Attachment to C-408/94-132
Section 806
January 06, 1998



COMMONWEALTH OF PENNSYLVANIA

Department of Transportation
Harrisburg

WATER COURSE AND SLOPE EROSION PROTECTION

Supplementing the Specifications
Publication 408 dated 1994


SECTION 806 EROSION CONTROL AND SOIL PROTECTION. Revise as follows:

SECTION 806.1 DESCRIPTION - This work is furnishing, placement and maintenance of soil erosion control material of the type indicated.


SECTION 806.2 MATERIAL - From a manufacturer listed in Bulletin 15 and meeting the following requirements:

(a) Erosion Control Mats (ECM) and Mulch Blankets (ECB).

1. Erosion Control Mat. Undyed, flexible, non-treated biodegradable heavy jute, coconut coir, photodegradable polypropylene multifilament and tape yarn or other yarns woven into a dimensionally stable uniform open plain weave mesh meeting the following physical properties:



2. Erosion Control Mulch Blanket. One of the following:

2.a Organic Mulch Material. A machine produced mat of organic, biodegradable mulch material such as straw, curled wood cellulose, coconut fiber or combinations of material evenly distributed and attached on one side of a photodegradable polypropylene mesh with high strength threads meeting the following physical properties:



2.b Reprocessed Wood Fiber. A flexible, non-woven,
biodegradable water absorbing mat of mechanically defibrated wood fibers and synthetic fibers with a photodegradable polypropylene netting laminated to one side of the mat and meeting the following physical properties:



3. High Velocity Erosion Control Mulch Blanket. Section 806.2(a)2.a except mulch material is evenly distributed between two layers of photodegradable polypropylene mesh.

(b) Turf Reinforcement Mat (TRM). A three dimensional web of mechanically or melt bonded nylon or polymer netting, monofilaments or fibers that are entangled to form a strong and dimensionally stable matrix mat. Matrix manufactured to have sufficient thickness, resiliency and void space to fill with soil to provide erosion protection while facilitating vegetative establishment. Matrix components stabilized against ultraviolet degradation and inert to chemicals normally encountered in a natural soil environment meeting the following physical properties:



  • Mat Thickness
0.5 inch, Average Nominal Thickness
(ASTM D5199)
  • Weight Per Unit Area
11 ounces per square yard* (ASTM D5261) or (ASTM D3776)
  • Tensile Strength
10 x 8 pounds force per inch*
(ASTM D4595) or 7.8 x 4.5 pounds force per inch* (ASTM D5035)
  • Ultraviolet Stability
80% tensile strength retained (ASTM D4355)

*Minimum Average Roll Value

(c) Erosion Control and Revegetation Mat (ECRM). One of the following:

1. Type A. A flexible, three dimensional web of mechanically or melt bonded nylon or polymer netting, monofilaments or fibers that are entangled to form a strong and dimensionally stable matrix mat. Matrix to provide sufficient thickness and ground cover to provide erosion protection while facilitating vegetative establishment. Matrix components stabilized against ultraviolet degradation and inert to chemicals normally encountered in a natural soil environment and meeting the following physical properties:




  • Mat Thickness
0.125 inch, Average Nominal Thickness
(ASTM D5199)
  • Weight Per Unit Area
7 ounces per square yard* (ASTM D5261) or (ASTM D3776)
  • Tensile Strength
9.1 x 4.9 pounds force per inch*
(ASTM D4595) or 8.3 x 4 pounds force per inch* (ASTM D5035)
  • Ultraviolet Stability
 80% tensile strength retained (ASTM D4355)

*Minimum Average Roll Value

2. Type B. A flexible, randomly oriented polyvinylchloride monofilaments bonded together to form a stable three dimensional entangled, porous matrix resistant to natural soil and groundwater chemical degradation. Matrix to provide sufficient thickness and ground cover to provide erosion protection while facilitating vegetative establishment and meeting the following physical properties:


  • Mat Thickness
0.10 inch, Average Nominal Thickness
(ASTM D5199)
  • Weight Per Unit Area
24 ounces per square yard* (ASTM D5261)
  • Wide Width Tensile Strength
12 x 4 pounds force per inch*
(ASTM D4595) or (ASTM D3776)
  • Ultraviolet Stability
 85% tensile strength retained (ASTM D4355)

(d) Anchoring Devices.

1. Staples. No. 8 gage steel wire, bent U-shaped or square top with a throat width of 1 to 2 inches, with an effective minimum driving depth of 8 inches.

2. Metal Pin. Carbon Steel pin, 3/16-inch shank diameter, 18-inch length with attached 1-1/2 inch minimum outside diameter steel washer head.

3. Wood Stakes. Sound, rough sawn, approved hardwood
1 x 4 stake tapered to a point throughout, with a minimum length of 18 inches.

4. Substitutes. Other anchoring devices as recommended by the mat manufacturer may be submitted for review and approval.

(e) Seeding and Soil Supplements. Section 804.

(f) Mulch for Seeded Areas. Section 805.

(g) Certification. Section 106.03(b)3.

SECTION 806.2(h) Fiber Roving System. Add the following:

(h) Fiber Roving System. A nontoxic, photodegradable material applied as a long continuous strand of fibrillated, fine denier yarn which is blown onto the soil surface and then adhered to the ground surface with an application of approved tackifier material, and meeting the following typical requirements:

1. Fiber Roving.

  • Material Type
UV stabilized
  • Mass of Strand
360 denier (ASTM D 1907)
  • Tensile Strength
15.6 N (ASTM D 2256)
  • Elongation at Break
15.5% (ASTM D 2256)
  • UV Stability
80% Strength retained (after 500 hrs) (ASTM D 4355)
  • Strands per Rove
20 to 28


2. Tackifier. Anionic emulsified asphalt, AASHTO grade SS-1 (E-6A), with a furol viscosity at 77F less than 50 seconds, and meeting the requirements of Bulletin 25. Obtain material from a producer listed in Bulletin 15.

3. Wood Stakes. Section 806.2(d).


SECTION 806.3 CONSTRUCTION -

(a) Erosion Control Mats and Mulch Blankets.

1. General. Place erosion control materials after slope, swale or channel has been final graded and dressed to define flow area and designated soil supplements, seed and mulch, when indicated, have been applied. Install erosion control materials to conform to shape of soil surface.

Unroll, place and anchor mat evenly and smoothly without stretching to ensure contact with mulch surface at all points. Use appropriate anchoring devices and follow installation directions of the mat manufacturer. If staples are used, drive flush with soil surface.

2. Erosion Control Mulch Blanket and High Velocity Erosion Control Mulch Blanket. Install blanket having mesh on only one side with mesh side on top. Mulch application normally associated with seeding operation is not required for installation of erosion control blankets.

(b) Turf Reinforcement Mat.

1. Site Preparation. Prepare final graded and dressed soil surfaces to receive permanent seeding in accordance with Section 804.3. Soil surfaces to be free of rocks or other obstructions which would prevent mat from lying in direct contract with soil.

2. Mat Installation. Unroll, place and anchor mat evenly and smoothly without stretching to conform to shape of and be in uniform contact with soil surface. Use appropriate anchoring devices and follow installation directions of mat manufacturer. Drive staples or anchoring pins flush with soil surface.

3. Seeding. After mat installation, broadcast designated seed formula mixture into mat matrix in accordance with Section 804.3.

4. Topsoil Placement. After seeding, uniformly place 1/2 to 3/4-inch of approved topsoil on mat. Work soil into mat voids to completely fill mat matrix flush with top of mat. Remove excess topsoil.

5. Mulching. Mulch area with designated mulch in accordance with Section 805.3.

(c) Erosion Control and Revegetation Mat.

1. Site Preparation. Prepare final graded and dressed soil surfaces to receive permanent seeding in accordance with Section 804.3. Soil surfaces to be free of rocks or other obstructions which would prevent mat from lying in direct contact with soil.

2. Seeding. Place designated seed formula mixture in accordance with Section 804.3. Mulch application normally associated with seeding operation is not required for installation of mats.

3. Mat Installation. Unroll, place and anchor mat evenly and smoothly without stretching. Use appropriate anchoring devices and follow installation directions of mat manufacturer. Drive staples or anchoring pins flush with soil surface.

(d) Maintenance. Properly maintain designated erosion control fabrics until entire project has been accepted. If a protected slope, swale or other soil surface failure occurs after satisfactory installation of work, redress affected soil areas and reinstall protection material as specified for original treatment unless directed otherwise.

SECTION 806.3(e) Fiber Roving System. Add the following:

(e) Fiber Roving System.

1. General. Prepare seedbed, apply seed, and soil amendments in accordance with Section 804.3. Construct anchor trenches, check slots, or place wood stakes as specified. Apply fiber roving through an ejector with compressed air as recommended by the manufacturer. Do not apply fiber roving during wet or cool weather conditions, when rainfall is anticipated within one hour of application, or when wind is greater than 20 mph.

2. Channels and Swales. Construct a 6 to 12 inch deep anchor trench/check slot at the upslope end of the installation. For areas of moderate runoff, construct 6 to 12 inch deep check slots at approximately 25 foot intervals along the channel. As an alternative to check slots, install a row of wood stakes across the channel on 12 inch centers, protruding 3 to 4 inches above the soil surface, and at approximately 25 foot intervals. Apply fiber roving at an approximate rate of 0.35 lb/sy to form a mat of polypropylene. Backfill, compact, and reseed soil in anchor trenches and check slots.

3. Tackifier. Apply approved tackifier material. Overspray tackifier at the specified rate of 0.35 gal/sy using spraying pressure recommended by manufacturer. Spray entire polypropylene mat area. Allow one hour for tackifier to dry. Do not apply during rainfall or if rain is anticipated within the specified one hour drying time necessary to cure the material.


SECTION 806.4 MEASUREMENT AND PAYMENT -

(a) Erosion Control Mat. Square Yard

(b) Erosion Control Mulch Blanket. Square Yard

(c) High-Velocity Erosion Control Mulch Blanket. Square Yard

(d) Turf Reinforcement Mat. Square Yard

(e) Erosion Control and Revegetation Mat. Square Yard

(f) Seeding and Soil Supplements. Section 804.4 for the type indicated.

(g) Mulch. Section 805.4 for the type indicated.

Reinstallation of protection material on failed soil surfaces will be paid for at the contract unit price in addition to the original installation work.

SECTION 806.4(h) Fiber Roving System. Add the following:

(h) Fiber Roving System. Square Yard

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