U.S. Geological Survey - http://www.usgs.gov U.S. Geological Survey - http://www.usgs.gov


   Historical Reports:
  • Floods
  • Flood Frequency
  • Low-Flow Frequency
  • Basin Characteristics
  • Hydraulics
  • Channel Stability & Scour
    • Mississippi Department of Transportation

    Magnitude and Frequency of Floods in Mississippi

    Problem:

    Knowledge of magnitude and frequency of floods is essential to the design of bridges, highway embankments, culverts, levees, dams, and other structures near streams. Effective flood-plain management and determination of flood insurance rates require accurate information on magnitude and frequency of floods

    The statewide flood-frequency reports by Landers and Wilson (1991) and Wilson and Landers (1991) provided estimates of magnitude and frequency of floods at gaging stations and provided techniques for estimating magnitudes and frequency of floods at ungaged sites in Mississippi. Observed annual peak-flow data collected through 1988 at 358 gaging stations were used in the analyses. Since the 1991 statewide flood-frequency reports, an additional 11 years of observed annual peak-flow data has become available and data have been collected on several large floods. Also, the 1991 regional flood-frequency equations were developed using generalized least-squares (GLS) regression (Stedinger and Tasker, 1985; and Tasker and Stedinger, 1989). GLS regression had and still has advantages over the ordinary least-squares and weighted least-squares regression, but since the 1991 reports, Tasker and Slade (1994) demonstrated that GLS regression coupled with a site-specific approach [referred to as "interactive" by Tasker and Slade (1994) and as "region-of-influence" by Hodge and Tasker (1995)] had smaller root-mean-square errors than the traditional geographic regional approach. Analyses of flood frequency using these additional data with a site-specific approach may substantially change and improve the accuracy of techniques for estimating magnitudes and frequencies of floods in Mississippi.


    Objectives:

    The objectives of this 3-year project (beginning October 1, 2000, and ending September 30, 2003) are to prepare an updated version of the flood-frequency reports that would:
    1. Document the maximum known flood at gaged sites in Mississippi and compare with a previously published envelope curve;


    2. Document flood data and flood-frequency estimates at gaging stations in Mississippi; and


    3. Present methods for estimating the magnitude and frequency of floods in Mississippi having recurrence intervals ranging from 2 to 500 years.


    It is anticipated that the results of this project will be reviewed and discussions toward renewal after 2003 will be made to include additional GIS work on automated basin delineation, which is currently in the development stages.


    Final Products:

    Reports will be published that contain maximum known flood data, annual peak-flow data, flood-frequency estimates at gaging stations, and equations and (or) computer programs for estimating the magnitude and frequency of annual floods in Mississippi.

    The reports will be provided in paper form (with a diskette or CD) and will also be made available in digital form on the Internet.


    References:

    Hodge, S.A., and Tasker, G.D., 1995, Magnitude and frequency of floods in Arkansas: U.S. Geological Survey Water-Resources Investigations Report 95-4224, 275 p., 1 diskette.

    Landers, M.N., and Wilson, K.V., Jr., Flood characteristics of Mississippi streams: U.S. Geological Survey Water-Resources Investigations Report 91-4037, 82 p.

    Stedinger, J.R., and Tasker, G.D., 1985, Regional hydrologic analysis—Ordinary, weighted, and generalized least squares compared: Water Resources Research, v. 21, no. 9, p. 1,421-1,432.

    Tasker, G.D., and Slade, R.M., Jr., 1994, An interactive regional regression approach to estimating flood quantiles, in Fontane, D.G., and Tuvel, H.N., eds., Water policy and management—Solving problems: Proceedings of the 21st Annual Conference of the Water Resources Planning and Management Division, American Society of Civil Engineers, P. 782-875.

    Tasker, G.D., and Stedinger, J.R., 1989, An operational GLS model for hydrologic regression: Journal of Hydrology, v. III, p. 361-375.

    Wilson, K.V., Jr., and Landers, M.N., Annual peak stages and discharges for streamflow-gaging stations in Mississippi: U.S. Geological Survey Water-Resources Investigations Report 91-4098, 705 p.





    For questions or comments, contact K. Van Wilson.
    URL: http://ms.water.usgs.gov
    Contact: mtwade@usgs.gov