Revised_Attachment_2_Specifications.docx

Swannanoa Creek Stream Enhancement Project 2019 – Specifications

APPENDIX A – STREAM RESTORATION SPECIFICATIONS

EQUIPMENT AND OPERATOR SPECIFICATIONS

A) Manner of Construction - Excavation will be done in a manner which will minimize sedimentation in the stream channel. Silt fence will be installed downstream of the construction area to reduce the risk of sediment entering the stream.

B) Equipment Operator Performance - Equipment operators shall be experienced and competent in the use of the equipment to which they are assigned. They shall be expected to demonstrate a level of proficiency with the equipment which enables them to be productive in all aspects of stream restoration work. Equipment operators shall be experienced in the construction of Rosgen designed structures; including the cross vane, J-hook vane, and Toe-wood/Sod mat.

Operators will be instructed by the construction inspector as to the desired result of construction activities. Operators will be responsible for determining how best to use equipment to achieve the desired results. Chain saw operators will be required to cut trees, limbs and root masses as necessary to facilitate the removal and placement of debris in the stream.

C) Environmental Considerations - Earth moving equipment will cross and operate in the stream flow only when necessary and only when directed to do so by the construction inspector. Equipment shall be new or of low hours and be maintained to prevent fuel, oil and lubricant spills in the vicinity of the stream. Refueling, repairs and lubrication will be performed at a safe distances from the stream and only at locations approved by the construction inspector where water is controlled by runoff control measures.

D) Safety Considerations - At work sites, where equipment will be operated on Forest Roads, flagman shall be stationed to warn oncoming traffic of congestion. Construction road signs shall be in place and a means of removing sediment, mud or rocks from roadways shall be established. The contractor will be responsible for the implementation of these measures.

E) Equipment Specifications Hydraulic Excavator:

Track mounted, hydraulic powered.

Excavator:

· Min weight – 27,000 lbs

· Min. Reach – 22 feet

· Min Digging Depth – 20 feet

· Min Bucket size – 1.0 Cu Yd.

· Min 115 HP

· Equipped with hydraulic thumb (More than 1 excavator may be required. Unit price bid should be for one excavator for one hour of running time with experienced operator as described above).

Dump – Track Truck:

· Track mounted

· Min. weight – 8,000 lbs

· Min. carrying capacity – 7,000 lbs (Unit price bid should be for one truck for one hour of running time and experienced operator).

IN-STREAM STRUCTURES SPECIFICATIONS

Structure Stone Description The work covered by this section consists of furnishing, stockpiling, placing and maintaining approved stone to be utilized to construct rock and log vanes, root wad structures, the step-pool structures, stream crossings, sediment and erosion control measures for use in locations as directed by the Designer. The quantity of stone may be increased, decreased, or eliminated entirely at the direction of the Designer. Such variations in quantity will not be considered as alterations in the details of construction or a change in the character of the work.

Materials Stone for "Boulder" shall consist of blasted stone or other stone approved by the Designer. The stone shall be sound, tough, dense, resistant to the action of air and water, and suitable in all other respects for the purpose intended.

All stone shall meet the approval of the Designer. While no specific gradation is required, the various sizes of the stone shall be equally distributed within the required size range. The size of an individual stone particle will be determined by measuring its long dimension.

Acceptance Criteria for Stone

CLASS

CLASS

REQUIRED STONE SIZES (INCHES)

Minimum

Average

Maximum

Boulder 48" x 24" x 24"

No more than 5 percent of the material furnished can be less than the minimum size specified, more than 10 percent of the material can exceed the maximum size specified. Boulders shall be relatively flat on either side in the same dimension, preferably the long dimension.

Construction The Contractor shall place stone, in locations shown on the construction plans to the thickness, widths, and lengths as shown on the construction plans or directed by the Designer. All stone shall be placed neatly and uniformly with an even surface to form an in-stream structure or a sediment and erosion control device or in accordance with the construction plans and special provisions, and shall meet the approval of the Designer.

Method of Measurement The quantity of stone required to construct the structures or sediment and erosion control measures detailed in these special provisions will be incidental to those bid items. However, field conditions may warrant the need for additional stone greater than the quantity specified or detailed for each bid item. The quantity of stone that has been incorporated into the project, as directed or approved by the Designer, which exceeds 110% of the quantity required for each bid item will be measured by weight. Measured by weight will require the quantity to be weighed in trucks on certified platform scales. Stone that was previously stockpiled for other bid items will not be measured a second time for this provision.

Basis of Payment When field conditions dictate the need for additional quantity greater than 10% of the bid item, the quantity of stone measured as provided above, will be paid for at the contract unit price per ton for "Misc. Boulder". Such price and payment will be full compensation for all work covered by this section, including but not limited to furnishing, weighing, stockpiling, re-handling, placing, and maintaining the stone and disposal of any materials not incorporated into the project if directed by the Designer.

Payment will be made under:

Boulder...............................................................................................................................................TON Boulder J-hook & Cross Vane Description Boulder/rock J-hook and Cross Vanes are primarily used for grade control. These structures serve to maintain the integrity of the upstream riffle while promoting scouring in the downstream pool. The design shape is roughly that of the letter "J" or “U” with the apex located on the upstream side at the foot of the riffle. Footer boulders are placed in the channel bottom for stability. Header boulders are then placed on top of these footer boulders. Header boulders in the middle of the channel are at approximately the same depth as the riffle. For the J-hook, on one side of the channel, wing boulders are placed at an angle to the stream bank, gradually inclining in elevation until they are located near the bankfull surface directly adjacent to the stream bank. On the other side, the structure turns downstream to create the hook of the “J”, matching the slope of the wing until it goes directly toward the bank as a sill. Water flowing downstream is forced over these boulders towards the middle and opposite side of the channel, effectively turning flow and scouring out a pool below. Boulders placed at the apex hold back streambed material and prevent it from washing downstream.

The quantity of Rock J-hook Vanes may be increased, decreased, or eliminated entirely at the direction of the Designer. Such variations in quantity will not be considered as alterations in the details of construction or a change in the character of the work (See Rock J-hook Vane detail below).

Materials All materials shall meet the requirements of boulder as outlined in Special Provision "Structure Stone". Back fill material shall be obtained from the stream channel bed, likely from the constructed pool. Large woody debris may be incorporated into the structure as directed by the Designer.

Installation A trench shall be dug in such a manner that the footer boulders, the hook header boulders and at least 1/3 of the wing boulders are buried beneath the bed surface elevation. Refer to the construction plans for exact installation guide and locations of vane to be installed. An excavator, with a bucket that includes a hydraulic thumb, shall be used to place boulders under the supervision of Designer. Footer boulders shall be placed first with header boulders placed on top prior to any back filling of the trench. Boulders shall be selected and positioned such that they butt tightly together and there are multiple contact points between all boulders (flat smooth surfaces that fit together). Gaps between boulders shall be filled (chinked) with a combination of class A and No. 57 size stone found on site until plugged. In the center portion of the channel (vane invert), the header boulder shall be placed with gaps between the rock with the top of the header boulder at an elevation designated by the Designer. The header boulders in the side, or wing, portion shall be placed in such a manner as they slope up from bed elevation to bankfull or below at a 2 to 7 percent slope or as shown in detail. Header and footer boulders at both banks shall be tied in securely to the bank in such a way that eliminates the possibility of water diverting around them. A rock sill shall be utilized to further prevent water from cutting around the structure. The area between the stream bank and vane on the upstream side of the structure will be backfilled with stream bed material.

Structures shall be built to the approval of the Designer. The Designer may adjust the number and placement of structures in the field.

Basis of Payment Payment for installation of Rock J-hook Vane shall be as outlined. This payment shall be considered full compensation for all labor, equipment, hauling, placing, handling, sorting, fitting, materials, and incidentals necessary to construct the rock vane.

Payment will be made under:

Equipment & Labor……………………………………..…….…………………………..………..……..HOURS Materials: Boulders………………………………………………………………………………….……..TON

Log Vane

Description This structure serves to decrease stress in the near-bank region while promoting scouring in the downstream pool. Logs are placed at an angle to the stream bank, gradually inclining in elevation until they are located near ½ bankfull elevation directly adjacent to the stream bank. Water flowing downstream is forced over these logs towards the middle of the channel, effectively scouring out a pool below. The quantity of log vanes may be increased, decreased, or eliminated entirely at the direction of the designer. Such variations in quantity will not be considered as alterations in the details of construction or a change in the character of the work.

Materials Trees to be used for the vane shall be provided by the Forest Service from near the site. All log materials shall be at least 10 inches in diameter. A sheet of non woven geotextile fabric (4oz. or greater) shall be placed the length of the vane arm on the upstream side, stapled to the top log in a manner that they will be covered by back fill material. Back fill material shall be obtained from the stream channel bed.

Installation A trench shall be dug in such a manner that the footer and header logs are buried beneath the bed surface elevation at least three feet. An excavator, with a bucket that includes a hydraulic thumb, shall be used to place logs under the supervision of Designer. Logs shall be tightly sealed with no gaps between the header and footer log. Filter fabric shall be placed on the upstream side of the structure and backfilled with materials excavated on-site to prevent the washout of sediment through log gaps. Filter fabric shall extend from the bottom of footer log to the finished grade elevation and shall be placed the entire length of the structure. Header and footer logs shall be tied in securely to the bank in such a way that eliminates the possibility of water diverting around them. Structures shall be built to the approval of the Designer. The Designer may adjust the number and placement of structures in the field.

Basis of Payment This payment shall be considered full compensation for all labor, equipment, hauling, placing, handling, sorting, fitting, materials, and incidentals necessary to construct the Log Vane. Trees to be used for the vane shall be provided by the Forest Service.

Payment will be made under:

Equipment & Labor………………………………………………………………………..….…..HOURS Materials:

Non woven geotextile fabric……………………………..……….……………....LINEAR FOOT

Toe-wood/Sod-mat Revetment (bankfull bench) Description This structure serves to protect a length of stream bank by biulding a new bank with a bankfull area where one did not exist before due to unstable conditions (See Toe-wood/Sod mat detail below). The structure creates a large undercut bank providing an abundance of aquatic cover type habitat.

Materials Trees and brush to be used for the structure shall be provided by the Forest Service from near the site. Shrubs and willow shall be provided by the Forest Service from near the site. Seed, mulch and coir matting shall be provided and installed by the contractor.

Installation The channel shall be excavated to build a bench on the channel bottom on the outside of the meander bend. Its elevation shall be well below determined low water elevation. A deep pool shall be constructed where the new thalweg will be located, and excavated material shall be used to build the point bar and back fill the structure. Footer logs laying parrallel to the stream channel shall be placed on the bench, then the toe-wood on top of that. Toe-wood shall consist of a mixture of sizes, but include several large tree stems with root wads attached. Stems shall be pushed into the bank were possible. Trees, brush, and limbs shall all be used to fill this area with woody debris, and be placed up to the low flow elevation. Bundles of live stakes, e.g. willow, shall be placed on top of the woody debris and alluvial backfill shall be placed on the structure (amount determined by Designer). Shrubs, excavated from nearby, shall be placed on top of the toe-wood up to the bankfull elevation. This shrub mat will replace the “sod mat”. From the bankfull elevation the verticle slope shall be excavated to the 2:1 slope (run to rise). Excavated soil material shall be scattered on the adjacent terrace. All slopes shall have seed, mulch, and coir matting installed.

Basis of Payment This payment shall be considered full compensation for all labor, equipment, hauling, placing, handling, sorting, fitting, materials, and incidentals necessary to construct the bankfull bench. Trees to be used for the structure shall be provided by the Forest Service.

Payment will be made under:

Equipment & Labor…………………………………………………………………………..….…..HOURS Materials:

EROSION CONTROL SPECIFICATIONS

Seed (Native)

Description Seeding shall occur within 24 hours of ground disturbing activities. Seed shall be applied by hand or with a cyclone seeder and on steep slopes be immediately covered lightly (~60%) with leaf litter as a mulch, raked in from the surrounding area. On stream banks, biodegradable Coir-700 matting shall be placed to keep seed and soil in place. Below are native grass species to be sown and their seeding density of pure live seed.

Community Type: Riparian

Materials All materials shall meet the approval of the Designer.

Basis of Payment Payment for installation of seed and mulch will be paid for as outlined. This payment shall be considered full compensation for all labor, equipment, furnishing materials, hauling, rehandling, sorting, materials, and incidentals necessary to seed and mulch.

Payment will be made under:

Seed ………………..……………………………………………………………….………..………………..ACRE

Matting

Materials All materials shall meet the approval of the Designer and include Coir fiber mat 700 and hardwood stakes.

Installation Coir fiber mat 700 shall be used on upper and lower stream banks (above and below the bankfull elevation). The matting shall be fastened in place using hardwood stakes. Provide stakes made of hardwood to anchor the matting. Stakes shall be installed to no less than 1 foot deep for use on side slopes and along the top edge of matting.

Place the matting upon final grading, following seed and mulch application. Provide a smooth soil surface free from stones, clods, or debris which will prevent the contact of the matting with the soil. Unroll the matting on the contour, starting at the bottom of the slope and apply without stretching such that it will lie smoothly but loosely on the soil surface. Bury the top end of each piece of matting in a narrow trench at least 6 in. (150 mm) deep and tamp firmly after staking with evenly spaced stakes. Stake the matting according to the manufactures recommended pattern for specific product and slope. Where one roll of matting ends and a second roll begins, install matting end-over-end with approximately 6 inches of overlap. Stake through overlapped area. Install stakes across the matting at ends, junctions, and trenches approximately 1.3 feet apart.

Basis of Payment Payment for installation of matting will be paid for as outlined. This payment shall be considered full compensation for all labor, equipment, furnishing materials, hauling, stockpiling, rehandling, sorting, fitting, materials, and incidentals necessary to install matting.

Payment will be made under:

Matting …………..……………………………………………………………….……….………..LINEAR FOOT

APPENDIX B – MINIMIZING DETRIMENTAL IMPACTS

A. Minimize the area and degree of soil disturbance that reduces infiltration capacity and permeability, and destroys protective forest floor and ground cover.

B. All hazardous materials will be stored outside of flood-prone areas and surrounded with sediment fence to reduce the risk of materials reaching the river.

C. Work activities would not be scheduled on rainy days.

D. During in-stream work, divert flow away from the work area as possible to minimize sedimentation.

E. Heavy Equipment Operation.

1. All equipment shall be cleaned before entering the project area and stream, so as to reduce the risk of fine grained sediment and oils and grease from entering the stream. This would also reduce the risk of invasive weed spread onto the Forest.

2. Do not operate on wet soils when they are most susceptible to damage and erosion.

3. Operate heavy equipment on slopes less than 12 percent so as to reduce the risk of soil erosion. Avoid operating heavy equipment on over-hanging stream banks.

4. Move large woody debris in a manner that minimizes disturbance of the forest floor, exposure of mineral soil, or degradation of stream bank stability.

F. Install sediment fence to trap potential sediment. Stabilize any disturbed area at the end of each workday.

G. Re-vegetate exposed soils as soon as possible to take advantage of the loose soil conditions for seeding.

1. Exposed soil will be covered with straw mulch or erosion control matting at the end of the project. Matting will be secured in place with stakes and live stakes where conditions allow.

2. Seeding will occur on all bare soil within five days of ground disturbing activities to provide long-term erosion control.

H. Do not move sediment trap devices until the vegetation in the disturbed areas has been established.

I. During on-going operations inspect the site frequently; inspect occasionally during inactive periods.

1. Check for potentially damaging or failing situations that may cause unacceptable water quality impacts.

2. Correct failing situations as soon as practical.

J. Conduct visual inspections of Swannanoa Creek while the work is being conducted to maintain acceptable turbidity levels.

Use a skilled heavy equipment operator, trained in stream restoration and construction of in-stream structures. Instruct the operator to minimize disturbance to the streambed.

Swannanoa Creek Stream Enhancement Project Page 1

Microsoft_PowerPoint_Slide1.sldx

Constructed pool bankfull elevation toe of bank bankfull elevation

20o angle

1/3 channel bankfull width toe of bank

CROSS VANE DETAIL

PLAN VIEW

HEADER ROCK

Flow Direction

High Flow

MATERIAL FROM POOL USED TO CONSTRUCT INNER BERM

MATERIAL FROM POOL USED TO CONSTRUCT INNER BERM

Brady Dodd

NFNC Hydro

1/3 channel bankfull width

FOOTER ROCK

20o angle

High Flow image1.jpeg image2.jpeg image3.jpeg image4.jpeg image4.jpg image5.emf image1.png image2.png image3.emf