MAP-BASED TESTS ON CONTROLS OF ANABRANCH RIVER CHARACTER ON THE LOWER YELLOWSTONE RIVER by Patricia Ann Jenkins A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Earth Sciences MONTANA STATE UNIVERSITY Bozeman, Montana November 2007 © COPYRIGHT by Patricia Ann Jenkins 2007 All Rights Reserved - ii - APPROVAL of a thesis submitted by Patricia Ann Jenkins This thesis has been read by each member of the thesis committee and has been found to be satisfactory regarding content, English usage, format, citations, bibliographic style, and consistency, and is ready for submission to the Division of Graduate Education. Dr. Stephan G. Custer Approved for the Department of Earth Sciences Dr. Stephan G. Custer Approved for the Division of Graduate Education Dr. Carl A. Fox - iii - STATEMENT OF PERMISSION TO USE In presenting this thesis in partial fulfillment of the requirements for a master’s degree at Montana State University, I agree that the library shall make it available to borrowers under rules of the library. If I have indicated my intention to copyright this thesis paper by including a copyright notice page, copying is allowable only for scholarly purposes, consistent with “fair use” as prescribed by the U.S. Copyright Law. Requests for permission for extended quotation from or reproduction of this thesis in whole or parts may be granted only by the copyright holder. Patricia Ann Jenkins November 2007 - iv - ACKNOWLEDGMENTS I wish to thank my main advisor, Dr. Stephan Custer, for his perpetual enthusiasm and encouragement. I also wish to express appreciation for my committee members, Dr. Brian McGlynn and Dr. Mark Skidmore, for their constructive guidance and support. Many thanks to Karin Boyd of Applied Geomorphology, Inc., and James Robinson, Water Resources Specialist of the Department of Natural Resources and Conservation, for sound advice and suggestions during the earliest research phases. This study drew upon the data collected for the Geomorphic Reconnaissance and GIS Development Yellowstone River, Montana report, prepared by Applied Geomorphology, Inc. and DTM Consulting, Inc., without which this project would not have been possible. Much thanks to my fellow graduate students for many stimulating dialogues and their consistent, fervent friendship. And finally, most importantly, I would like to thank my exceptional, wonderful family for tremendous, unwavering support and continual encouragement throughout my education. - v - LIST OF TABLES Table Page 1. Stratigraphy of rock units exposed in the lower Yellowstone River valley............................................................................17 2. Tributary drainage basin characteristics ................................................................41 3. Yellowstone River stream power data table ..........................................................44 4. Tributary stream power data table .........................................................................45 5. Ratio of tributary stream power to Yellowstone River stream power ...................47 6. Bedrock lithology and erosion resistance of the lower Yellowstone River...........50 7. Statistics on valley width and anabranch intensity ................................................58 - vi - LIST OF FIGURES Figure Page 1. Flow chart of possible responsible controls and associated influencing mechanisms of anabranch river systems.......................................................3 2. Plot of number of channels vs distance downstream; from Tooth and Nanson, 1999 ......................................................................5 3. Map of Montana and the Yellowstone River Basin...............................................14 4. USGS stream gage station locations on lower Yellowstone River and tributaries.............................................................................................15 5. Cities along the lower Yellowstone River, tectonic features, and bedrock erosion resistance.......................................................................................16 6. Reference towns and glacial features along lower Yellowstone River corridor .............................................................20 7. Irrigation withdrawal dams on lower Yellowstone River and tributary dams......................................................................................21 8. Climograph for Billings, MT .................................................................................22 9. Hydrograph for the Yellowstone River monthly mean discharge .........................23 10. Hydrographs for gaged tributaries to lower Yellowstone River, mean monthly discharge ...........................................................................24 11. Air photos of Yellowstone River in Stillwater County .......................................25 12. Air photos of Yellowstone River at Rosebud Creek confluence .........................26 13. Air photos of Yellowstone River in Dawson County ..........................................27 - vii - LIST OF FIGURES - CONTINUED Figure Page 14. Anabranching reach of the Yellowstone River between river mile 213 and 214...................................................................33 15. A. Slope of the Yellowstone River B. Change in slope on the Yellowstone River ............................................35 16. Comparison of elevation values collected from LIDAR data and topographic maps ............................................................37 17. Frequency of anabranch intensity on lower Yellowstone River...........................38 18. Cumulative frequency distribution of tributary basin area ...................................39 19. Relative drainage basin area of tributaries to the lower Yellowstone River.........41 20. Flood frequency curves for gage sites along the Yellowstone River.....................42 21. Flood frequency curves for major tributaries to the lower Yellowstone River ....43 22. Profiles of anabranch intensity at tributary junctions along the lower Yellowstone River ............................................................................48 23. Stream power ratio vs change in anabranch intensity at a confluence ..................49 24. Distribution of valley width along the lower Yellowstone River..........................52 25. A. Distribution of valley width relative to bedrock B. Normalized distribution...........................................................................53 26. Bedrock hardness and valley width along the lower Yellowstone River ..............54 27. Correlation of bedrock and valley width downstream...........................................55 - viii - LIST OF FIGURES - CONTINUED Figure Page 28. Frequency and cumulative percent of anabranch character and bedrock hardness.................................................................................56 29. Correlation of bedrock and anabranch intensity downstream................................57 30. Valley width and anabranch intensity on lower Yellowstone River......................57 31. Scatter plot of valley width and anabranch intensity on the lower Yellowstone River ...............................................................59 32. Correlation of valley width and number of channels downstream ........................59 33. Summary figure of geomorphic properties of the lower Yellowstone River.........61 34. Hypothesized anabranch system at tributary junctions .........................................67 - ix - TABLE OF CONTENTS 1. INTRODUCTION ...................................................................................................1 2. STUDY REACH....................................................................................................13 3. METHODS ............................................................................................................28 Methods for Tributary Junction Test .....................................................................28 Methods for Valley Width Test .............................................................................32 Methods for Bedrock Test .....................................................................................33 4. RESULTS ..............................................................................................................35 Yellowstone River Channel Character...................................................................35 Tributary Junction Influence on Anabranch Character..........................................38 Bedrock and Valley Width Influence on Anabranch Character ............................49 5. DISCUSSION........................................................................................................62 Tributary Junction Analysis...................................................................................62 Bedrock and Valley Width Analysis......................................................................73 Complexity and Causality......................................................................................78 Conclusions............................................................................................................79 6. CONCLUSION......................................................................................................80 REFERENCES CITED................................................................................................82 APPENDICES .............................................................................................................92