Estimating Joint Probabilities of Design Coincident Flows at Stream Confluences

Highway drainage structures often are located near the confluence of two streams where they may be subject to inundation by high flows from either stream. Highway drainage structures usually are designed to meet specified performance objectives for floods to equal or less than a specified magnitude stated as a return period (e.g. the 100-year flood). Because areas adjacent to the confluence of streams can be flooded by either stream, the probability of recurrence for a given high-water elevation at the confluence, known as the joint probability, is produced by a combination of the flood-probability relationships for both of the streams. The objectives of this research are to: a) develop a practical procedure for determination of joint probabilities of design peak flows at stream confluences that is applicable to both stream confluences and to storm drain systems tributary to larger natural streams, b) develop practical guidelines for applying the procedure, and c) develop accompanying computer software, if necessary, for practical and efficient application of the procedure.


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  • Status: Completed
  • Funding: $378058.00
  • Contract Numbers:

    Project 15-36

  • Sponsor Organizations:

    Federal Highway Administration

    1200 New Jersey Avenue, SE
    Washington, DC  United States  20590

    American Association of State Highway & Transportation Officials (AASHTO)

    444 North Capitol Street, NW, Suite 225
    Washington, DC  United States  20001

    National Cooperative Highway Research Program

    Transportation Research Board
    500 Fifth Street, NW
    Washington, DC  United States  20001
  • Project Managers:

    Reynaud, David

  • Performing Organizations:

    Kilgore Consulting and Management

  • Principal Investigators:

    Kilgore, Roger

  • Start Date: 20060511
  • Expected Completion Date: 0
  • Actual Completion Date: 20101031
  • Source Data: RiP Project 11107

Subject/Index Terms

Filing Info

  • Accession Number: 01547501
  • Record Type: Research project
  • Source Agency: National Cooperative Highway Research Program
  • Contract Numbers: Project 15-36
  • Files: RIP
  • Created Date: Dec 10 2014 1:03AM