Channel Migration and Geology on the Chickasawhay River, Southeast Mississippi
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CHANNEL MIGRATION AND GEOLOGY ON THE CHICKASAWHAY RIVER, SOUTHEAST MISSISSIPPI By MARILYN C. OGBUGWO A THESIS PRESENTED TO THE GRADUATE SCHOOL OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE UNIVERSITY OF FLORIDA 2005 To my Ocala family and my family back home, for love that’s free. To my friends who have helped to make the U.S. a little more like home. And to Chineke, for who you are. ACKNOWLEDGMENTS I thank my entire field team: Jim Rasmussen, for his invaluable help with the fieldwork and sample collection; Glenn Hermassen, for complaining, and for not complaining about my canoeing skills; and Miles, Cara, and Llew, for camping out and for the ride home. I thank David Coley, for his help with creating and running the GIS, and for all his editing and quality assurance work on the GIS aspects of this project. I thank my committee: Dr. Brenner for his suggestions, patience and great help, and for reviewing and editing the entire manuscript; Dr. Jaeger, for his helpful suggestions and invaluable help with the sedimentology aspects of this work. And I thank Dr. Mossa. I thank her for her guidance and for all that I have learned. I thank her for always being the steer woman on our canoe trips, and for taking care of all the logistics. Funding for this project was provided by the U.S Army Corps of Engineers, Mobile District. Local sponsors include the Pat Harrison Waterway District, and the Mississippi Nature Conservancy through the United States Geological Survey. iii TABLE OF CONTENTS page ACKNOWLEDGMENTS ................................................................................................. iii LIST OF TABLES............................................................................................................. vi LIST OF FIGURES ......................................................................................................... viii ABSTRACT....................................................................................................................... xi CHAPTER 1 INTRODUCTION ........................................................................................................1 Literature Review .........................................................................................................4 Bank Vegetation and Cohesiveness.......................................................................4 Geologic Framework.............................................................................................6 Drainage Basin Size and Stream Power ................................................................9 Flood Frequency and Channel Slope...................................................................11 Large Woody Debris ...........................................................................................12 Geographic Information Systems ........................................................................13 2 STUDY AREA...........................................................................................................16 General Overview.......................................................................................................16 Climate and Flood History ..................................................................................21 Land Use/Land Cover and Geology....................................................................22 3 RESEARCH METHODS...........................................................................................28 GIS Methods...............................................................................................................28 National Map Accuracy Standards (NMAS)..............................................................35 Field Methods .............................................................................................................35 Laboratory Methods....................................................................................................40 4 CHANNEL CHANGE................................................................................................42 Lateral Migration By Geologic Reach........................................................................43 Width Change Analysis ..............................................................................................48 Analysis By Morphologic Reach................................................................................51 iv Sinuosity Analysis ......................................................................................................56 Results.........................................................................................................................57 5 DISCUSSION.............................................................................................................66 Overview.....................................................................................................................66 Morphologic Patterns and Geology............................................................................66 Other Factors ..............................................................................................................69 Channel Change and Bank Lithology.........................................................................75 Conclusions.................................................................................................................83 APPENDIX A MAPS .........................................................................................................................86 B TABLES ...................................................................................................................107 LIST OF REFERENCES.................................................................................................115 BIOGRAPHICAL SKETCH ...........................................................................................120 v LIST OF TABLES Table page 2-1. 1:24,000 USGS quadrangle elevations.....................................................................21 2-2. Geologic units and their description.........................................................................24 3-1. Digitized channel parameters...................................................................................34 3-2. Depth intervals and withdrawal times for pipette analysis.......................................41 4-1. Map and digitizing scales for the three time periods. ..............................................43 4-2. Calculated lateral migration values per reach. .........................................................45 4-3. Lateral migration as a percentage of channel width.................................................47 4-4. Correlation coefficients............................................................................................47 4-5. Average channel widths. ..........................................................................................50 4-6. Reach parameters for the seven morphologic reaches. ............................................53 4-7. Mean lateral migration for the seven morphologic reaches. ....................................53 4-8. Calculated sinuosity per geologic reach...................................................................56 4-9. Calculated sinuosity values for the seven morphologic reaches..............................56 4-10. Mean lateral migration values..................................................................................60 4-11. Particle size analysis results for percent mud and sand, WL samples. ....................62 4-12. Particle size analysis results for percent mud and sand, MB samples. ....................63 4-13. Estimated average channel cross sectional widths...................................................64 4-14. Calculated channel change values............................................................................64 5-1. Lateral migration and width change values..............................................................76 B-1. Field observations..................................................................................................108 vi B-2. Grain size analysis results for waer line and mid-bank samples............................109 B-3. Annual stream flow data ........................................................................................113 B-4. GPS field locations.................................................................................................114 vii LIST OF FIGURES Figure page 1-1. Chickasawhay bridge at DeSoto. ...............................................................................2 2-1. Study area showing drainage network and digitized reach of the Chickasawhay ...17 2-2. Map showing geologic formations in study area......................................................18 2-3. Mississippi physiographic regions MARIS (1994)..................................................19 2-4. Surface geological formations in the study area. .....................................................23 3-1. Digitizing vertices on aerial photograph of the Chickasawhay, Clarke county .......31 3-2. Digitized channel boundaries for the 1990s coverage. ............................................31 3-3. Transects at 100m intervals, and clipped to channel extents. ..................................32 3-4. Valley lengths were digitized using USGS 1:24,000 topographic maps. ................33 3-5. Field sampling..........................................................................................................36