Evaluation of Floodplain Modifications to Reduce the Effect of Floods Using a Two-Dimensional Hydrodynamic Model of the Flint River at Albany, Georgia
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Complete publication (20 MB)
Appendix A (5 MB)
Appendix B (10 MB)
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By Jonathan W. Musser
U.S. Geological Survey Scientific Investigations Report 2008–5223, 12 pages (Published December 2008)
Prepared in cooperation with the City of Albany, Georgia, and Dougherty County, Georgia
Potential flow characteristics of future flooding along a 4.8-mile reach of the Flint River in Albany, Georgia, were simulated using recent digital-elevation-model data and the U.S. Geological Survey finite-element surface-water modeling system for two-dimensional flow in the horizontal plane (FESWMS-2DH). The model was run at four water-surface altitudes at the Flint River at Albany streamgage (02352500): 181.5-foot (ft) altitude with a flow of 61,100 cubic feet per second (ft3/s), 184.5-ft altitude with a flow of 75,400 ft3/s, 187.5-ft altitude with a flow of 91,700 ft3/s, and 192.5-ft altitude with a flow of 123,000 ft3/s. The model was run to measure changes in inundated areas and water-surface altitudes for eight scenarios of possible modifications to the 4.8-mile reach on the Flint River. The eight scenarios include removing a human-made peninsula located downstream from Oglethorpe Boulevard, increasing the opening under the Oakridge Drive bridge, adding culverts to the east Oakridge Drive bridge approach, adding culverts to the east and west Oakridge Drive bridge approaches, adding an overflow across the oxbow north of Oakridge Drive, making the overflow into a channel, removing the Oakridge Drive bridge, and adding a combination of an oxbow overflow and culverts on both Oakridge Drive bridge approaches. The modeled inundation and water-surface altitude changes were mapped for use in evaluating the river modifications. The most effective scenario at reducing inundated area was the combination scenario. At the 187.5-ft altitude, the inundated area decreased from 4.24 square miles to 4.00 square miles. The remove-peninsula scenario was the least effective with a reduction in inundated area of less than 0.01 square miles. In all scenarios, the inundated area reduction increased with water-surface altitude, peaking at the 187.5-ft altitude. The inundated area reduction then decreased at the gage altitude of 192.5 ft.
Description of Study Area
Previous Studies
Evaluation of Floodplain Modifications
Remove-Peninsula Scenario
Increase-Bridge-Opening Scenario
East-Culvert Scenario
West-and-East-Culvert Scenario
Oxbow-Overflow Scenario
Oxbow-Channel Scenario
No-Bridge Scenario
Combination West-and-East-Culvert and Oxbow-Overflow Scenario
Model Limitations
Summary and Conclusions
Appendix A. Maps Showing Changes in Simulated Flood Inundation Between Model Scenarios and Original Model
Appendix B. Maps Showing Simulated Water-Surface Altitude Changes Between Model Scenarios and Original Model