Hancock County Marsh Living Shoreline Section 404 Joint

Transcription

Hancock County Marsh Living Shoreline
Section 404 Joint Application and Notification
Form
SAM-2013-00088-MJF
Hancock County, Mississippi
December 2014
Submitted to:
Mississippi Department of Marine Resources
U.S. Army Corps of Engineers
Mississippi Department of Environmental Quality
HANCOCK COUNTY MARSH LIVING SHORELINE
JOINT APPLICATION AND NOTIFICATION
DECEMBER 2014
1.0
Cover Letter
2.0
Joint Application and Notification
3.0
Supplement
Attachments
Attachment A: Maps/Drawings
Attachment B: Agent Authorization
Attachment C: Environmental Assessment
Attachment D: Variance or Revisions to Mississippi Coastal Program
Attachment E: Adjacent Landowners
Attachment F: Summary of Agency Coordination
Attachment G: Cultural Resource Feasibility Study for the Hancock County Marsh Living
Shoreline Project and Section 106 Compliance Recommendations
Attachment H: Heron Bay SAV and Oyster Survey
Attachment I: USFWS Concurrence Letter
Attachment J: MDMR Mississippi Coastal Program Consistency Determination
Attachment K: NOAA (PRD) Concurrence Letter
Attachment L: NOAA (HCD) Essential Fish Habitat Concurrence Letter
Attachment M: NOAA Design Memorandum for Living Shorelines and Marsh Restoration Project
in Hancock County
Section 404 Joint Application and Notification
Form Supplement
December 2014
Hancock County, Mississippi
Joint Application and Notification Form Supplement
Table of Contents
Page
1.0
INTRODUCTION ............................................................................................................ 1
2.0
PURPOSE AND NEED .................................................................................................... 2
3.0
ALTERNATIVES ANALYSIS.............................................................................................. 2
3.1
Site Alternatives ........................................................................................................... 2
3.1.1 Buccaneer State Park ................................................................................................... 3
3.1.2 Bayou Caddy ................................................................................................................ 3
3.1.3 Hancock County marsh (Preferred alternative) ............................................................. 4
3.2
Construction Alternatives Analysis ............................................................................... 7
3.2.1 No Construction Alternative ........................................................................................ 7
3.2.2 Construct Living Shoreline Structure in Heron Bay and Provide 70 acres of Sub-Tidal
Oyster Reef ........................................................................................................................... 7
3.2.3 Heron Bay to Pearl River Construction Alternatives ...................................................... 7
3.2.4 St. Joseph’s Point Construction Alternatives ................................................................. 8
3.2.5 Final Construction Alternative Selection ....................................................................... 8
4.0
PROJECT LOCATION ...................................................................................................... 9
5.0
PROJECT DESCRIPTION ............................................................................................... 10
5.1
Anticipated Construction Process ............................................................................... 13
5.2
Aids to Navigation ..................................................................................................... 17
5.3
Geotechnical Pilot Study ............................................................................................ 17
5.4
Water Quality Certification ........................................................................................ 17
5.5
Project Adverse and Beneficial Impacts ...................................................................... 21
6.0
REFERENCES ............................................................................................................... 27
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1.0
INTRODUCTION
This report supports the Joint Application and Notification Form for the Hancock County Marsh Living
Shoreline project in coastal Mississippi. The report details the project location, purpose and need,
alternatives analysis, preferred alternatives, and project impacts. The attachments to the Joint
Application and Notification Form include:
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Attachment A: Maps/Drawings
Attachment B: Agent Authorization
Attachment C: Environmental Assessment
Attachment D: Variance or Revisions to Mississippi Coastal Program
Attachment E: Adjacent Landowners
Attachment F: Summary of Agency Coordination
Attachment G: Cultural Resource Feasibility Study for the Hancock County Marsh Living
Shoreline Project and Section 106 Compliance Recommendations
Attachment H: Heron Bay SAV and Oyster Survey
Attachment I: USFWS Concurrence Letter
Attachment J: MDMR Mississippi Coastal Program Consistency Determination
Attachment K: NOAA (PRD) Concurrence Letter
Attachment L: NOAA (HCD) Essential Fish Habitat Concurrence Letter
Attachment M: NOAA Design Memorandum for Living Shorelines and Marsh Restoration Project
in Hancock County
The Mississippi Department of Environmental Quality (MDEQ), is the Mississippi Trustee for the
Deepwater Horizon Oil Spill and related response actions (the Spill) and is partnering with the National
Oceanic and Atmospheric Administration (NOAA) to propose an early restoration project that would
protect a shoreline and marsh area by employing living shoreline techniques in Hancock County,
Mississippi (see Figure 4).
The proposed Hancock County Marsh Living Shoreline Project is included in the Final Programmatic and
Phase III Early Restoration Plan and Final Early Restoration Programmatic Environmental Impact
Statement (Phase III ERP/PEIS); which was released for public review and comment on December 6,
2013. On June 26, 2014 after considering all public comments received on the draft plan, the Trustees
adopted and released a final Phase III Early Restoration Plan that included the Early Restoration Project.
Thereafter, the Trustees approved the final Phase III Early Restoration Plan (“Phase III Plan”) and
selected the Early Restoration Project in a Record of Decision dated October 2, 2014. The Trustees’
Record of Decision and the final Phase III Plan are available publicly
(http://www.gulfspillrestoration.noaa.gov/restoration/early-restoration/phase-iii/).
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The Final Phase III ERP/PEIS addresses programmatic early restoration project types as well as specific
Phase III early restoration projects (including this project – See Chapter 10) that may be selected for
implementation in accordance with the Oil Pollution Act, Natural Resource Damage Assessment (NRDA)
regulations, the National Environmental Policy Act and the “Framework for Early Restoration Addressing
Injuries Resulting from the Deepwater Horizon Oil Spill” (Framework Agreement).
2.0
PURPOSE AND NEED
For the purpose of accelerating meaningful restoration of injured natural resources and their services
resulting from the Spill, the Mississippi Trustee along with other state and federal Trustees propose to
continue implementation of Early Restoration in accordance with the Framework Agreement and other
applicable statutes and regulations. In April 2011, the Trustees entered into the Framework Agreement
under which BP, a responsible party, agreed to provide up to $1 billion toward Early Restoration projects
in the Gulf to address injuries to natural resources caused by the Spill. This Framework Agreement is
intended to facilitate and expedite restoration in the Gulf in advance of the completion of the NRDA
process. The Framework Agreement provides a mechanism through which the Trustees and BP can work
together “to commence implementation of Early Restoration projects that will provide meaningful
benefits to accelerate restoration in the Gulf as quickly as practicable” prior to completion of the NRDA
process or full resolution of the Trustees’ natural resource damage claims. In order to accelerate
meaningful restoration, the Trustees have identified restoration projects that will contribute to making
the environment and the public whole for injury to or loss of natural resources and services resulting
from the Spill.
3.0
ALTERNATIVES ANALYSIS
3.1
SITE ALTERNATIVES
Throughout the Early Restoration process, the Trustees have used preliminary results from the NRDA to
inform and guide the selection of Early Restoration projects. To date, the NRDA work clearly
demonstrates extensive oiling of marsh and beach shorelines from Texas to the Florida Panhandle.
Preliminary results also make clear that the oiling had significant adverse impacts on coastal and nearshore habitats and their biological communities. Early Restoration reflects the Trustees’ proposal to
focus on those injury categories for which the nature of the adverse impacts is reasonably well
understood and is limited to those areas at this time. Once the Trustees’ Assessment is complete, a final
damage assessment and restoration plan will be developed to address injuries not fully addressed by the
Early Restoration program.
Three sites were considered for the creation of a living shoreline project, all of which are located in
southwestern Hancock County, in close proximity to the selected Hancock County Marsh Living
Shoreline site. The Hancock County Marsh is uniquely important because it is one of the largest
remaining, intact marsh habitats in Mississippi, but it is experiencing high rates of shoreline erosion and
marsh loss, and was directly impacted by oiling from the Spill. The three potential sites that were
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considered included 1) a site near Buccaneer State Park, 2) a site near Bayou Caddy, 3) and the preferred
alternative, the Hancock County Marsh Living Shoreline Project. The three sites are discussed below.
3.1.1 BUCCANEER STATE PARK
Buccaneer State Park is located southwest of Waveland, Mississippi. Buccaneer State Park includes
numerous camping sites, a water park, pavilions, an activity building, nature trails, and other
recreational amenities. The Mississippi Sound shoreline associated with Buccaneer State Park was
considered for the project; however, the site was not considered feasible due to the following factors:
1. Submerged Aquatic Vegetation (SAV) Cover - The shallow water in the Mississippi Sound
adjacent to Buccaneer State Park has historically contained colonies of SAV (ground-truthed
as recently as 2010) in the vicinity of the park. Siting the project in this vicinity would likely
result in impacts to existing SAVs especially for marsh creation project components.
2. Shoreline Erosion and Marsh Loss - This site is not identified as a priority area in the
Beneficial Use (BU) Master Plan (CH2M HILL for the Gulf of Mexico Alliance/Habitat
Conservation and Restoration Team. May 2011. Final Master Plan for the Beneficial Use of
Dredged Material for Coastal Mississippi).
3. Previous Mitigation Measures - None
3.1.2 BAYOU CADDY
Bayou Caddy is located southwest of Waveland, in southwestern Mississippi. The shoreline associated
with Bayou Caddy was considered for the project.
1. SAV Cover - The project area adjacent to Bayou Caddy has shallow water and has historically
contained colonies of SAV. Siting the project in this vicinity would likely result in impacts to
existing SAVs especially for marsh creation project components.
2. Shoreline Erosion and Marsh Loss - The Bayou Caddy site was identified as a priority area
within the Hancock County Coastal Preserves in the BU Master Plan due to shoreline loss
related to erosion.
3. Previous Mitigation Measures - The Bayou Caddy site was listed as a high priority site in the
Final Project Management Plan for Selected Beneficial Use Projects along Coastal Mississippi
(CH2M HILL for the Gulf of Mexico Alliance/Habitat Conservation and Restoration Team,
September 2011) and the project was implemented by the USACE under the Mississippi
Coastal Improvements Plan as an Interim Project to protect the shoreline and create marsh.
A significant portion of this project has now been completed, so the scale of project
required to achieve the NRDA offsets is not tenable at this location.
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3.1.3 HANCOCK COUNTY MARSH (PREFERRED ALTERNATIVE)
The Hancock County Marsh Preserve is located in southwestern Hancock County. The preserve includes
adjoining marshlands bordering the Mississippi Sound from the Pearl River to Point Clear. The project
area includes the shoreline of the Hancock County marsh from the mouth of the Pearl River on the west
to approximately 1.86 miles past the heel of St. Joseph’s Point, including Heron Bay.
1. SAV Cover – A SAV and Oyster Survey was conducted in June 2013 in Heron Bay, located in
the center of the Preferred Alternative Location site (provided in Attachment H). SAV
presence was limited to very shallow waters along the fringe of the marsh edge, which
would not be impacted by the marsh creation or breakwater construction portions of the
proposed project, but could result in short-term, minor, adverse impacts to SAV during
deployment of the oyster cultch. Widgeon grass exists in scarce amounts in very shallow
waters along the fringe of the marsh edge in Heron Bay and grows on eroded marsh
platforms. Any disturbance would be re-vegetated naturally.
2. Shoreline and Marsh Erosion - The northern portion of the Preferred Alternative Location
site was identified in the BU Master Plan as the Saint Joseph Point Project, and was
considered to be a priority project site. The same project was listed as a high priority in the
Final Project Management Plan for Selected Beneficial Use Projects along Coastal
Mississippi. Saint Joseph Point has experienced extreme marsh loss in the past 60 years,
with over 260 acres of land loss since the 1950s (National Oceanographic and Atmospheric
Administration [NOAA] Office of Coastal Survey, 2011). There has been over 1,600 linear
feet of shoreline loss with over 1,000 feet of this loss occurring within the last 20 years
(NOAA 2011) in this area.
Shoreline regression since 1850 was studied and is depicted in Figures 1 through 3 below
(Schmid 2002). These figures represent the change in shorelines over the course of three
different periods: from 1850 to 2001, from 1969 to 2001, and from 1986 to 2001. Analysis of
this data reveals that 45 to 60 percent of the shoreline was receding at a rate of one meter
per year (Schmid 2002). That rate is the anticipated shoreline loss rate going forward. The
loss of shoreline along the Hancock County Marsh is not uniform. The area from Three Oaks
Bayou to Heron Bay Point has shown shoreline loss at a rate higher than one meter per year.
This area is important because once it is breached, shoreline erosion will start taking place
within Heron Bay. Presently the shoreline along Heron Bay is stable. Furthermore, Schmid
indicates that approximately 6.2 acres of shoreline in Hancock County Marsh are being lost
per year, and there is no evidence of any new marsh area being created, meaning that wave
action is the main mechanism for loss of shoreline.
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Figure 1: Shoreline Change Levels from 1850 to 2001 (Schmid 2002)
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3. Previous Mitigation Measures – None
Based on the criteria evaluated during the site alternatives analysis, the Hancock County Marsh Site was
selected as the Preferred Alternative. The other identified sites would either have more impacts to SAV,
were not identified as a restoration priority, did not have comparable amounts of shoreline erosion, and
/ or were already implemented under other funding mechanisms. Selection of the Hancock County
Marsh Living Shoreline project site also ensures that the Trustees meet our responsibilities under the
Framework Agreement and OPA, including:
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The project would restore within Mississippi the injured salt marsh and lost benthic secondary
productivity resulting from the Spill in an effort to make the environment whole by restoring,
rehabilitating, replacing or acquiring the equivalent of these natural resources injured by the
Spill.
The nexus to resources injured by the Spill is clear;
The project is technically feasible and utilizes proven techniques with established methods and
documented results. Government agencies have successfully implemented similar projects in
the region. For these reasons, the project has a high likelihood of success, and;
The cost estimates are based on similar past projects, and the project can be conducted at a
reasonable cost.
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3.2
CONSTRUCTION ALTERNATIVES ANALYSIS
Once the project site was selected through the Site Selection Process described above (Section 3.1),
project and construction alternatives were developed, including a “no construction” alternative. These
alternatives were evaluated to determine whether the following project goals were capable of being
achieved with each alternative:
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Reduce shoreline erosion, particularly around St. Joseph Point and Lighthouse Point;
Create and protect marsh habitat and provide for future marsh creation areas;
Construct a sub-tidal oyster reef in Heron Bay in areas that historically contained oyster reefs
and
Achieve environmental, habitat and secondary production goals established for the project.
3.2.1 “NO CONSTRUCTION” ALTERNATIVE
This alternative was evaluated and rejected because it would not achieve the project goals.
3.2.2 CONSTRUCT LIVING SHORELINE STRUCTURE IN HERON BAY AND PROVIDE 70
ACRES OF SUB-TIDAL OYSTER REEF
An approximately 18,600’ living shoreline structure was proposed around the shoreline of Heron Bay. A
70 - acre sub-tidal oyster reef was proposed at the mouth of Heron Bay in water deeper than -3’ MSL.
The living shoreline structure was to be constructed of rip rap with a 9” veneer of oyster shell. The crest
width was to be 10’ with an overall structure height of 2.5’. The sub-tidal oyster reef was to be 6” of
oyster shell. The total cost of project was estimated to be approximately $20.7M. This alternative was
rejected since it did not address reducing erosion along major erosion areas (St. Joseph Point,
Lighthouse Point and between Heron Bay and Pearl River). Additionally, this alternative did not provide
areas for marsh creation.
3.2.3 HERON BAY TO PEARL RIVER CONSTRUCTION ALTERNATIVES
Two types of structures (1) a low-crested rip rap breakwater structure and (2) a low-crested living
breakwater structure (a breakwater structure topped with oyster shell), both approximately 1.9 miles in
length, were evaluated. The proposed low-crested rip rap breakwater structure had a crest width of 15’
and a total structure height of 2.5’. The living breakwater structure would be identical in structure but
with a 9” veneer of oyster shell. Although the living breakwater structure was slightly more expensive
to construct, this alternative was selected because it achieved the habitat and secondary production
goals established for the project.
Two locations for the breakwater structures were evaluated – close to the existing shoreline (lowcrested rip rap breakwater structure) and along the -3.5’ MSL contour (low-crested living breakwater
structure). The location along the -3.5’ MSL contour was preferred because it provided more
opportunity to construct marsh shoreward of the structure, provided a structure on which secondary
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productivity could occur and allowed wave dissipation along the shoreline, thus, providing greater
shoreline erosion reduction, while providing a structure suitable for secondary production.
3.2.4 ST. JOSEPH’S POINT CONSTRUCTION ALTERNATIVES
The living breakwater structure was the only construction alternative evaluated along this reach of the
project given its proximity to existing submerged oyster reefs and the secondary production benefit that
could be derived from this type of substrate (oyster shell as opposed to only riprap). The living
breakwater structure had a 15’ crest width and varied in overall structure height from 2.5’ to 4’,
depending on the location of the structure.
The location of the living breakwater structure varied from close to shore to varying locations generally
along the -3.5 msl contour to allow designated areas for construction of marsh on the landward side.
The location that was closest to the existing shoreline was rejected because this location would have
required an exposed breakwater structure in order to reduce erosion and would not allow for marsh
creation opportunities. Additionally, the breakwater structure would not provide adequate habitat for
secondary benthic production due to the exposed nature of the structure. By placing the living
breakwaters generally along the -3.5 msl contour, there were opportunities to create from 66 to 257
acres of marsh, in addition to reducing the erosion along the existing shoreline.
3.2.5 FINAL CONSTRUCTION ALTERNATIVE SELECTION
After looking at several alternative locations and construction alternatives, as described above, it was
decided that a living breakwater constructed of a rip rap core with a 9” oyster shell veneer would be
constructed along the -3.5 msl contour from Heron Bay to Pearl River (approximately 1.9 miles in length)
and from Heron Bay eastward along St. Joseph’s Point (approximately 4.0 miles in length). There would
be approximately 297 acres available for marsh creation, of which, 46 acres of marsh would be created
under this project. A location in Heron Bay was selected to construct 46 acres of sub-tidal oyster reef
due to the historical presence of submerged oyster reefs in this location and an oyster survey conducted
in June 2013 (Attachment H). The oyster reef would consist of 6” of cultch material (oyster shell or
limestone).
After further consideration of the construction techniques and sub-surface soil conditions, the
construction of the living shoreline structure was modified to utilize marine mattresses filled with rip rap
and a 9” oyster veneer on the seaward side of structure and the crest. The structure would still have a
15’ crest width and be approximately 3.75’ in total height. To minimize settlement, the lowest layer of
marine mattresses would have a geotextile fabric on the underside of the mattress. The marine
mattresses would be constructed on shore, loaded on material barges, and transported to the site
where they will be deployed from barges to construct the living breakwaters. Further the oyster reef
height in Heron Bay was increased to 9” in order to provide the necessary secondary production goals.
The advantages to this alternative are:
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better quality control of the construction of the structure;
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4.0
less time on site to construct the structure;
less turbidity generated during the construction process;
reduction of the depth of temporary flotation channels to meet the construction needs; and
minimization of settlement of the structure.
PROJECT LOCATION
The proposed project is located (Figure 4) in Hancock County, Mississippi (Bounding Coordinates: West 89.530339 W, 30.184 N; South: -89.462 W, 30.169 N; East: -89.415 W, 30.233 N; North: -89.53 W,
30.184 W. Centroid = -89.457 W, 30.19 N).
Figure 4: Hancock County Marsh Living Shoreline Site Vicinity.
The Hancock County Marsh Preserve is managed by the MDMR and is the second largest continuous
marsh area in the state. The preserve includes adjoining marshlands bordering the Mississippi Sound
from the Pearl River to Point Clear. The project area includes the shoreline of the Hancock County marsh
from the mouth of the Pearl River on the west to approximately 1.86 miles past the heel of St. Joseph’s
Point, including Heron Bay. On the seaward side, the project area extends approximately to the -8 ft.
contour from the proposed breakwater to incorporate potential impacts from temporary flotation
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channels that would be utilized by work barges during construction. Table 1 lists the Sections,
Townships, and Ranges and the USGS topographic maps are located in Attachment A.
TABLE 1 – Sections, Township, and Range of Project
Section
Township
Range
1
10 South
15 West
5
10 South
15 West
6
10 South
15 West
9
10 South
15 West
10
10 South
15 West
11
10 South
15 West
12
10 South
15 West
13
10 South
15 West
14
10 South
15 West
5.0
PROJECT DESCRIPTION
The Hancock County Marsh Living Shoreline project would include shoreline/marsh protection, marsh
creation, subtidal reef restoration, and increased benthic secondary productivity. Specifically, the
proposed project consists of three restoration components:
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Use of living shoreline techniques that utilize natural and artificial breakwater material to
reduce shoreline erosion by dampening wave energy while encouraging reestablishment of
habitat that was once present in the region
As part of the living shoreline approach, approximately 46 acres of salt marsh habitat will be
created in areas that have experienced high rates of shoreline and marsh habitat erosion
Placement of approximately 46 acres of oyster cultch in areas that have historically supported
oyster habitat
The following description is intended to be a conservative description of the project components in
order to evaluate a maximum environmental impact for environmental permitting purposes. Project
refinement(s) are anticipated as part of the design and construction process; however, any project
revisions will be restricted to the current project footprint presented in this plan and on the project
exhibits (Attachment A). Notification to the appropriate agencies will occur if revisions are made.
The proposed Hancock County Marsh Living Shoreline project is intended to employ living shoreline
techniques including natural and artificial breakwater material and marsh creation to reduce shoreline
erosion by dampening wave energy while encouraging reestablishment of habitat that was once present
in the region. Utilizing living shoreline techniques, the project would provide for construction of up to
5.9 miles of breakwater, approximately 46 acres of marsh creation, and approximately 46 acres of
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subtidal oyster reef would be created in Heron Bay to increase secondary productivity in the area. The
project would provide shoreline erosion reduction, creation of habitat for secondary benthic
productivity, and protection and creation of salt marsh habitat.
Figure 5: Project Features (Preferred Alternative)
For this project, the living shoreline approach includes constructing a breakwater made of limestone
with oyster shell veneer that provide erosion control benefits and enhances natural shoreline habitat
and creation of 46 acres of salt marsh shoreward of the breakwaters. A breakwater can be defined as
linear structures that may utilize artificial and/or shell‐based materials placed parallel to the shore in
medium to high-energy open-water environments for the purpose of dissipating wave energy to reduce
shoreline erosion.
Living Breakwaters
The breakwaters would be constructed at two locations: along St. Joseph’s Point (eastern reach) and
Pearl River to Heron Bay (western reach).
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•
St. Joseph’s Point Breakwater (eastern reach): The conceptual design for the breakwater would
be approximately four miles long, extending from Heron Bay to approximately four miles to the
northeast, which includes openings throughout, with a crest width of approximately 15.0 ft. and
total height of approximately 4.0 ft. (to +0.87 ft., North American Vertical Datum [NAVD]). The
breakwater would have a footprint of approximately 14.4 acres and would be placed on a
substrate of fine-grained sediment. It would be composed of a core of riprap and some or all
could be covered by a 9-inch-thick layer of bagged oyster shell.
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Pearl River to Heron Bay Breakwater (western reach): This conceptual breakwater would be
approximately 1.9 miles long, with openings throughout, with a crest width of 15.0 ft. and a
total height of approximately 4.0 ft. (to +0.87 ft., NAVD). Its design and sediment substrate are
to be similar to the St. Joseph’s Point breakwater. The Pearl River to Heron Bay breakwater
project area footprint would be approximately 5.5 acres, consisting of fine-grained sediment.
The conceptual design is subject to refinement.
Creation of Marsh in the Vicinity of St. Joseph’s Point
In addition to the breakwaters, the living shoreline approach would include creating a total of
approximately 46 acres of salt marsh in one to several locations. Salt marshes are defined as transitional
marsh areas between land and water that occur in coastal areas at salinities at or approaching that of
ocean water. Typical vegetation in salt marsh habitat includes species such as smooth cordgrass
(Spartina alterniflora), black needlerush (Juncus romerianus), and saltgrass (Distichlis spicata). The area
behind the constructed breakwater at St. Joseph’s Point would be backfilled with dredged material and
allowed to re-vegetate by natural colonization of estuarine marsh species. Dredged fill material would
be obtained through the Mississippi Beneficial Sediment Use Program as available or excavated from a
suitable borrow source. Dredged material would be hydraulically placed to obtain the target elevation.
Placement of Oyster Reef Cultch in Heron Bay
In addition to the living shoreline components, oyster cultch would be deployed over approximately 46
acres in Heron Bay in areas that currently support or previously supported oyster production. Oyster
reefs are typically colonial aggregations of living oysters and other bi-valves that can have subtidal as
well as intertidal portions and that provide habitat for a community of other species. Oyster cultch
deployment would occur generally in water depths of approximately -3 to -5 ft. MLLW. The reef(s)
would be sited based on data gathered from an oyster presence survey and would consist of an
approximately 6- to 9-inch-thick layer of oyster shell or limestone. The project exhibits (Attachment A)
show a larger cultch footprint within which the cultch will be deployed.
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5.1
ANTICIPATED CONSTRUCTION PROCESS
This Section describes the anticipated construction process. The design drawings are included in the
application packet as Attachment A. NOAA performed preliminary design calculations for the project
based on tidal datum information from the Bay-Waveland Yacht Club NOAA tidal station, bathymetry
based on nautical chart of the area, wind data from West Pier, Gulfport and design parameters and
transmission coefficients for various wave heights and for the proposed breakwater cross-section.
NOAA’s design summary is provided as Attachment M.
Breakwaters
The specific breakwater construction elevation was selected to maximize shoreline protection.
Preliminary specifications are shown on Table 2. Construction would include placement of linear
structures that would utilize artificial and/or shell‐based materials. The alignment and limits of the
breakwaters would be surveyed; the outer limits of the breakwaters would be marked with poles driven
into the bottom and extended approximately 3 feet above the water surface. The height of the
breakwaters along the alignment would be constructed based on bottom elevations and the anticipated
crest elevation (0.87 foot NAVD88 – Mean Tide Level). Barriers, navigation warning signs (up to
approximately 185, lighted), and other safety devices would be installed along the work area to protect
boaters as required.
Table 2. Preliminary living shoreline (breakwater) specifications.
Living Shoreline (Breakwater) Design
Data
Total project length
Total project acreage
Crest width
Base width
Assumed bottom elevation
Total structure height
Bagged shell veneer thickness
Riprap Core volume
Bagged shell volume
Depth of material (riprap/marine
mattress)
Estimate initial settlement
Design side slopes
Breakwater distance from shoreline
St. Joseph’s Point
Breakwater (eastern
reach)
Approx. 4 miles
14.4 acres
15.0 feet
30 feet
-3.5 MLLW
3.75 feet
9 inches
Pearl River to Heron Bay
Breakwater (western
reach):
Approx. 1.9 miles
5.5 acres
15.0 feet
30 feet
-3.5 MLLW
3.75 feet
9 inches
51,600 cubic yards
16,400 cubic yards
16,900 cubic yards
6,300 cubic yards
3 feet
1 foot
2v:1h
30’-90’
3 feet
1 foot
2v:1h
30’-90’
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Reach of each breakwater
Length of each gap between breakwater
75 feet
25 feet
75 feet
25 feet
The dimensions for the breakwaters would be approximately 30 feet wide at the base and
approximately 15 feet wide at the crest. (Table 2). The breakwaters would be installed in segments with
each segment being approximately 75 feet with 25-foot gaps between the segments.
The riprap core of the breakwaters would either be constructed using marine mattresses, which would
consist of 2- to 6-inch-diameter rocks assembled on land, or loose boulders. The marine mattresses or
loose boulders would be transported to the work area on barges and installed by a crane located on a
separate barge to construct the living breakwaters. The loose boulders or marine mattresses would be
underlain by geotextile fabric, and placement of the material would be monitored to ensure the
breakwater dimensions, slopes, and crest elevations are achieved. After installation of the loose
boulders or marine mattresses, some or all of the breakwater segments would be covered with bags of
shell. Construction details are provided on Sheet C13.0, Appendix A. The deployment of the
breakwaters may extend over a period of ten to twelve months. Through consultations with
appropriate federal agencies (Attachments I, K and L), construction activities would be conducted in
accordance with Construction Conditions and best management practices (BMPs) established by federal
agencies. These Construction Conditions and BMPs are presented in paragraph 5.5, below. Total
installed volumes would be as follows:
• St. Joseph’s Point Breakwater (eastern reach): The target depth for deployment is
approximately -3.5 ft. MLLW, but could be between -3.0 and -5.0 ft. MLLW. The volume of
placed material would be approximately 51,600 cubic yards of riprap and 16,400 cubic yards of
shell. The breakwater would cover a footprint of approximately 14.4 acres of fine-grained
sediment.
• Pearl River to Heron Bay Breakwater (western reach): The target depth for deployment is
approximately -3.5 MLLW-; but could be between -2.0 ft and -5.0 ft. MLLW. The volume of
placed material would be approximately 16,900 cubic yards of riprap and 6,300 cubic yards of
shell. The breakwater would cover a footprint of approximately 5.5 acres of fine-grained
sediment.
The project is designed to use temporary flotation channels (Table 3) to facilitate access for work barges
into the work area. Channels will be excavated parallel to the alignments of the two breakwaters with
additional channels excavated perpendicular to these channels to provide access from the Mississippi
Sound. These channels will allow work barges entry and exit to the project area (See Attachment A) and
will allow work to proceed much more quickly. All excavated dredged material not used for marsh
creation would be cast on the seaward side of the channels so they naturally fill back in after
construction. The channels are anticipated to fill in naturally in five years (based on project engineer
14
and contractor experience). A sediment transport study will be conducted using current and readily available
data during the final design process. The study will seek, among other things, to address the redeposition of the
proposed flotation channels. The depth of the channels would be 8 feet below MLLW to accommodate
barge draft. The bottom width of the channels would be approximately 80 feet with 3H:1V side slopes
(see Project Exhibits - Attachment A, Sheet Numbers C14.0 and C15.0). The entry locations for the
channels would be determined by analyzing the shortest distance from the breakwaters to the
appropriate depth of -8 feet and excavated using BMPs to minimize environmental impacts. For the
purposes of project planning, the preliminary temporary flotation channel footprint was calculated
based on an estimate of a heavy, fully- loaded barge. Proposed temporary flotation channel dimensions
are summarized in Table 3.
Table 3. Preliminary temporary flotation channel specifications.
COMPONENT
Channel length
Existing depth
Barge draft (proposed Depth)
Channel width
Area temporarily impacted
Cubic yards of material to be moved
Location of spoil disposal area
Material type
Dimensions of spoil area
Method of excavation
How will spoil area be contained?
DIMENSION
55,008 feet
3-7 feet
8 feet
80 feet
101 acres
650,000
Adjacent to the new channel on the seaward side or
potential beneficial use for marsh creation.
Silty substrate
22.9 acres seaward side of channel
Barge mounted excavator
Uncontained, Intended to naturally refill channel over
time
After completion of construction, the breakwater structure would be surveyed and permanent
navigation signs would be installed in accordance with safety requirements.
Creation of Marsh in the Vicinity of St. Joseph’s Point
After the breakwater along St. Joseph’s Point has been installed, selected areas totaling 46 acres
landward of the breakwater within a 297-acre area (Attachment A, Sheet C13.0) would be filled with
dredged material obtained from the MDMR Beneficial Use of Sediment Program, if material is available,
or a suitable borrow source. If dredged materials are utilized for marsh creation, a Beneficial Use Permit
would be required with MDMR as the permit holder, because the volume of material required will
exceed 2,500 cubic yards. It is anticipated that a dike (containment structure) would be constructed at
the seaward extent of the marsh. Sheet C14.0, Appendix A, provides details. Upon location of suitable fill
material, the dike would be constructed by excavating existing material from the landward side of the
proposed dike location, but not borrowing from the existing marsh (no existing marsh impact). Once an
area of the marsh is diked, the area landward of the dike would be filled with dredged material until
15
final marsh grades are achieved. Sediment would be pumped through a floating pipeline from a
hydraulic dredge located where suitable fill material is available. Pumps and sediment controls would
remain in place throughout the dredging and filling process and after initial settling has occurred. Once
the entire marsh area(s) is constructed, the area would be monitored for natural re-vegetation. The
following table details the specification of this project component.
Table 4. Preliminary marsh creation specifications.
COMPONENT
Dimensions of fill area
Cubic yards of fill
DIMENSION
46 acres minimum
375,000
MDMR Beneficial Use of Sediment Program as available
Type of fill
OR material from a suitable borrow source
Other regulated activities
None
Placement of Oyster Cultch Reefs in Heron Bay
Oyster cultch would be deployed in Heron Bay in water depths of -3 to -5 ft. MLLW in areas that
currently support or previously supported oyster production. An oyster presence survey has been
completed that identified suitable areas (Attachment G). The cultch would be deployed as a 6- to 9-inchthick layer of oyster shell or limestone. Prior to deployment, the limits of the oyster cultch deployment
area(s) would be marked with buoys or poles. Oyster shells or other cultch material would be deployed
by a barge-mounted crane with a clam shell bucket. A material barge loaded with cultch material would
be moored to the crane barge. As a construction alternative, water jetting of cultch material off of a
material barge may be used in case of water-depth constraints. Similar to the breakwater construction
described above, temporary flotation channels will be used to access the oyster cultch area (Attachment
A, Sheets C12.0 and C15.0). The flotation channels will be excavated from the Mississippi Sound into
Heron Bay to facilitate barges carrying oyster cultch. Depending on the method of deployment, smaller
deployment vessels will be used to spread the 46 acres of cultch material while the material barge
anchors in the channel. If cultch material is deployed directly from the material barge, it will be
necessary to dredge additional flotation channels perpendicular to the main flotation channel. It is
expected that these channels will fill in naturally within five years of excavation, but will also be marked
with lighted navigational signs to warn boaters of the presence of the spoil pile. Upon completion, the
deployment area would be surveyed and no impacts are anticipated to result from the survey work. The
following table details the specification of this project component.
Table 5. Preliminary oyster cultch specifications.
COMPONENT
Dimensions of fill area
Cubic yards of fill
Type of fill
Other regulated activities
Flotation Channel
DIMENSION
46 acres
37,150
Oyster shells or limestone
None
Included in the Table 6.0 estimate
16
5.2
AIDS TO NAVIGATION
Aids to Navigation signage would be coordinated with the U.S. Coast Guard to determine the type of
signage required and the locations of the signage. This is normally coordinated after the Section 404
Permit is issued. The signage and placement would be in accordance with the Coast Guard’s “U.S. Aids
to Navigation System” guidelines. Preliminary discussions with the U.S. Coast Guard, New Orleans
District indicates that all signage would need to be lighted. The signs would need to be approximately
300’ apart and located either seaward of the excavated material from the flotation channels along the
proposed living breakwater structures, if the excavated material is not backfilled into the flotation
channel during the project, or seaward of the living breakwater structure, if the excavated material is
backfilled into the flotation channel during the project. If the excavated material from the temporary
flotation channel to the oyster reef in Heron Bay remains, lighted signs would be required every 300’
along both sides of the excavated material. If the excavated material is backfilled into the flotation
channel, temporary signage would be required during construction operations only. The permit
drawings reflect these requirements and the anticipated lighted sign that would be required (Appendix
A, Sheets C14.0 and C15.0).
5.3
GEOTECHNICAL PILOT STUDY
In order to determine the potential settling rate (both short-term and long-term) and constructability of
the proposed living shoreline breakwater structure, a geotechnical pilot study was proposed, permitted
and implemented. A permit application was submitted to the Mississippi Department of Marine
Resources (MDMR), the Mississippi Department of Environmental Quality (MDEQ) and the Mobile
District, Corps of Engineers (USACE). The permit was approved by all regulatory agencies with the last
approval being obtained from the USACE on July 15, 2014 (SAM-2014-00063-MJF).
The geotechnical pilot study consisted of two 25’ X 25’ living breakwater marine mattress structures in a
portion of the project area where the anticipated softest soils were identified. The two (2) living
segments were installed on September 11, 2014. Two (2) settlement plates were installed with each
structure and monitored for both initial and longer term settlement. Elevations of the existing footprint
of each structure were taken prior to installation in order to determine the initial bottom elevation. As
each structure was being installed, elevations of each settlement plate were taken. The initial
settlement on September 11, 2014 was 0.07’ (0.84”) to 0.11’ (1.32”). Through October 27, 2014 (47
total days), the settlement was 0.18’ (2.16”) to 0.27’ (3.24”).
5.4
WATER QUALITY CERTIFICATION
In accordance with Section 401 of the Federal Act, 33 U.S.C. Section 1341, a Water Quality Certification
from the Mississippi Department of Environmental Quality (MDEQ) is required for this project.
According to Rule 1.3.4 (Scope of Review for Application Decisions) of the MDEQ Wastewater Pollution
Control Regulations, the following 11 factors related to the construction and operations of the activity
must be addressed by the applicant and will be considered in determining certification action.
17
1.
FEASIBLE ALTERNATIVES TO THE ACTIVITY
An alternatives analysis is presented in Section 3.0 of this Joint Application and
Notification Form Supplement. The site location alternatives analysis and the
construction alternatives analysis are presented in Section 3.1 and 3.2, respectively.
2.
MITIGATION
Placement of the breakwater, created marsh, and deployment of oyster cultch would
result in short-term, minor impacts to water quality as a result of resuspension of
sediment by vessels (barges, tugs, skiffs, etc.) moving in and out of the project area,
excavation of the temporary flotation channels, and filling of the marsh. The suspended
sediment may be transported into surrounding wetlands, waterways, and the
Mississippi Sound. However, the area is currently exposed to elevated turbidity levels as
a result of resuspension of sediment from river transport, erosion of existing shoreline
and during frequent storms, tides, and other typical weather events. Best management
practices, along with other avoidance and mitigation measures required by state and
federal regulatory agencies, would be employed to minimize potential water quality and
sedimentation impacts. Impacts from turbidity would be minor, short term and limited
in spatial extent.
In addition to turbidity, the water quality could be impacted by leaks or spills of fuel and
lubricants used by vessels and other equipment during the construction of the
breakwater, marsh, and oyster cultch deployment. Appropriate best management
practices, such as routine maintenance, inspection, and proper refueling of construction
equipment, would be used to prevent, control, and mitigate impacts. Suitable
maintenance dredge sediments that have been examined for levels of contamination,
consistent with applicable requirements, would be used as fill material in the project
area.
3.
INITIAL AND SECONDARY IMPACTS ON ALL EXISTING AND ALL CLASSISIFED USES OF THE
WATERS OF THE STATE
The project area classified as “Recreation” from Heron Bay eastward, and as “Fish and
Wildlife” from the western boundary of Heron Bay west to the mouth of the Pearl River
(State of Mississippi Water Quality Criteria for Intrastate, Interstate, and Coastal Waters,
2007). Dissolved solids (turbidity) may increase temporarily during construction as
described above but will dissipate and are not expected to result in conditions other
than those which naturally occur in this area. Turbidity curtains will not be required. In
a response to request for amendments memorandum dated September 26, 2014
(included in Attachment K of this application package), Dr. Roy E. Crabtree of NOAA
18
NMFS discussed turbidity issues associated with the proposed project and indicated that
Ms. Florance Watson of the MDEQ had indicated by email to the applicant that
“Turbidity screens are required for activities that will be ongoing for a significant period
of time. [The Hancock County project] is temporary in nature, has minimal construction
activities in water, and the construction timeframe is very short. Also, the water quality
standard establishes that turbidity shall not exceed 50 NTUs of the ambient turbidity
outside a 750-foot mixing zone. This activity will likely occur well within the mixing zone
and is not expected to disturb the water bottoms to an extent that exceeds this
standard”. This project is not anticipated to result in an increase in total fecal coliform
bacteria. This project is not expected to have any secondary impact on existing and
classified uses of the waters of the state. The waters of the State affected by the
proposed project area not currently listed as impaired.
4.
DEGREE OF COMPLIANCE OF THE PROPOSED ACTIVITY AND WITH THE STATE OF
MISSISSIPPI WATER QUALITY CRITERIA FOR INTRASTATE, INTERSTATE, AND COASTAL
WATERS
The project is in compliance with water quality criteria outlined in the 2007 State of
Mississippi Water Quality Criteria for Intrastate, Interstate, and Coastal Waters. It is not
anticipated that this project will result in an increase in total fecal coliform bacteria.
Dissolved solids (turbidity) may increase temporarily during construction but will
dissipate and are not expected to result in permanent exceedances beyond those which
currently exist.
5.
DEGREE OF PHYSICAL, CHEMICAL, AND BIOLOGICAL IMPACTS ON WATERS OF THE STATE
Physical impacts would be limited to temporary increased turbidity, as described above.
No chemical impacts on waters of the state are anticipated due to the proposed project.
During marsh creation and excavation of the flotation channels there could be shortterm, minor, impacts to the benthic infauna and epifauna and flora in the immediate
area of construction. Biological impacts would be beneficial in the long term, due to
increased secondary productivity benefits created by the living shoreline breakwater
structure and the placement of oyster cultch in approximately 46 acres in Heron Bay.
6.
THE EFFECT ON CIRCULATION PATTERNS AND WATER MOVEMENT ON WATERS OF THE
STATE
No long-term impacts from the breakwater and the created marsh to the tidal hydrology
of Hancock County marsh and surrounding areas are anticipated. Gaps would be present
between breakwater segments and created marsh areas that would allow tidal
exchange flows and waterway access. Access to all of the tributaries within the Hancock
19
County Marsh will be maintained (see Figure 5 and Attachment A). The general shape of
the shoreline would remain the same; therefore, there would be no anticipated impacts
to tides and currents as a result of the project activities. Using final engineering design
criteria, best available regional current, wind and sediments dynamics data will be
utilized to determine the effects of the structure on hydrology and sediment dynamics
in the project area. Additionally, the long-term monitoring would identify any
erosion/sediment accumulation issues associated with the project that would be
addressed through the maintenance budget included in the overall project budget.
7.
DEGREE OF ALTERATION OF THE AQUATIC ECOSYSTEM
The project will result in long term benefits to the aquatic ecosystem. This project is
intended to enhance the aquatic ecosystem through the creation of oyster and benthic
habitat thus increasing secondary benthic productivity, the creation of new marsh
habitat and protection of existing marsh habitat, and reduction of shoreline erosion.
Although temporary impacts to benthic communities could occur during dredging of
temporary flotation channels and marsh creation, these communities are anticipated to
recover quickly. The project has been coordinated with the US Fish and Wildlife Service
and they concurred that the project is Not Likely to Adversely Affect any species
regulated under the Endangered Species Act, Migratory Bird Treaty Act, and Bald and
Golden Eagle Protection Act (Attachment I). Additionally, the NMFS Habitat
Conservation Division concurred that the project will not adversely affect any Essential
Fish Habitat (EFH) components regulated under the Magnuson-Stevenson Act
(Attachment K). The project has also been coordinated with the National Marine
Fisheries Service (NMFS) Protected Resources Division and they concurred that the
project is Not Likely to Adversely Affect any species protected under the ESA or the
Marine Mammal Protection Act (Attachment L).
8.
DEGREE OF CONSISTENCY WITH APPROVED WATER QUALITY MANAGEMENT PLANS
ADOPTED BY THE COMMISSION
The water bodies located within the project area (Heron Bay and Mississippi Sound) are
not listed as impaired water bodies in the “Mississippi 2014 Section 303(d) List of
Impaired Water Bodies” dated July 24, 2014. There are no TMDLs assigned to these
waters. Compliance of proposed activity with the water quality criteria is discussed in
Factor 4, above.
9.
STORM WATER MANAGEMENT
Construction activities will occur in water; therefore no storm water management issues
are anticipated.
20
10.
COMPLIANCE HISTORY OF THE APPLICANT
The Applicant obtained a Joint Application permit (SAM-2014-00063-MJF) for
conducting a Geotechnical Pilot Study within the project area. The Geotechnical Pilot
Study consisted of installing small lengths of the proposed breakwater structure utilizing
proposed construction techniques. The Applicant has complied with all terms and
conditions of this permit.
5.5
PROJECT ADVERSE AND BENEFICIAL IMPACTS
Adverse and beneficial impacts of the Hancock County Marsh Living Shoreline project were evaluated in
detail in the project specific Environmental Assessment included in Chapter 10 of the Final Phase 3 Early
Restoration Plan and Programmatic Environmental Impact Statement
(http://www.gulfspillrestoration.noaa.gov/restoration/early-restoration/phase-iii/). There will be no
direct impacts to the existing shoreline or marsh habitat. Access to all of the tributaries within the
Hancock County Marsh Preserve will be maintained (see Figure 5). The project is expected to result in
minor, short-term adverse impacts in several resource categories, but overall the project is expected to
result in a net long-term benefit due to shoreline protection, marsh creation, and restoration of
submerged reef habitat that was once prevalent in this area. The following table identifies each
resource category that was evaluated and whether the project will result in no effect, an adverse effect,
or a beneficial effect.
Public Health and
Safety and Shoreline
Protection
Infrastructure
Tourism and
Recreational Use
Aesthetics and Visual
Resources
Land and Marine
Management
Socioeconomics and
Environmental Justice
Habitats
Protected Species
Living Coastal and
Marine Resources
Noise
Air Quality and GHGs
Hydrology and Water
Resources
Geology and
Substrates
Table 6. NEPA effects summary table for Hancock County Marsh Living Shoreline Project
Hancock
County
N
-/+
-/+
S
S
+
+
-/+ +
+
S
+
+
Marsh Living
E
Shoreline
- Represents an adverse impact; + represents a beneficial impact; s represents a short-term adverse impact; NE
represents no effect
( - ) Represents an adverse impact; ( + ) represents a beneficial impact; ( S) represents a short-term adverse impact; ( NE ) represents no effect
In addition to NEPA review, several other federal consultations have been completed. The project has
been coordinated with the US Fish and Wildlife Service and they concurred that the project is Not Likely
21
to Adversely Affect any species regulated under the Endangered Species Act, Migratory Bird Treaty Act,
and Bald and Golden Eagle Protection Act (Attachment I). Additionally, the NMFS Habitat Conservation
Division concurred that the project is will not adversely affect any Essential Fish Habitat (EFH)
components regulated under the Magnuson-Stevenson Act (Attachment K). The project has also
been coordinated with the National Marine Fisheries Service (NMFS) Protected Resources Division and
they concurred that the project is Not Likely to Adversely Affect any species protected under the ESA or
the Marine Mammal Protection Act (Attachment L). Best Management Practices and conservation
measures associated with these consultations are described below.
The impacts to aquatic resources and benefits are discussed below and listed in Table 6.
St. Joseph’s Point Area Living Breakwater Construction Activity Area
The St. Joseph’s Point Area Living Breakwater Structure is anticipated to be 4 miles long with a footprint
of approximately 14.4 acres. Fine-grained sediment will be filled with riprap to form a breakwater, and
then partially to completely covered with a bagged shell veneer. If the temporary flotation channels are
backfilled during construction, approximately seventy 6-inch diameter treated posts will be driven
adjacent to the submerged reef and will be used to mount warning signs. A total of 14.4 acres of open
water with fine-grained sediment bottom habitat will be permanently converted to reef habitat. The
project footprint has little to no vegetative cover and consists of only shallow open water as described in
the Environmental Assessment (Attachment C).
Pearl River to Heron Bay Living Breakwater Construction Activity Area
The Pearl River to Heron Bay Living Breakwater Structure is anticipated to be 1.9 miles long with a
footprint of approximately 5.5 acres. Fine-grained sediment will be filled with riprap to form a
breakwater, and then partially to completely covered with a bagged shell veneer. If the temporary
flotation channels are backfilled during construction, approximately 35 6-inch diameter treated posts
will be driven adjacent to the submerged reef and will be used to mount warning signs. A total of 5.5
acres of open water with fine-grained sediment bottom habitat will be permanently converted to reef
habitat. The project footprint has no vegetative cover and consists of only shallow open water as
described in the Environmental Assessment (Attachment C).
Temporary Flotation Channels Construction Activity Area
Temporary flotation channels would be excavated for the construction of the breakwaters and
deployment of oyster cultch in Heron Bay. The temporary flotation channels are anticipated to be
55,008 feet long with a footprint of 101 acres. The construction activities would include disturbing finegrained sediment bottom habitat due to the excavation of approximately 101 acres of channel. Material
from channels would be sidecast adjacent to the temporary flotation channels to facilitate natural filling
due to ocean currents, if not utilized for beneficial use in marsh creation. A short-term impact would be
caused by sidecasting material on 22.93 acres. These impacts would be temporary as the channel will
fill back in with the sediment to the seaward side in five years (based on project engineer and contractor
experience). If the temporary flotation channels are not backfilled during construction, approximately
185 6-inch diameter treated posts will be driven adjacent to and seaward of the sidecast material and
22
will be used to mount warning signs. A sediment transport study will be conducted using current and
readily available data during the final design process. The study will seek, among other things, to
address the redeposition of the proposed flotation channels.
Oyster Reefs in Heron Bay
Loose oyster shell or suitable cultch material would be used to create approximately 6-9 inch thick
subtidal reefs in Heron Bay. A total of 46 acres of cultch material would be placed on remnant oyster
beds/hard bottom habitat that would be permanently converted to submerged reefs that would
recolonize with benthic organisms. The project footprint has little to no vegetative cover and consists of
only shallow open water as described in the Environmental Assessment (Attachment C).
Marsh Creation at St. Joseph’s Point
A total of 46 acres of open water with fine-grained sediment bottom habitat would be filled with
suitable material and permanently converted to salt marsh habitat. The majority of this open water
area was historically marsh that eroded over time. The project footprint has no vegetative cover and
consists of only shallow open water as described in the Environmental Assessment (Attachment C).
Table 6. Summary of Impacts
Project
Component
Area Submerged
Reef Construction
Activity Area
Pearl River to
Heron Bay
Submerged Reef
Construction
Activity Area
Temporary
Flotation Channels
Temporary
Flotation Channel
Sidecast material
Oyster Reefs in
Heron Bay
Marsh Creation at
Impact Type
Duration of
Impact
Long-Term
Habitat Type
Impacted
Shallow water/finegrained sediment
bottom
Acreage
of Impact
14.4
Permanent
Shallow water/finegrained sediment
bottom
5.5
Excavation of sea
bottom
Short-Term
101.0
Placement of
excavated sea bottom
of seaward side of
flotation channels or
for use in marsh
creation
Filling with Oyster
Cultch (shells,
limestone)
Filling with suitable
material
Short-Term
Water depths of 2 to
8 feet with finegrained sediment
bottom
Water depths of 2 to
8 feet with finegrained sediment
bottom
Long-Term
Shallow water/hard
bottom
46.0
Long-Term
Shallow water with
fine-grained
46.0
Filling fine-grained
sediment with riprap,
covered with bagged
shell veneer
Filling fine-grained
sediment with riprap,
covered with bagged
shell veneer
22.9
23
sediment bottom
Total Temporary Impacts
Total Permanent Impacts
Total Impacts
123.9
111.9
242.2
Construction of the Hancock County Marsh Living Shoreline project would result in long-term impacts to
benthic soft and hard bottom habitat (approximately 111.9 acres) over the life of the project. The area
would be covered with hard structure and sediment for the creation of breakwaters, marsh, and oyster
reefs. There would be temporary impacts to approximately 123.9 acres of fine-grained sediment for the
creation of temporary flotation channels including sidecast of spoil on the seaward side of the channel.
The net benefits of the habitat protection and restoration would include increased benthic habitat
diversity, structural complexity, greater diversity and abundance of marine aquatic species. In addition,
the entire Hancock County marsh would experience reduced shoreline erosion. The project would
provide long-term benefits by creation of approximately 46 acres of salt marsh, approximately 46 acres
of oyster habitat, and create approximately 5.9 miles (19.9 acres) of high-profile reef. Approximately 5.9
miles of shoreline would be protected (Table 7). Overall, there would be a long-term benefit to geology
and substrates in the Hancock County marsh. There would be no long-term adverse impact as a result of
excavation of temporary flotation channels.
Table 7. Habitat Created or Protected
Habitat Type
Shoreline
Oyster Reef
Marsh
Means of Protection/Creation
Creation of living breakwaters
Restoration Measures
5.9 miles; 19.9 acres of high
profile reef
Placement of loose oyster shells or other
46 acres
cultch material
Placement of dredged material behind living
46 acres
breakwaters
Best Management Practices
Throughout the design and construction process, every practical attempt would be made to avoid and
minimize potentially adverse environmental, social, and cultural impacts. The following conservation
measures and BMPs (sorted by resource type) would be implemented to minimize impacts to resources:
•
Green House Gas Emissions
o Shut down idling construction equipment, if feasible.
o Locate staging areas as close to construction sites as practicable to minimize driving
distances between staging areas and construction sites.
o Encourage the use of the proper size of equipment for the job to maximize energy
efficiency.
o Encourage the use of alternative fuels or power sources for generators at construction
sites, such as propane or solar power, or use electrical power where practicable.
24
•
•
•
•
•
Marine Mammals
o If manatee(s) are found to be present in the immediate project area during restoration
activities, construction would be halted until the species moves away from the project
area.
Protected Species
o Awareness of potential turtle presence. If any sea turtles are found to be present in the
immediate project area during restoration activities, construction will be halted until
species moves away from project area.
o Awareness of manatee presence. If manatee(s) are found to be present in the
immediate project area during restoration activities, construction will be halted until
species moves away from project area. For in-water work in Mississippi where
manatees could be present, the Trustee will follow conditions a, b, c, and d of the
Standard Manatee Conditions for In-water Work (USFWS 2011). The Trustee would
report any collisions to the U.S. Fish and Wildlife Service or State trust resource agency.
Temporary signs, if necessary, would be modified from the standard template to reflect
local conditions.
o Measures to protect Gulf Sturgeon. Project restoration features will be built close to the
shoreline in shallow water (1-4 feet) and will not impede any migratory paths. Project
construction activities will be subject to a stop work order if the species is observed in
the project footprint. Work will continue once the species leaves the area.
o Construction activities will adhere to special conditions specified in the Sea Turtle and
Smalltooth Sawfish Construction Conditions, dated March 23, 2006 (NMFS 2006).
The project will follow Measures for Reducing Entrapment Risk to Protected Species, revised
May 22, 2012 (NMFS 2006).
Migratory Birds
o Pre-construction nesting surveys for migratory birds and raptors would be conducted
and if evidence of nesting is found, coordination with the USFWS would be initiated to
develop and implement appropriate conservation measures.
Essential Fish Habitat
o Work barges would be moored for overnight and weekends/holidays in areas where
previous impacts have occurred (flotation channels, deployment areas).
o Spoil from flotation channels will be placed on the seaward side of the channel to
facilitate current-driven backfilling of channels.
o Pilings would be driven instead of jetting to reduce the disturbance of bottom
sediments and bottom dwelling organisms.
o Where practicable, shell obtained from commercial vendors that did not or will not
impact the aquatic environments will be utilized for reef construction.
o Monitoring will be conducted before, during, and after project implementation to
ensure compliance with project design and completion. If immediate post-construction
monitoring reveals that unavoidable impacts to EFH have occurred, appropriate
coordination with regional EFH personnel will take place to determine appropriate
25
•
•
response measures, possibly including mitigation. If additional adaptive management of
the breakwater structure is necessary after monitoring evens, all minimization measures
discussed above will be followed.
o Any temporary access channels will be filled in naturally following construction to reestablish baseline elevations. Monitoring will assess whether unexpected impacts to
EFH have occurred.
Invasive Species
o All equipment to be used during the project, including personal gear, will be inspected
and cleaned such that there is no observable presence of mud, seeds, vegetation,
insects and other species.
o Oyster cultch and vegetation will be treated or inspected to remove “non-target”
species.
General Construction BMPs
o Spoil from temporary flotation channels would be placed on the seaward side of the
channel to facilitate current-driven backfilling of channels.
o Placement of all signage pilings would be achieved by “driving” in lieu of “jetting” to
reduce the disturbance of bottom sediments and bottom-dwelling organisms.
Attachment C is a complete environmental analysis of the preferred alternative including the Mississippi
Coastal Program decision factors.
26
6.0
REFERENCES
CH2M HILL for the Gulf of Mexico Alliance/Habitat Conservation and Restoration Team. May 2011.
Final Master Plan for the Beneficial Use of Dredged Material for Coastal Mississippi.
CH2M HILL for the Gulf of Mexico Alliance/Habitat Conservation and Restoration Team. September
2011. Project Management Plan for Selected Beneficial Use Projects Along Coastal Mississippi.
Final Programmatic and Phase III Early Restoration Plan and Final Early Restoration Programmatic
Environmental Impact Statement http://www.gulfspillrestoration.noaa.gov/restoration/earlyrestoration/phase-iii/
Mississippi Department of Marine Resources (MDMR). 2013. Coastal Zone Management, Coastal
Preserves Missions Values and Goals. Accessed online on July 9 at
http://www.dmr.state.ms.us/coastal-ecology/coastal-preserves/60-coastal-preserves-missionvision-and-goals. 2013.
NMFS. 2006. Sea Turtle and Smalltooth Sawfish Construction Conditions. Southeast Regional Office. St.
Petersburg, Florida. Revised March 23.
Schmid, Keil. 2002. Shoreline Change: Hancock County Marsh 1850 to Present. RPG # 0664, Mississippi
Department of Environmental Quality, Office of Geology. Accessed online on June 10 at
http://geology.deq.state.ms.us/coastal/NOAA_DATA/Publications/Publications/Hancock/Shoreline
%20and%20Area%20Change%20of%20Hancock%20Marsh-1850%20to%20Present.pdf. 2013.
State of Mississippi 2014 Section 303(d) List of Impaired Water Bodies, July 24, 2014.
State of Mississippi Water Quality Criteria for Intrastate, Interstate, and Coastal Waters, 2007
USFWS. 2011. Standard Manatee Conditions for In-water Work. Available at:
http://www.dep.state.fl.us/water/wetlands/forms/spgp/SPGP_IV_Attachment_3ManateeConstructionConditions.pdf.
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Hancock County Marsh Living Shoreline Section 404 Joint

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