CHANNEL AND BANK STABILITY OF BAKERS CREEK AT STATE HIGHWAY 547 NEAR PORT GIBSON, CLAIBORNE COUNTY, MISSISSIPPI by D. Phil Turnipseed and W. Trent Baldwin Prepared in cooperation with the MISSISSIPPI STATE HIGHWAY DEPARTMENT Jackson, Mississippi 1992 Open-File Report 92-636 TABLE OF CONTENTS Abstract Introduction     Purpose and scope     General description of Bakers Creek     Acknowledgements Channel-bed stability Channel-bank stability     Botanical evidence of widening     Stability analyses     Widening analyses Summary References ILLUSTRATIONS 1. Map showing the location of Bakers Creek at State Highway 547 near Port Gibson 2. Graph showing channel-bed profiles in 1989 and 1992 for Bakers Creek in the vicinity of State Highway 547 near Port Gibson 3. Graph showing measured channel-bed elevations for Bakers Creek at State Highway 547 near Port Gibson, 1961-92 4. Bank profile showing critical failure surfaces for the right(east) bank of Bakers Creek, 300 feet upstream from State Highway 547 near Port Gibson, 1989 5. Cross section showing critical failure surfaces for channel banks of Bakers Creek, 75 feet downstream from State Highway 547 near Port Gibson, 1989 6. Channel cross section showing estimate of near-future widening for Bakers Creek, 300 feet upstream from State Highway 547 near Port Gibson, 1989 7. Channel cross section showing estimates of near-future widening for Bakers Creek, 75 feet downstream from State Highway 547 near Port Gibson, 1989 TABLES 1. Measured channel-bed elevations for Bakers Creek at State Highway 547 near Port Gibson, 1961-92 2. Botanical and geomorphological data collected in 1989 on Bakers Creek in the vicinity of State Highway 547 near Port Gibson 3. Dry bulk-unit weight and shear-strength properties of bank material as determined from borehole shear tests on the right(east) bank of Bakers Creek about 75 feet downstream from State Highway 547 near Port Gibson ABSTRACT The channel bed of Bakers Creek at the State Highway 547 crossing near Port Gibson, Claiborne County, Mississippi, has been relatively stablr since 1961 except for about 2 feet of aggradation, which occurred between 1989 and 1992, probably because of floods in 1990 and 1991. Some changes have occurred in the channel width, however. Botanical evidence indicates that several bank failures in the vicinity of the crossing occurred during extreme floods in the spring of 1974. Rates of channel gradation and widening--as determined from channel descriptions and botanical and geomorphological evidence along the banks--were used in conjunction with soil properties to estimate probable future channel changes in the next 10 to 20 years. If changes in channel-bed elevations in the past 30 years are representative of gradation patterns in the near future, then no significant channel degradation in the next 10 to 20 years is expected at the highway crossing. However, projections indicate bankfull channel width could increase as much as 8 feet upstream and 15 feet downstream of the highway crossing in the next 10 to 20 years. These projections are based on the assumption that no channel or watershed modifications and no unusually large and destructive flooding will occur before the year 2010. LizardTech's Djvu plug-in is needed to view these reports. CLICK HERE TO VIEW THE ENTIRE REPORT For questions or comments, contact K. Van Wilson.