0003 CFT Supplemental Specification 911-912.pdf

CATAWBA FALLS TRAIL

SUPPLEMENTAL SPECIFICATION 911-912

Native surface trail restoration and construction for this project shall be in accordance with the following specifications and referenced sections of the USFS Standard Specifications for Construction of Trails and Trail Bridges on Forest Service Projects, October 30, 2014. Where any discrepancies exist between plan drawings, typical detail drawings, standard specifications and this Supplemental Specification 911-912, the latter takes precedence as related to restoration and construction of native surface trail segments. The segments of existing trail restoration and new trail construction for native surface trail, and existing trail obliteration are shown on Sheet 1 of the Trail Construction Plans between “Existing Foot Bridge” at station 10+00 and “Begin Boardwalk” approximately at station 12+12.

Trail Name: Catawba Falls Trail, TR225

Total Length of trail to upper falls: approximately 1.35 miles

Catawba Trail Project Subject Lengths

Existing native surface trail restoration: 80 linear feet total (42 LF from existing trail station 10+00 to 10+42; and 38 LF from existing trail station 11+74 to 12+12)

New native surface trail construction: 182 linear feet (From new trail station 10+00 to 11+82;

note that corresponding begin/end points on existing trail stations are at 10+42 and 11+74 respectively, see plan sheet 1)

Existing native surface trail obliteration: 115 linear feet (Approximately from existing trail station 10+55 to 11+70)

Design Criteria for Trail Work:

Design Class: Trail Class 4 Design Use: Hike only Design Surface: Native Design Tread Width: 5 ft.

Protrusions: 3 inches maximum Obstacles: 8 inches maximum height Target Grade: 2% - 8% (max grade NTE 10%) Design Cross Slope: 5% Clearing Height: 10 ft.

Clearing Width: 10 ft.

Trail Construction:

New trail construction for the relocation shall include all work items required for the construction of a double-lane hiking trail that meets all Trail Class 4 design criteria. Work items include (but are not limited to) Clearing & Grubbing, Excavation and Embankment, Drainage, Brush Cutting, Logging Out, Danger Tree Removal, Loose Rock Removal, Rock and Root Removal. Trails shall be full-bench cut trail wherever possible. All trails shall be built as rolling contour trail, with grade reversals built in at frequent intervals.

A minimum of two rolling grade dips shall be constructed on the new, relocated trail.

The contractor shall stop work immediately and contact COR if any potential archeological concerns are encountered.

Tree Removal within Clearing Limits:

All tree removal work required for the construction of the new, relocated trail, is included in the Clearing, Construction Staking, Flagging and Cleanup line item on the Schedule of Items. This shall include all trees removed within the trailway, centered on the centerline of the proposed trail.

Hazard Tree Removal:

Where required, the Contractor shall cut identified hazard trees which are outside the trail clearing limits. The COR will identify and flag all hazard trees to be cut prior to issuing the Notice to Proceed. Hazard trees may be located any distance from the trail work, but do not include trees which must be cut within the trail clearing limits for the purpose of trail construction or restoration. Any portion of felled hazard trees which land within the trail clearing limits shall be bucked and moved outside the trail corridor. Hazard Tree Removal work is included in the Hazard Tree Removal line item on the Schedule of Items. Note that quantities in the Schedule of Items are approximate and contractors shall be paid for actual trees cut per unit price.

Tree Felling:

If possible, Contractor shall fell trees (greater than 3 inches in DBH) required for the project or to alleviate safety hazards during bat hibernation season (prior to April 15) for the Northern Long-eared bat. When this is not possible, trees to be removed shall be assessed for bat habitat suitability. If trees to be removed do not support suitable bat habitat characteristics (loose bark, crevices), then they can be removed outside of the hibernation season. If suitable bat habitat characteristics are noted, Contractor should consult the Inspectors prior to felling trees.

Existing Trail Restoration:

Two short segments of the existing trail, on either side of the new trail relocation, shall be restored (see Sheet 1). The total length of trail restoration is 80 LF. These segments are located as follows:

1-Existing trail segment from existing foot bridge to the beginning of relocation: 42 LF.

2-Existing trail segment from end of relocation to the location of proposed boardwalk: 38 LF

The 115 LF of existing trail located between these two segments shall be obliterated; this is the segment being replaced by the relocation. See Obliteration of Existing Trail section below.

For existing trail restoration, grading operations shall be conducted as required to remove ruts, potholes, and corrugations, remove berm, and outslope tread. All suitable dislodged material shall be smoothly redistributed over the entire traveled way and firmly packed. Loose and embedded rock shall be removed as well as roots and other materials exceeding the specifications for protrusions and obstacles.

Fill material or disturbed soils must be well-compacted and stable with positive drainage established such that the fill material/soil will not be washed away. Where required, the Contractor shall construct new drain dips. The COR will flag drainage dip locations prior to construction.

Acceptable results of grading operation shall be a trail bed that is firm, smooth, and finished to a width as specified, without berms or undercutting at shoulders. No roots or rocks (exceeding maximum height as specified) are protruding from the graded surface.

Obliteration of Existing Trail:

The Contractor shall obliterate the existing trail at the location identified (segment to be replaced by new trail relocation).

Obliterated segment shall be recontoured to drain, and brushed in (i.e., using brush, rocks, logs, or any other material along the trail that can be used in this manner). Recontouring and brushing in shall be done for the full-width and length of the subject trail segment.

Acceptable results of obliteration shall be a closed trail that is no longer noticeable or accessible to users. All such work shall be incidental to “Obliterate Portion of Existing Trail” line item in the Schedule of Items.

Soil Moisture Conditions and Temperatures:

Suitable moisture content (MC) for trail grading shall be within the range of five (5%) percent to fifteen (15%) percent by weight. Unless authorized, no grading may be performed while the moisture content is outside this range. Below 5% MC, the trailbed visually appears to contain little, if any, moisture. Heavy dusting is present. Wetting precipitation has not occurred in the recent past. Unacceptable results below 5% MC would be indicated by extreme powdering and dusting. Above 15% MC, the trailbed appears over-saturated, contains standing water, or may be rutting slightly. Recent heavy precipitation has occurred. Unacceptable results above 15% MC would indicate clumping, rutting and inability to spread material. Unacceptable results below 5% and above 15% MC would indicate inability to obtain maximum compaction of material.

No grading or other maintenance operations shall be performed during periods of freeze/thaw or when the ground is frozen.

Compaction:

Compaction of trail bed and associated earthwork within the trail, (e.g., rolling dips and grade dips) shall be performed with the material moisture content suitable for optimum compaction.

The entire width of the trail shall be uniformly and thoroughly compacted. Complete compaction is obtained when no noticeable displacement of material is observed.

When properly compacted, the entire trail width shall be smooth and dressed to produce a uniform cross-slope with a surface free of hollows, depressions, and projections. The entire trail tread width shall hold together under normal use.

Drainage:

The Contractor shall clean, repair, reshape, reconstruct drainage structures and construct new drainage structures on trails, as required, to provide positive drainage for the entire length of trail. Existing dips may be utilized if they are cleaned, repaired, or re-constructed such that they produce adequate positive drainage from the trail.

The Contractor shall divert water that is eroding the trail bed or is in imminent danger of eroding the trail bed. Water shall be diverted by cleaning and repairing failed or non-functioning drainage structures and constructing diversions such as shallow ditches or out-sloping

All ditches shall be cleared and maintained to the shape and grade required to ensure trail drainage. Drainage structures and trail appurtenances shall not be damaged during this operation. Handwork required to properly connect ditch flow to drainage structure inlets is considered a part of this activity. Cleaning lead-off ditches to drain is included in this item of work.

All suitable material having the same character as the trail surface excavated through ditch cleaning shall be reclaimed and used within the trail.

Unsuitable material from construction shall be spread along trail shoulders, in depressions, or on fill slopes in a manner which will not affect watercourses and drainage from the traveled way or shoulders.

Erosion and Sedimentation Control:

If the work of the contract creates potential for soil erosion or silt migration over areas of mature vegetation or natural areas, the contractor will be responsible for providing silt fence, straw bales or other suitable containment. Such work includes, but is not limited to, culvert cleaning, excess dirt generation from drainage dip and ditch cleaning, and disposal of slough or silt trap material.

This does not include newly graded ditch line.

Prior to grading activities, remove and stockpile duff. After grading activities are complete, naturalize the trail corridor by scattering the saved duff on and alongside the newly restored trail

(on any disturbed or scattered soils). The intent is for the duff to naturalize the newly restored trailway and to provide erosion prevention. Do not create a berm with the duff. Do not place materials in stream channels, drainage-ways, ditches, culvert inlets, or other locations where they would prevent the free flow of water away from the trailbed.

Seed and mulch all disturbed areas (exposed soil outside of trail tread such as lead-off ditches, etc.) using a 50/50 mix of annual rye and creeping red fescue.

Drainage: