Monitoring of Prospective Bridge Deck Runoff BMPs: Bioretention and Bioswale at Mango Creek/I-540

North Carolina Department of Transportation (NCDOT) is required by the National Pollutant Discharge Elimination System (NPDES) stormwater program to mitigate stormwater runoff from its facilities. NC Senate Bill 2008-107 further mandates runoff from bridge decks be evaluated and treated using best methods. Bioretention and bioswales show promise for stormwater treatment in the linear highway environment. Two bioretention cells and a bioswale were constructed in a Department of Transportation (DOT) maintained right-of-way underneath a bridge deck at the intersection of Mango Creek and I-540. One bioretention cell was sized correctly per North Carolina Department of Environment and Natural Resources (NCDENR) requirements, while the other has half the bowl storage and surface area that is required for its drainage area. The bioretention cells and bioswale were constructed using advanced practices, including internal water storage, engineered fill media, and specialized vegetation. Undersized bioretention cells have a high potential to be used as retrofits. However, little is known about their relative performance when compared to full-sized bioretention cells. This grant may allow NCDOT and NCDENR to award undersized bioretention cells a portion of the credit that full-sized cells receive. Also, this research will evaluate bioswale hydrologic and water quality performance. No research has been completed on bioswales in North Carolina. Monitoring of these practices began in November 2009 under NCDOT grant HWY-2009-29, but is forced to be completed by June 30, 2010. This grant proposal will allow continued monitoring of the bridge deck runoff quality, the undersized bioretention cells, and bioswale beyond FY 2010, essentially for a full year. Completing the data collection will allow the researchers to make appropriate conclusions about performance of each system.


  • English


  • Status: Completed
  • Funding: $56237.00
  • Contract Numbers:


  • Sponsor Organizations:

    North Carolina Department of Transportation

    Research and Development
    1549 Mail Service Center
    Raleigh, NC  United States  27699-1549
  • Project Managers:

    Kirby, John

  • Performing Organizations:

    North Carolina State University, Raleigh

    Department of Biological and Agricultural Engineering
    Box 7625
    Raleigh, NC  United States  27695
  • Principal Investigators:

    Hunt, William

  • Start Date: 20100816
  • Expected Completion Date: 0
  • Actual Completion Date: 20110815
  • Source Data: RiP Project 28940

Subject/Index Terms

Filing Info

  • Accession Number: 01463332
  • Record Type: Research project
  • Source Agency: North Carolina Department of Transportation
  • Contract Numbers: 2011-12
  • Files: RIP, STATEDOT
  • Created Date: Jan 3 2013 2:21PM