County-Specs-02270-Erosion-Control.pdf

EROSION CONTROL 02270-1

GREENVILLE COUNTY

PUBLIC WORKS

STANDARD SPECIFICATIONS

SECTION 02270

EROSION CONTROL

EROSION CONTROL 02270-2

EROSION CONTROL

SECTION 02270

RELATED DOCUMENTS: Attention is directed to related sections of the Specifications, as they pertain to the guidelines, materials, and methods described in this section. Also, the General Provisions and Special Provisions of the Contract shall apply to all Sections of the Work. The Contractor shall comply with current County guidelines for land disturbance and erosion control including State and Federal regulations wherever they apply.

1.0 SCOPE

a. General: The work includes the provision of temporary erosion control measures to prevent the pollution of air, water, and land. Installation of temporary erosion control features shall be coordinated with the construction of permanent erosion control features to assure effective and continuous control of erosion.

2.0 CONSTRUCTION

a. Gravel Construction Entrance: Provide as indicated, a minimum of 6 inches thick, at points of vehicular entrance and exit on the construction site. Gravel shall be as specified in S.C.

Highway Department, "Standard Specifications for Highway Construction", Section 305 for Composite Mixture Macadam Base Course.

b. Dust Suppression: ASTM D-98 calcium chloride, magnesium chloride, or other standard manufacturer's products designed for dust suppression. Apply dust suppressors in accordance with manufacturer's instruction. Protect treated surfaces from traffic for a minimum of 2 hours after treatment. Repeat application of dust suppressors as required to control dust emissions.

c. Sediment Fence: Install posts at the spacing indicated, and at an angle between 2 degrees and

20 degrees towards the potential silt load area. Do not attach filter fabric to existing trees.

Secure filter fabric to the post and wire fabric using staples, wire, or hog rings. Imbed the filter fabric into the ground as indicated. Splice filter fabric into the ground as indicated. Splice filter fabric at the support pole using a 6 inch overlap and security seal. Top of the filter fabric shall have a 1 inch tuck or a reinforced top end section. Preassembled silt fences may be used as approved by the County Engineer.

1. Posts: 4 inch by 4 inch wood posts, minimum 3 inch diameter wood, or 1.33 pound per linear foot steel posts. Posts shall be minimum 5 feet long.

2. Wire Fabric: ASTM A-185, 6 by 6, minimum 14 gage.

3. Filter Fabric: A woven or nonwoven polypropylene, nylon, or polyester containing stabilizers and/or inhibitors to make the fabric resistant to deterioration from ultraviolet light. Filter cloth shall be of the type recommended by its manufacturer for the intended application.

4. Straw Bales: Constructed from grain straw or hay with each bale bound together with binding wire or twine. Posts shall be ASTM A-615, 1-1/2 inch diameter wood posts or 1.0 pound per linear foot steel posts. Imbed the bottom row of bales in a 4 inch deep trench and place straw bales tightly abutting each other. Bales shall be placed so the bindings are horizontally oriented around the bales, wire adjoining bales together. Anchor each bale with two stakes, driving the first stake towards the previously laid bale. Wedge straw in gaps between bales. After the bales are staked, the excavated soil from the trench shall be backfilled against the straw bales to ground level on the downhill side and to 4 inches above ground level on the uphill side.

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d. Gravel Dam and Silt Trap: Provide as indicated, adjusting dimensions as directed by the County Engineer to fit grading and location.

1. Riprap: SCHD "Standard Specifications for Highway Construction", Section 804, Stone for

Hand Placed Riprap and ranging in size from 3 inches to 6 inches.

2. Filter Stone: #5 Washed Stone.

e. Erosion Control Matting: Jute, excelsior, straw, or paper matting that has not been bleached or dyed. Provide matting in minimum 4 foot widths. Staples for anchoring the matting shall be minimum throat width of 1 inch minimum length of 6 inches after forming. Place matting in the direction of the flow of water. The up channel matting end shall be placed in a narrow trench a minimum of 5 inches deep. 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 to provide a 6 inch overlap. Where matting widths are laid side by side, the overlap between matting shall be 4 inches. Provide check slots every 50 feet longitudinally in the matting. Construct check slots by providing a narrow trench 5 inches deep and folding the matting down into the trench, across the bottom of the trench, and then back up the trench to the existing ground. Backfill and compact the trench using the excavated material from the trench. Staple matting ends, junctions, and check slots at 10 inches on center. Staple matting outer edges, overlaps and the center of each matting strip at 3 feet on center. Install excelsior matting with the woven fabric on top.

f. Temporary Seeding: Within 48 hours after attaining the grading increment specified herein, provide seed, fertilizer, and mulch on graded areas when any of the following conditions occur:

1. Grading operations stop for an anticipated duration of 30 days or more.

2. Provide on the slopes of cuts and fill slopes for every 5 foot increment of vertical height of the cut or fill.

3. When it is impossible or impractical to bring an area to finish grade so that permanent seeding operations can be performed without serious disturbance from additional grading.

4. When an immediate cover is required to minimize erosion, or when erosion has occurred.

5. Provide on erosion control devices constructed using soil materials.

g. Temporary Seeding Operations: Temporary seeding operations shall consist of the following:

1. Procedure: Loosen subgrade to a minimum depth of 4 inches. Uniformly apply the seed, fertilizer, and mulch at the specified rates. Roll the seeded area after applying seed and fertilizer. Do not seed or fertilize when the County Engineer determines conditions are unfavorable. Provide water to promote turf growth.

2. Seed: Provide certified seed type and quantity (pounds per acre) as follows:

SEED TYPE MAY 1 - SEPT. 1 SEPT. 1 - MAY 1

Annual Rye 100 lbs/Ac 150 lbs/Ac Common Bermuda 50 lbs/Ac ---

3. Fertilizer: Apply 10-10-10 fertilizer at the rate of 1000 pounds per acre.

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4. Mulch: Spread hay or straw mulch at the rate of 1.5 tons per acre and anchor by crimping mulch with a disc. Provide in an air dried condition for placement with commercial mulch blowing equipment.

5. Alternate Bid: Temporary seeding shall be bid as an alternate bid item to be provided only as required above.

h. Maintenance and Inspection: Inspect erosion control devices after each rainfall and daily during prolonged rainfall. Remove sediment deposits after each rainfall or when sediment reaches approximately one-half the barrier height or storage capacity. Immediately repair damaged erosion control devices and damaged areas around and underneath the devices. Maintain erosion control devices to assure continued performance for their intended function. Modify the erosion control plan as required to control problem areas noticed after each inspection.

i. Clean Up: At the completion of the job, or when directed by the County Engineer, erosion control devices shall be removed. Erosion control devices and areas immediately adjacent to the device shall be filled (where applicable), shaped to drain and to blend into the surrounding contours, and grassed or landscaped as specified.

END OF SECTION