Urban Mentors: Erosion Prevention & Sediment Control

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This is a training on erosion prevention & sediment control for small projects using the most commonly available and effective methods for various runoff conditions.

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Urban Mentors: Erosion Prevention & Sediment Control

  1. 1. Erosion Prevention & Sediment Control for Small Scale/Homeonwer Projects Sustainability for all the places between the buildings.
  2. 2. About Me
  3. 3. About You
  4. 4. Today, we will discuss Best management practices (BMPs) for: Preventing erosion & Controlling sediment
  5. 5. Brief Activity Shake the Soil Jars!
  6. 6. The Water Balance Model Water Quantity Before 25% baseflow (infiltration) 50% evaporation 0.5% runoff 100%average Annualrainfall 25%groundwater (infiltration)
  7. 7. Water Balance BEFORE Development Simplified
  8. 8. The Water Balance Model Water Quantity After 0” baseflow (infiltration) reducedevapo- transpiration 100%rainfall yearlyavg 98% runoff 2%evapo- transpiration Reduced infiltration
  9. 9. Water Balance AFTER Development Example: EVERYWHERE
  10. 10. “Before” & “After” Runoff Compared 0.5% runoff 98% runoff
  11. 11. Runoff Volumes: A Watershed Perspective
  12. 12. The Water Balance Model Water Quality Before Some sediment
  13. 13. The Water Balance Model Water Quality After Sediment (air particulates) Nutrients Feces Other debris Sediment/turbidity Hydrocarbons Heavy metals (particles & soluble) Other chemicals Runoff volume Sediment/turbidity fertilizers pesticides herbicides Runoff volume 13
  14. 14. Water Quality & Soil: A Watershed Perspective STR ESS C O VER ABAN D O N ED * AVO ID AN C E * IN C R EASED R ESPIR ATIO N * R ED U C ED FEED IN G * IN C R EASED C O U G H IN G R ATES R ED U C ED G R O W TH R ATES * D ELAYED H ATC H IN G * LO N G TER M R ED U C TIO N IN FEED IN G D EATH RELATIONSHIP OF FISH ACTIVITY TO TURBIDITY TIME (LOG 10) TURBIDITY(LOG10)
  15. 15. Soil is a Precious Resource (but very mobile) Image from Soil Quality Information Sheet, U.S. Department of Agriculture
  16. 16. Soil disturbance water quality approaches Prevent impacts/Source control Protect resources Mitigate impacts Restore resources
  17. 17. An Ounce of Prevention…
  18. 18. Source Control Materials Handling Place stockpiles so they don’t drain towards the street or a catch basin inlet Protect the soil from spills
  19. 19. Source Control Keep dirty stuff covered
  20. 20. Source Control Sweep your pavement
  21. 21. Erosion Prevention Retain Natural Vegetation
  22. 22. Tree Health During Construction http://tinyurl.com/TreeProt
  23. 23. Soil Quality Protection Limit Compaction The fencing below is great for protecting the tree, but its purpose is defeated when you move the fence to store materials inside it. Rent track-hoe or flotation tire equipment to do the heavy lifting.
  24. 24. Erosion Prevention Erosion prevention is any practice that protects the soil surface and prevents the soil particles from being detached by rainfall or wind.
  25. 25. Erosion Prevention Keep soils covered Courtesy of James Santana Rills have formed as a result of impervious soils concentrating runoff A generous covering of straw is one way to protect soil. Compost works, too! Courtesy of Paul Keiran
  26. 26. Erosion Prevention Cover Soils with Hydroseeding Hydroseeding is more expensive than straw and isn’t as reliable, but has the benefit of future vegeation growth.
  27. 27. Erosion Prevention Cover Soils with Fabrics
  28. 28. Erosion Prevention Limit Disturbance Fencing Plan new infrastructure over old
  29. 29. Soil disturbance water quality approaches Prevent impacts Protect resources Mitigate impacts Restore resources
  30. 30. Soil Quality Protection Time of Year Matters - Erosion Dry weather is the best time to avoid impacts
  31. 31. Habitat Value Time of Year Matters Primary nesting season is Apr 15 – Jul 31 Anna’s Humingbirds Photo by G. Engstrom Graphics from BES Terrestial Ecology Publication “Avoiding Impacts on Nesting Birds During Construction & Revegetation Projects”
  32. 32. Soil disturbance water quality approaches Prevent impacts Protect resources Mitigate impacts Restore resources
  33. 33. Sediment Control “Sediment Control is any practice that traps the soil particles after they have been detached and moved by wind or water”…
  34. 34. Sediment Control …to prevent this! Photo excerpted from “ODEQ Erosion and Sediment Control Manual”, DEQ, Apr 2005
  35. 35. Different strategies for two kinds of flow Overland (aka Sheet Flow) Concentrated
  36. 36. Sediment Control - Overland Flow Sediment Fence Use & Maintenance
  37. 37. Sediment Control - Overland Flow Silt Fence Effectiveness If you MUST use a sediment fence, use it only in sandy soils, never in clayey soils! Photos and study and text excerpted from “BMPs for Stormwater Discharges Associated with Construction Activities”, DEQ, Feb 2006
  38. 38. Sediment Control for Overland Flow Compost Berm May be vegetated (foreground) or non-vegetated (background)
  39. 39. Sediment Control for All Flows Compost Sock Heavy & expensive, but there’s really no substitute for controlling sediment on pavement, as shown
  40. 40. Sediment Control for All Flows Wattle Courtesy of Paul Keiran
  41. 41. Sediment Control for Concentrated Flows at Inlets Inlet Filters
  42. 42. Sediment Control: Concentrated Flows Protecting Catch Basin Inlets
  43. 43. Soil disturbance water quality approaches Prevent impacts Protect resources Mitigate impacts Restore resources
  44. 44. Restore Soil Quality Compost Amendment All photos from Soils for Salmon website
  45. 45. Restore Soil Quality Amend Disturbed Soils with Compost
  46. 46. Restore Soil Quality Mycoryhzal Treatment from www.fungi.com
  47. 47. Confirm Establishment Before Removing Controls Courtesy of Paul Keiran
  48. 48. Take Home Messages •A little bit of dirt can muddy a lot of water •Your best, best management practices for protecting water resources from excess soils on a variety of projects are: •Sweeping •Soil cover strategies (fabrics, compost, straw) •Biobags •Compost berms •Wattles •Like everything, how you install and maintain determines how well they work
  49. 49. For much more detailed (but easy to understand) info… Oregon DEQ Publication: Construction Stormwater Erosion and Sediment Control Manual http://www.deq.state.or.us/wq/wqpermit/docs/general/npd es1200c/ErosionSedimentControl.pdf
  50. 50. Have fun
  51. 51. Thank You! Sustainability for all the places between the buildings.
  52. 52. Erosion Control Gravel Construction Entrance Existing Pavement or approved access point 4-6” Crushed Aggregate (ie. Big, angular rocks) Geotextile fabric (aka Filter fabric) underneath
  53. 53. Reduce Excavation
  54. 54. Salvage Materials
  55. 55. Recycle Construction Materials

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