Stormwater Quality Management Session II

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Stormwater Quality Management Session II

• Road School 2005
• Purdue University
• West Lafayette, Indiana
• Speaker Ted Blahnik, P.E.

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AGENDA

• Session II (90 Minutes)
• Example Design Problem

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Roadway Improvement Site
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Roadway Improvement Site

• 4.5 ac roadway
• 0.6 ac greenspace in roundabout
• 50 buffer on roadway
• Assume no offsite flow into proposed improvement
  area
• Objective Design post-construction BMPs for
  proposed impacts

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Wet Pond Offline BMP
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Wet Pond Offline BMP
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Wet Pond Offline BMP
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Wet Pond Offline BMP
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Wet Pond Offline BMP
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Wet Pond Offline BMP
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Wet Pond Offline BMP
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Wet Pond Offline BMP
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Filter Strip with Detention
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Roadway Improvement Site
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Filter Strip with Detention

• General Considerations
• Provide freeboard to prevent backwater flooding
  into roadway
• Level spreader must be provided at influent end
  of slope

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Filter Strip with Detention

• General Considerations (cont)
• Specify appropriate vegetation for staging depth
  and drain time. No-mow fescue works wewll at
  depths equal to or less than 6 inches of water
  provided drain times are at the low end of range
  (12 hours)
• Place underdrain at toe of filter strip near
  retention berm or slope opposite roadway

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Filter Strip with Detention
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Filter Strip with Detention
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Filter Strip with Detention
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Filter Strip with Detention
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Detention Swale
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Roadway Improvement Site
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Detention Swale

• General Considerations
• Provide freeboard to prevent backwater flooding
• Size overflow weir to pass 100-yr event to storm
  drain
• Size underdrain orifice to provide between 12 and
  48 hour drain times
• Specify appropriate vegetation for staging depth
  and drain time
• Recommended slope of underdrain gt 0.3

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Detention Swale
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Detention Swale
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Bioretention in Roundabout
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Roadway Improvement Site
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Bioretention in Roundabout

• General Considerations (similar to swale)
• Provide freeboard to prevent backwater flooding
• Size overflow weir to pass 100-yr event to storm
  drain
• Size underdrain orifice to provide between 12 and
  48 hour drain times
• Specify appropriate vegetation for staging depth
  and drain time
• Recommended slope of underdrains gt 0.3

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Bioretention in Roundabout
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Bioretention in Roundabout
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Bioretention in Roundabout
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Recommended Reference Texts

• Recommended Reference Texts
• Municipal Stormwater Management, T. Debo and A.
  Reese, 2002
• Stormwater Treatment, G. Minton, 2002
• Design Hydrology and Sedimentology for Small
  Catchments, C.T. Haan, Barfield, and Hayes, 1994
• Controlling Urban Runoff, Metropolitan Coundil of
  Governments, T. Schueler, 1987

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Contact Information - Indiana

• WILLIAMS CREEK CONSULTING, INC.
• Babeca Building
• 919 North East Street
• Indianapolis, Indiana 46202
• 317/423.0690 p.
• 317/423.0696 f.
• P.O. Box 5606
• Lafayette, Indiana 47904
• 765/477.6170 p./f.