- 693 - SECTION 816 -- SILT FENCE
816.01 Description
1.This work consists of installing the silt fence at locations shown in the contract and at locations as appr oved or determined by the Engineer. The installation shall be in accordance with the contract.
816.02 Material Requirements
1.All silt fence material shal l be selected from the Department’s Approved Products List.
a.Low Porosity Silt Fence is typically used for perimeter control. b. High Porosity Silt Fence is used for velocity control.
c.Low Profile Silt Fence is us ed for perimeter control and inlet protection
d.Coir Silt Fence is used for perimeter control of wetlands and locations specified to use a biodegradable silt fence.
e.Temporary Silt Fence shall be any product from the silt fence category of the Department ’s Approved Products List with a use appropriate to the situation.
2.Silt Fence Posts a. The silt fence posts shall be Studded “T” Steel Posts with a minimum weight of 1.25 lbs/foot (37 Kg/m).
b.Used Studded “T” St eel Posts are acceptable.
c.Coir Silt Fence wooden posts shall be derived from hardwood tree species.
3.Zip ties shall be UV stabilized, black with a 50 lb (22 Kg) minimum tensile strength.
816.03 Construction Methods
1.The silt fence shall be install ed and in good working condition prior any grading or excavation operations and as needed throughout the construction process. The silt fence installation shall not exceed the amount required for the current construction season.
2.Silt Fence may be installed in the ground by either of the two methods listed below.
a.Trenching Method
1.The Contractor shall excavate a trench to the depth, width, and length shown in the contract.
2.The Contractor shall place the silt fence in the trench and pin it as shown in the contract.
3.Wire staples shall be us ed for anchoring the silt fence.
4.The Contractor shall ba ckfill the trench, compact the soil, and attach the fabric to the posts as shown in the contract. The posts shall be driven until firm.
b.Slicing Method (1) The Contractor shall inst all silt fence by mechanically slicing the material into the soil.
816.03 Silt Fence
- 694 - (2) The Contractor shall compact the soil and attach the fabric to the posts as shown in the contrac t. The posts shall be driven until firm.
3.Silt Fence installed in below water conditions. a. Trenching is not required. b. Fold a 6 inch (150 mm) flap toward the sediment source and pin as shown in the contract. Install the stakes as for a dry installation. Attach the fabric to the posts with zip ties or other approved methods and secure from slipping down the post.
4.All silt fence splice joints sha ll be overlapped a minimum of 6 feet (1.8 m).
5.The Contractor shall remove sediment that accumulates near the silt fence during construction and di spose of it in an upland location.
a.Sediment removal shall be initiated when sediment depth has reached one-half the height of the above ground porti on of the silt fence or as directed by the Engineer in conjunction with silt fence repairs.
b.Sediment shall be removed to approximately 6 inches (150 mm) from the face of the silt fence.
c.Each time sediment is remo ved, the silt fenc e shall be repaired to a good working condition. Good work ing condition includes fabric repair, retrenching, post repair, tie replacement, and any associated handwork.
6.The Contractor shall maintain the silt fence in good working condition throughout the life of the construction project. Upon completion of the project silt fence shall remain in place in good working condition, in locations specified in the contract or at locations specified by the Engineer.
a.Silt Fence may be removed from locations during construction or upon completion of the project as spec ified in the contract or as directed by the Engineer.
b.Silt Fence that has been determined to be unnecessary and is subject to removal shall be cut off at ground level and shall remain the property of the Contractor for dispos al. Any accumulated sediment shall be removed to an upland location.
c.Silt Fence posts from remove d fence shall remain the property of the Contractor and may be reused on other installations.
d.Temporary Silt Fence shall be removed at the completion of the project or when it is no longer functional.
816.04 Method of Measurement
1.Silt fence will be measured by th e length of the silt fence in linear feet (meter).
2.Removal of sediment from the silt fence will be measured based on equipment rental. Silt Fence 816.05 - 695 - 816.05 -- Basis of Payment
1.P a y I t e m P a y U n i t Fabric Silt Fence “Low Porosity” Linear Foot (LF) [Meter (m)] Fabric Silt Fence “High Porosity” Linear Foot (LF) [Meter (m)] Fabric Silt Fence “Low Profile” Linear Foot (LF) [Meter (m)] Fabric Silt Fence “Coir Fiber” Linear Foot (LF) [Meter (m)] Temporary Silt Fence Linear Foot (LF) [Meter (m)] Rental of Skid Loader, Fully Operated Hour (h) Rental of Loader, Fully Operated Hour (h) Rental of Dump Truck, Fully Operated Hour (h) Rental of Backhoe, Fully Operated Hour (h) Rental of Crawler Mounted Hydraulic Hour (h) Excavator, Fully Operated
2.All silt fence repairs, such as fabric repair, tie replacement, retrenching, and splicing and associated handwork are subsidiary to the appropriate silt fence item.
3.Removal of silt fence and all of its components is subsidiary to the initial silt fence item.
4.Payment is full compensation for all work described in this Section. - 696 - SECTION 817 -- SLOPE TRACKING
817.01 Description
1.Slope tracking consists of placing cleat marks on a slope parallel to the contours to minimize erosion as show n in the contract or identified by the Engineer.
817.02 Construction Methods
1.Slope tracking shall be accomplished by the walking of tracked equipment perpendicular to the contour of a slope (not parallel to the contours of a slope) over an erodible area.
2.Slope tracking is performed using equipment pr opelled by tracks with parallel cleats at least 1-1/2 inch high.
817.03 Method of Measurement
1.Slope Tracking will be measured by the Square Yard (Square Meter) of roughened area.
817.04 Basis of Payment
1.P a y I t e m P a y U n i t Slope Tracking Square Yard (SY) {Square Meter (SM)}
2.Payment is full compensation for all work described in this Section.
Source: Nebraska Standard Specifications for Highway Construction, 2017 Edition. Pages 727–729 of 1,048.