Construction Site

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Building Green in Bowling Green

• Construction Site
• Stormwater Management

Barry Tonning Tetra
Tech
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State and local rules require

• Local and state permit coverage
• SWPPP available for review
• BMPs in the field that match the SWPPP
• Contractors weekly inspection forms available
  for review

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Minimizing the active construction area
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Consistency between whats in the SWPPP and BMPs
installed in the field
Site Drainage Plan
Site Building Plan
Site Grading Plan
Existing Site Conditions
Final Site Land-scaping Plan
Stormwater Pollution Prevention Plan
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SWPPP Applicability, Preparation, Contents, and
Process for Amending

• SWPPP applies to the site AND offsite
  borrow/disposal areas
• SWPPP is prepared BEFORE filing the NOI and
  beginning work
• SWPPP describes site, pollutants at site, plan
  for controlling pollutant discharges,
  construction procedure, responsible parties
• SWPPP is amended by site personnel or project
  engineer as construction proceeds on an as-needed
  basis

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Basic SWPPP outline

• Site description map
• Description of receiving waters
• Description of construction project
• Identification of pollutants, sources, and any
  non-stormwater discharges
• Erosion sediment controls
• Controls for other pollutants
• Procedures for inspections, BMP maintenance, and
  recordkeeping
• Certification signatures

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Building, stabilizing, and preserving the
drainage system (ditches, traps, ponds)
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Drainage system controls

• Inlets for storm drains and channels
• Pond up the runoff to settle filter it
• Use rock berms, rock bags, or other items
• Storm drain channel outlets
• Protect areas receiving discharge flows from
  erosion caused by flow velocities
• Use rock or turf reinforcement mats seed heavily
• Ditches convey water without eroding
• Traps pond and settle out muddy runoff

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Good application of silt fence and rock bags for
inlet protection Lots of options available
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Other inlet protection approaches
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Outlet Protection
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Drainage ditch liner materials

• Steep or high flow channels (gt 20)
• Use concrete or riprap
• Moderately steep channels ( 10)
• Use riprap or turf mats seeding
• Slightly sloping channels (5)
• Use turf mats or blankets seeding
• Mostly flat channels (2)
• Use seeding with blankets
• Seed ditches immediately after construction
• Triple the seeding rate

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Sediment traps basins

• Designed placed to pool runoff so sediment can
  settle out
• Installed before grading/fill work begins!
• Seeded immediately after construction
• Located in swales or low-lying areas where flows
  are concentrated
• Should not be placed near flowing streams
• Outlets should be made of rock or pipe

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Rock filter as sediment trap
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Good siting installation of sediment traps
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Protecting riser during construction! Wrap
with filter fabric Use rock inlet dam Pile
57s around pipe
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Buffer zone requirements

• 25 ft undisturbed buffer between disturbed areas
  and bankfull elevation of high quality waters /
  impaired waters
• 50 buffer required between sediment-impaired
  waters with no TMDL and disturbed areas
• Dredge/fill areas,
• stream crossings,
• or other deviations
• require adequately
• protective alternate
• practices, explained
• in SWPPP

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Buffer Zone

• Edge of Receiving Water is defined as bankfull
  elevation of a water of the Commonwealth

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Slope stabilization
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Slope protection basics

• Seed and mulch immediately after grading
• Divert upland runoff with berms or channels
• Tread-track or terrace highly erodible soils
• Install sediment barriers at toe of slope and at
  correct spacing on long slopes
• Use blankets, mats, or mulch on steep slopes
• Control runoff from upland areas with drain pipes
  or lined downdrain channels

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Mass grading tips

• Install all downgradient silt fences, traps,
  basins before clearing grubbing
• Use grubbed-out debris as sediment barriers /
  berms downhill from your work
• Use soil stockpiles as sediment berms / traps
  that intercept concentrated/sheet flow
• Seed and mulch/blanket/mat your ditches and
  slopes as soon as you build them

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Blankets and mats(rolled erosion control
products)

• Excellent for slope and channel protection
• Use blankets for slopes flatter than 31 and
  channels flatter than 201
• Use mats for slopes greater than 31 and channels
  steeper than 201
• KY TC requires blankets in all channels slopes
  gt 41

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Wishful thinking . . .
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Stabilization requirements

• Temporary stabilization required on portions of
  the site where construction activities have
  temporarily ceased shall be initiated within 14
  days
• Final stabilization also required within 14 days
  after permanently ceasing work
• Final stabilization required if work is suspended
  for more than 180 days

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Homebuilder lot BMP compliance
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Fiber roll installation
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Good housekeeping pollution prevention
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Good housekeeping

• Mud tracking on roadways
• Fuel, oil, paint, hazardous waste mgmt
• Concrete washout sites
• Trash debris management
• Sewage management
• Dust control (if needed)

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Waste management

• Provide convenient, well-maintained toilet
  facilities

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Establish proper building material handling and
storage areas

• Building materials with runoff potential should
  be stored indoors or under cover

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Designate concrete washout areas Or wash out
material in formed-up areas ready for the next
pour
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Establish proper equipment/vehicle fueling and
maintenance practices

• Your on-site fueling and maintenance area should
  have a spill kit
• Conduct vehicle fueling and maintenance
  activities in areas away from ditches
• Conduct maintenance on vehicles and equipment
  off-site if possible

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Develop a spill prevention and response plan

• Note the locations of chemical storage areas,
  storm drains, ditches, and surface waters
• Specify how to notify appropriate authorities
• Describe the procedures for spill cleanup
• Identify personnel responsible for implementing
  the plan

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The Good, The Bad, and the Ugly

• The Good stabilized exit pads, initial silt
  fence installation, initial inlet protection
• The Bad temporary seeding/mulching, silt fence
  maintenance, inlet maintenance, waste and
  materials management
• The Ugly ditch and channel protection, some
  homebuilder lots

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Fair construction entrance poor silt fence
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Good fence, needs seed/mulch
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Good inlet protection
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Good stabilization on pipe job
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Well vegetated sediment basin, with poorly
vegetated inactive area in foreground
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Poor vegetation and no sign of active grading
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Unstabilized slope
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Lot with poor vegetation and poor silt fencing
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Lack of inlet maintenance and sediment management
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Poor stabilization drainage management

Left northwest corner discharge location,
showing sediment in discharge. Right stopped up
curb inlet (lower middle) with pooled water. No
grading occurring in this area.
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Eroding, unstabilized drainage swale
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Poor site stabilization, drainage system, and
sediment trap construction maintenance
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Overflowing concrete washout
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Vacant inactive site with poorly installed silt
fence and poor vegetation
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Poor soil stabilization, shaky silt fence,
ineffective inlet protection
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Torn and frayed
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Poor site management