Section_836-8_Road_Decommissioning_Revised_7-25-16.pdf

Route Decommissioning 2016

Section 836-8 SPS

SPECIAL PROJECT SPECIFICATION

836-8 Route Decommissioning

836-8.01 Description This work consists of performing Route Decommissioning through the methods of Chunking and Ripping within the former unauthorized travelled way. This work also consists of Slashing whereby brush is spread over disturbed areas as described below. Work includes all labor and equipment and transportation necessary to perform the work in this specification.

836-8.02 Chunking (a.k.a pocking or gouging ) is a method used to intercept and trap sediment on a micro-scale. Chunking also collects moisture, which improves vegetation establishment and consequently prevents erosion. This method is highly recommended for moderate to steep slopes. But it is also useful for flat or gently sloping areas with erosive soils and arid climates. Chunking is most practical for use on small disturbed areas of fewer than fifty acres or for critical portions of large disturbances, such as highly erosive soils and areas adjacent to streams. When soils are shallow and bedrock is prominent, it may be necessary to add water bars and/or lead off ditches.

Basic Design and Construction

1. Use a small excavator or backhoe to create micro basins.

2. Dig a bucket load of soil to depth of 18-24 inches.

3. Drop bucket load 2-3 feet above the soil.

4. Repeat this process in a random and overlapping pattern throughout the site, making it impossible for water to flow down slope.

5. Finished roughened soil should be difficult to walk over.

6. Additional description may be found in Restoration of Forests, Grasslands, and Wetlands Damaged by Off-Highway Vehicles, available from the U.S. Government Printing Office.

836-8.03 Ripping is a method used to create intercepting ditches on a compacted surface along a contour line such that water will not readily travel along the ditch.

1. Shank Type Rippers

a. This work shall consist of ripping an existing roadbed with a shank type ripper.

b. The distance between the ripper shanks shall not exceed 36 inches. Rippers shall have a minimum of two shanks.

c. The minimum ripping depth shall be 20 inches. The Government may agree to a lesser depth when excessive rock is encountered.

d. Equipment shall not be operated on ripped areas.

2. Wing Rippers

a. This work shall consist of subsoiling an existing roadbed by ripping with a winged ripper.

b. The distance between ripper shanks shall not exceed 36 inches. Each shank shall be equipped with a shoe and wings which have a total width of at least 18 inches.

The design of the shank and wing will be such that the treated soils are slightly lifted and well fractured rather than plowed, mixed or displaced.

c. Ripping shall be accomplished to a minimum depth of 20 inches. The Government may agree to a lesser depth when excessive rock is encountered.

d. Equipment shall not be operated on ripped areas.

3. WATERBARS: Waterbar work will be included under Ripping AS SHOWN IN THE SCHEDULE OF ITEMS. Waterbars should be installed at an angle of at least 45 degrees, with an increased angle as the grade approaches steeper grades – up to 60 degrees angle to the slope.

Waterbars should extend into undisturbed native material as it is intended to divert water off of the hardened surface. Waterbar spacing should be as follows:

Slope Spacing 5-15% every 75’

15-30% every 50’ over 30% every 35’.

836-8.04 Outsloping/Recontouring

1. Designated routes or segments of routes to remain shall be outsloped by pulling the fill shoulder towards the cut bank. Excavated material shall be spread over the route forming a minimum outslope equal to the existing road grade percent. The Government may agree to a lesser outslope percent if soil conditions warrant.

2. Recontouring is intended to remove the route and should match the natural slope when finished.

3. Any existing ditches at the toe of the cut shall be filled with the material excavated during outsloping.

836-8.05 Slashing

1. This work shall consist of placing woody material over the disturbed route to discourage vehicle or other traffic.

2. Woody material shall be dead timber and slash removed from an area within twenty five (25) feet of the road shoulders in the vicinity of the areas where it is to be placed.

3. Material shall be placed randomly over the routes to give a similar appearance of the surrounding area and may include rocks and other material.

836-8.06 Measurement

The quantity to be measured will be the completed number of miles of Route Decommissioning based upon an average eight to ten foot wide swaths listed in the SCHEDULE OF ITEMS measured and accepted under this section.

836-8.05 Payment

Payment will be made for the Actual Quantity of accepted quantities at the contract unit price shown in the SCHEDULE OF ITEMS.

Payment will be made under:

Pay Item Description Unit 836-8(1) Route Decommissioning (RIPPING) MILE 836-8(2) Route Decommissioning (SLASHING) MILE 836-8(3) Route Decommissioning (CHUNKING) MILE