Statement_of_Work.pdf

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Statement of Work

For

Shoreline Stabilization

National Park Service, Cumberland Island, GA – PMIS 305281

Plum Orchard Shoreline

Objective for Shoreline Stabilization at Plum Orchard

The overall goal of restoration for Plum Orchard Shoreline is to reduce erosion and stabilize this area, to reduce the risk of impacts from storms and sea level rise to the shoreline vegetation and increase the resiliency of the shoreline. In the time period since the hurricane impacts in 2017 plans were to reclaim and stabilize shoreline using geotextile cloth and quarried stone to be placed on the existing shoreline above the high tide line. The project includes protecting the existing trees, re-vegetate where suitable conditions allow using a combination of bioengineering, livable landscape and appropriate plantings in concert with rip rap to restore undercut shorelines from the 2017 hurricanes.

The Plum Orchard Historic District includes a historic designed landscape of sites and structures along Brickhill River on the western edge of Cumberland Island, approximately seven miles north of Dungeness. The boundary of the National Register listed Plum Orchard Historic District encloses approximately 60 acres west of the Main Road.

Site Location Map

1.0 Scope of Work

Contractor will supply supervision, equipment, operators, laborers, and materials required for installing geotextile fabric, bioengineering, livable landscaping, and riprap at Plum Orchard shoreline.

(Refer to Exhibit A)

Plum Orchard

Cumberland Island, GA

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Exhibit A

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TASK 1 – Riprap/Geotextile Fabric/Debris for Shoreline Protection at Plum Orchard and Sea Camp

Table 1: Riprap Requirements

Min/Max

Gradation Size (inch)

Percent Passing

(by Weight) Uniform Graded

Min 18*

Max 24*

Min 16*

Max 22*

Min 12*

Max 17*

Min 9 -

Max 13 -

Min - 1

Max - 6

Min 8 - 0

Contractor shall provide the recommended maximum and minimum requirements for riprap gradation size and passing percentage for the shoreline protection shall meet Table 1 requirements. The amount of rip rap needed is approximately 300 tons. (Refer to Exhibit B) A barge is required to bring all material and equipment to the site. All shoreline work will be staged on the barge. The barge will require a ramp to allow material and equipment to access shoreline work. All the work must be accomplished during low tide. Contractor may access areas not otherwise accessible at low tide to haul riprap to shoreline via the existing gravel road. The Northern end of the shoreline is not accessible at low tide. Contractor shall abide by permits for shoreline work. NPS will secure permits and provide to contractor for shoreline work.

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-EXHIBIT B-

VIEW OF SHORELINE

FACING SOUTH

FACING NORTH

CONTRACTOR SHALL REMOVE DEAD TREE

AND CUT UP IN 2’ LENGHTS AND HAUL TO

CAMPGROUND

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1. The proposed slope of the shoreline stabilization shall be a maximum slope of 2H (Horizontal):1V (Vertical). Contractor shall use appropriate mechanical equipment to place riprap and reduce damage to the existing vegetation and shoreline so minimal natural resource impacts will occur. (Refer to Exhibit C)

2. The proposed slope of the shoreline stabilization shall be a maximum slope of 2H

(Horizontal):1V (Vertical). Contractor shall use appropriate mechanical equipment to place riprap. Refer to Exhibit C1 and Exhibit B for the Livable Landscape detail. Contractor shall supply oyster shells in mesh bags approximately 3’ x 3’ x 8”h along the edge of the shore (185’ of shoreline). Contractor shall plant approximately 425 each Spartina Alterniflora Smooth Cordgrass on 4’ center in this area. Grasses shall be sprig plantings and plants shall have sufficient root system to assure success rate of 85%. Trumpet Creeper (25 ea. Campus radicans) shall be planted on top of the slope. Nursery stock shall be 1 gallon.

The geotextile fabric layer selected shall have a minimum grasp tensile strength of 370 pounds (lb.), and a minimum trapezoidal tear strength of 100 lb. All geotextile fabric will be placed by hand and secured to the shoreline before placing the stones for the riprap layer.

The amount of geotextile fabric needed is approximately 5400 square feet.

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3. The amount of fill needed for shoreline reclamation/stabilization is approximately 460 cu/yds. T h e fill material will be provided by NPS and will be staged on the Southern portion of the island. Contractor will be responsible for loading and hauling (approximately 7 miles one way) material from the source site. See below diagram.

4. Contractor shall place 500 tons of surge stone (3”-8”) in size on approximately 400 linear feet of shoreline on the Northern end of the site adjacent to the Plum Orchard Residence. This area will be covered with 8” of soil and planted with bioengineering for the plants to root in the mix of soil and stone. Plantings will include 600 bareroot Spartina Alterniflora Smooth Cordgrass, 120 Green Cuttings from Wax Myrtle cuttings from Cumberland Island, and Southern Bayberry 20 bundles with 5 canes/bundle to be 3/8” diameter minimum and bundles 3’ long. R e f e r t o Exhibit D and D1. See Exhibit E for where Wax Myrtle and Southern Bayberry plants can be found on island and used for bioengineering in accordance with Exhibit D crossection.

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-Exhibit D1-

FACING NORTH

Down Trees shall be removed in order to place rip rap. Place trees back in the corner of bulkhead with the root mass facing the river

2.0 Meetings, Plans and Submittals:

Task 2 - Post Award Meeting/ Deliverables/Submittals/Construction Plan and Limits:

Post Award Meeting

Contractor and all the principal team members shall meet with NPS Representatives; COR: Darrell Stone and CO: William Vazquez to clarify tasks, discuss logistics and schedule. Period of performance shall be 120 days after the NTP.

Deliverables/Submittals:

• Project meeting

• Project schedule

• Construction Plan

• Geotextile Fabric submittal

• Rip Rap and Surge Stone

• Quality Control Plan

• Designation letter and description of qualifications of Superintendent

• List of Sub-Contractors

• Accident Prevention / Safety Plan

• Coordination Meeting Summary Report

• Contractor Quality Control Daily Reports

• Project schedule updates – Included with monthly invoice submissions

• Schedule of Values

Notes for Construction Plan Inclusion:

Contractor shall submit a construction plan which will address the following:

• NPS shall obtain all required environmental permits. (electronic copy provided to contractor)

• Mobilize equipment,

• Identify and maintain haul roads and project site as necessary. The Main Road will have to provide access to shoreline for construction. The road for hauling dredge spoil from the laydown area has been identified by NPS for use by Contractor. The Main Road will need to be maintained weekly as construction traffic will be damaging to the road. Maintenance shall include filling all potholes, grading, and leveling. The Main Road is a historic feature of the cultural landscape; Contractor shall stay within the boundaries of the existing road and shoulder and shall not conduct work to go below existing grade.

• Complete Stabilization Design Installation Exhibits A-D,

• Receive acceptance of the project by NPS.

Construction Limits

Construction activities for the Plumb Orchard shoreline project will be limited to areas around shoreline.

Shoreline access will be approximately 800 feet long. This access will extend approximately 25 feet from top of shoreline in toward the island. Construction activities will extend approximately 25 feet from the top of shoreline toward the water. The shoreline will normally be established as the top erosion point;

however, some visual judgment will need to be applied. Contractor shall delineate and mark the shoreline prior to the start of construction. The NPS shall approve layout prior to construction.

Contractor shall submit a detailed plan showing limits of the construction activities to the COR for NPS approval.

Laydown Limits

All Contractor equipment and material must be staged at the Laydown area at Plumb Orchard as shown below.

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Bayberry found in this area (Live Oak)

Wax Myrtle found in this area (Longleaf Pine)

-Exhibit E-