HYDRAULIC MODELING OF ALLUVIAL FANS USING DAMBRK (NWS COMPUTER MODEL). FINAL REPORT

The design of hydraulic structures such as bridges on distributary flow areas and alluvial fans require methods that can adequately determine discharges at the structures. Flow conditions on distributary flow areas such as alluvial fans are quite complex and require an understanding of unsteady flow hydraulics and sometimes need multi-dimensional flow analysis. The primary objective of this report is to explore the use of the U.S. National Weather Service DAMBRK model, to describe the unsteady flow of floods on distributary flow areas. The DAMBRK model was applied to several hypothetical situations to determine the capability of the program to describe unsteady flows. Three distributary flow areas below the McDowell Mountains in Scottsdale, Arizona, were modeled using the DAMBRK code. Lost Dog Wash, a relatively simple distributary flow area which has been referred to as an alluvial fan, was selected to develop an application procedure. After successfully modeling Lost Dog Wash, two of the six distributary flow areas (alluvial fans 4 and 5) in north Scottsdale were modeled. Both fan 4 and fan 5 demonstrated subcritical and supercritical flows. The flood plains computed using DAMBRK are compared with the flood plains using the FEMA method. It is recommended that models describing erosion and sediment transport and transmission losses and infiltration be incorporated into the DAMBRK code. Similar studies using two-dimensional models are also recommended to determine the advantages and limitations of these approaches to model flood flows on alluvial fans.

  • Corporate Authors:

    Arizona State University, Tempe

    Department of Civil Engineering
    Tempe, AZ  United States  85287

    Arizona Department of Transportation

    206 South 17th Avenue
    Phoenix, AZ  United States  85007

    Federal Highway Administration

    1200 New Jersey Avenue, SE
    Washington, DC  United States  20590
  • Authors:
    • Mushtaq, H
    • Mays, L W
  • Publication Date: 1991-2

Media Info

  • Features: Appendices; Figures; References; Tables;
  • Pagination: 133 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00605761
  • Record Type: Publication
  • Report/Paper Numbers: FHWA-AZ90-349
  • Contract Numbers: PL-1(37) Item 349
  • Files: TRIS, USDOT, STATEDOT
  • Created Date: Mar 31 1991 12:00AM