Summary of data-collection activities and effects of flooding from tropical storm Alberto in parts of Georgia, Alabama, and Florida, July 1994

Abstract

Parts of central and southwestern Georgia, southeastern Alabama, and the western panhandle of Florida were devastated by floods resulting from rainfall produced by Tropical Storm Alberto in July 1994. As tributary floodwaters combined and moved downstream in the Flint, Ocmulgee, and Choctawhatchee Rivers, peak discharges exceeded the 100-year flood discharges along most stream reaches. Along the Flint River, the 100-year flood stage was exceeded at Montezuma by 3.7 ft; at Albany, by 5.1 ft; at Newton, by 3.9 ft; and at Bainbridge by 2.2 ft. Along the Ocmulgee River, the 100-year flood was exceeded at Juliette, by 5.4 ft; at Macon, by 2.2 ft; and at Hawkinsville by 3.9 ft. Peak discharges exceeded the 100-year flood discharges along the Choctawhatchee River from Newton, Ala., to Bruce, Fla. Discharge measurements were made at many gaging stations throughout the area of flooding. Streamflow velocities are obtained during the process of making the discharge measurement. Velocity data are given for selected gaging stations on two streams in Georgia. Scour around pier and abutment foundations caused settling or washout at most bridge failures. Scour mechanisms at these bridges include local scour, contraction scour, and scour plus bank instability of the general stream reach where the bridge is located. Eighteen feet of predominantly contraction scour was measured during the flood at the U.S. Highway 82 crossing of Flint River at Albany, Ga.