New and Recommended Construction Best Management Practices

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New and Recommended Construction Best Management
Practices

• Joe Willingham, P.E.
• Professional Engineer III
• Industrial Wastewater Enforcement Section
• Water Quality Division
• Department of Environmental Quality

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Outline

• Planning and Design
• Sediment Transport
• Structural BMPs
• Non-Structural BMPs

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Planning and Design

• Size of the site vs. plans for disturbed area
• Site drainage with acreage specifics
• Slopes, sheet flow and drainage controls

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Timing of Controls

• Scheduling Its all about timing.
• When to start?
• How long will it take?
• Is rainfall imminent?
• What is the purpose?
• Erosion control, runoff control, sediment control

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Disturb as Necessary
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Timing of Controls

• Perimeter controls generally should be installed
  properly before construction commences.
• Perimeter controls does not necessarily mean a
  silt fence wrapped around the site.
• These also include sediment basins and traps,
  especially the outlets from the site.
• Mature vegetation

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The Sediment Cycle

• Detachment can occur in a variety of ways
  including raindrop impact and abrasion
• Entrainment the lifting of the detached
  particle by the energy of the eroding medium
• Transport the carrying of the detached and
  entrained particle from its source to another
  location
• Deposition the placement of the transported
  particle

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Particle TransportStream flow velocity vs.
particle size
Source PhysicalGeography.net
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Particle Transport
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Structural BMPs

• Management of runoff utilizing detention,
  retention, attenuation, infiltration or a
  combination of these
• Velocity dissipation
• Erosion vs. sediment control
• Erosion control BMPs measures to limit
  detachment and entrainment of soil particles
• Sediment control BMPs measures to limit
  transport of soil particles

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Erosion Controls

• Erosion controls
• Protect soils from the erosive forces of falling
  stormwater, sheet flow and rill erosion
• Reduce DETACHMENT by impact and abrasion and
  ENTRAINMENT

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Erosion Controls
Beat sediment where it starts.
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Erosion Controls

• Examples
• Erosion Control Blankets (ECBs)
• Turf Reinforcement Mats (TRMs)
• Surface roughening

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Erosion Controls

• Examples
• Vegetative (straw) mulches
• Anchoring
• Crimping, tracking, discing or punching into soil
• Netting
• Spraying with asphaltic or organic tackifier
• Tacking with cellulose fiber mulch
• Wood (chips or bark) mulches
• Hydraulic (recylcled paper or wood fiber) mulches

VS
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Erosion Controls

• Examples
• Compost blankets
• Riprap
• Hydroseeding
• Hydromulching
• Gradient terraces
• Dust control

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The Best Erosion Control BMP
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Undisturbed vs. Disturbed
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Runoff Controls

• Runoff controls
• Protect soils by reducing velocities and thereby
  reducing rill and gully erosion and sediment
  transport capacity
• Reduce ENTRAINMENT and TRANSPORT capacity

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Runoff Controls

• Examples
• Grass-lined channels
• Check dams
• Permanent or temporary diversions

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Sediment Controls

• Sediment controls
• Reduce sediment transport capacity through
  ponding
• Reduce TRANSPORT capacity by providing DEPOSITION

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Sediment Controls

• Examples
• Sediment basins
• Sediment traps
• Sediment barriers

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Sediment Basins

• Permit Requirements
• 10 acres of disturbed soil draining to one
  discharge point
• 3600 ft3 per acre drained
• or
• A basin that will hold a 2 yr/24 hr storm event
  (USGS Depth-Duration-Frequency)
• Maintenance
• When a basin or trap is filled to 50 capacity
  with sediment, it must be cleaned out to maintain
  successful sedimentation

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Sediment Basins

• Construction Considerations
• Retention time is the key to settling as much as
  possible
• A 36 ft deep hole, 10 ft X 10 ft on the surface
  is not equal to a 60 ft X 60 ft surface area
  pond, 1 ft deep
• A 100 ft wide pond, with a distance of 10 ft from
  the inlet area to the outlet structure, 3.6 ft
  deep is not equal to a 10 ft wide pond, with a
  distance of 100 ft from the entrance area to the
  outlet structure, 3.6 ft deep
• Outlet structures Top to bottom notch, floating
  outlet, sized tinhorns or pipes to control flow
  rate

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Sediment Basins

• I dont need to worry about silt fences and
  crap, I got a sediment basin down the hill! -
  _____________
• Even at 90 trapping efficiency for bare soil due
  to particle size distribution, the sediment
  discharged from a basin will be significantly
  greater (10 times) than for vegetated soils
  simply due to the fact that vegetation will
  greatly decrease the amount of sediment entering
  the basin in the first place.

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Velocity Dissipation
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Sediment Controls

• Examples
• Filter berms
• Fiber rolls/wattles
• Construction entrances
• Silt fence
• Silt dike
• Storm drain inlet protection
• Vegetated buffers

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Coir Rolls or Straw Wattles
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Sediment Controls

• Examples
• Drop inlet sediment barriers
• Curb inlet sediment barriers
• Stream diversion (check COE requirements)
• Pole planting and live staking (tree
  establishment)
• Straw rolls (coirs) and brush layering

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Types of Inlet Protection
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Other Controls

• Other Controls
• Reduce the potential for pollutants to come in
  contact with stormwater and be transported
  offsite
• Examples
• Concrete washouts
• Waste management
• Spill prevention and control

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Concrete Washouts
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Lot Controls
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Lot Controls
Regular or As Needed Street Sweeping
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Non-Structural BMPs

• Scheduling of construction activity
• During dryer periods
• Phased construction to limit amount of exposed
  soil
• Housekeeping activities
• Training
• Are employees aware of stormwater runoff
  direction, pollution sources onsite, etc.?
• Maintenance of mature vegetation

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Resources

• National Menu of Stormwater BMPs
• http//cfpub.epa.gov/npdes/stormwater/menuofbmps/i
  ndex.cfm?actionmin_measuremin_measure_id4
• International Stormwater BMP Database
• http//www.bmpdatabase.org/

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DEQ Stormwater Contacts

• Permitting
• Mark Derichsweiler (405) 702- 8188
• Karen Milford (405) 702- 8191
• Permit Administration
• Matt Pace - (405) 702- 6209
• Amber McIntyre - (405) 702- 6167
• Matt Johnson- (405) 702- 6182
• Compliance/Enforcement
• Wayne T. Craney - (405) 702- 8139
• Bob Giger (North) - (405) 702- 8112
• Michele Loudenback (West) (405) 702 - 8116
• Joe Willingham (South) - (405) 702- 8129

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Questions, Comments, Discussion