Drainage Area Limitations for NDOT Hydrologic Computations

The NDOT Roadway Design Division and Bridge Division commonly use three traditional methods (“traditional”) to predict peak discharge for the design of storm drains, culverts, and bridges: the Rational Method, Soil Conservation Service (SCS) methods based on curve numbers, and statistical regression equations. Which method is most appropriate depends on, besides other factors, the size of the contributing watershed (drainage area). Designers are not confident about the drainage area limitations associated with each method. Guidelines based on actual performance of these methods is needed to ensure consistent application for the hundreds of peak discharge estimates made throughout Nebraska each year. While such guidelines are needed, state-of-the-art applications in hydrology suggest there may be new approaches (“Next Gen Hydrology”) and tools available to designers. There is a lack of performance-based guidance on drainage area-based use of hydrologic methods to predict peak discharge. Specifically, a lack of guidance when using SCS curve number-based methods leaves designers with less confidence about the applicability decisions.


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    • Status: Active
    • Funding: $114,528.00
    • Sponsor Organizations:

      Nebraska Department of Transportation

      1500 Nebraska 2
      Lincoln, NE  United States  68502
    • Project Managers:

      Halsey, Lieska

    • Principal Investigators:

      Hotchkiss, Rollin H.

    • Start Date: 20230701
    • Expected Completion Date: 20250531
    • Actual Completion Date: 0

    Subject/Index Terms

    Filing Info

    • Accession Number: 01881386
    • Record Type: Research project
    • Source Agency: Nebraska Department of Transportation
    • Files: RIP, STATEDOT
    • Created Date: Apr 27 2023 4:24PM