B08_Solicitation_Attachment_1_SOW_Bridge_Removal.pdf

STATEMENT OF WORK (SOW)

Katahdin Woods and Waters (KAWW) National Monument Remove Substandard Culverts and Bridges, Penobscot

County, Maine PMIS KAWW 314638A- Bridge Removal/Restoration Big Spring Brook New River

Road Road T4-R8 WELS #7239

1.0 Background

Project is in the National Park Service unit, Katahdin Woods and Waters National Monument (KAWW), located in Penobscot County of Northern Maine. Katahdin Woods and Waters National Monument includes more than 80,000 acres and several hundred miles of aggregate-surface logging roads customary to the Maine Northern Woods.

This contract will remove a bridge system and restore the streams banks and approach. Bridge is in a state of collapse.

2.0 Scope

This contract requires the contractor to provide all tools, labor, equipment, supervision, transportation, and materials necessary to remove an existing bridge system and restore the streams banks. Work is to be done in accordance with all existing Federal, State, and local codes.

The restored crossing area will have a bank width of ≈ 22 feet and will have its banks regraded to more naturally match the stream channel and its banks, but also to allow easy approach for users of the hiking and biking trail to readily cross the stream during times of normal low flows. The stream banks to be reestablished will connect to and match existing stream banks upstream and downstream using native material at the site. The stream bed will remain little changed from its current elevations, but it will be widened in part to accommodate natural dimensions, and also to allow for the addition of several key "stepping stone" boulders placed to help trail users to cross the stream.

These boulders will be placed as others exist in the natural channel in areas upstream especially and will allow the stream to flow around them as in those natural portions of the stream.

3.0 Objectives

The objective of this contract is to fully remove a bridge system and remove any barriers to accommodate natural waterflow.

4.0 Tasks

Tasks include:

• Remove one existing bridge system 24 ft. in length.

• Rehabilitate site to attached design specs.

Remove Bridge: Bridge is on the New River Road 6 ½ miles from Haskell Gate of on narrow gravel road T4-R8 WELS in Penobscot County – See Attachment 1, Location Map and Specifications.

1. Bridge – Removal of bridge includes the removal of all materials associated with existing bridge, gravel roadway reconstruction, crossing and approach work.

Stream banks and crossing will be established per attached deign. Dewatering will be required.

2. Detailed information for the Big Spring Brook Bridge Removal on New River

Road project is attached. Attachment 1, Location Map and Specifications, includes a map of the project location, proposed crossing inlet elevations, a partial list of materials and information on water control.

3. Quote Item: Remove road Bridge System and restore stream banks and approaches per attached design.

5.0 Delivery

• The Contractor shall provide all tools, labor, equipment, supervision, transportation, and materials necessary to repair the road, restore stream and remove bridge.

• All work to take place will be within Katahdin Woods and Waters National

Monument (KAWW), located in Penobscot County of Northern Maine.

• Excess gravel and dirt will be dumped and graded to level a nearby road to Big Spring Brook Hut. Road is 0.15 miles from bridge site (Shown on attached map).

• The Contractor shall submit a safety plan to the Contracting Officer prior to performing any work under this contract.

• The Contractor shall submit a work schedule and sequence of events to the Contracting Officer prior to performing any work under this contract. There will be a pre-construction meeting held prior to the start of work on-site.

• The contractor shall follow attached dewatering and watercourse management plan for the bridge work.

• A final inspection must be held with the government upon completion of the work.

• All vehicles and equipment shall be cleaned of any dirt or vegetation, particularly on the undercarriage, tracks, and sprockets before coming to the jobsite.

6.0 Government-Furnished Property

The Government will not be furnishing nor providing any property to the contractor for this contract. Excess excavated material due to project can be deposited within 0.15 miles of the project. Offsite disposal of the old bridge components and appurtenances will be the contractor’s responsibility.

7.0 Security

Contractor shall be responsible for securing the work site, materials, equipment, and tools during the duration of the contract. If a temporary staging area is required, KAWW may identify and agree to a location with KAWW. The Government will take no responsibility for lost, stolen or damaged property as a result.

8.0 Place of Performance

The contract work shall be performed on the New River Road within Katahdin Woods and Waters National Monument (KAWW), located in Penobscot County, Maine.

9.0 Period of Performance

The onsite work can only be done between the 15th of July and the 30th of September in any calendar year. The period of performance for this contract begins with a notice to proceed and shall end on 30 September 2025.

Submittals identified in Section 5.0 shall be provided to the Government within 14 days of award of this contract for review and approval. It is anticipated that the Government will require a minimum of 5 business days to review the submission.

Once the submittals are approved by the NPS, the contractor shall commence work, completing it within the period of performance specified above.

Site Map - Drainage Area

Site Photos

Inlet Outlet

Top of Survey Reach - Downstream View Bottom of Survey Reach - Downstream View

Failing Bridge

Failing Bridge

Site Topography - Existing Conditions

Stream Profile - Existing Conditions

Note: This view is vertically exaggerated, reflecting the different scales of units for elevation and distance.

Road/Trail

Existing Bridge Deck on failing log abutments

XS2

XS1

Cross-Section 1 - Reference Reach Upstream of Crossing

Upstream to Cross-Section Downstream to Cross-Section

Bankfull Width ≈ 22'

Bankfull XS Area ≈ 18 ft2

Cross-Section 2 - Reference Reach Downstream of Crossing

Upstream to Cross-Section Downstream to Cross-Section

Bankfull Width ≈ 20'

Bankfull XS Area ≈ 28 ft2

Site Topography - Proposed Conditions

Fill Information:

Permanent Fill = 100 sq. ft.

Temporary Fill = 80 sq. ft.

Stream Profile - Proposed Conditions

Note: This view is vertically exaggerated, reflecting the different scales of units for elevation and distance.

Trail

Proposed Restoration Area Banks Rebuilt

Boulders Placed for Trail Crossing

Existing Stream Bed

Expected Stream Bed

Scour under old bridge

Proposed Restoration Area - Trail Crossing Elevation

* Low wood or concrete curbing recommended to retain gravel over top of bridge deck panels

Trail Surface at ≈ 840' Elevation on North Side

Bankfull Width = 22.0'

1% Probability Flow

Bank Armor Bank Armor

Example "Stepping Stone"

Boulders

Proposed Restoration Area Profile

Bed and Bank Schematic:

Crossing Stream Bed

Elevation 827'

Expected Stream Bed

Former Bridge Abutment Width = 20'

Banklines are composed of 24-48 inch (average intermediate dimension – not longest or shortest measure) competent, angular to sub-angular foundation rock. Banklines must connect to the natural stream banks upstream and downstream. Additional smaller rock and fines are also necessary for filling gaps in the larger material to provde more stable banklines.

Embankment above banks should be protected by a layer of smaller rock (12"-18") to stabilize those areas while vegetation is reestablished, and to protect against significant flood events.

Plan View

Example "Stepping Stone" Boulders (Mid-Stream)

Existing Stream Bed

Bank Armor (2-4' rock)

Embankment Armor (12-18" rock)1% Probability Flow

Flow

Proposed Restoration Area - Grading Plan

Bankfull Width = 22.0'

Bank Armor

≈ 72 yds of road fill to be removed *

≈ 72 yds of road fill to be removed *

Install water bars to control drainage

* A potentially large portion of fill may consist of rock to be used for bank armoring

Hydrology & Hydraulic Analysis

HY-8 Hydraulic Analysis Program of the U.S. Federal Highway Administration provides results for the above peak flow estimates for the proposed crossing design, and indicates that the crossing as proposed will successfully pass the expected 1% probability storm event.

Attribute Value Units Definition References:

Drainage Area 2.98 sq. miles Area that drains to crossing 99 90 Wetlands 1.9 percent Percentage of NWI storage 50 201 Elevation 1,443 feet Mean basin elevation 20 323 Precipitation 45.6 inches Mean annual precipitation 10 412 Aquifer Unknown percent 4 535

2 632 X-coordinate 514492 State Plane m Basin centroid E/W location 1 734 Y-coordinate 5097741 State Plane m Basin centroid N/S location 0.2 974

Return Probability (%)

Peak QT

(ft3/s)1

1 Lombard, P.J., and Hodgkins, G.A.,2020, Estimating flood magnitude and frequency ongaged and ungaged streams in Maine: U.S. Geological Survey Scientific InvestigationsReport 2020–5092, 56 p.

(https://doi.org/10.3133/sir20205092)Percentage of land underlain by sand & gravel aquifers

Discharge Names

Total Discharge

(cfs)

Headwater Elevation

(ft) Flow Type

Outlet Depth

(ft)

Outlet Velocity

(ft/s) 99 90.00 829.82 1-S2n 1.75 5.88 50 201.00 830.76 1-S2n 2.44 6.81 20 323.00 831.47 1-S2n 2.88 7.74 10 412.00 831.89 1-S2n 3.14 8.27 4 535.00 832.40 1-S2n 3.45 8.84 2 632.00 832.76 1-S2n 3.68 9.23 1 734.00 833.11 1-S2n 3.89 9.56

0.2 974.00 831.76 1-S2n 4.32 10.38

Water Control:

Material Specifications:

It is critical that water be controlled during construction, maintaining stream flow, and eliminating potential sedimentation and erosion, which is best accomplished at a low-flow period. All Maine Department of Environmental Protection Best Management Practices for Sediment and Erosion Control should be followed, particularly in case of unexpected stream flow. Sandbag or other cofferdams should be placed upstream and downstream to control stream flow to isolate the work area and maintain water quality during construction while allowing pumping of clean stream water around the site. Old abutments can be removed while the site is isolated, with dirty water from the work zone pumped out and filtered in nearby forest to avoid contamination of the stream. Sufficient pump capacity is essential to maintain water control, with backup pumps on hand or readily available.

22' Bankfull Width Naturalized Stream Crossing suitable for foot traffic during low flow times

Rock for bank scour protection: 15-20 yds @ 24-48" local, rounded rock (most rock needed may already be on site) Rock for embankment scour protection: 20 yds @ 12-18" local rock (some rock needed may already be on site) Sandbags for Cofferdams: 10 1-ton sandbags, with additional 20 small sandbags for filling voids Polyethylene Sheeting (6 mil - for cofferdam sealing as needed) ) 400 sq. ft

Pump conveys streamflow during construction

Removal of existing culvert Dirty water pumped from work site Dirty water filtered in nearby forest

Water Control: Cofferdam, Pump & Filtration Placement

Cofferdam

Dirty Water PumpClean

Water Pump

Block Net

Block Net

Filtration Basins

Cofferdam

Attachment 1

Big Spring Brook Bridge Removal

Orin Falls Road Culverts

Big Spring Brook Bridge Removal