Open-File Report 2007–1030
U.S. Geological Survey Open-File Report 2007–1030
By K.G. Lee and T.S. Hedgecock
Download PDF file for OFR 2007–1030 (7.0 MB)
A one-dimensional step-backwater model was used to simulate flooding conditions for Fivemile Creek at Tarrant, Alabama. The 100-year flood stage published in the current flood insurance study for Tarrant by the Federal Emergency Management Agency was significantly exceeded by the March 2000 and May 2003 floods in this area. A peak flow of 14,100 cubic feet per second was computed by the U.S. Geological Survey for the May 2003 flood in the vicinity of Lawson Road. Using this estimated peak flow, flood-plain surveys with associated roughness coefficients, and the surveyed high-water profile for the May 2003 flood, a flow model was calibrated to closely match this known event. The calibrated model was then used to simulate flooding for the 10-, 50-, 100-, and 500-year recurrence interval floods.
The results indicate that for the 100-year recurrence interval, the flood profile is about 2.5 feet higher, on average, than the profile published by the Federal Emergency Management Agency. The absolute maximum and minimum difference is 6.80 feet and 0.67 foot, respectively. All water-surface elevations computed for the 100-year flood are higher than those published by the Federal Emergency Management Agency, except for cross section H. The results of this study provide the community with flood-profile information that can be used for existing flood-plain mitigation, future development, and safety plans for the city.
Abstract
Introduction
Purpose and Scope
Description of the Study Reach
Flood History
Acknowledgments
Approach
Data Collection
Land-Use Determination
Hydrologic Analyses
Hydraulic Modeling
Model Calibration
Simulation of Flood Flows
Summary
References Cited
Appendix. Photographs Showing Locations of Cross Sections
Contact Information: K.G. Lee
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