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1 Course Highlights –Introduction –Planning for Erosion and Sediment Control –Erosion Control BMP Implementation –Sediment Control BMP Implementation –Class.

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Presentation on theme: "1 Course Highlights –Introduction –Planning for Erosion and Sediment Control –Erosion Control BMP Implementation –Sediment Control BMP Implementation –Class."— Presentation transcript:

1 1 Course Highlights –Introduction –Planning for Erosion and Sediment Control –Erosion Control BMP Implementation –Sediment Control BMP Implementation –Class Exercise –Field Demonstration of BMPs

2 2 SEDIMENT CONTROL BMPs SC-1 SILT FENCE SC-4 CHECK DAMS SC-5 FIBER ROLLS SC-6 GRAVEL BAG BERM SC-8 SAND BAG BARRIER SC-9 STRAW BALE BARRIER SC-10 STORM DRAIN INLET PROTECTION

3 3 SEDIMENT CONTROLS Intercept sediment laden runoff, slow the flow, and allow the suspended sediment particles to drop out of suspension.

4 4 SEDIMENT CONTROL BMPs SC-1 Silt Fence –Permeable fabric designed to intercept and slow flow of sediment-laden sheet flow runoff

5 5 SC-1 SILT FENCE Material Requirements –Silt fence shall be woven polypropylene fabric –Minimum width of 900 mm (36 inches) –The fabric shall conform to the requirements in ASTM designation D4632 and have an integral reinforcement layer –The permittivity of the fabric shall be between 0.1 sec -1 and in conformance with ASTM designation D4491

6 6 SC-1 SILT FENCE Stakes Requirements –Wood stakes shall be commercial quality lumber –Stake dimensions: 50 x 50 mm by 1200 mm in length –Stakes shall be free from decay, splits or cracks longer than the thickness of the stakes –Bar reinforcement may be used, and its size shall equal to or greater than (4) and end protection is required –2.5 m maximum stake spacing

7 7 SC-1 SILT FENCE Design and layout –Maximum length of slope draining to any point shall be 61 m (200 ft) –Slope of area draining to the silt fence shall be less than 1:1 VH –For slopes steeper than 1:2 that contain large numbers of rocks or dirt clods that tend to dislodge additional protection may be necessary

8 8 SC-1 SILT FENCE Installation Requirements –“Key-in” bottom of silt fence a minimum of 150 mm (12 inches) –Reach of silt fence shall not be longer than 150 m (490 ft) –Construct each reach so that the base elevation does not exceed 1/3 the height of the barrier –Construct silt fence with a set-back of a least 1 m (3 ft) from the toe of the slope

9 9 SC-1 SILT FENCE 2000 to 2003 Manual Changes: –Added limitations for: Not implementing on slope subject to creeping, slumping and landslides Not implementing in areas of concentrated flow Do not use silt fences for diverting flow –Added specification for silt fence to meet Standard Specification Section –Added specification to key silt fence a minimum of 300 mm

10 10 SEDIMENT CONTROL BMPs SC-4 Check Dams –Are small devices constructed of rock, gravel bags, sand bags, fiber roll, of other proprietary devices placed across natural or man-made channels or ditches

11 11 SC-4 CHECK DAMS Material (bags) Requirements –Bags shall be either polypropylene, polyethylene, or polyamide woven fabric –Minimum unit weight of 135 g/m2 (four ounces per square yard) –Burst strength exceeding 2,070 kPa (300 psi) in conformance with ASTM designation D3786 –Ultraviolet stability exceeding 70% in conformance with ASTM designation D4355

12 12 SC-4 CHECK DAMS Bag size Requirements : –Each gravel-filled bag shall have a length of 450 mm (18 inches), width of 300 mm (12 inches), thickness of 75 mm (3 inches), and mass of approximately 15 kg (33 lbs) –Alternate bags sizes need approval by the Resident Engineer Fill material: –Fill material shall be between 10 mm and 20 mm (0.4 and 0.8 inches) in diameter –Be free from clay balls, organic matter and other deleterious material –Filled bag shall be between 13 kg and 22 kg (28 and 48 lbs) in mass

13 13 SC-4 CHECK DAMS Installation Requirements –Limit area draining to check dams to 4 ha (10 ac) or less –Install along a level contour –Tightly abut bag and stack in a pyramid fashion –Place at a distance and height to allow small pools to form behind them –Install the first check dam 5 m (16 ft) from the outfall –Space bags based on slope gradient and soil type –Gravel bags shall not be stacked higher than 1 m (3.2 ft)

14 14 SC-4 CHECK DAMS 2000 to 2003 Manual Changes: –Gravel bags, fiber roll and other proprietary products add as construction material –Fiber rolls need RE or NPDES Coordinators approval –Gravel bags may be used with new specifications Gravel diameter between mm Bag size and material added Installation specification for stacking

15 15 SEDIMENT CONTROL BMPs SC-Fiber Rolls –Consist of wood excelsior, rice or wheat straw, or coconut fibers that are rolled and bound into a tight tubular roll and placed on slopes to intercept runoff

16 16 SC-5 FIBER ROLLS Material Requirements : –Fiber roll shall be either (1) prefabricated rolls or (2) rolled tubes of erosion control blankets –For filled rolled fiber rolls; roll into a minimum of 200 mm (8 in) diameter, and bond every 1.2 m (4 ft) along the length of the roll

17 17 SC-5 FIBER ROLLS Installation Requirements: –For breaking-up slope length fiber roll spacing is based on slope inclination 1:4 or flatter – spacing shall be placed 6.0 m apart 1:4 to 1:2 – spacing shall be 4.5 m apart 1:2 or greater – spacing shall be 3.0 m apart –Place fiber rolls into a 50 to 100 mm trench –Stake or tie fiber rolls into place Tied fiber rolls staking is spaced at 600 mm (2 ft) apart Stake spacing at 1.2 m (4 ft) apart

18 18 SC-5 FIBER ROLLS 2000 to 2003 Manual Changes: –Fiber roll materials change –Specifications that rolls be placed at grade breaks, toe and face of slopes –Specifies that they can be used for drain inlet protection –Specifies that they can be used as check dams –Larger size may be needed at toes of slopes –Restricts use on slopes subject to creep, slumping or landslides –Spacing intervals on slopes reduced –Overlapping of ends and new detail –Maintenance features added with sediment build-up removal

19 19 SEDIMENT CONTROL BMPs SC-6 Gravel Bag Berms –Are woven fabric type of bags placed across slopes to intercept runoff, reduce its flow velocity, and release it as sheet flow

20 20 SS-6 GRAVEL BAG BERMS Material (bags) Requirements –Bags shall be either polypropylene, polyethylene, or polyamide woven fabric –Minimum unit weight of 135 g/m2 (four ounces per square yard) –Burst strength exceeding 2,070 kPa (300 psi) in conformance with ASTM designation D3786 –Ultraviolet stability exceeding 70% in conformance with ASTM designation D4355

21 21 SS-6 GRAVEL BAG BERMS Bag size Requirements : –Each gravel-filled bag shall have a length of 450 mm (18 inches), width of 300 mm (12 inches), thickness of 75 mm (3 inches), and mass of approximately 15 kg (33 lbs) –Alternate bags sizes need approval by the Resident Engineer Fill material: –Fill material shall be between 10 mm and 20 mm (0.4 and 0.8 inches) in diameter –Be free from clay balls, organic matter and other deleterious material –Filled bag shall be between 13 kg and 22 kg (28 and 48 lbs) in mass

22 22 SS-6 GRAVEL BAG BERMS Installation requirements: –Install along a level contour –Turn ends of bags up slope to prevent flow around ends –Use in conjunction with temporary soil stabilization –Construct barriers with a set-back of a least 1 m from toe of slope –For concentrated flows: stack bags using a pyramid approach, overlap upper joints from lower rows

23 23 SS-6 GRAVEL BAG BERMS 2000 to 2003 Manual Changes: –Added language for application where flows are moderately concentrated –Revised specifications for fill materials –Burlap bags are no longer allowed –Added application and installation for linear sediment control, on slopes, toe of slopes, stockpiles, concentrated flows and perimeter barriers –Add Certification of Compliance per Standard Specs

24 24 SEDIMENT CONTROL BMPs SC-8 Sandbag Barrier –Are a woven fabric type of bag designed to intercept and slow flow of sediment- laden sheet flow runoff

25 25 SC-8 SANDBAG BARRIER Material (bags) Requirements –Bags shall be either polypropylene, polyethylene, or polyamide woven fabric –Minimum unit weight of 135 g/m2 (four ounces per square yard) –Burst strength exceeding 2,070 kPa (300 psi) in conformance with ASTM designation D3786 –Ultraviolet stability exceeding 70% in conformance with ASTM designation D4355

26 26 SC-8 SANDBAG BARRIER Bag size Requirements : –Each gravel-filled bag shall have a length of 450 mm (18 inches), width of 300 mm (12 inches), thickness of 75 mm (3 inches), and mass of approximately 15 kg (33 lbs) –Alternate bags sizes need approval by the Resident Engineer Fill material: –All sandbag fill material shall be non-cohesive, Class 1 or Class2 permeable material free from clay and deleterious material –Conform to section of the Standard Specifications –Fill Material is subject to approval of the RE

27 27 SC-8 SANDBAG BARRIER Installation requirements: –Install along a level contour –Turn ends of bags up slope to prevent flow around ends –Use in conjunction with temporary soil stabilization –Construct barriers with a set-back of a least 1 m from toe of slope

28 28 SC-8 SANDBAG BARRIER 2000 to 2003 Manual Changes: –Burlap bags are no longer allowed –Category changed from “linear sediment removal” to “Linear sediment control”

29 29 SEDIMENT CONTROL BMPs SC-9 Straw Bale Barrier –Are temporary linear sediment barriers consisting of straw bales, designed to intercept and slow sediment-laden sheet flow runoff

30 30 SC-9 STRAW BALE BARRIER Material (bales) Requirements –Material shall conform to the provisions in Standard Specifications Section “straw” –Straw shall be derived from wheat, rice, or barley –The contractor shall furnish evidence that clearance has been obtained from the County Agriculture Commissioner, as required by law, if straw is obtained from outside the country

31 31 SC-9 STRAW BALE BARRIER Straw Bale size Requirements: Each bale shall be a minimum of 360 mm (14 in) wide, 450 mm (18 in) in height, 900 mm (36 in) in length and shall have a minimum mass of 23 kg (51 lbs) Bales shall be composed entirely of vegetative matter, except binding material

32 32 SC-9 STRAW BALE BARRIER Stakes –Wood stakes shall be commercial quality lumber –Stake dimensions: 50 x 50 mm by 1200 mm in length –Stakes shall be free from decay, splits or cracks longer than the thickness of the stakes –Bar reinforcement may be used, and its size shall equal to or greater than (4) and end protection is required –2.5 m maximum stake spacing

33 33 SC-9 STRAW BALE BARRIER Installation Requirements: –Limit upstream drainage area to 0.3 ha/100 m –Limit length of slope draining to barrier to 30 m (100 ft) –Slopes of 2:100 V:H or flatter are preferred –If slope exceeds 1:10 V:H slope length must be less than 15 m (50 ft) –Install along level contours –Bales must be trenched in and tightly abutted together –Construct barriers with a set-back of a least 1 m from toe of slope

34 34 SC-9 STRAW BALE BARRIER 2000 to 2003 Manual Changes: –Added limitations verbiage that bales can invite undesirable non- native plants and be an attractive animal food source –Added option to allow use of #4 steel bars as stakes

35 35 SEDIMENT CONTROL BMPs SC-10 Storm Drain Inlet Protection –Device used at storm drain inlets to detain of filter sediment-laden runoff

36 36 SC-10 INLET PROTECTION DI Protection Types –Filter fabric fence –Excavated drop inlet sediment trap –Gravel bag –Foam barrier and fiber rolls

37 37 SC-10 INLET PROTECTION General requirements: –Requires adequate area for ponding without encroaching upon the traveled way –Frequent maintenance is required –Draining areas greater than 0.4 ha (1 ac) shall be routed to a sediment trapping device –May require other methods of temporary protection to prevent sediment-laden storm water and non-storm water flow from entering inlets –If high flows are expected use other sediment trapping devices in conjunction with inlet protection

38 38 SC-10 INLET PROTECTION Type -1 Filter Fabric Fence –Appropriate in open areas subject to sheet flows –Flows should not exceed m3s (0.5 cfs) –Do not place fabric underneath grate inlet

39 39 SC-10 INLET PROTECTION Type-2 Excavated Drop Inlet Sediment Trap –Appropriate where relatively high heavy flows are expected and over flow capacity is needed –Size excavated trap to provide a minimum storage capacity of 130 m3 per ha of drainage area

40 40 SC-10 INLET PROTECTION Type-3 Gravel Bag –Appropriate where flows exceed m3/s (0.5 cfs) and it is necessary to allow overtopping to prevent flooding –Flows shall not overtop curb –Construct in accordance with BMP SC-6 –In areas with high silts and clayey soils use additional media for protection

41 41 SC-10 INLET PROTECTION Type-4 Foam Barriers and Fiber Rolls –Not appropriate for locations where they can not be properly anchored –Intended for use in areas around inlets are unpaved –Requires RE or DSWC approval

42 42 SC-10 INLET PROTECTION 2000 to 2003 Manual Changes: –Sandbags are no longer allowed (gravel bags) –Added option of using foam barriers of fiber rolls if they can be properly anchored (RE/DCSWC approval) –Type 1 - use of filter fabric fence added to spec when grade is established and erosion control seeding is installed or pending –Type 2 – excavated drop inlet specified in areas of exposed soils –Type 3 – gravel bag barriers are specified in areas of paved surfaces –Added specification on removing built-up sediment from foam barriers and silt fences


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