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Mid-America Transportation Center

NDOR Characterization of Bridge Deck Runoff

Final Report
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Researchers

  • Principal Investigator: Shannon Bartelt-Hunt (sbartelt2@unl.edu 402-554-3868)
  • Project Status
    Complete
    Sponsors & Partners
  • Nebraska Department of Roads
  • Abstract
    In this study, time-weighted composite samples of bridge runoff and hourly traffic data were collected at four sampling locations in Nebraska. Total suspended solids (TSS) and hexane extractable material (HEM) had the highest concentrations during the first rainfall event of the year, while other constituent concentrations peaked during the third rainfall event of the year. In general, constituent concentrations were highest in the spring, and then decreased throughout the summer and fall. Average concentrations of TDS, TSS, chloride, iron, and lead measured in this study were higher than those found in the previous NDOR study at the same sampling locations. For lead and iron, it was difficult to observe a direct relationship between concentration and ADP, or concentration and daily traffic. However, there was a stronger correlation (R2 = 0.3716) between traffic during ADP and the concentration of zinc. This difference may be explained in the sources of these metals in runoff. The only source of zinc in bridge deck runoff is vehicle wear, but the sources of iron include the materials and structure of the bridge in addition to vehicle materials. Therefore, to improve the correlation for iron and lead, it is necessary to consider other variables such as bridge design and bridge materials, or other non-bridge related sources.
    Project Amount
    $ 142,462