recommendations ............................................................................................... 34

References .......................................................................................................................................... 36

Tables

Table 1. Summary of Case Study Findings ........................................................................................ 18

Table 2. Beach width over time.......................................................................................................... 25

Table 3. Marsh area over time. ........................................................................................................... 27


Page | iii

Figures

Figure 1. Seawall .................................................................................................................................. 3

Figure 2. Groins .................................................................................................................................... 3

Figure 3. Living Shoreline design ........................................................................................................ 5

Figure 4. Grand Isle Living Shoreline, LA .......................................................................................... 8

Figure 5. Grand Isle, LA oyster substrate ............................................................................................ 9

Figure 6. Saw Grass Point Living Shoreline, AL ............................................................................... 10

Figure 7. Coastal Haven System, Dauphin Island, AL .................................................................... 11

Figure 8. Winyah Bay, SC Living Shoreline ..................................................................................... 12

Figure 9. Castle Blocks, Winyah Bay, SC ......................................................................................... 13

Figure 10. Johns Point Landing Living Shoreline .............................................................................. 14

Figure 11. Oyster shell bags as oyster substrate ................................................................................. 15

Figure 12. Gandy's Beach/Money Island, NJ ..................................................................................... 16

Figure 13. Coir fiber logs ................................................................................................................... 17

Figure 14. GTMNERR and Wright's Landing ................................................................................... 21

Figure 15. Wright's Landing Living Shoreline................................................................................... 22

Figure 16. Measurement Sites, Upper Peninsula ............................................................................... 23

Figure 17. Measurement Sites, Lower Peninsula ............................................................................... 24

Figure 18. Beach width over time ...................................................................................................... 26

Figure 19. Marsh area over time ........................................................................................................ 27

Figure 20. Hurricane Mathew damage, Ponte Verde Beach, FL ....................................................... 28

Figure 21. Hurricane Irma damage, St. Johns County ....................................................................... 29

Figure 22. Destroyed bulkhead .......................................................................................................... 30


Page | 1

Abstract

Erosion is a principal problem in coastal areas exacerbated by heavy residential and infrastructure

development. Traditionally, communities have used structures such as seawalls and groins to protect

their shorelines, yet new research suggests these structures increase erosion on site. Many land

managers are now turning to the Living Shoreline technique which uses ecosystem engineers to create

a more naturally protected shoreline. Five case studies were examined to determine whether clear

trends leading to living shoreline success existed. Satellite images of the Guana Tolomato Matanzas

National Estuarine Research Reserve (GTMNERR) from 2005, 2008, 2011, 2013, 20015, and 2017

were also analyzed to determine whether the living shoreline installed in 2012 has had any large

impacts on the shoreline over time.

Analysis of the GTMNERR site revealed little to no change in beach width or marsh area despite

heavy hurricane activity. These findings suggest the living shoreline installation may be protecting

the shoreline although no detectable accretion or erosion exists. A similar result was seen in the

Dauphin Island, AL case study. Other case studies revealed a possible benefit to marine concrete as

an oyster substrate and that these projects may need more time to establish before large impacts to

the shorelines will be seen. Proper planning, site selection, and monitoring are key to successful

living shorelines.


Page | 2

Introduction

Coastal areas continue to be developed due to high economic opportunity and aesthetic value,

resulting in communities facing the important problem of erosion. To combat this, communities often

invest heavily in traditional forms of shoreline armoring (e.g. seawalls, groins, see Figures 1 & 2).

Conservative estimates as recent as 2015 have determined that the continental United States’ coasts

are roughly 14% armored (Dethier 2016). However, these traditional armoring techniques have been

found to intensify erosive forces instead of reducing them as intended (Cheong 2013) (Scyphers

2011). Furthermore, these armoring measures have been found to reduce the retention of wrack, or

organic beach debris (e.g. seaweed, drift wood) usually forming a “wrack line” at the high tide extent,

on the beach and the invertebrate populations residing within it. This reduces the diversity of mobile

macroinvertebrates, reduces high shore habitat for beach-spawning forage fish, and increases beach

temperatures resulting in increased fish egg mortality (Dethier 2016). Armored shorelines are often

found to be much narrower than unarmored shorelines (Pilkey 1988), likely due to the prevention of

the upper beach migrating inland as it naturally would (Dethier 2016).


Page | 3

Figure 1. Seawall

Figure 2. Groins

Source: https://www.nccoast.org/protect-the-coast/advocate/terminal-groins/


Page | 4

While negative effects of traditional armoring techniques are generally localized when a few, small

installations exist on a shoreline, ecosystem scale impacts can materialize when installations become

larger and more frequent. Benthic infaunal organisms, those which live burrowed into sediment,

experience decreased densities, likely due to a loss of nutrients from marsh detritus that these

organisms would usually consume. Reduced benthic infauna densities can affect higher levels of the

food chain as less prey species will be available to the predator species (National Oceanic and

Atmospheric Administration 2015). Considering these findings, academics and public servants alike

have been searching for better alternatives for shoreline protection.

Living shorelines is a new approach to shoreline protection gaining attention for its nature-based or

biophilic design. Living shoreline designs (Figure 3) emphasize positive interactions that generate

synergies (Cheong 2013) by using ecosystem engineers. Ecosystem engineers are species that either

reduce constraining variables or provide limiting resources to other species in response to their

changing environment (Crain 2006). Such species typically provide ecosystem services and influence

ecosystem function greatly (Crain 2006). Research has shown that by incorporating several abiotic

and biotic features into a living shoreline design (e.g. oyster reefs, saltmarsh, coir fiber logs, etc.),

community recovery and stability can be increased by orders of magnitude. The living shoreline

approach allows for multiple use design integrating recreation and ecosystem services, coastal

defense, and climate-adaptive and disaster coastal management (Cheong 2013).


Page | 5

Figure 3. Living Shoreline design

Traditional armoring techniques are usually considered “easier” to implement as they are the status

quo in shoreline protection and tend to have little issue gaining funding and public support. Fewer

experts are needed to successfully accomplish these installations and time has allowed for refined

design and installation practices. However, as discussed above, these techniques do not typically

provide the desired goal of long-term shoreline protection health. While living shorelines can be

more expensive and require more experts to install, monitor, and maintain, the living shoreline

technique can protect shorelines from storm surges and sea level rise much more effectively than

traditional armoring techniques. Improved wildlife habitat, ecosystem services, and more

aesthetically pleasing shoreline protection are also benefits of this new approach (National Oceanic

and Atmospheric Administration 2015).


Page | 6

Constructed oyster reefs, used as natural breakwaters, are a common feature among living shoreline

projects and can be a self-sustaining armoring technique used to prevent erosion in estuaries as long

as adequate recruitment and survival rates are maintained on the reef (Scyphers 2011). Reef success

is highly dependent on proper site selection, most significantly appropriate salinity regimes, tidal

exposure indices, and wave energy impacts (La Peyre 2015). While researchers are still working to

understand the needs of successful oyster reefs, environmental benefits from oyster presence has been

well defined. Oyster reefs have been found to have significant influence on water quality, primary

production, turbidity, suspended organic material, and bacteria (Cheong 2013). Oysters participate

in bioturbation and bioirrigation, processes in which sediment and water are filtered causing

disturbances which affect bulk density, oxygen availability, and nutrient fluxes resulting in increased

soft-sediment habitat heterogeneity. In turn, these interactions affect both ecological function and

biodiversity (Norkko 2011). Examples of these impacts include improved demersal, or benthic, fish

populations (Scyphers 2011) and positive effects on nutrient dynamics, commercial fisheries, and

saltmarsh retreat (La Peyre 2015).

With these benefits in mind, many land managers are beginning to integrate these promising natural

breakwaters into their coastal defense systems. However, there has been little research into how

constructed oyster reefs impact shorelines over time. The purpose of this study was to analyze and

identify the shoreline change of the Guana Tolomato Matanzas National Estuarine Research Reserve

(GTMNERR)’s western shore before and after the addition of the Wright’s Landing Living Shoreline

restoration project. Case study reviews of five other living shoreline projects along the East and Gulf

coasts of the United States were also included to analyze trends of successful projects. This research

will contribute to the understanding of living shoreline impacts across time and at a larger scale,

potentially leading to better implementation and management.


Page | 7

Case Studies

Five living shoreline projects were reviewed to gain insight into the factors that contribute to

successful living shorelines on the East and Gulf coasts of the United States. Living shoreline projects

were discovered predominantly through the Living Shorelines Academy databases (Living Shorelines

Academy n.d.) and were evaluated based on the following metrics: accretion, saltmarsh advance,

oyster recruitment, oyster substrate used, land area intended to be restored, land type (urban or

protected land), and reported success. Results were then compared to determine if clear trends for

successful living shorelines exist.

Several different techniques were used in the following case studies to reestablish oyster reefs and

saltmarsh areas. Because oyster larvae, known as spat, will only attach to and complete its life cycle

on other oyster shells, each design incorporates oyster shell in some fashion.


Page | 8

Grand Isle and St. Bernard Oyster Reef, Louisiana

The Grand Isle and St. Bernard Oyster Reef project, located on one of Louisiana’s southwestern

peninsulas (Figure 4), was constructed from 2010 to 2013 by The Nature Conservancy and partners

with over $4 million of funding from National Oceanic and Atmospheric Administration (NOAA)

through the Recovery Act (The Nature Conservancy 2017).

Figure 4. Grand Isle Living Shoreline, LA


Page | 9

The project was installed with the intention of restoring 5.47177 km of oyster reefs (The Nature

Conservancy 2017), improving habitat, and promoting the use of living shorelines as a sustainable

option for storm protection and erosion prevention. This project also aimed to create both temporary

and permanent jobs for local people, investing in both the local and state economies (The Nature

Conservancy n.d.). Coastal Environments, Inc., a local business, was employed to construct the

triangular steal structures used to attach the oyster substrate to (Figure 5).

Figure 5. Grand Isle, LA oyster substrate

Bags of oyster shell, collected through an oyster shell recycling program in which oyster shell from

local restaurants are rerouted from the landfill to restoration projects, were then attached to the steel

structures and were used to recruit spat. Two years of monitoring was completed for this project by

Louisiana State University, concluding that this project was a success based on the following factors:

claimed reef establishment, nondescript shoreline changes, and improved habitat (The Nature

Conservancy 2017).


Page | 10

Saw Grass Point Salt Marsh, Dauphin Island, Alabama

The Saw Grass Point Salt Marsh Living Shoreline, constructed in April 2005 by the Mississippi-

Alabama Sea Grant Consortium and partners, is located at the mouth of Mobile Bay (Figure 6) and is

the only inhabited barrier island in Alabama.

Figure 6. Saw Grass Point Living Shoreline, AL

The goal of this project was to control erosion caused by the prevention of saltmarsh naturally

migrating inland by both a major highway and residential development as well as periodic harbor and

channel dredging reducing sand over-wash necessary to sustain the beach. The Coastal Haven

system, pyramids of marine concrete with triangular openings in the sides to reduce pressure inside

the structure (Figure 7), was used as oyster substrate for this project. Marine concrete is a 100%

natural building material, the exact contents of which are protected by the manufacturing company

and not shared with the public (Allied Concrete Co. 2010).


Page | 11

Figure 7. Coastal Haven System, Dauphin Island, AL

182 Coastal Haven units were positioned in two rows, creating 62m of structure. Despite the very

active storm season of 2005, measurements in November 2006 revealed an increase in oyster density

from less than one oyster/m2 before the installation to 205 oysters/m2 after installation and a 15cm

accretion along the protected 14.1hc of shoreline. This project both proved and raised public

awareness of the ability of living shorelines to protect private and public property from coastal storms

(Swann 2008).


Page | 12

Winyah Bay South Island Living Shoreline, Yawkey Wildlife Preserve, South

Carolina

The Winyah Bay South Island Living Shoreline pilot project is located in northern South Carolina

(Figure 8).

Figure 8. Winyah Bay, SC Living Shoreline

This living shoreline was constructed in September 2010 by the South Carolina Department of Natural

Resources, Horry-Georgetown Technical College, the US Fish and Wildlife Service and other

partners to restore habitat, enhance environmental benefits, and improve human wellbeing and quality

of life. Because there were oysters already established in other parts of Winyah Bay, the research


Page | 13

team felt this would be an appropriate site for their living shoreline installation. Manufactured marine

concrete blocks, known as castle bocks (Figure 9), were used as oyster substrate for this project.

Figure 9. Castle Blocks, Winyah Bay, SC

Approximately 1,000 castle blocks were used as oyster substrate and saltmarsh was transplanted in

October 2010 behind each castle group. This project was considered unsuccessful after the site

suffered further loss of saltmarsh and slow oyster colonization. Project managers suspect that project

failure was due to the high energy tidal flow washing away oyster spat and newly planted saltmarsh

(McColl 2011).


Page | 14

Johns Point Landing, Virginia

The Johns Point Landing Living Shoreline project was constructed in 2013 and is located on a

Virginia peninsula extending into the Chesapeake Bay (Figure 10).

Figure 10. Johns Point Landing Living Shoreline

Bagged oyster shell was used as oyster substrate in this project, a common approach to reef

construction. With this approach, the natural fibers of the bags biodegrade over time, leaving nothing

but the newly recruited reef (Figure 11). Saltmarsh was also transplanted on site.


Page | 15

Figure 11. Oyster shell bags as oyster substrate

One month after reef construction, oyster spat maturation and recruitment were observed. Saltmarsh

advance and seeding was also documented within the first growing season (April to August 2014).

Mussels benefited from the installation as well, their population tripling at the site. The species

diversity of benthic macroinvertebrates did not change post installation, but species composition did.

Only a select few species were present both before and after reef construction, suggesting that the

introduction of constructed reefs may alter the larger habitat. This living shoreline has restored 535m2

of saltmarsh habitat and was considered a success (Bilkovic 2014).


Page | 16

Gandy’s Beach/Money Island, Downe, New Jersey

The Gandy’s Beach/Money Island Living Shoreline Project is located in southern New Jersey (Figure

12). Construction begun in 2014 by the US Fish and Wildlife Service, the Nature Conservancy, and

partners in response to the damage seen during Hurricane Sandy in 2012. The goal of this project

was to stabilize the surrounding creek banks and improve habitat and natural coastal defense and

stability.

Figure 12. Gandy's Beach/Money Island, NJ

Coir fiber logs made of coconut fibers (Figure 13), castle blocks with oyster shell bags, and

transplanted saltmarsh were all used in this living shoreline design.


Page | 17

Figure 13. Coir fiber logs

When completed, this project will have restored 136.379 ha of coastline. The success of this project

has yet to be determined as it is still considered in progress. At this time, project managers claim to

have observed sediment accretion (US Fish and Wildlife Service 2016) and, as of October 2016, have

reported that the structures reduced wave action on the marsh by 15% throughout a full tidal cycle.

During low and mid tides, the installation has been recorded to reduce wave action by 50% (Brunetti

2016).

Source: http://floridalivingshorelines.com/project/escambia-bay-2/


Page | 18

Summary

Table 1 provides a summary of the case study findings.

Table 1. Summary of Case Study Findings

U = Unknown

Project

Installation

Date

Last

Monitoring

Report

Accretion

Saltmarsh

Advance

Oyster

Recruitment

Oyster

Substrate

Restored

Area

Land

Type

Success

Grand

Isle, LA

2010-2013 2015 U U Yes

Triangular

frames

5.47177

km

Protected Yes

Dauphin

Island,

AL

2005 2008 Yes No Yes

Coastal

Haven

14.1 ha Protected Yes

Winyah

Bay, SC

2010 2011 No No No

Castle

blocks

U Protected No

Johns

Point,

VA

2013 2014 U Yes Yes Shell bags

0.0535

ha

Protected Yes

Gandy’s

Beach,

NJ

2014-

present

2016 Yes U U

Castle

blocks &

Shell bags

136.379

ha

Protected U


Page | 19

Information on the current status of these projects proved difficult to find. Many projects are

considered successful, but do not explain the metrics used to determine success. Projects are often

built ambitiously, but then forgotten about once public interest subsides. Project monitoring is poorly

maintained, generally due to lack of funding and labor.

However, monitoring is critical for effective adaptive management. Without data describing the

conditions and health of the living shoreline, project managers do not know when intervention is

needed to sustain the project and its benefits. Because living shorelines appear very natural and are

intended to be self-sustaining, it may not be obvious when possible maintenance is required and

failure may only be evident when it is too late to correct.

The living shorelines analyzed here have all been installed on protected lands, typical of living

shorelines implemented to date. Yet project designers are beginning to explore the possibilities of

implementing living shorelines on more urban coasts. Examples of this include but are not limited to

Pensacola Bay, Florida scheduled to begin construction in October of 2018 (The City of Pensacola

n.d.) and Staten Island, New York City, New York in 2018 (McKee 2017). Time will tell whether

the trends seen on protected lands will translate to urban shorelines.


Page | 20

Study Site

The Guana Tolomato Matanzas National Estuarine Research Reserve (GTMNERR) is a 74,000 acre

peninsular conservation area managed collaboratively by the Florida Department of Environmental

Protection and the National Oceanic and Atmospheric Administration (NOAA) as part of the National

Estuarine Research Reserve (NERR) system (Guana Tolomato Matanzas National Estaurine Research

Reserve 2017a). NERRs are federally designated conservation areas used for estuarine protection

and research. Established through the Coastal Zone Management Act, NERRs are operated as a

partnership between the federal and state governments in which NOAA provides funding and

guidance while a lead state agency or university manages the land with input from public partnerships.

Nationally, 1.3 million acres of estuarine land is protected through the NERR system (National

Oceanic and Atmospheric Administration 2017b).

A restoration project was undertaken in 2012 at GTMNERR’s Wright’s Landing site bordering the

Tolomato River on the western side of the peninsula (Figure 14). The restoration project was

developed by the Northeast Florida Aquatic Preserves Program, part of the Florida Department of

Environmental Protection’s Florida Coastal Office, with the goal of constructing a living shoreline to

reduce erosion and prevent further saltmarsh retreat at the site. Oyster reefs were constructed with

bagged oyster shell from a local oyster shell recycling program placed along coir fiber logs (Figure

15) and smooth cordgrass (Spartina alterniflora) was transplanted from a GTMNERR propagation


Page | 21

program to facilitate oyster and vegetation reestablishment (Guana Tolomato Matanzas National

Estuarine Research Reserve 2017b).

Figure 14. GTMNERR and Wright's Landing


Page | 22

Figure 15. Wright's Landing Living Shoreline

Since installation, the Wright’s Landing living shoreline has not been consistently monitored.

GTMNERR self-reports that the living shoreline has resulted in increased biodiversity and successful

oyster recruitment (Guana Tolomato Matanzas National Estuarine Research Reserve 2017b), but does

not reveal the methods or metrics used to determine this.

http://www.gtmnerr.org/oceanwise-and-stewardship/


Page | 23

Methods

To determine whether the living shoreline installation has had large scale impacts on the site, satellite

images of the Wright’s Landing restoration site at the GTMNERR were obtained from Google Earth

from the years 2005, 2008, 2011, 2013, 2015, and 2017. All images were taken in the fall and winter

months (October through January), providing seasonal consistency among measurements. Beach

width and saltmarsh area were then measured to capture shoreline changes over time. Beach width

was measured by taking the measurement from the center of the channel to the line of established

vegetation at six points along the GTMNERR peninsula: at the Wright’s Landing reef site, roughly

350m north and south of the reef site, and at three points along Guana Point. The area of coverage of

three saltmarsh sections 200 m2 each were also measured. All measurements were taken using Google

Earth’s measurement tools. Measurement points are illustrated in Figures 16 and 17.

Figure 16. Measurement Sites, Upper Peninsula


Page | 24

Figure 17. Measurement Sites, Lower Peninsula

All beach width and saltmarsh measurements were compared to reveal shoreline changes. Major

shoreline changes were compared to two extreme weather events experienced at the site to account

for large shoreline changes from natural processes. Proximity, strength, and photographic evidence

of severe storm damage from Hurricanes Mathew (2016) and Irma (2017) were considered.


Page | 25

Results

Beach Width

Beach width remained almost constant from 2005 to 2017, as illustrated in Table 2 and Figure 18.

Table 2. Beach width over time

Date

North

Beach (m)

Wright's

Landing (m)

South

Beach (m)

Guana

Beach (m)

Point 3 (m)

Guana

Point (m)

Mar-05 298 291 201 204 243 127

Jan-08 295 287 196 203 244 126

Dec-11 294 291 200 204 244 125

Jan-13 296 284 198 204 247 128

Nov-15 299 288 200 203 248 131

Sep-17 294 288 200 205 250 133


Page | 26

Figure 18. Beach width over time

Marsh Area

Marsh area also did not experience large change. The most variable marsh area was C and Marsh A

did see some decline in coverage. Marsh B reached full coverage by 2008, maintaining this level of

coverage to September 2017. These results are illustrated in Table 3 and Figure 19.

298 295 294 296 299 294291 287 291 284 288 288

201 196 200 198 200 200204 203 204 204 203 205

243 244 244 247 248 250

127 126 125 128 131 133

0

50

100

150

200

250

300

350

Mar-05 Jan-08 Dec-11 Jan-13 Nov-15 Sep-17

Bea

ch W

idth

(m

)

Axis Title

Beach Width Change Over Time

North Beach (m) Wright's Landing (m) South Beach (m)

Guana Beach (m) Point 3 (m) Guana Point (m)


Page | 27

Date Marsh A (m2) Marsh B (m2) Marsh C (m2)

Mar-05 124 150 30.4

Jan-08 111 200 53.4

Dec-11 101 200 33

Jan-13 97.2 200 41

Nov-15 85 200 62.4

Sep-17 68.7 194 21.78

Table 3. Marsh area over time.

Figure 19. Marsh area over time

124111

101 97.285

68.7

150

200 200 200 200 194

30.4

53.4

3341

62.4

21.78

0

50

100

150

200

250

Mar-05 Jan-08 Dec-11 Jan-13 Nov-15 Sep-17

Mar

sh A

rea

(m2 )

Date

Marsh Area Change Over Time

Marsh A (m2) Marsh B (m2) Marsh C (m2)


Page | 28

Discussion

Although there were no drastic changes of GTMNERR’s Wright’s Landing shoreline from 2005 to

2017 and accretion was not measured by this study, this living shoreline installation may have

protected the site from the extensive damage caused by Hurricane Mathew in October 2016 and

Hurricane Irma in September of 2017. Figures 20 and 21 showcase the resulting damage from each

of these storms, at Ponte Verde Beach and in St. Johns County respectively.

Figure 20. Hurricane Mathew damage, Ponte Verde Beach, FL

Source: http://abcnews.go.com/US/florida-images-show-destruction-hurricane-matthew/story?id=42664304


Page | 29

Figure 21. Hurricane Irma damage, St. Johns County, FL

Despite the damage at sites near the GTMNERR depicted above, GTMNERR’s Wright’s Landing

experienced minimal damage and no detectable erosion. While estuaries naturally benefit from some

inland protection and usually see less damage as the beach fronts shown in Figures 20 and 21, erosion

and other damages often still occur. These results are similar to those found at the living shoreline

project on Dauphin Island, AL. After being installed in April of 2005, Dauphin Island was subjected

to Tropical Storm Arlene in June, Hurricanes Cindy and Denis in July, and Hurricane Katrina in

August of 2005. Minimal damage was found at the site and measurements from November 2006

revealed a 15cm accretion at 55 locations along the living shoreline installation and no erosion at

three nearby reference sites. According to the research team on site, the Dauphin Island Living

Shoreline not only prevented private property damage on the island, but also raised public awareness

of this possibility (Swann 2008).

Source: https://www.accuweather.com/en/weather-news/reports-irma-leaves-over-6-million-without-power-across-florida/70002687


Page | 30

Living shoreline installations along the coast of North Carolina’s outer banks also proved to provide

better protection than traditional armoring techniques during storm events. After Hurricane Irene in

2011, shorelines protected by living shorelines experienced sediment accretion whereas 75% of

bulkheads surveyed in the same region failed and were damaged (Figure 22). Similarly, 58% of

bulkheads near Charleston, South Carolina were destroyed in 1989 during Hurricane Hugo (National

Oceanic and Atmospheric Administration 2015).

Figure 22. Destroyed bulkhead

Not only do living shorelines appear to protect property during heavy storm activity, they may also

provide sea level rise mitigation. From 1993 to 2014 NOAA recorded a global sea level rise of 2.6

inches, with an expected 1/8th of an inch rise per year (National Oceanic and Atmospheric

Administration 2017a). Sea level rise experienced locally can be more subtle or more extreme based

on factors including but not limited to: upstream flood control, erosion, land subsidence,

topographical differences, and regional ocean currents (National Oceanic and Atmospheric

http://brick.shorebeat.com/2017/03/storm-blew-hole-in-manasquan-inlet-bulkhead-fishing-off-limits/


Page | 31

Administration 2017a). Healthy living shorelines maintain a wide beach front and may prevent

further erosion of its protected shore, reducing the loss of available land from sea level rise.

Lack of long term monitoring appeared to be the greatest downfall of the reviewed living shoreline

projects. Many projects were considered successful, but were not descriptive on what metrics were

used to determine success. As with other restoration projects, living shoreline monitoring is often

poorly maintained, frequently due to lack of funding and labor. However, proper monitoring is

critical for effective adaptive management. If not improved, project managers will not know the

status of their work or be able to intervene to sustain projects when necessary.

It is important to note that, ecologically speaking, the living shoreline projects reviewed here are still

very young and may still need many years to fully establish themselves. Accretion is not always

detected in these projects. However, further erosion is usually not either. This may indicate that the

living shorelines may only hold the existing shoreline in place. While some would like to see

accretion, preventing or ending erosion at a site can be just as beneficial. Marine concrete used to

construct castle blocks and the Coastal Haven system may be the best oyster substrate, but further

research is needed on the material to determine this definitively. In order to better understand the

factors which make living shorelines successful, a meta-analysis of existing living shoreline projects

would be beneficial. Meta-analyses involve taking data from many different projects to analyze

trends in regard to factors that may determine outcomes or responses, which in this case is either

project success or failure based on factors such as shoreline wave energy, slope, salinity, materials

used, spatial configuration of design, and other project design factors (Biostat, Inc. 2017). Large

scale experimentation may also provide valuable insights, such as using different materials and spatial

designs at the same site to compare success.


Page | 32

Because the primary material used to construct living shorelines are living organisms, it is essential

that proper planning, site selection, and monitoring are conducted throughout the entirety of the

project. While many communities wish to take action immediately, project failure can be disastrous

when tax payers’ money is used to fund a multimillion dollar living shoreline project such as the

planned $10.8 million Pensacola Bay (The City of Pensacola n.d.) and $60 million Staten Island

(Rebuild by Design n.d.) living shorelines. Project failure may lead to miseducation or mistrust of

the benefits of living shorelines as the public begins to doubt the technology’s ability to produce

desired outcomes, resulting in increased difficulty gaining necessary funding for future living

shoreline projects and other green infrastructure installations.

As an advocate for successful living shorelines, NOAA recommends that land managers and city

planners encourage living shoreline and green infrastructure design in disaster planning. To

accomplish this goal, NOAA offers partnership, along with other federal agencies and non-

governmental organizations, providing technical assistance and funding for living shoreline research

and design. NOAA has also provided several guiding principles to land managers considering

restoration efforts. Most importantly, NOAA stresses that shorelines should be left to erode as they

naturally would unless infrastructure is being threatened. Planting of Spartina spp. can reduce wave

energy by 50% and planted wetland vegetation significantly reduces damages to coastal communities

as well as provides fish habitat and nitrogen removal (National Oceanic and Atmospheric

Administration 2015).

NOAA also developed the Conceptual Framework for Considering Living Shorelines in 2015. The

framework consists of twelve guiding questions for land managers to consider when determining the

most appropriate shoreline stabilization approach for a particular site. The framework stresses proper

site selection and planning for sea level rise as well as acknowledges that the best solution at a site is


Page | 33

likely a balance between living shoreline and traditional techniques. This document also outlines the

available grants and other support, including design guidance and policy considerations, NOAA and

other federal agencies have available to aid in successful execution of these projects (National

Oceanic and Atmospheric Administration 2015).

Conclusions

Project Limitations

The living shoreline projects included in this study are still relatively young thus limiting the

conclusions that can be drawn. Large shoreline impacts and changes may be detectable once these

living shorelines further mature and stabilize. Conversely, older living shoreline projects may reveal

that such installations only halt the erosive process, not cause accretion.

Case study analysis was limited by lack of public information. Information gathered by this study

was obtained largely from websites explaining the plan to the public which only stated that monitoring

had been or would be completed. Few monitoring reports were available to the public. Those that

were available did not always incorporate sufficient data or explain their methods and metrics well.

Long term monitoring is rarely conducted at these sites resulting in large knowledge gaps as to the

status and success of these living shoreline installations. Most projects complete two years of

monitoring after which efforts are usually terminated due to lack of funding. It is likely that other

sites are informally monitored by management staff when time allows as done by the GTMNERR,

but formal reports with empirical data are lacking. Such data would give further insights into living

shoreline success and impacts and should be considered highly valuable by policy and budget

planners.


Page | 34

The GTMNERR living shoreline is a small study site with limited available data. If monitoring

records were better maintained, it is possible that more insight into the success of this installation may

be discovered. Because of the landscape-level analysis of this study, accretion may not be detectable.

Satellite images used may not have been taken at a fine enough scale to reveal what may be minute

accretion at this time as illustrated by the 15cm accretion recorded at the Dauphin Island living

shorelines. However, there is an opportunity to increase the monitoring of this site as it continues to

mature so that greater knowledge can be obtained about the viability of this type of design and

ecosystem.

Future Research Recommendations

The development of a standardized assessment of living shoreline project health and success may be

helpful in determining the value and effectiveness of existing and future projects. A similar approach

taken to site selection could also be very beneficial. This could include more systematic identification

of sites at the regional landscape scale that may be the best locations for achieving success and

providing the most benefit. In addition, more research into the basic biology, habitat needs, and

preferences of living shoreline species is needed to properly inform such a rubric.

Determining the best measuring technique for shoreline change would result in more accurate records

of living shoreline success and impacts. On site measurements at consistent tidal phases from a fixed

point may prove a much better measure of shoreline accretion or erosion than measurements made

from satellite images. However, the retrospective benefit of historical satellite images is an advantage

that may be better capitalized by methods different from those used in this study.

Research focusing on how long living shorelines will take to fully establish and mature may reveal a

more accurate timeline for land managers to begin to expect to see shoreline impacts. With this


Page | 35

timeline in mind, better evaluations of living shoreline status and success may be possible. Similar

research may also definitively determine whether living shorelines truly are preventing erosion or

causing accretion on site and/or down site from the installation.

An important issue in establishing living shorelines is the “energy level” a shoreline receives from

wave action. High energy shorelines with frequent significant wave action are unlikely to harbor

successful living shoreline installations due to species’ intolerance, whereas low energy shorelines

provide a much greater opportunity for success. However, one of the potentially key future research

findings would be to determine what techniques might work in moderate to higher energy shoreline

ecosystems to provide the benefits of these projects in places that would currently be difficult or

impossible to implement successfully.

As living shorelines gain more popularity and begin to be implemented in the urban setting, extensive

research will be necessary to determine if the benefits of these installations do in fact extend to urban

shorelines and what, if any, adaptations or special considerations need to be made to the existing

technology to ensure success. Because these settings often deal with more intense ecological

degradation, living shorelines may not be as easily established in these areas and may require site

conditioning before installation occurs.

The living shorelines depicted here use species and designs adapted to the Gulf and East coasts of the

United States which are generally considered lower energy systems. Research focuses on determining

energy thresholds for different species and techniques would be extremely valuable to the

advancement of living shoreline technology. With these thresholds determined, alternative

techniques for higher energy systems will soon follow, as will adaptations to different areas of the

world.


Page | 36

References

Allied Concrete Co. 2010. Oyster Castles. Accessed December 8, 2017.

http://www.alliedconcrete.com/materials/oyster-castles/.

Bilkovic, Donna Marie, Molly Mitchell, and Robert Isdell. 2014. Johns point landing living shoreline

-- Ecological monitoring: Final report to Gloucester County. Virginia Institue of Marine

Science, College of William and Mary. doi:10.21110/V5742P.

Biostat, Inc. 2017. Comprehensive Meta-analysis. Accessed December 8, 2017. https://www.meta-

analysis.com/pages/why_do.php.

Brunetti, Michelle. 2016. "Even if man-made, living shorelines protect marsh and wildlife." Press of

Atlantic City, October 28. Accessed December 3, 2017.

http://www.pressofatlanticcity.com/even-if-man-made-liiving-shorelines-protect-marsh-and-

wildlife/article_4a550e2f-716d-5850-ba64-d524a424649d.html.

Cheong, So-Min, Brian Silliman, Poh Poh Wong, Bregie van Wesenbeeck, Choong-Ki Kim, and Greg

Guannel. 2013. "Coastal adaptation with ecological engineering." Nature Climate Change 3.

doi:10.103/NCLIMATE1854.

Crain, Caitlin Millan and Mark D. Bertness. 2006. "Ecosystem engineering across environemental

gradients: Implications for conservation and managment." Bioscience 56 (3).

Dethier, Megan N., Wendel W. Raymond, Aundrea N. McBride, Jason D. Toft, Jeffery R. Cordell,

Andrea S. Ogston, Sarah M. Heerhartz, and Helen D. Berry. 2016. "Multiscale impacts of

armoring on Salish Sea shorleines: Evidence for cumulative and threshold events." Estaurine,

Coastal and Shelf Science 175. doi:10.1016/j.ecss.2016.03.033.

Google Earth V 7.3.0.3832. 2017. Historical Imagery. GTMNERR, Florida.

Guana Tolomato Matanzas National Estaurine Research Reserve. 2017a. About. Accessed October 1,

2017. http://www.gtmnerr.org/about/.

Guana Tolomato Matanzas National Estuarine Research Reserve. 2017b. Aquatic Resource

Management. Accessed October 1, 2017. http://www.gtmnerr.org/stewardship/aquatic-

resource-management/.

La Peyre, Megan K., Kayla Serra, T. Andrew Joyner, and Austin Humphries. 2015. "Assessing

shoreline exposure and oyster habitat suitability maximizes potential success for sustainable

shoreline protection using restored oyster reefs." PeerJ 3 (e1317). doi:10.7717/peerj.1317.

Living Shorelines Academy. n.d. Highlighted Projects. Accessed September 29, 2017.

https://livingshorelinesacademy.org/index.php/highlighted-projects.

McColl, David and Joy Brown. 2011. "Yawkey living shorelines pilot project: Oyster recruitment &

erosion control on South Island." Accessed September 29, 2017.


Page | 37

http://projects.tnc.org/coastal/assets/SC/WinyahBaySouthIslandLivingShoreline/WinyahBay

SouthIslandLivingShoreline_FinalReport.pdf.

McKee, Brad. 2017. "Kate Orff Wins MacArthur Grant." Landscape Architecture Magazine.

Accessed December 6, 2017. https://landscapearchitecturemagazine.org/2017/10/11/kate-

orff-wins-macarthur-grant/.

National Oceanic and Atmospheric Administration. 2015. Guidance for considering the use of living

shorelines. Accessed November 24, 2017.

http://www.habitat.noaa.gov/pdf/noaa_guidance_for_considering_the_use_of_living_shoreli

nes_2015.pdf.

—. 2017a. Is sea level rising? Accessed December 3, 2017.

https://oceanservice.noaa.gov/facts/sealevel.html.

—. 2017b. NEERs Overview. Accessed October 4, 2017. https://coast.noaa.gov/nerrs/about/.

Norkko, Joanna and Sandra E. Shumway. 2011. "Shellfish aquaculture and the environment."

ResearchGate. doi:10.1002/9780470960967.ch10.

Pilkey, Orrin H. and Howard L. Wright III. 1988. "Seawalls versus beaches." Journal of Coastal

Research 4. Accessed April 14, 2017. http://jstor.org/stable/25735351.

Rebuild by Design. n.d. Living Breakwaters. Accessed December 6, 2017.

http://www.rebuildbydesign.org/our-work/all-proposals/winning-projects/ny-living-

breakwaters.

Scyphers, Steven B., Sean P. Powers, Kenneth L. Heck Jr., and Dorothy Byron. 2011. "Oyster reefs

as natural breakwaters mitigate shorelie loss and facilitate fisheries." PLoSONE 6 (8:e22396).

doi:10.1371/journal.pone.0022396.

Swann, LaDon. 2008. "The use of living shorelines to mitigate the effects of storm events on

Dauphine Island, Alabama, USA." American Fisheries Society Symposium 64:000-000.

Accessed Novemeber 24, 2017.

http://livingshorelinesolutions.com/uploads/Dr._LaDon_Swann_Living_Shorelines_Paper.p

df.

The City of Pensacola. n.d. Pensacola Bay Living Shoreline Project. Accessed September 29, 2017.

http://cityofpensacola.com/1123/Living-Shoreline.

The Nature Conservancy. n.d. Louisiana: Grand Isle and St. Bernard marsh shoreline protection

project. Accessed December 3, 2017.

https://www.nature.org/ourinitiatives/regions/northamerica/unitedstates/louisiana/placeswep

rotect/la-summary-grand-isle.pdf?redirect=https-301.

—. 2017. Louisiana: Restoring oyster reefs at Grand Isle and St. Bernard Marsh. Accessed

Spetember 29, 2017.

https://www.nature.org/ourinitiatives/regions/northamerica/unitedstates/louisiana/restoring-

oyster-reefs-at-grand-isle-and-st-bernard-marsh.xml?redirect=https-301.


Page | 38

US Fish and Wildlife Service. 2016. Hurricane Sandy recovery: Gandy's Beach shoreline protection.

Accessed September 29, 2017.

https://www.fws.gov/hurricane/sandy/projects/Gandy'sBeach.html.

Living Shorelines as an Erosion Mitigation...

Documents

Transcript of Living Shorelines as an Erosion Mitigation...