1. Module 4: Temporary Sediment Controls

2. Learning Objectives n Identify locations for sediment control BMPs n Identify applications for different types of sediment control BMPs n Identify installation requirements for sediment control BMPs

3. Groups of BMP Techniques n Soil Stabilization n Sediment Control n Other BMPs Tracking Controls Wind Erosion Controls Non-Storm Water Management Materials and Waste Management

4. Sediment Control BMPs Introduction n Filtration: Silt Fence BMP n Basins and Traps: Desilting Basin, Sediment Trap, and Check Dam BMPs n Removal: Street Sweeping and Vacuuming BMP n Interception: Fiber Rolls, Gravel Bag Berm, Sand Bag, and Strawbale BMPs n Inlet Protection BMP

5. Silt Fence BMP (SC1) Field Manual –Page 62

6. Silt Fence BMP (SC1) Use n Toe of bare slopes n Down slope of exposed soil stockpiles along critical areas such as streams

7. Silt Fence BMP (SC1) Limitations n Not in mid-slope locations or slopes steeper than 4:1 n Maintenance required n Not for large water volumes n Not for live streams

8. Silt Fence BMP (SC1) Additional Considerations n Keying in fence (vertical entrenchment or ‘L’ entrenchment) n Stabilized or unstabilized installation n Proper positioning Toe of slope On the contour

9. Silt Fence BMP (SC1)

11. Silt Fence BMP Detail (SC1) Silt Fence Cross Section Silt Fence Oblique View Anchor Trench Support Fencing Field Manual –Page 65

12. Desilting Basin (SC2) Field Manual –Page 66

13. Use n Sediment may enter drainage or watercourse (cannot be used within a waterway) n Drainage area is between 2 and 4 ha (5-10 acres) n Failure will not cause loss of life or property Desilting Basin (SC2)

14. Limitations n Requires large surface area for settlement n Cannot be located in live stream n May be a safety concern requiring fencing n Risk of failure under high flow conditions

15. Desilting Basin (SC2) Additional Considerations n Locate where permanent detention basins will be n Size  capacity equal to 100 m 3 of storage per hectare  length more than twice the width  1 to 1.5 m depth

16. Desilting Basin (SC2) Additional Considerations (cont) n Overflows or bypasses protected from scour n Drainage within 72 hours following storm events Access for maintenance Inlet protection: rock or vegetation Forebay to collect debris “High hazard” Basins must be approved by P.E.

18. Desilting Basin BMP Detail (SC2) Stabilized Outlet Emergency Spillway Stabilized Inlet Field Manual –Pages 70 and 71

19. Sediment Trap (SC3) Field Manual –Page 72

20. Use n Located across a drainage way n Excavated/constructed of earthen material n For drainage areas < 2ha Sediment Trap (SC3)

21. Limitations n Requires large surface area to permit settling n Not appropriate for drainage areas > 2ha n Hazardous; may require fencing n Not appropriate in live stream n May be a safety concern requiring fencing

22. Sediment Trap (SC3) Additional Considerations n Use where failure will not cause loss of life or property n Capacity and Dimensions  Settling zone: 130 m 3 /ha of drainage area  storage zone: 65 m 3 /ha of drainage area  Length to width >3:1

23. Sediment Trap (SC3) Additional Considerations (cont) n Basins >1,000m 3 and/or levees >1.5m must be approved by registered PE n Must have access for maintenance

25. Sediment Trap BMP Detail (SC3) Sediment trap Stabilized Oultet Field Manual –Page 75

26. Check Dams (SC4) Field Manual –Page 76

27. Check Dams (SC4) Use n Located across a drainage way n Constructed of rocks, sandbags, or fiber rolls n Small channels and drainage areas < 4ha n Can be used in steep channels with high runoff velocities n In association with grass-lined channels

28. Check Dams (SC4) Limitations n Not appropriate for channel areas > 4ha n Not in live stream areas or well-vegetated channels n Will require maintenance after high flows n Sediment can be re-suspended n Not to be constructed using silt fence

29. Additional Considerations n Dam height and spacing n Safely pass high stormwater flows n Remove when grass established n Hand work may be required to shape dam Check Dams (SC4)

33. Check Dams BMP Detail (SC4) Check Dam Cross Section Lowered Center Spillway Field Manual –Page 78

34. Dugout Ditch Basin BMP (SC11) Sediment Control Basin Field Manual –Page 100

35. Dugout Ditch Basin BMP (SC11) Use n One or a series of small dugout basins located within a flow channel n Reduce runoff velocity, promote sediment retention n Sediment traps, interceptor ditches, toe of slope protection n Spacing dependent on ditch slope

36. Dugout Ditch Basin BMP (SC11) Limitations n Not to be used in live streams n Not to be used in vegetated channels n Require maintenance n Trapped sediment can be resuspended during subsequent storms

37. Dugout Ditch Basin BMP (SC11) Additional Considerations n Designed for 2-year, 24 hour rain event n Can remain in place and seeded with permanent seeding of ditch

38. Dugout Ditch Basin BMP Detail (SC11) Cross Section Dugout basins Field Manual –Page 102

39. Fiber Rolls (SC5) and Gravel Bag Berm (SC6) SC5 - Field Manual – Page 79 SC6 - Field Manual – Page 82

40. Fiber Rolls (SC5) and Gravel Bag Berm (SC6) Use n Designed to shorten slope lengths and intercept and slow sheet flow, reduce flow velocity, and trap and remove some sediment n Fiber Rolls - straw, flax, rolled and bound n Gravel Bag Berms - a single roll of gravel bags n Used on the face of slopes, at the top of slopes, and at grade breaks

41. Fiber Rolls (SC5) and Gravel Bag Berm (SC6) Limitations n Gravel Bags may rupture when removed, are laborious to install, and have limited durability for long projects n Fiber rolls may not degrade in the short term

42. Additional Considerations n Locate on level contour n Fiber rolls are typically left in place n Gravel bag berms may be removed Fiber Rolls (SC5) and Gravel Bag Berm (SC6)

43. Fiber Rolls

44. Fiber Rolls BMP Detail (SC5) Roll Anchored in Trench Rolls placed on contour Field Manual –Page 81

45. Gravel Berm Bag BMP Detail (SC6) Gravel Bags placed on contour Field Manual –Page 84

46. Street Sweeping and Vacuuming (SC7) Field Manual –Page 85

47. Street Sweeping and Vacuuming (SC7) Use n Remove tracked soil to prevent it’s entry into storm drain or watercourse

48. Limitations n Not effective in wet conditions n May require daily treatment Street Sweeping and Vacuuming (SC7)

49. Additional Considerations n May collect hazardous materials

51. Sandbag Barrier (SC8) Field Manual –Page 87

52. Sandbag Barrier (SC8) Use n Linear barrier of stacked sandbags n Slows sheet water flow n Increases detention time and sedimentation

53. Sandbag Barrier (SC8) Limitations n Installation can be labor intensive n Only where the up-gradient area is small (i.e., < 2 ha) n Limited durability

54. Sandbag Barrier (SC8) Additional Considerations n To create a temporary sediment basin n As sediment berms in stream beds (< 2ha) n When extended construction period limits the use of either silt fences or straw bale barriers n Along the perimeter of vehicle and equipment fueling and maintenance areas or chemical storage areas n To capture and detain non-storm water flows until proper cleaning operations occur

56. Sand Bag Barriers BMP Detail (SC8) Plan View Lowered Center Spillway Field Manual –Page 90

57. Straw Bale Barriers (SC9) Field Manual –Page 91

58. Straw Bale Barriers (SC9) Use n Linear barrier of straw bales designed to intercept and slow sheet flow n Increases on-site detention time and sedimentation n Along the perimeter of site and stream channels n Along roadways and around stockpiles n Across minor swales

59. Straw Bale Barriers (SC9) Limitations n Not in channels or live streams with high flows n Labor intensive installation and removal n Maintenance intensive (disintegration) n Can not be used on paved surfaces n Drainage area small (<100m) slopes short (30m)

60. Straw Bale Barriers (SC9) Additional Considerations n Wooden stakes used to anchor bales to soil n Bales embedded into soil n Install bales on the contour n Tightly abut bales n Offset second rows of bales when used

61. Straw Bale Barriers (SC9)

64. Straw Bale Barriers BMP Detail (SC9) Bales embedded in soil Bales overlapping Bales anchored with stakes Field Manual –Page 93

65. Storm Drain Inlet Protection (SC10) Field Manual –Page 94

66. Storm Drain Inlet Protection (SC10) Use n Devices used to prevent sediment from entering storm drains n Used with other BMPs as the last defense n Appropriate Use:  Where ponding of water will not cause flooding  During wet and snow-melt seasons  Need to allow water into inlet

67. Storm Drain Inlet Protection (SC10) Limitations n Last line of defense n High flow may damage n Heavily sediment laden storm water may plug n Adversely effected by ponding

68. Additional Considerations n Various BMPs applicable to sediment control n Filter fabric n Sandbags n Straw bales n Gravel check dam Storm Drain Inlet Protection (SC10)

69. No inlet protection Filter Fabric Application

70. Storm Drain Inlet Protection BMP Detail (SC10) Straw Bale Application Filter Fabric Application Field Manual –Page 98

71. Storm Drain Inlet Protection BMP Detail (SC10) Sand Bag Application Gravel Check Dam Application Field Manual –Page 99

72. Summary of SC BMPs n Toolbox of different techniques n Need to be adapted to site conditions n Capture sediment from runoff n Require maintenance n Generally removed after vegetation established

73. Discussion photo

77. The end of Sediment Control BMPs Discussion