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CONSTRUCTION SPECIFICATIONS
(SEDIMENT FENCE)
I . Construct the sediment barrier of standard strength or extra strength synthetic filter fabrics.
2. Ensure that the height of the sediment fence does not exceed 24 inches above the ground
surface. (Higher fences may impound volumes of water sufficient to cause failure of the
structure.)
3. Construct the filter fabric from a continuous roll cut to the length of the barrier to avoid joints.
When joints are necessary, securely fasten the filter cloth only at a support post with 4 feet
minimum overlap to the next post,
4. Support standard strength filter fabric by wire mesh fastened securely to the upslope side of
the posts. Extend the wire mesh support to the bottom of the trench. Fasten the wire
reinforcement, then fabric on the upslope side of the fence post. Wire or plastic zip ties should
have minimum 50 pound tensile strength.
5. When a wire mesh support fence is used, space posts a maximum of 8 feet apart. Support posts
should be driven securely into the ground a minimum of 24 inches.
6. Extra strength filter fabric with 6 feet post spacing does not require wire mesh support fence.
Securely fasten the filter fabric directly to posts. Wire or plastic zip ties should have minimum
50 pound tensile strength.
7. Excavate a trench approximately 4 inches wide and 8 inches deep along the proposed line of
posts and upslope from the barrier (Figure 6.62a).
8. Place 12 inches of the fabric along the bottom and side of the trench.
9. Backfill the trench with soil placed over the filter fabric and compact. Thorough compaction of
the backfill is critical to silt fence performance.
10. Do not attach filter fabric to existing trees.
MATERIALS
(SEDIMENT FENCE)
1. Use a synthetic filter fabric of at least 95% by weight of polyolefins or polyester, which is certified by the manufacturer or
supplier as conforming to the requirements in astin d 6461, which is shown in part in table 6.62b.
2. Synthetic filter fabric should contain ultraviolet ray inhibitors and stabilizers to provide a minimum of 6 months of
expected usable construction life at a temperature range of 0 to 1200 f.
3. Ensure that post for sediment fences are 1.25 lb/linear ft minimum steel with a minimum length of 5 feet. Make sure that
steel posts have projections to facilitate fastening the fabric.
4. For reinforcement of standard strength filter fabric, use wire fence with a minimum 14 gauge and a maximum mesh
spacing of 6 inches.
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SEDIMENT FENCE INSTALLATION USINGTHE SLICING METHOD
Instead of excavating a trench, placing fabric and then backfilling trench, sediment fence may be
installed using specialty designed equipment that inserts the fabric into a cut sliced in the ground
with a disc (Figure 6.62b).
Installation Specifications
I The base of both end posts should be at least one foot higher than the middle of the fence.
Check with a level if necessary.
2, Install posts 4 feet apart in critical areas and 6 feet apart on standard applications.
3. Install posts 2 feet deep on. the downstream side of the silt fence, and as close as possible to the
fabric, enabling posts to support the fabric from upstream water pressure.
4. Install posts with the nipples facing away from the silt fabric.
5. Attach the fabric to each post with three ties, all spaced within the top 8 inches of the fabric.
Attach each tie diagonally 45 degrees through the fabric, with each puncture at least I inch
vertically apart. Also, each tie should be positioned to hang on a post nipple when tightened to
prevent sagging.
6. Wrap approximately 6 inches of fabric around the end posts and secure with 3 ties.
7. No more than 24 inches of a 36 inch fabric is allowed above ground level.
8. The installation should be checked and corrected for any deviations before compaction,
9. Compaction is vitally important for effective results. Compact the soil immediately next to the
silt fence fabric with the front wheel of the tractor, skid steer, or roller exerting at least 60
pounds per square inch. Compact the upstream side first, and then each side twice for a total of
4 trips.
.SEDIMENT FENCE
4' MIN
SILT FENCE
TOP OF SILT FENCE
MUST BE AT LEAST 1'
ABOVE THE TOP OF
THE WASHED STONE.
N10T.E.S.
1. REMOVE SEDIMENT WHEN HALF OF STONE OUTLET IS COVERED
2. REPLACE STONE AS NEEDED TO ENSURE DEWATERING.
FRONT VIEW
STEEL POST SET
MAX 2' APART MIN'
2' INTO SOLID GROUND
STEEL POST
WOVEN WIRE FABRIC--"
MAINTENANCE: HARDWARE CLOTH-
1. INSPECT SILT FENCE STONE OUTLET WEEKLY OR AFTER EACH
SIGNIFICANT RAINFALL EVENT (4 INCH OR GREATER). MAKE ANY
REQUIRED REPAIRS IMMEDIATELY.
2. REMOVE SEDIMENT DEPOSITS AS NECESSARY, RESTORE TO ITS
ORIGINAL DIMENSIONS AND REPLACE STONE THAT IS IMPAIRED BY
SEDIMENT.
FILTER OF #57
WASHED STONE
1� N
BURY WIRE FENCE,
FILTER FABRIC.
AND HARDWARE
CLOTH IN TRENCH.
TSECTION VIEW
16"MIN
3' FILTER FABRIC APRON
ON GROUND
BURY 6" UPPER EDGE OF
BURY WIRE FENCE AKIO 4" FILTER FABRIC APRON IN TRENCH
HARDWARE CLOTH
SILT FENCE STONE OUTLET
N.T.S
Table 6.62b Specifications For Sedin4n& Fence Fabric
T-emporary Silt Feflce Material Property R&cluirements
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MAINTENANCE SPECIFICATIONS
(SEDIMENT FENCE)
1. Inspect sediment fences at least once a week and after each rainfall. Make any required repairs
immediately.
2. Should the fabric of a sediment fence collapse, tear, decompose or become ineffective, replace it
promptly.
3. Remove sediment deposits as necessary to provide adequate storage volume for the next rain and to
reduce pressure on the fence, Take Care to avoid undermining the fence during cleanout.
4. Remove all fencing materials and unstable sediment deposits and bring the area to grade and
stabilize it after the contributing drainage area has been properly stabilized.
NOTES
USE NO. 5 OR NO. 57 STONE FOR SEDIMENT
CONTROL STONE.
USE HARDWARE CLOTH 24 GAUGE WIRE MESH
WITH % INCH MESH OPENINGS.
INSTALL 5 FT, SELF FASTENER ANGLE STEEL
POST 2 FT. DEEP MINIMUM.
SPACE POST A MAXIMUM OF 3 FT.
FOR INSTALLATION BETWEEN SECTIONS OF
SILT FENCE, EXTEND SEDIMENT CONTROL
STONE A MINIMUM OF 12" IN WIDTH ON EACH
SIDE OF SPECIAL SEDIMENT CONTROL FENCE
SECTION.
Section 4.4.2 1 Slope Protection - Special Sediment Control Fence
E &S C Manual January 2015
-4 - 3 ft --7
VARIABLE
DIMENSION 1/4 WIRE MESH-\
SEDIMENT CONTROL STONE
2 ft
1 ft min
1/4 WIRE MESH
SEDIMENT CONTROL STONE A
r- 1 ft min
WATER FLOW
7IIi�1b! ;II�II(�II-III
STEEL POST 2 ft DEPTH
WIRE MESH2 ft
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NCDOT,
Erosion & Sedimen
CONTROL MANUAL
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Section 4.4.2 Slope Protection - Special Sediment Control Fence
E&SC Manual January 2015
NCDOT,
E S
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WNIROLMANUAL
n s Checki._,
• Check the environmental permits to verify that the fence is placed in the proper location and in accordance
with the permit drawings and provisions. Fence materials shall meet the requirements of Section 16o6.
• Install the fence in advance of the need to contain sediment.
• Make any necessary additions or adjustments to SSCF based on field conditions.
• Install materials according to plan details. (See Roadway Standard Drawing No. 16o6.ol.)
• Remove silt accumulation when silt reaches half the height of the stone and dispose of waste properly.
• Measure the silt removed for payment.
• Remove fence, posts and stone when the permanent controls have been established. Do not leave the
stone on site and do not place any stone in permitted areas.
�2 Z_,, V, M e 11 t
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Y4-inch Hardware Cloth Linear Foot
Sediment Control Stone Ton
Silt Excavation Cubic Yard
Maintenance
• Inspect the device periodically and after each significant rainfall event for damage and sediment
accumulation to confirm the device is functioning properly,
• At a minimum, remove sediment from the device when accumulations reach one-half the height of the
sediment control stone.
• Replace or clean the sediment control stone as needed to allow water to drain through the device between
rainfall events.
• Rebuild and/or repair the device when it is damaged.
• Repair areas where SSCF becomes undermined due to concentrated flows,
Typical Problems
• Sediment accumulations are not removed in a timely fashion, causing sediment to be released offsite.
• The sediment control stone is not cleaned and becomes clogged, preventing proper drainage.
• The device is not rebuilt or repaired when damaged by storms, equipment, etc.
• The device is not built wide enough to prevent water from washing around it. Water should always flow
through or over the device, not around.
• Runoff becomes concentrated in areas and undermines the hardware cloth and sediment control stone.
IN,
Section �,Slope,Pr2tection - Special Sediment Control Fence
E&SC Manual January 2015 IN
1�1_1_ CONSTRUCTION SHALL BE IN ACCORDANCE WITH CASWELL COUNTY
NCDEQ AND NCDOT STANDARDS, SPECIFICATIONS, AND DETAILS
CA
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11/03/2020
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