Erosion & Sediment Control for Stream Restoration Projects<br />Greg Jennings, PhD, PE<br />Professor & Extension Speciali...
NC Sediment Pollution Control Act, 1973<br />15A NCAC 04B .0105	<br />    PROTECTION OF PROPERTY<br />Persons conducting l...
Construction Practices<br />Site Preparation<br />Grading<br />Structures<br />Site Stabilization<br />
1. Site Preparation<br /><ul><li>Construction entrance
Silt fence
Staging & stockpile
Temporary crossings
Stream flow diversion</li></li></ul><li>Silt Fence<br />Metal Posts 8 feet apart<br />Reinforcing wire backing (14 ga. w/ ...
Silt Fence Problems<br />
Silt Fence Problems<br />
Staging and Stockpile<br />
Stockpile AreaSilt fence & seeding<br />
Problems?<br />
Temporary Stream Crossing<br />Rock ford<br />Culvert<br />Portable log mat<br />
Problems?<br />
	Prevent erosion around culvert<br />
Problems?<br />
Stream Flow Diversion<br />Open channel<br />Pipe<br />Pump around<br />Work in wet<br />
Open channel<br />	Must dissipate energy at end<br />
Problems?<br />
Pipe<br />
Pipe Undersized<br />
Pump Around:  Match pump to 2 x base flow<br />
	Check dam to retain base flow<br />	Quiet pump in residential area<br />
	Pump discharge downstream<br />
Problem?<br />
Special Stilling Basin:  Filter Bag<br />
Problem?<br />
Problem?<br />
2. Grading<br />Stage project to limit exposed areas<br />Use temporary ground cover<br />Use track equipment if possible<...
Clearing & Grubbing<br />Followed by Survey Stakeout<br />
Problem?<br />
Problem?<br />
3. Structures<br />Build according to design<br />Check elevations (twice)<br />Footer boulders and backer logs<br />Seal ...
Filter fabric for all structures</li></li></ul><li>Boulder Cross Vane<br />20-30 degree angles<br />2-5 % arm slopes<br />...
Laser Level for Grade Check<br />
Log Vane (with root wad)<br />Backer Log<br />
Woven filter fabric nailed to top log<br />
Geotextilenailed to top log<br />
Overhanging top log for fish cover<br />
Why do structures fail?<br /><ul><li>Rocks or logs not placed properly
Piping under or through rocks or logs
Lack of geotextile, improperly placed
Excess scour
Poor vegetation & bank stability</li></li></ul><li>Structure Problems<br /><ul><li>Wrong Location
Too Steep
Not Keyed Into Bank
Poor Vegetation Establishment
Not Sealed</li></li></ul><li>Poor placement and not keyed in<br />
Drop too great<br />
Easy to spot during high flows…<br />
Also easy to spot…after the flows have receded<br />
Too steep<br />
Too steep<br />How about this one?...<br />Keep log wet…even at normal daily flow<br />
Structural collapse<br />
Root Wads Too High<br />Too Few & Washed Out Behind<br />
Problem?<br />
Problem?<br />
Problem?<br />
4. Site Stabilization<br />Temporary ground cover (mulch & matting)<br />Permanent ground cover (vegetation)<br />Prepare ...
Straw Mulch:  75% cover (2 tons/acre)<br />
Hydroseeder (mulch, seed, fertilizer)<br />
Matting<br />Biodegradable (coir, jute, excelsior, straw)<br />Seed and straw UNDER matting<br />Keep matting relaxed<br /...
No Plastic!<br />
Each Day:<br />Seed, straw, matting<br />
Erosion control every day<br />
Large stakes at toe of slope<br />
Problem?<br />
Irrigation<br />
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Rc401 construction jennings e&s

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Rc401 construction jennings e&s

  1. 1. Erosion & Sediment Control for Stream Restoration Projects<br />Greg Jennings, PhD, PE<br />Professor & Extension Specialist<br />Biological & Agricultural Engineering<br />North Carolina State University<br />jenningsenv@gmail.com<br />Thanks to Wyatt Brown, LSS, CPESC<br />NC Ecosystem Enhancement Program<br />
  2. 2. NC Sediment Pollution Control Act, 1973<br />15A NCAC 04B .0105 <br /> PROTECTION OF PROPERTY<br />Persons conducting land‑disturbing activity shall take all reasonable measures to protect all public and private property from damage caused by such activities.<br />History Note: Authority G.S. 113A‑54(b); 113A‑54(d)(2);<br />Eff. February 1, 1976;<br />Amended Eff. August 1, 1988; November 1, 1984.<br />
  3. 3. Construction Practices<br />Site Preparation<br />Grading<br />Structures<br />Site Stabilization<br />
  4. 4. 1. Site Preparation<br /><ul><li>Construction entrance
  5. 5. Silt fence
  6. 6. Staging & stockpile
  7. 7. Temporary crossings
  8. 8. Stream flow diversion</li></li></ul><li>Silt Fence<br />Metal Posts 8 feet apart<br />Reinforcing wire backing (14 ga. w/ 6-inch mesh)<br />Bury fence 8 inches deep<br />
  9. 9. Silt Fence Problems<br />
  10. 10. Silt Fence Problems<br />
  11. 11. Staging and Stockpile<br />
  12. 12. Stockpile AreaSilt fence & seeding<br />
  13. 13. Problems?<br />
  14. 14. Temporary Stream Crossing<br />Rock ford<br />Culvert<br />Portable log mat<br />
  15. 15.
  16. 16. Problems?<br />
  17. 17.
  18. 18. Prevent erosion around culvert<br />
  19. 19.
  20. 20. Problems?<br />
  21. 21. Stream Flow Diversion<br />Open channel<br />Pipe<br />Pump around<br />Work in wet<br />
  22. 22. Open channel<br /> Must dissipate energy at end<br />
  23. 23. Problems?<br />
  24. 24. Pipe<br />
  25. 25. Pipe Undersized<br />
  26. 26. Pump Around: Match pump to 2 x base flow<br />
  27. 27. Check dam to retain base flow<br /> Quiet pump in residential area<br />
  28. 28. Pump discharge downstream<br />
  29. 29. Problem?<br />
  30. 30. Special Stilling Basin: Filter Bag<br />
  31. 31. Problem?<br />
  32. 32. Problem?<br />
  33. 33. 2. Grading<br />Stage project to limit exposed areas<br />Use temporary ground cover<br />Use track equipment if possible<br />Keep stormwater runoff away from site<br />
  34. 34. Clearing & Grubbing<br />Followed by Survey Stakeout<br />
  35. 35.
  36. 36. Problem?<br />
  37. 37. Problem?<br />
  38. 38. 3. Structures<br />Build according to design<br />Check elevations (twice)<br />Footer boulders and backer logs<br />Seal structures to prevent piping<br /><ul><li>“Chink” rock structures
  39. 39. Filter fabric for all structures</li></li></ul><li>Boulder Cross Vane<br />20-30 degree angles<br />2-5 % arm slopes<br />20-30 degrees<br />2-5 % arm slopes<br />
  40. 40. Laser Level for Grade Check<br />
  41. 41.
  42. 42.
  43. 43.
  44. 44. Log Vane (with root wad)<br />Backer Log<br />
  45. 45. Woven filter fabric nailed to top log<br />
  46. 46. Geotextilenailed to top log<br />
  47. 47. Overhanging top log for fish cover<br />
  48. 48. Why do structures fail?<br /><ul><li>Rocks or logs not placed properly
  49. 49. Piping under or through rocks or logs
  50. 50. Lack of geotextile, improperly placed
  51. 51. Excess scour
  52. 52. Poor vegetation & bank stability</li></li></ul><li>Structure Problems<br /><ul><li>Wrong Location
  53. 53. Too Steep
  54. 54. Not Keyed Into Bank
  55. 55. Poor Vegetation Establishment
  56. 56. Not Sealed</li></li></ul><li>Poor placement and not keyed in<br />
  57. 57. Drop too great<br />
  58. 58. Easy to spot during high flows…<br />
  59. 59. Also easy to spot…after the flows have receded<br />
  60. 60. Too steep<br />
  61. 61. Too steep<br />How about this one?...<br />Keep log wet…even at normal daily flow<br />
  62. 62. Structural collapse<br />
  63. 63. Root Wads Too High<br />Too Few & Washed Out Behind<br />
  64. 64. Problem?<br />
  65. 65. Problem?<br />
  66. 66. Problem?<br />
  67. 67. 4. Site Stabilization<br />Temporary ground cover (mulch & matting)<br />Permanent ground cover (vegetation)<br />Prepare for rain!<br />
  68. 68. Straw Mulch: 75% cover (2 tons/acre)<br />
  69. 69. Hydroseeder (mulch, seed, fertilizer)<br />
  70. 70. Matting<br />Biodegradable (coir, jute, excelsior, straw)<br />Seed and straw UNDER matting<br />Keep matting relaxed<br />Stakes: wood or biodegradable plastic<br />
  71. 71.
  72. 72. No Plastic!<br />
  73. 73.
  74. 74. Each Day:<br />Seed, straw, matting<br />
  75. 75. Erosion control every day<br />
  76. 76. Large stakes at toe of slope<br />
  77. 77. Problem?<br />
  78. 78. Irrigation<br />
  79. 79. Overland Flow<br />
  80. 80. Straw Wattle used as Berm<br />
  81. 81. Straw Wattle used as Berm<br />
  82. 82. Site Inspection<br />
  83. 83. Note: Channel stabilized before floodplain<br />
  84. 84. Successful Project:<br />Good design considering hydraulic & sediment transport processes<br />Communication between designer & contractor<br />Flexibility to make field changes<br />Understanding of environmental regulations<br />Prepare for flooding!<br />
  85. 85. Use Common Sense<br />
  86. 86. Thanks to:Wyatt Brown, NC EEPDan Clinton, CaryDarrell Westmoreland, North State EnvironmentalJan Patterson, Cary, NC<br />
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