C04_1-12445526Q0113-Att3-Specs.pdf

PROJECT SPECIFICATIONS

Elk Lick Dam Decommissioning and Restoration

Contents

PROJECT SPECIFICATIONS

Project Specifications

1. General Requirements

1.1. Project Information

1.2. Summary of Work

1.3. Objective and Background

1.4. Dam Description

1.5. Reservoir Description

1.6. Reservoir Sediment Conditions

1.7. Construction Flow Characteristics

1.8. Design Flow

1.9. Channel Capacity

1.10. Hydraulic transition at Dam

1.11. Reference:

1.12. Contractor Facilities, Utilities and Communications

1.13. Site Access

1.14. Downstream Access

1.15. Upstream Access

1.16. Construction Access Strategy

1.17. Laydown Areas

1.18. General Material Handling, Salvage, Reuse and Disposal

2. Site Preparation and Earthwork

2.1. Clearing, Grubbing, Salvage, and On-Site Use of Woody Material

2.2. Insufficient Woody Material

2.3. On-Site Use of Excess Material

2.4. Unsuitable Material

2.5. Disposal and Final Handling of Remaining Material

2.6. Protection of Salvaged Material

2.7. Demolition

2.8. Concrete Handling and Disposal

2.9. Riprap, Armoring, and Scour Protection

2.10. Final Grading and Restoration

2.11. Payment

2.12. Temporary Working Platforms

2.13. Temporary Access Road

2.14. Downstream Laydown and Staging Area

2.15. Reservoir Sediment Excavation and Grading

2.16. Pilot channel Excavation in Saturated Sediment

3. Reservoir Dewatering and Temporary Flow Control

3.1. Controlled Reservoir Drawdown

3.2. Temporary Flow Bypass

3.3. Storm Configuration

3.4. Turbidity Control Measures

4. Dam Demolition and Breach Construction

4.1. Saw cutting and Controlled Demolition

4.2. Dam Breach Construction

4.3. Breach Constraints

4.4. Payment

5. Construction Sequencing

5.1. Construction Sequencing Plan

5.2. Access and Setup

5.3. Phase 1: Controlled Drawdown (No Breach)

5.4. Phase 2: Breach Hard Control and Hard Control Preparation

5.5. Phase 3: Controlled Hydraulic Connection

5.6. Contingency Pumping

5.7. Phase 4: Breach

5.8. Appurtenant Dam Structure Decommissioning

6. Reservoir Restoration, Grade Control, and Stabilization

6.1. Stream Channel Construction

6.2. Streambed Simulation / Channel Bedding Material

6.3. Bedrock-Controlled Channel Excavation

6.4. Bedform Development and Channel Feature Construction

6.5. Channel Features and Bedform Controls

6.6. Riprap Stabilization

6.7. Riprap Gradation

6.8. Large Wood Structures

6.9. Sediment Corridor Width Control

6.10. Spoil Areas / Sediment Rehandling and Placement

7. Final Grading and Stabilization

7.1. General

7.2. Final Grading around Channel Features and Transitions

7.3. Temporary Structure Removal

8. Erosion, Sediment, and Water Quality Controls

8.1. Erosion and Sediment Controls

8.2. Turbidity Monitoring

8.3. Construction Hold Points

9. Vegetation Establishment and Slope Stabilization

9.1. General

9.2. Site Preparation

9.3. Seeding

9.4. Seed Mix Types

9.5. Wetland Meadow Seed Mix

9.6. Seed Mix Submittals

9.7. Seed Quality

9.8. Seeding Rates

9.9. Cover Crop

9.10. Seeding Timing

9.11. Mulch and Erosion Control

9.12. Wetland and Channel-Margin Areas

9.13. Upland and Disturbed Access Areas

9.14. Acceptance and Repair

10. Final Cleanup and Demobilization

10.1. General

10.2. Removal of Temporary Facilities

10.3. Site Restoration

10.4. Debris and Waste Disposal

10.5. As built

10.6. Final Inspection

11. Submittals

11.1. The following submittals shall be provided in addition to those otherwise required by these specifications. No separate payment will be made for preparation, revision, or resubmitting these items unless specifically provided in the Schedule of Items

12. Temporary Facilities and Controls

13. Environmental Protection

13.1. Downstream Waters

13.2. Equipment Fluids and Spill Prevention

14. Closeout and Site Restoration

14.1. Removal

15. Option Additional Breach Width & Upstream Restoration

15.1. Breach Width

16. Schedule of Bid Items

17. Optional Bid Item

Figure 1 - Turbidity Limits Figure 2: Optional Large Wood Structures

Project Specifications Elk Lick Dam Decommissioning and Restoration

1. General Requirements

1.1. Project Information

1.1.1. Project Identification: Elk Lick Dam Decommissioning & Restoration

1.1.2. Project Location: N39.052018, E -79.669349

1.1.3. No work shall be performed on weekends or federal holidays without written permission from the Contracting Officer (CO)

1.1.4. Period of performance: 365 Days

1.1.5. All construction equipment will be cleaned and free of dirt, debris and plant materials. All equipment will be inspected by the Contracting Officer Representative (COR) before mobilization. A minimum of five day notice must be given to COR to schedule inspection.

1.1.6. Contractor is responsible for all damages to roads, drainage structures, bridges, and facilities.

Contractor will repair any damages incurred at the contractor’s expense in accordance with

FP-14 specifications.

1.1.7. Temporary closures of FR701 may occur as needed. Coordination with the COR and approval must be obtained prior to any closure. A traffic control plan must be submitted at least 15 days before the start of construction for COR approval.

1.1.8. Forest Service will be responsible for instream and Section 404 permits. Contractor will be responsible for any haul or other required permits.

1.1.9. No utilities have been identified at the project location. Contractor is responsible for verifying this with local utility companies prior to starting construction. The dam was once used as water supply for the city of Parsons, WV. An abandoned water line exists downstream of the dam. Any protrusions of the water line out of the ground should be removed inside the limit of work.

1.2. Summary of Work

1.2.1. Work consists of decommissioning the Elk Lick Dam (also known as Parsons Reservoir) and restoring a stable stream channel through the former reservoir footprint. Major work includes clearing and grubbing; preparation of upstream and downstream laydown and access areas;

temporary access road improvements and stream crossings; staged reservoir drawdown;

temporary low-flow bypass installation; staged controlled breach of the concrete dam;

removal of downstream apron and appurtenant concrete within breach limits; removal and disposal or approved on-site reuse of concrete debris; on-site sediment excavation, management, and grading; downstream turbidity-control reach construction; restored channel construction; grade control and riprap stabilization; optional large wood structures where shown on the plans; erosion, sediment, and water-quality control; and final stabilization and revegetation.

1.2.2. Base bid work shall include a 30-foot breach. Additional 10-foot breach widening and associated restoration may be included as optional bid items. Optional in-stream woody debris placement may also be included as shown on the plans.

1.2.3. Payment for the work described in this section shall be made under the applicable bid items in the Schedule of Items. Work not specifically identified as a separate bid item shall be incidental to the related pay item.

1.3. Objective and Background

The Elk Lick Dam Decommissioning & Restoration Project involves the removal of a portion of the existing concrete gravity dam and restoration of a stable stream channel through the former reservoir footprint. The dam currently impounds a small headwater tributary within the Monongahela National

Forest. The structure has reached the end of its service life and no longer provides operational or recreational benefit. The project will restore natural stream continuity, eliminate long-term dam safety concerns, and improve aquatic habitat connectivity.

1.4. Dam Description

1.4.1. The existing structure is a concrete gravity dam constructed across a narrow valley. The dam is approximately:

1.4.1.1. Height: 18 ft effective height above bedrock

1.4.1.2. Crest Elevation: 2148 ft

1.4.1.3. Foundation Elevation: 2130 ft

1.4.1.4. Dam Base Width: 16 ft

1.4.1.5. Crest Width: 4 ft

1.4.1.6. Total Length: 156 ft

1.4.1.7. Apron Width: 10 ft

1.4.1.8. Apron Thickness: 4 ft

1.4.1.9. Apron Length: 156 ft

1.4.2. The downstream face of the dam includes a concrete spillway section that discharges onto a concrete splash apron extending downstream of the dam toe.

1.4.3. The structure was historically equipped with outlet works; however, the outlet system is currently non-functional and has not been operable for several decades. As a result, reservoir sediment has accumulated behind the dam, and the reservoir pool cannot be actively managed through controlled outlet operation.

1.4.4. Dam removal will include demolition of a central section of the dam and apron structures to create a permanent channel opening through the former dam alignment.

1.5. Reservoir Description

1.5.1. The reservoir created by the dam currently covers approximately 1.8 acres at normal pool. The reservoir extends approximately 600 ft upstream of the dam within a confined valley corridor.

1.5.2. The valley side slopes have a grade of approximately 76% and are densely forested, limiting lateral access to the reservoir margins. The water level is approximately 31 ft below the road surface that runs parallel to the reservoir. Existing access to the site is primarily provided by a forest road located downstream of the dam and by an old access route located near the upstream extent of the reservoir.

1.5.3. The reservoir bottom has gradually been filled with sediment over the decades since construction. Field observations and diver probing indicate that sediment depth near the dam may exceed 14 ft in thickness and decrease gradually upstream from the dam. The reservoir was last drained and cleaned out in 1983.

1.6. Reservoir Sediment Conditions

1.6.1. Sediment within the reservoir is composed of fine silts, sands, organic detritus, and decomposed vegetative material accumulated over several decades of impoundment. No geotechnical report is currently available for the dam area; however, hard bedrock is known to underlie the accumulated silt and support the dam foundation.

1.6.2. The lower portions of the reservoir, particularly near the dam, contain highly saturated organic deposits (“muck”). Diver observations indicate that these deposits are low density, gas charged and exhibit buoyant behavior when disturbed. These sediments are expected to possess:

1.6.2.1. Low shear strength

1.6.2.2. High water content

1.6.2.3. Slow drainage characteristics

1.6.2.4. Limited bearing capacity for construction equipment until partially drained

1.6.2.5. High probability of Hydrogen Sulfide and other nuisance gases being released from the decomposing materials

1.6.3. Because the outlet works have been nonfunctional for approximately 40 years, sediment accumulation has continued without interruption. Uncontrolled dam removal could mobilize a large volume of fine sediment; therefore, the project design incorporates staged drawdown and controlled breaching to minimize sudden sediment release.

1.6.4. Sediment thickness is expected to vary throughout the reservoir, with shallower deposits toward the upstream end and deeper, more organic material concentrated near the dam. The sediment at the center of the dam is estimated to be 14 feet thick. Even where sand is present within the profile, the material is expected to remain saturated and intermixed with organics, reducing strength and increasing the likelihood of instability during excavation.

1.6.5. The Contractor shall assume that sediment excavated from the channel corridor will behave as saturated, unstable material. Excavation methods shall be staged to maintain equipment stability and to prevent uncontrolled sediment movement.

1.6.6. All excavation and sediment handling shall be performed so that disturbed material remains within the reservoir footprint. Sediment shall not be placed where it may enter the active stream channel or migrate downstream. Sediment placement locations must be accessible from stable working surfaces and within typical excavator reach; placement in areas that cannot be safely graded and stabilized is not permitted.

1.6.7. Where sediment is placed adjacent to the constructed channel, the Contractor shall grade the material to stable slopes and prevent sloughing or raveling into the channel corridor.

Excessively steep or unsupported sediment margins will not be allowed.

1.6.8. If field conditions differ from the sediment characteristics described above, the Contractor shall notify the COR prior to continuing excavation so that excavation limits and placement procedures can be reassessed.

1.7. Construction Flow Characteristics

1.7.1. Elk Lick Run is a small headwater stream with relatively low ordinary flow and a flashy runoff response typical of a steep, confined watershed. Stream assessment data indicate a bankfull channel width of approximately 22.5 feet, a bankfull depth of about 1.5 feet, and a bankfull discharge of approximately 113 cfs. The flood-prone width has been estimated at approximately 80 feet. Ordinary flow conditions are expected to be much lower than bankfull.

1.7.2. For the June 1 through September 30 construction window, available StreamStats seasonal low-flow information indicates that Elk Lick Run is expected to carry very low ordinary summer flows. On that basis, a 24-inch temporary bypass appears adequate for expected low-flow conditions during construction. Its adequacy is not controlled by ordinary low flow, but rather by storm events, overtopping, debris, and temporary stabilization during construction.

1.7.3. Construction Staking and Clearing Limits

1.7.3.1. The Contractor shall stake or otherwise clearly mark the limits of clearing, grubbing, access improvement, laydown areas, stockpile areas, channel excavation, breach limits, downstream turbidity-control reach, and other principal work features prior to beginning disturbance in those areas.

1.7.3.2. Clearing limits shall be marked on trees to remain standing, on stakes, or on lath at intervals sufficient to make the limits clearly visible in the field.

1.7.3.3. No clearing, grubbing, excavation, or material placement shall occur outside the marked limits unless approved by the COR.

1.7.3.4. Any work outside approved limits shall be repaired or restored at no additional cost to the

Government.

1.7.3.5. Payment is incidental to Bid Item A5 Survey, layout, staking, as-builts.

1.8. Design Flow

For design purposes, the restored channel was evaluated relative to the stream’s bankfull and larger flood events. StreamStats estimates the approximately 2-year event at about 115 cfs, which is consistent with the assessed bankfull discharge of approximately 113 cfs. The estimated 1-percent annual exceedance probability flood is 588 cfs. The probable maximum flood used for project evaluation is approximately 7,790 cfs.

1.9. Channel Capacity

The restored channel is intended to convey normal and moderate storm flows while allowing overbank flow across adjacent floodplain areas during larger events. Channel geometry is therefore designed to balance sediment transport capacity, channel stability, and floodplain connectivity.

1.10. Hydraulic transition at Dam

Removal of the dam structure will substantially reduce the existing hydraulic control created by the impoundment. Following removal, the restored channel will provide a continuous longitudinal profile through the former reservoir reach consistent with upstream and downstream channel conditions.

1.11. Reference:

1.11.1. U.S. Geological Survey StreamStats Report, Elk Lick Run below the dam, clicked point at Latitude 39.05265, Longitude -79.66948.

1.12. Contractor Facilities, Utilities and Communications

1.12.1. The Contractor shall provide all temporary facilities, utilities, services, and accommodations necessary to complete the work.

1.12.2. No electrical service is available at the project site. The Contractor shall provide generators, fuel for temporary power, lighting, battery charging, or other temporary power necessary for construction support, testing, communications, safety, and administrative needs.

1.12.3. No potable water, sanitary sewer, restroom facilities, or bathroom facilities are available at the project site. The Contractor shall provide temporary sanitary facilities, handwashing facilities, potable water, and any other worker-support facilities required by applicable law, regulation, permit, or safety requirement.

1.12.4. Cell phone service at the project site is limited, unreliable, or unavailable. The

Contractor shall not rely on cellular service as the sole means of routine or emergency communication. The Contractor shall provide an appropriate communication plan and equipment necessary for routine communication, emergency communication, coordination with the COR, and worker safety.

1.12.5. The Contractor shall maintain temporary facilities in a clean, safe, sanitary, and secure condition. Temporary facilities shall be located only in approved staging or laydown areas and shall not obstruct access, drainage, construction sequencing, erosion-control measures, or public use areas unless approved by the COR.

1.12.6. The Contractor shall remove all temporary facilities, utilities, sanitary facilities, waste, and related materials from the site before final acceptance unless otherwise approved by the COR.

1.12.7. Measurement and Payment

1.12.7.1. Temporary facilities, sanitary facilities, handwashing facilities, potable water, temporary power, generators, fuel for temporary power, lighting, battery charging, communication planning, communication equipment, maintenance of temporary facilities, and removal of temporary facilities shall be considered incidental to A1 Mobilization / Demobilization.

1.12.7.2. No separate payment will be made for providing, maintaining, relocating, servicing, or removing temporary facilities, utilities, sanitary facilities, temporary power, or communication equipment required to complete the work.

1.13. Site Access

1.13.1. Due to steep abutments adjacent to the dam, direct access from the reservoir to the dam crest is limited. As a result, dam demolition activities will occur primarily from the downstream side of the structure and from the reservoir bottom after dewatering.

1.13.2. Upstream and downstream access improvements, temporary stream crossings, temporary material storage and road maintenance are incidental to Bid Item A3, Temporary access improvements, crossings, mats, and work pads. Access-related erosion control is incidental to Bid Item A4 Erosion & sediment controls, installation and maintenance.

1.14. Downstream Access

1.14.1. The primary construction access route originates from an existing forest road located approximately 735 ft downstream of the dam. This road crosses the stream channel downstream of the dam and will require improvement to accommodate construction equipment and truck traffic.

1.14.2. A temporary stream crossing will be required. Provide and install temporary articulated concrete block (ACB) mats designed for vehicular loadings equal to or greater than the heaviest project construction equipment. Mats shall be installed on exposed rock with a geotextile underlayment and shall be fully removable. Installation, anchoring, maintenance, and removal shall conform to the manufacturer’s recommendations. The Contractor shall prevent displacement of the mats during use and shall remove all mats, anchoring hardware, geotextile, and associated materials at the end of construction. The crossing area shall be restored to pre-construction condition upon removal.

1.14.3. Access improvements will include widening the existing road corridor to approximately 12 ft, localized grading, and the installation of temporary surfacing where required.

1.14.4. A downstream staging, laydown, and water management area will be cleared near the dam toe to allow equipment mobilization and temporary material storage.

1.15. Upstream Access

1.15.1. A secondary access route exists near the upstream extent of the former reservoir area.

This route is 715 ft long and will allow construction equipment to access the reservoir footprint following initial reservoir drawdown.

1.15.2. A temporary stream crossing will be required. Provide and install temporary ACB mats designed for vehicular loadings equal to or greater than the heaviest project construction equipment. Mats shall be installed on exposed rock with a geotextile underlayment and shall be fully removable. Installation, anchoring, maintenance, and removal shall conform to the manufacturer’s recommendations. The Contractor shall prevent displacement of the mats during use and shall remove all mats, anchoring hardware, geotextile, and associated materials at the end of construction. The crossing area shall be restored to pre-construction condition upon removal.

1.16. Construction Access Strategy

1.16.1. Because of the steep abutments and narrow crest width, equipment will not operate directly on the dam crest during demolition. Instead, construction access will rely on a combination of:

1.16.1.1. Downstream access and staging area for dam demolition operations.

1.16.1.2. Upstream access along the former reservoir floor for channel restoration work.

1.16.1.3. Temporary access along the channel corridor following initial drawdown.

1.16.1.4. Following reservoir drawdown and partial sediment consolidation, construction equipment will enter the reservoir footprint from the upstream access route and progress downstream during channel construction. This approach minimizes disturbance to unstable sediment near the dam and allows channel restoration work to proceed toward the breach location.

1.17. Laydown Areas

Three Laydown areas are identified for material staging, equipment, and other construction needs.

Payment for clearing, grubbing, and handling is incidental to Bid Item A2 Clearing, grubbing, tree removal / salvage handling. Clearing and Grubbing will be required at these sites. The area is approximately .5 acres in total size between the three locations. The upstream location is approximately .12 acres, downstream is approximately .26 acres and the area located near the equipment sheds is approximately .12 acres. Cleared woody debris shall be stockpiled and reused within the reservoir as stream restoration features. Note, in some cases root wads will be required to be salvaged and reused.

1.18. General Material Handling, Salvage, Reuse and Disposal

1.18.1. General

1.18.1.1. The Contractor shall handle, sort, salvage, reuse, stockpile, remove, and dispose of materials generated by the work in accordance with this section and the specific requirements of the applicable work sections.

1.18.1.2. Materials generated by the work may include, but are not limited to, concrete, stone, soil, sediment, rock, woody material, brush, slash, pipe, metal, abandoned utility materials, trash, debris, and unsuitable material.

1.18.1.3. Materials suitable for approved reuse on site shall be salvaged and reused to the maximum extent practical where shown on the drawings specified herein, or approved by the COR. Materials not suitable or not approved for reuse shall be legally disposed of offsite unless otherwise approved by the COR.

1.18.2. Contractor Responsibility

1.18.2.1. The Contractor shall be responsible for all handling, loading, hauling, temporary stockpiling, sorting, processing, reuse, and disposal of materials generated by the work.

The Contractor shall conduct all material handling and disposal activities in accordance with applicable federal, state, and local laws and regulations; permit conditions; project drawings; erosion-control requirements; and directions from the COR. The Contractor shall not bury, dump, spread, burn, abandon, or otherwise dispose of material on National

Forest System lands unless specifically allowed by the specifications, shown on the drawings, or approved by the COR.

1.18.3. Salvage and Reuse Priority

1.18.3.1. The preferred order of material handling shall be:

1.18.3.2. Salvage and reuse suitable material in the work

1.18.3.3. Stockpile suitable material for later approved use

1.18.4. Use suitable excess material on site for approved restoration, stabilization, access-road restoration, grading, slope roughening, or closure feature

1.18.5. Recycle material off site where practical and lawful

1.18.6. Legally dispose of unsuitable or excess material off site

1.18.7. The contractor shall not dispose of, chip, crush, bury, or otherwise discard material suitable for reuse until the material has been reviewed and approved for disposal by the COR

1.18.8. On Site Reuse

1.18.8.1. Reuse of suitable woody material for stream restoration, racking material, toe roughness, slope roughening, access-road restoration, or habitat features

1.18.8.2. Reuse of approved broken concrete in designated downstream work platform fill areas, shall be free of rebar and crushed into pieces not larger than 12” with a minimum of

18” of cover.

1.18.8.3. Incidental to Bid Item A3 Temporary access improvements, crossings, mats, and work pads.

1.18.8.4. Reuse of suitable excavated soil, rock, or stone for backfill, grading, stabilization, or restoration

1.18.8.4.1. Reuse of excess brush or slash for approved upland restoration or closure features

1.18.8.4.2. Use of non-erodible material for backfilling removed structures, abandoned utilities, or scour areas

1.18.9. Unsuitable Material

1.18.9.1. Unsuitable material shall be separated from salvageable or reusable material and handled as directed by the COR. Unsuitable material includes, but is not limited to:

1.18.9.2. Trash, garbage, and construction debris

1.18.9.3. Treated lumber, pallets, dimensional lumber, and manufactured wood products

1.18.9.4. Concrete containing rebar, wire mesh, metal, asphalt, trash, petroleum contamination, or other deleterious material unless cleaned and approved for reuse

1.18.9.5. Pipe, valves, fittings, wire, cable, metal, and abandoned utility materials not approved for reuse

1.18.9.6. Petroleum-contaminated material or material with evidence of chemical contamination

1.18.9.7. Excessively organic material, muck, roots, stumps, duff, and vegetation not approved for restoration reuse

1.18.9.8. Material containing invasive species where spreading is a concern

1.18.9.9. Rotten, unstable, or decomposed material unsuitable for the intended use

1.18.9.10. Other material determined unsuitable by the COR.

1.18.10. Unsuitable material shall not be incorporated into structural fill, channel backfill, embankments, access-road fills, concrete reuse areas, or restoration features unless specifically approved by the COR for that use.

1.18.11. Temporary stockpiles shall be located only in approved laydown areas. Stockpiles shall be placed, shaped, and maintained to prevent erosion, sediment discharge, slope instability, obstruction of drainage, damage to vegetation outside the limits of disturbance, and interference with construction sequencing or access. Stockpiles shall not be placed in flowing water, wetlands, ponded areas, active drainageways, constructed stream channels, bypass channels, or locations where material may be mobilized by storm flow unless specifically approved by the COR. The Contractor shall segregate stockpiles by material type where necessary to preserve salvage value and prevent contamination of reusable material.

Stockpiled reusable material shall be protected from contamination by trash, unsuitable material, sediment, fuel, oil, or other deleterious substances.

1.18.12. Off Site Disposal

1.18.12.1. Material not reused on site or not approved for on-site placement shall be removed from the project area and legally disposed of at an approved off-site disposal, recycling, or processing facility.

1.18.12.2. The Contractor shall be responsible for all loading, hauling, disposal, recycling, tipping fees, permits, approvals, and documentation required for off-site disposal.

1.18.12.3. Upon request, the Contractor shall provide the COR with documentation identifying the disposal or recycling facility used for off-site disposal.

1.18.12.4. Off-site disposal shall comply with applicable federal, state, and local requirements.

1.18.13. Burning

1.18.13.1. Burning of cleared material, woody debris, slash, or other waste material shall not be permitted unless specifically authorized in writing by the COR.

1.18.13.2. If burning is authorized, it shall be conducted in accordance with applicable federal, state, local, and Forest Service requirements, including fire restrictions, permits, smoke-management requirements, and any required burn plan.

1.18.14. Protection of Waters and Drainageways

1.18.14.1. The Contractor shall conduct material handling, stockpiling, reuse, and disposal activities in a manner that prevents material from entering streams, wetlands, ponded areas, bypass channels, drainageways, or other waters unless specifically authorized as part of the work.

1.18.14.2. The Contractor shall immediately remove any unauthorized material that enters flowing water, wetlands, drainageways, or areas outside approved limits, unless removal would cause greater disturbance and the COR directs otherwise.

1.18.15. Correction of Unauthorized Disposal or Placement

1.18.15.1. Material placed, buried, dumped, spread, or disposed of outside approved limits or in a manner inconsistent with the specifications shall be removed, relocated, or corrected by the Contractor at no additional cost to the Government.

1.18.15.2. Unauthorized disposal of suitable material designated or suitable for reuse may require replacement with equivalent material at no additional cost to the Government.

1.18.16. Measurement and payment

1.18.16.1. Material handling, sorting, salvage, temporary stockpiling, on-site reuse, loading, hauling, recycling, disposal, tipping fees, documentation, and cleanup shall be incidental to the applicable Bid Items that generate the material.

1.18.16.2. No separate payment will be made for unauthorized disposal, rehandling caused by improper sorting or stockpiling, correction of improperly placed material, replacement of reusable material disposed of without approval, or removal of material placed outside approved limit.

2. Site Preparation and Earthwork

2.1. Clearing, Grubbing, Salvage, and On-Site Use of Woody Material

2.1.1. Contractor is responsible for all survey, layout and staking prior to any clearing or earthwork, incidental to Bid Item A5 Survey, layout, staking, as-builts.

2.1.2. The Contractor shall clear and grub the areas shown on the drawings or designated by the

COR. Clearing and grubbing shall include removal of trees, saplings, brush, stumps, roots, downed woody material, surface vegetation, and other organic material necessary to complete the work.

2.1.3. Clearing and grubbing shall be limited to the minimum area necessary for access, staging, dam removal, channel construction, sediment handling, bypass installation, and restoration work. No clearing shall occur outside the approved limits without written authorization from the COR.

2.1.4. Before clearing begins, the Contractor shall meet with the COR to review:

2.1.4.1. Clearing limits

2.1.4.2. Trees to be protected

2.1.4.3. Trees and woody material to be salvaged

2.1.4.4. Stockpile locations

2.1.4.5. Access routes

2.1.4.6. Disposal and on-site reuse methods

2.1.4.7. Areas where grubbing is required

2.1.4.8. Areas where cutting flush is acceptable.

2.1.4.9. The Contractor shall mark the limits of disturbance prior to clearing. Trees and vegetation outside the approved disturbance limits shall be protected from unnecessary damage.

2.1.5. Salvageable Woody Material

2.1.5.1. The Contractor shall salvage woody material suitable for use in the restoration work.

Salvaged material may include whole trees, logs, root wads, trunks, limbs, crowns, brush, slash, and other woody material generated from clearing and grubbing.

2.1.6. Key Large Wood

2.1.6.1. Key large wood pieces shall generally consist of sound whole trees, trunks, or logs suitable for use as structural or semi-structural restoration elements within the optional cross valley log jams and wood deflectors.

2.1.6.2. Key large wood should generally meet the following criteria:

2.1.6.2.1. Minimum approximate diameter: 10 inches

2.1.6.2.2. Preferred diameter: 12 inches or greater

2.1.6.2.3. Minimum length: 12 feet

2.1.6.2.4. Preferred length: 15 to 30 feet, or as long as can be safely handled and placed

2.1.6.2.5. Wads preferred where available

2.1.6.2.6. Forks, irregular trunks, crowns, and attached limbs preferred over clean, straight sawlogs.

2.1.6.2.7. Key large wood shall be stockpiled separately from brush, slash, and unsuitable material.

2.1.7. Root wads

2.1.7.1. Root wads shall be salvaged where practical. Root wads with attached trunk sections are preferred. Root wads shall be handled in a manner that preserves the root mass and attached woody structure to the extent practical.

2.1.7.2. Root wads containing excessive soil, rock, trash, metal, or other unsuitable material may be rejected or directed to be cleaned, trimmed, or used only in approved upland locations.

2.1.8. Racking Material

2.1.8.1. Racking material shall include smaller logs, limbs, tops, crowns, and irregular woody material suitable for placement around larger wood features.

2.1.8.2. Racking material may include:

2.1.8.3. Limbs generally 2 inches diameter and larger

2.1.8.4. Tree tops and crowns

2.1.8.5. Small logs

2.1.8.6. Forked or irregular branches

2.1.8.7. Shorter wood pieces that are not large enough to function as key large wood.

2.1.8.8. Racking material shall be reasonably clean and free of excessive soil, trash, and construction debris.

2.1.8.9. Brush and Slash

2.1.9. Brush and slash may be used for:

2.1.9.1. Toe roughness

2.1.9.2. Void filling around larger wood

2.1.9.3. Material

2.1.9.4. Brush packing

2.1.9.5. Temporary sediment and erosion control

2.1.9.6. Slope roughening

2.1.9.7. Access-road restoration

2.1.9.8. Habitat complexity

2.1.9.9. Other approved restoration uses.

2.1.10. Brush and slash shall not be substituted for required key large wood unless approved by the COR.

2.1.11. Material to Be Retained

2.1.11.1. Unless otherwise directed by the COR, the Contractor shall retain the following material generated within the clearing and grubbing limits:

2.1.11.2. All sound trees 10 inches diameter and larger suitable for restoration use

2.1.11.3. All salvageable root wads

2.1.11.4. All sound logs 8 inches diameter and larger and at least 8 feet long

2.1.11.5. Tree crowns and limbs suitable for racking material

2.1.11.6. Brush and slash suitable for toe packing, bank roughness, erosion control, slope roughening, or restoration features

2.1.11.7. Naturally downed woody material within the disturbance area if sound and usable.

2.1.11.8. The Contractor shall not chip, burn, remove from site, bury, or otherwise dispose of woody material suitable for restoration until the material has been reviewed and approved for disposal or reuse by the COR.

2.2. Insufficient Woody Material

2.2.1. The Government anticipates that woody material generated from clearing and grubbing will be used as the primary source of large wood, root wads, racking material, brush, and slash for the restoration work.

2.2.2. If sufficient suitable woody material is not generated from the approved clearing and grubbing limits, the Contractor shall notify the COR before importing, substituting, disposing of, or omitting woody material.

2.2.3. In the event of insufficient woody material, the Government will identify and provide additional tree locations within or near the project area for use in the work. The Contractor shall not cut trees outside the approved clearing limits unless the additional tree locations have been designated and approved by the COR.

2.2.4. Additional trees designated by the Government shall be cut, salvaged, handled, stockpiled, and incorporated into the work in accordance with this specification.

2.2.5. Stockpiling Requirements

2.2.5.1. Salvaged wood shall be stockpiled in approved locations within the project limits.

Stockpiles shall be separated by material type as follows:

2.2.5.1.1. Large wood / key pieces

2.2.5.1.2. Root wads

2.2.5.1.3. Racking material

2.2.5.1.4. Brush and slash

2.2.6. Unsuitable organic debris

2.2.6.1. Stockpiles shall not be placed in flowing water, wetlands, active drainageways, ponded areas, or locations where material may be mobilized by storm flow. Stockpiles shall not block access roads, bypass routes, sediment-control features, construction sequencing, or emergency access.

2.2.6.2. The Contractor shall handle salvaged wood in a manner that preserves root wads, limbs, crowns, and irregular features to the extent practical.

2.3. On-Site Use of Excess Material

2.3.1. Woody material not needed for direct placement within the constructed channel or restoration features shall be reused on site to the maximum extent practical, as approved by the COR. On-site use shall not create drainage obstructions, unstable piles, floatable debris hazards, public safety hazards, or conditions that may cause material to enter the active channel during storm events. Woody material used outside the constructed channel shall be placed above ordinary high water unless otherwise approved. Material shall be spread, arranged, keyed, or stabilized as necessary to prevent mobilization.

2.3.2. Excess brush, slash, stumps, roots, and non-structural wood may be used on site for:

2.3.2.1. Slope roughening

2.3.2.2. Erosion control

2.3.2.3. Access-road decommissioning

2.3.2.4. Habitat piles above ordinary high water

2.3.2.5. Mulch or scattered slash outside constructed channel areas

2.3.2.6. Filling voids in restoration areas where approved

2.3.2.7. Restoration of disturbed upland areas

2.4. Unsuitable Material

2.4.1. The following material shall not be used as restoration woody debris:

2.4.1.1. Rotten or punky wood that breaks apart during handling

2.4.1.2. Excessively small twigs, leaves, duff, and loose forest litter

2.4.1.3. Stumps or root masses containing excessive soil, rock, trash, wire, metal, or construction debris

2.4.1.4. Wood containing nails, hardware, fencing, wire, cable, or other embedded metal

2.4.1.5. Invasive species material where spreading is a concern

2.4.1.6. Other deleterious material determined unsuitable by the COR.

2.4.2. Payment shall be incidental to Bid Item A2 Clearing, grubbing, tree removal / salvage handling.

2.5. Disposal and Final Handling of Remaining Material

2.5.1. The preferred method of disposal for excess cleared and grubbed material is beneficial on-site use. The Contractor shall use excess woody material on site where practical and where approved by the COR.

2.5.2. Material not incorporated into stream restoration features may be used on site for slope roughening, erosion control, access-road restoration, habitat piles, scattering in upland disturbed areas, or other approved uses.

2.5.3. Material shall not be placed in the constructed stream channel, bypass channel, wetlands, ponded areas, concentrated drainageways, or areas where it may be transported downstream unless specifically approved as part of a restoration feature.

2.5.4. Organic material, stumps, roots, slash, brush, topsoil, and other deleterious material shall not be buried in structural fill, channel embankments, access-road fills, dam breach backfill, or other constructed features unless specifically shown on the drawings or approved for habitat or restoration use.

2.5.5. If material cannot be reused on site and is not suitable for approved restoration, erosion-control, or upland placement, the Contractor shall notify the COR for direction. Off-site disposal shall not occur unless approved by the COR.

2.6. Protection of Salvaged Material

2.6.1. Woody material generated from clearing and grubbing is considered Government-furnished project material intended for beneficial reuse in the restoration work.

2.6.2. The Contractor shall not remove, chip, burn, bury, or dispose of suitable woody material without prior approval. Suitable material shall be segregated, protected, and made available for incorporation into the work.

2.6.3. Disposal of suitable woody material without approval may require replacement with equivalent material at no additional cost to the Government.

2.6.4. Measurement and Payment

2.6.4.1. Payment for clearing, grubbing, salvage, stockpiling, on-site use, and handling of woody material shall be made under the applicable bid item A2. Installation of Woody Debris

Features are incidental to E3-Option Cross-valley log jams and E4-Option Wood Deflector as applicable.

2.7. Demolition

2.7.1. Dam Demolition and Temporary Working Platforms

2.7.1.1. Concrete demolition within the base 30-foot breach shall be paid under Bid Item C1 Base breach demolition and formation (first 30 LF), Dam Demolition – Base Breach (30 LF).

Concrete haul and disposal should be paid under Bid Items C2 Concrete / masonry haul (off site and C3 Concrete / masonry disposal fee (off site. Temporary working platforms and construction mats should be incidental to Bid Item A3 Temporary access improvements, crossings, mats, and work pads.

2.7.2. Limits of Demolition

2.7.2.1. Concrete demolition shall be limited to the breach opening and other areas identified in the plans. Base bid breach opening shall be 30 feet wide with additional wider options.

2.7.2.2. The Contractor shall remove the concrete dam structure within the breach limits down to the channel invert elevation shown on the drawings. Concrete foundation elements keyed into bedrock may remain in place where removal would require excessive excavation into rock or where removal is not necessary for channel construction.

2.7.3. Demolition Methods

2.7.3.1. Concrete demolition shall be performed using controlled mechanical methods. Acceptable methods include drilling, hydraulic hammer attachments, hoe-ram breakers, saw cutting, or other mechanical demolition equipment.

2.7.3.2. Blasting shall not be permitted unless specifically approved in writing by the COR.

2.7.3.3. The Contractor shall conduct demolition in a controlled manner to avoid overbreak beyond the limits shown on the drawings.

2.8. Concrete Handling and Disposal

2.8.1. General

2.8.1.1. Broken concrete generated from demolition shall be handled, loaded, transported, and disposed of in accordance with this section. Concrete shall not be buried, placed, stockpiled, crushed, or reused on site except in locations and configurations approved by the COR.

2.8.1.2. Concrete crushing on site is not permitted unless specifically authorized in writing by the

COR.

2.8.2. Off-Site Disposal

2.8.2.1. Broken concrete not approved for on-site reuse shall be loaded, transported off site, and legally disposed of at an approved disposal or recycling facility.

2.8.2.2. Concrete transported off site shall become the Contractor’s responsibility and shall be disposed of in accordance with all applicable federal, state, and local requirements.

2.8.3. Placement, Void Filling, and Cover

2.8.3.1. Stone used on site for temporary work pads shall be covered with a minimum of 18 inches of suitable backfill material in areas intended for final soil cover and vegetation, unless otherwise shown on the drawings or directed by the COR.

2.8.3.2. Backfill material shall be soil or other approved material capable of supporting final grading, stabilization, and vegetation. Backfill shall be placed and graded to blend with adjacent ground and prevent ponding, erosion, or exposure of concrete.

2.9. Riprap, Armoring, and Scour Protection

2.9.1. Riprap or armoring shall be provided at a minimum at the upstream face, downstream face, toe areas, channel tie-ins, and other locations shown on the drawings or directed by the COR where concentrated flow, seepage, or future scour could occur.

2.9.2. Riprap shall be embedded, keyed, and graded to provide a stable transition to adjacent ground.

Soil cover and vegetation may be placed over buried armoring where approved, provided the final surface is stable and not subject to active concentrated flow.

2.9.3. Concrete rubble shall not be used as exposed riprap or final channel armor unless specifically approved by the COR.

2.10. Final Grading and Restoration

2.10.1. The completed on-site reuse area shall be graded to drain and to prevent concentrated flow from cutting through or around the fill. Final grades shall blend with adjacent ground and shall not create unstable slopes, ponding, or preferential flow paths.

2.10.2. The completed area shall be stabilized and vegetated at the end of construction in accordance with the project restoration, erosion-control, and seeding requirements.

2.10.3. Areas subject to concentrated flow or scour shall receive riprap, erosion-control matting, or other approved stabilization in addition to seeding.

2.11. Payment

2.11.1. Off-site hauling, handling, transportation, disposal, recycling, tipping fees, and all other costs associated with concrete shall be incidental to Bid Items C2 Concrete / masonry haul (off site and C3 Concrete / masonry disposal fee (off site, as applicable.

2.12. Temporary Working Platforms

2.12.1. The downstream work platform area is estimated to need 200 CY of fill. Reused concrete may be applied to this location if approved by COR and in accordance with 1.18.8.2 above

2.12.2. General

2.12.2.1. Where sediment conditions limit equipment stability, the Contractor may utilize temporary working platforms including timber construction mats, laminated crane mats, or composite construction mats.

2.12.3. Construction Mat Requirements:

2.12.3.1. Construction mats shall be of sufficient size and thickness to distribute equipment loads and reduce settlement within saturated reservoir sediments.

2.12.3.2. Typical mat dimensions shall be approximately 8 feet wide by 14 to 20 feet long with a minimum thickness of 6 to 8 inches, or equivalent composite mat systems capable of supporting tracked excavators.

2.12.4. Temporary Working Platforms consisting of stone fill, articulated concrete mats or wooden construction mats will be incidental to A3 Temporary access improvements, crossings, mats, and work pads.

2.12.5. Installation and Use

2.12.5.1. Mats may be installed to create temporary working surfaces allowing excavation equipment to extend reach into the reservoir footprint for channel excavation and sediment placement.

2.12.5.2. Mats shall be advanced progressively as excavation proceeds and shall be installed in a manner that minimizes disturbance of reservoir sediments.

2.12.5.3. All temporary mats and working platforms shall be removed upon completion of channel excavation unless otherwise approved by the COR. Areas disturbed during mat placement or removal shall be graded and stabilized in accordance with the vegetation establishment specifications.

2.13. Temporary Access Road

2.13.1. Temporary construction access roads shall be constructed beginning at the downstream access point and continuing to the downstream outlet of the dam. From the downstream outlet, the access road shall extend upstream to the reservoir. The roads shall be designed and constructed to support dump trucks, excavators, and all associated construction equipment required for the project.

2.13.2. Previous access roads exist on both the upstream and downstream sides of the dam.

These existing road alignments may be used where feasible; however, they shall be improved, regraded, or reconstructed as necessary to meet the required load bearing capacity and width for construction access.

2.13.3. Install drainage features and erosion control measures to prevent rutting and runoff related erosion. Maintain all access roads in a serviceable condition for the duration of the work.

2.13.4. Payment should be incidental to Bid Item A3 Temporary access improvements, crossings, mats, and work pads.

2.14. Downstream Laydown and Staging Area

2.14.1. A downstream laydown area shall be established to support equipment staging, truck turnaround, concrete handling, material storage, and water management facilities. The pad shall be cleared, graded, and stabilized.

2.14.2. Measured for payment under Bid Item A3, Temporary access improvements, crossings, mats, and work pads.

2.15. Reservoir Sediment Excavation and Grading

2.15.1. Reservoir channel excavation should be measured under Bid Item D1, Reservoir Channel Excavation to profile.

2.15.2. Sediment grading and redistribution shall occur within the drained reservoir footprint. Sediment shall remain on site unless otherwise directed. Material shall be placed outside the active restored channel corridor and graded to stable slopes.

2.15.3. Do not stockpile material in standing water or active flow.

2.15.4. Where practicable, allow sediments to drain and dry prior to rehandling.

2.15.5. Final side slopes shall be stable and blend with the restored corridor.

2.16. Pilot channel Excavation in Saturated Sediment

2.16.1. Where saturated reservoir sediment conditions prevent conventional broad excavation, the Contractor may excavate a pilot channel or pilot trench to initiate drainage, define alignment, and improve sediment consolidation. Equipment operations shall proceed from stable ground or previously improved work surfaces.

2.16.2. Pilot channel excavation should be incidental to Bid Item D1, Reservoir Channel Excavation to profile.

3. Reservoir Dewatering and Temporary Flow Control

3.1. Controlled Reservoir Drawdown

3.1.1. A detailed dewatering plan with all drawings and calculations will be provided to the COR for approval at least 15 days prior to the start of construction.

3.1.2. Reservoir drawdown shall occur in controlled increments of approximately 1–2 feet, with stabilization periods between stages. The Contractor shall monitor slopes, exposed sediment surfaces, and downstream turbidity during drawdown.

3.1.3. Do not proceed to the next drawdown stage if unstable sediment behavior or unacceptable turbidity is observed. Acceptable levels are listed in 8.2 below.

3.1.4. Route drawdown discharge to a stabilized discharge location.

3.1.5. Maintain records of drawdown stages and observations.

3.1.6. Payment for drawdown is incidental to Bid Item B1 Reservoir drawdown System.

3.2. Temporary Flow Bypass

3.2.1. Temporary 24-Inch Bypass with upstream weir, intake stabilization, outlet stabilization, and bypass protection should be incidental to Bid Item B2 Upstream temporary weir and 24-inch bypass .