The National Academies

NCHRP 25-61 [Active]

Development of On-Bridge Stormwater Treatment Practices

  Project Data
Funds: 500,000
Staff Responsibility: David M. Jared
Research Agency: Geosyntec, Inc.
Principal Investigator: Aaron Poresky
Effective Date: 9/14/2020
Completion Date: 9/14/2023

Stormwater treatment of bridge deck runoff continues to be a design challenge. Traditional methods of treating this runoff suggest treating an equivalent area of roadway offsite that discharges to the same receiving water body or piping the bridge deck stormwater to an offsite treatment location. NCHRP_Report_778: Bridge Stormwater Runoff Analysis and Treatment Options concludes that treatment of runoff from a comparable section of highway on land is preferable to treatment of runoff from the bridge deck. Where offsite mitigation is unacceptable due to (1) water quality restrictions placed on the receiving water body or (2) site-specific conditions making the piping of bridge runoff to bridge ends for offsite treatment infeasible or undesirable, stormwater designers have few options for effective on-bridge treatment of stormwater.
There is a growing need to develop more options for on-bridge treatment of stormwater. In addition to NCHRP_Report_778, the following reports provide relevant background on this topic and support the need for further research thereon:
  • NCHRP_Report_767: Measuring and Removing Dissolved Metals from Stormwater in Highly Urbanized Areas
  • NCHRP Web-Only Document 265: Field Testing of BMPs Using Granulated Ferric Oxide Media to Remove Dissolved Metals in Roadway Stormwater Runoff (pending)
Research is needed to address on-bridge stormwater treatment challenges, including, but not limited to level of service; structural integrity; hydraulic function (including spread width); litter and sediment loads; freeze-thaw cycles; maintenance operations; and work zone safety.
The objectives of this research are to develop the following:
(1) On-bridge stormwater treatment applications with a focus on retrofitting existing bridges utilizing proven stormwater treatment practices; and
(2) Guidelines for selection (e.g., by media and materials), design, placement, and maintenance of the developed on-bridge stormwater treatment applications. The primary users of these guidelines will be bridge and hydraulic designers.
STATUS: Research is in progress.

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