20010830 Ver 1_Year 6 Monitoring Report_20081121

LMG -0$30
LAND MANAGEMENT GROUP INC.
00 Environmental Consultants
November 18, 2008
TO: Ms. Debbie Wilson
NC Division of Coastal Management
127 Cardinal Drive Extension
Wilmington, NC 28405
RE: Lee Street Mitigation Site; Year Six Monitoring Report
Ocean Isle Beach, Brunswick County, NC
Dear Debbie:
Enclosed is the Year Six Monitoring Report for the Lee Street Mitigation Site. The mitigation
project restored approximately 1.41 acres and enhanced 2.8 acres of coastal marsh habitat to mitigate
for wetland impacts associated with the Ocean Isle West Destination Resort in Ocean Isle Beach, NC
(CAMA Major Permit #154-98 & DWQ #010830). During the five previous monitoring reports, it
was found that the site met the hydrological success criteria as outlined in the mitigation plan.
However, because vegetation was not planted and was allowed to revegetate through natural
recruitment, the site failed to meet the vegetation success criteria. DWQ and DCM requested that
bare areas be planted with Spartina alterniflora plants and that the vegetation be monitored for two
additional years to ensure success. This supplemental planting occurred in the spring of 2008. The
sixth monitoring report only evaluated vegetation and found that abundance was continuing to
increase.
Please give me a call if you have any questions. Thank you for your assistance with this
project.
Sincerely,
Kim Williams
Wetland Scientist 104
Nov 21 ?,?'`? e?
Encl. r??R a
aE?"st
?os
C: Ms. Tammy Hill, DWQ
Ms. LaDane Williamson
Dr. DeCarol Williamson
www.lmgroup.net • [e-mail] • Phone: [phone] • Fax: [phone]
3805 Wrightsville Ave., Suite 15, Wilmington, NC 28403 • P.O. Box 2522, Wilmington, NC 28402
9
01-0830
0
Lee Street Mitigation Site
Year Six Monitoring Report
(for Ocean Isle West Destination Resort
CAMA Major Permit #154-98)
Ocean Isle Beach
Brunswick County, NC
Prepared for:
DeCarol Williamson
and
LaDane Williamson
i
Prepared by:
Land Management Group, Inc.
Wilmington, NC
November 2008
0
Table of Contents
1.0 Introduction .............................................................................................................................1
2.0 Vegetation ................................................................................................................................3
2.1 Success Criteria ..............................................................................................................3
2.2 Methods ..........................................................................................................................3
2.3 Results ............................................................................................................................4
3.0 Conclusions ..............................................................................................................................5
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Tables, Figures, and Appendices
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Table 1. Species of vegetation and B/B value for the sampling plots at Lee Street ........................4
Table 2. Frequency, abundance, and density of vegetation over the past 6 years ............................6
Figure 1. Vicinity map ....................................................................................................................7
Figure 2. Pre-mitigation conditions at site .......................................................................................8
Figure 3. Post-mitigation conditions at site .....................................................................................9
Appendix A. Pictures of site
ii
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0
Monitoring Report
for the
Lee Street Mitigation Site
Year Six
1.0 Introduction
In March of 2001, a mitigation plan was developed by DeCarol and LaDane Williamson to
offset impacts to wetlands associated with the Ocean Isle West Destination Resort located in Ocean Isle
0 Beach, NC. The mitigation project restored approximately 1.41 acres and enhanced 2.8 acres of coastal
marsh habitat off site. In addition, 2.55 acres of existing coastal marsh habitat was preserved in
perpetuity to fulfill the remainder of the mitigation requirements. The five previous monitoring reports
concluded that the site had achieved hydrological success criteria between 2003 and 2007.
The mitigation site is approximately 6.77 acres in size and is located at the eastern end of Ocean
Isle Beach in Brunswick County, approximately 2.5 miles northeast of the impact site (Figure 1). It is
bound by the Atlantic Intracoastal Waterway (AIWW) to the north and the Atlantic Ocean to the south.
The salt marsh is fed by the Shallotte Sound. Prior to restoration, the site contained a manmade,
partially-constructed T-shaped finger canal that was dug through salt marsh in the late 1960's to early
1970's. This finger canal was being built to provide waterway access to lot owners, but was never
connected to the AIWW. During the construction of this canal, a bulkhead was built around the "T" end
of the structure and the spoil was spread over adjacent areas to create high ground. Excess spoil was
placed directly northeast of the lagoon in a large mound of sand that divided two areas of salt marsh to
its west and east (Figure 2). This spoil pile impeded tidal flow and degraded the salt marsh quality.
Restoration activities occurred in the summer of 2002 and included the following actions: 1)
pumping out the fresh water within the lagoon and irrigating grassed areas adjacent to the site, 2)
excavating the berm located alongside the lagoon to marsh grade, 3) filling the lagoon to marsh grade,
4) removing the upland plug between the marsh and the lagoon, and 5) creating a tidal slough from the
existing marsh to the restored area. These mitigation actions restored approximately 1.41 acres of high
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quality salt marsh habitat by connecting the lagoon and the spoil mound to the existing marsh. It should
be noted that the mitigation plan also required planting Spartina alterniflora on a 2' spacing throughout
the restoration area. However, it was later decided to let the mitigation site revegetate through natural
recruitment, with the consent of Janet Russell of DCM. Hydrology and vegetation monitoring were
conducted within the project area between 2003 and 2007.
During the previous five monitoring reports, it was found that the site met the hydrological
success criteria. However, because vegetation was not planted and was allowed to revegetate through
natural recruitment, the site failed to meet the vegetation success criteria as outlined in the mitigation
plan. Although it was agreed that the site was trending towards success, DWQ and DCM requested that
bare areas be planted with Spartina alterniflora plants and that the vegetation be monitored for two
additional years to ensure success. This supplemental planting occurred in the spring of 2008.
Hydrological data collected over the past five years clearly illustrated the site has achieved wetland
hydrology and no further hydrological monitoring was required. Therefore, this sixth monitoring report
only discusses vegetation monitoring.
2.0 Vegetation
2.1 Success Criteria
The mitigation plan states that the vegetation success criterion for this project is the
survival of at least 70% of the planted seedlings. The final plant density success criterion is the
establishment of a density at least 75% by the end of the fifth growing season. As stated above,
no planting originally occurred within the mitigation site and it was determined to allow the site
to vegetate through natural recruitment. Therefore, the success criterion for the survival of
planted seedlings is analyzed in terms of frequency and abundance of volunteers instead.
2.2 Methods
Year six vegetation monitoring within the site was performed on August 21, 2008 and
used techniques developed by the National Marine Fisheries Service and the U.S. Army
Corps of Engineers. The Braun-Blanquet (B-B) vegetation sampling technique was used to
measure vegetation cover. From the B-B method, cover values ranging between 0.1 and 5 are
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assigned to each species observed within a plot and are based on the species' density within
that plot. Using the sum of the cover values generated from this method, measures of
frequency, abundance, and density can be derived.
To collect vegetation data, a total of 22 1-m2 plots (15.4 plots/acre) were randomly
placed over the 1.41-acre restoration area and two plots were sampled within the adjacent
reference marsh (Appendix A). These plots were sampled for coverage and species
identification.
0 National Marine Fisheries Service provided guidelines on how to analyze vegetation
data collected using the B-B method in an emergent marsh mitigation site. Based on their
protocol, survival (frequency, in this case) was estimated using the following formula:
Frequency = # of occupied quadrats/total # of quadrats
The measure of abundance is not a part of the mitigation plan's success criteria.
However, because survivability cannot be assessed and because natural recruitment often
occurs in an uneven pattern, determining the abundance of volunteers is a helpful tool.
Abundance = sum of B-B values/ # of occupied quadrats
A density success criterion of 75% (a B-B value of 5) was required by the fifth year of
40 monitoring. The NMFS formula to calculate density is:
Density = sum of B-B values/ total # of quadrats
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2.3 Results
Vegetation was observed in 17 of the 22 plots sampled (Table 1). This is a frequency
of 77.3%, which is greater than the frequency observed in 2007 (68.2%). The only species
observed was Spartina alterniflora. Abundance within tidal marsh habitat was 3.7, which is
lower than what was observed in 2007 (4.1). Density was determined to be 2.83, which is
slightly higher than the density observed in 2007 (2.82). In terms of B-B cover values, this
average represents approximately 25% vegetative cover.
Table 1. Species of vegetation and B/B value for the sampling plots at Lee Street
Mitigation Site (August 21. 2009).
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Plot # Species Observed B/B Value
1 Spartina alterniora 5
2 Spartina alterniflora 5
3 Spartina alterniflora 4
4 Spartina alterniflora 5
5 -
6 Spartina alterniflora 4
7 Spartina alterniflora 0.1
8 -
9 Spartina alterniora 4
10 Spartina alterniflora 5
11 -
12 Spartina alterniflora 3
13 Spartina alterniflora 5
14 -
15 Spartina alterniflora 0.1
16 Spartina alterniflora 5
17 Spartina alterniora 4
18 Spartina alterniflora 4
19 Spartina alterniora 5
20 Spartina alterniflora 0.1
21 Spartina alterniflora 4
22 -
Total 62.3
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3.0 Conclusions
This mitigation project has restored approximately 1.41 acres and enhanced 2.8 acres of
coastal marsh habitat by reconnecting the lagoon and the spoil mound to the existing marsh. In
addition, 2.55 acres of existing coastal marsh habitat were preserved in perpetuity to fulfill the
remainder of the mitigation requirements.
With the authorization of DCM, planting did not originally occur within the site and
vegetation was allowed to naturally recruit into the area. However, because the site did not achieve
the vegetation success criteria at the end of five years, both DWQ and DCM requested that
supplemental planting of Spartina alterniflora occur and the site be monitored for an additional two
years. This supplemental planting occurred in the spring of 2008.
In August of 2008, year six vegetation monitoring was performed. This vegetation analysis
determined a frequency of 77.3%, which is an increase from what was observed in 2007 (68.2%).
This increase is mostly due to the supplemental planting, which resulted in vegetation being
observed in more plots. In 2008, abundance was determined to be 3.7. This is a decrease from the
abundance value observed in 2007 (4.1) and 2006 (4.2). Density within tidal marsh habitat after year
six monitoring was 2.83. This is a slight increase in the density observed in 2007 (2.82). In terms of
B-B cover values, this average represents approximately 25% vegetative cover.
Since mitigation activities commenced, there has been a steady increase in frequency (Table
2). However, abundance and density have either remained the same or slightly decreased since 2005.
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This is likely because Spartina alterniflora plants are slowly volunteering into new regions of the
mitigation site. Even with some supplemental planting in the spring of 2008, the vegetation in some
areas is still sparse. Therefore, more plots contain vegetation, but the plants have not yet become
dense in these newly colonized areas.
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Table 2. Frequency, abundance, and density of vegetation over the past six years at the Lee Street mitigation
site.
Year Frequency Abundance Density
2003 50 1.87 0.94
2004 59 4.31 2.54
2005 63.6 4.64 2.95
2006 68.2 4.2 2.86
2007 68.2 4.1 2.82
2008 77.3 3.8 2.83
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Vegetation within the Lee Street Mitigation Site was allowed to naturally recruit for the first
five years of monitoring. Even with the recent supplemental planting, vegetation within the site is
still patchy, with areas either densely populated by Spartina alterniflora or containing single plugs.
Although the density of vegetation does not yet meet the success criterion (75%), there has been a
steady increase in vegetation growth over the past six years. Vegetation within the site is healthy,
consists of the appropriate species for coastal habitat (S. alterniflora), and is steadily increasing in
number. We will continue to monitor the vegetation within the site for an additional year or until all
commenting agencies are satisfied.
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Appendix A. Pictures of the Site
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Lee Street
Year Six Monitoring Report
Ocean Isle Beach
Brunswick County, NC
i Looking south at mitigation site.
Land Management Group, Inc.
Environmental Consultants
Wilmington, N. C.
October 2008
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Pictures of site
1 Spartina alterniflora within vegetation sampling plot.
19
Looking north at mitigation site.
+ Small clumps represent recently planted vegetation.
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1 Looking west at planted and volunteer vegetation within site.
Lee Street
Year Six Monitoring Report
Ocean Isle Beach
Brunswick County, NC
Land Management Group, Inc.
Environmental Consultants
Wilmington, N.C.
October 2008
Pictures of site