Methods Of Sediment Control Steve Pudenz

1. Methods Of Sediment Control Steve Pudenz AGC/NDOR Partners in Construction

2. Properly installed silt fence is a very effective temporary sediment control device 100 ft. of silt fence can retain 180 tons of sediment. AGC/NDOR Partners in Construction

4. Goal of Silt Fence • Detain water for sedimentation to occur. • Occasionally used to divert stormwater to a storage area. • Retain large soil particles and prevent loss from the site. AGC/NDOR Partners in Construction

5. Effective silt fence works like a chain… Placement Installation Support Attachment Quantity Compaction Each link must work; if one link fails, the system fails AGC/NDOR Partners in Construction

6. Placement • Refers to specific location on each construction site. • Specific design (layout) at each location. Correct Incorrect AGC/NDOR Partners in Construction

7. J-hooks Designs called J-hooks insure water & sediment pond behind each silt fence. AGC/NDOR Partners in Construction

8. Proper Silt Fence Placement AGC/NDOR Partners in Construction

9. Proper Placement • Should pond water • Stop sediment before it reaches the pavement • Withstand concentrated flows • Should insure sedimentation AGC/NDOR Partners in Construction

10. The ends must always be long enough to pond water and sediment.

11. Incorrect Silt Fence Placement AGC/NDOR Partners in Construction

13. Myth – flat sites do not need protection AGC/NDOR Partners in Construction

15. Leave room for sediment storage at toe of slope AGC/NDOR Partners in Construction

16. DO NOT use silt fence: • Where you can not create a storage area for runoffExamples: Steep slopes, small areas, or shortsegments • Where you can not prevent water running around the end • In a V-shaped or shallow channel AGC/NDOR Partners in Construction

17. On-site adjustment is MANDATORY! • Grading plans are often drawn in an office many months prior to disturbance. • The ESC contractor must adjust the plan to properly control the site, or at a minimum notify the site managers of potential problems. AGC/NDOR Partners in Construction

18. QUANTITY Relates to area of control. The volume of water from a large site can not be controlled in one run of silt fence. Multiple locations or storage areas are often required. AGC/NDOR Partners in Construction

19. Long runs should be avoided. They tend to accumulate sediment in one area, causing premature overflow. AGC/NDOR Partners in Construction

21. Breaking up a run more than doubles storage area AGC/NDOR Partners in Construction

23. Multiple runs slow runoff velocity and add storage area on site. AGC/NDOR Partners in Construction

24. Proper Quantity • 100 ft. of silt fence per 10,000 sq. ft • of disturbed area seems to be an adequate rule of thumb for sediment control AGC/NDOR Partners in Construction

25. Installation Relates to how the fabric is placed in the soil, appropriate depth of placement, and appropriate backfill for an effective silt fence. AGC/NDOR Partners in Construction

27. Two Methods of Installation • Trenching • Mechanical/Slicing AGC/NDOR Partners in Construction

29. Mechanical Installation AGC/NDOR Partners in Construction

30. Mechanical Installation • Provides consistent, dependable silt fence • Reduces many labor related installation problems • Disturbs but does not excavate soil which creates an optimal condition for compaction AGC/NDOR Partners in Construction

31. Improper installation often leaves silt fence blowing in the wind. AGC/NDOR Partners in Construction

32. Compaction • Relates to soil permeability. Loose or trash-filled backfill is easily saturated with water and washed out under the silt fence. • Compacted soil resists saturation, and prevents washouts. AGC/NDOR Partners in Construction

33. Example of Poor Compaction AGC/NDOR Partners in Construction

34. Support Relates to a support system that will not fall over under the load of a full silt fence. AGC/NDOR Partners in Construction

35. 30” min. above ground 60" steel Support Post Spacing Posts should be 5 ½ ft. tall and spaced a maximum of 6 ft. apart. AGC/NDOR Partners in Construction

36. Properly supported silt fence will carry 24 inches of sediment. AGC/NDOR Partners in Construction

38. Proper attachment is the glue of the system, combing the strength of the fabric and the support posts into a unified structure. Attachment AGC/NDOR Partners in Construction

39. Attachment • Steel posts - recommend 3 plastic ties per post, located in the top 8 inches of the fabric, placed diagonally to attach as many threads as possible. • Wood posts - recommend several staples per post AGC/NDOR Partners in Construction

40. Attachment must be adequate to support a fully loaded silt fence AGC/NDOR Partners in Construction

42. Maintenance & Inspection • Key to successful silt fence • Inspect weekly and after every ½” rain event or as needed • Clean out when over half full or install a new silt fence above or below the current fence AGC/NDOR Partners in Construction

45. NDOR Silt Fence • Low Porosity • High Porosity • Coir Fence AGC/NDOR Partners in Construction

46. Low Porosity Silt Fence • Most Common • Used to contain sediment • Used for perimeter control • 42” Tall is NDOR standard • Low Profile is 36” tall used in urban areas and medians AGC/NDOR Partners in Construction

47. High Porosity Silt Fence • Used across ditches • Used to slow the flow of water • Not to be used for perimeter control AGC/NDOR Partners in Construction