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The work covered by this section consists of furnishing, placing, and maintaining a ditch liner and/or erosion control blanket of synthetic roving or matting for erosion control on previously shaped and seeded drainage ditches, slopes, or other areas at locations shown on the plans or in the special provisions, or as directed by the Engineer.
The quantity of synthetic roving and matting to be placed will be affected by the actual conditions which occur during the construction of the project. The quantity of matting may be increased, decreased, or eliminated entirely at the direction of the Engineer. Such variations in quantity will not be considered as alterations in the details of construction or a change in the character of the work.
All materials shall meet the requirements of Division 10 shown below:
Synthetic Roving Article 1054-5
Matting for Erosion Control Article 1060-8
Tacking material for use with synthetic roving shall be an emulsified asphalt diluted with no less than 50% asphalt content as approved by the Engineer.
(A) Synthetic Roving:
Placing of synthetic roving shall be done immediately following seeding. The earth surface shall be smooth and free from stones, clods, or debris which will prevent the contact of the fibers with the soil. Care shall be taken to preserve the required line, grade, and cross section of the area covered.
Synthetic roving shall be spread uniformly over the designated area to form a random mat of continuous fibers at the rate of 0.25 to 0.35 pounds per square yard of fiberglass roving or 0.15 to 0.20 pounds per square yard of polypropylene roving. Immediately after the roving has been placed, it shall be anchored to the ground with tacking material applied uniformly over the fibers at a rate of 0.25 to 0.35 gallons per square yard, to hold the fibers in place.
At the upgrade end and at maximum intervals of 50 feet along the ditches, the roving shall be buried to a depth of 5 inches to prevent undermining and tension failure. In addition to burying the roving, wooden stakes sawn in a triangular shape at one end, shall be used at the upgrade end and in an irregular pattern throughout the ditch. Stakes shall be placed in sufficient number to securely hold the roving in place but in no event shall they be more than 10 feet apart.
(B) Placing Matting:
Placing of matting shall be done immediately following seeding. The earth surface shall be smooth and free from stones, clods, or debris which will prevent the contact of the matting with the soil. Care shall be taken to preserve the required line, grade, and cross section of the area covered.
Matting shall be unrolled in the direction of the flow of water, and shall be applied without stretching so that it will lie smoothly but loosely on the soil surface. The up-channel or top of slope end of each piece of matting shall be buried in a narrow trench at least 5 inches deep and tamped firmly. After the end of the matting is buried, the trench shall be closed and tamped firmly. Where one roll of matting ends and a second-roll begins, the end of the upper roll shall be brought over the buried end of the second roll so that there will be a 6 inch overlap. Check slots shall be constructed at each 50 feet longitudinally in the matting or as directed by the Engineer. These slots shall be narrow trenches at least 12 inches deep. The matting shall be folded over and buried to the full depth of the trench, after which the trench shall be closed and firmly tamped. Where 2 or more widths of matting are laid side by side, the overlap shall be at least 4 inches.
Staples shall be placed across matting at ends, junctions, check slots and shall be spaced approximately 10 inches apart.
When excelsior or straw matting is used, the matting shall be installed with the fabric on the top side.
In the installation of erosion control matting on cut or fill slopes the Engineer may require adjustments in the trenching or stapling requirements to fit individual slope conditions.
The quantity of synthetic roving to be paid for will be the number of square yards of roving, measured along the surface of the ground, over which synthetic roving has been acceptably placed.
The quantity of matting for erosion control to be paid for will be the number of square yards, measured along the surface of the ground, over which matting has been acceptably placed.
The quantity of synthetic roving, measured as provided in Article 16314, will be paid for at the contract unit price per square yard for "Synthetic Roving".
The quantity of matting for erosion control, measured as provided in Article 16314, will be paid for at the contract unit price per square yard for Matting for Erosion Control
The above prices and payments will be full compensation for all work covered by this section, including but not limited to furnishing all synthetic roving, asphalt, matting, staples, and any other materials; excavation and backfilling; placing synthetic roving; applying asphaltic material; placing and securing matting; and maintaining the drainage ditch.
Payment will be made under:
Synthetic Roving Square Yard
Matting for Erosion Control Square Yard