KNICKPOINTS IN TRIBUTARIES OF THE SOUTH FORK EEL RIVER, NORTHERN CALIFORNIA by Melissa Foster A Thesis Presented to The Faculty of Humboldt State University In Partial Fulfillment Of the Requirements for the Degree Master of Science In Environmental Systems: Geology May, 2010 KNICKPOINTS IN TRIBUTARIES OF THE SOUTH FORK EEL RIVER, NORTHERN CALIFORNIA By Melissa Foster Approved by the Master’s Thesis Committee: Dr. Harvey M. Kelsey, Major Professor Date Dr. Benjamin T. Crosby, Committee Member Date Dr. William E. Weaver, Committee Member Date Dr. Christopher J. Dugaw, Graduate Coordinator Date Jená Burges, Vice Provost Date ABSTRACT KNICKPOINTS IN TRIBUTARIES OF THE SOUTH FORK EEL RIVER, NORTHERN CALIFORNIA Melissa Foster Multiple knickpoints are present in two tributary basins of the South Fork Eel River. These tributaries are downstream from a major knickpoint on the South Fork Eel River, which may be a transient knickpoint propagating base-level fall throughout the basin. Knickpoints are identified from longitudinal profiles extracted from LiDAR- derived DEMs. Knickpoints and knickzones, knickzones being the immediate downstream reach of higher gradient, are present throughout the two basins. Many of the knickpoints display correlative elevations between the two basins. Knickpoints are most common on first-order streams, and knickpoint frequency decreases with increasing stream order. Major knickzones were found throughout the basins, but the largest knickzone reaches were found closest to the basin outlets. Although only the lowest major knickpoints on each tributary likely correlate with the major knickpoint on the South Fork, it does appear that knickpoints in these tributary basins are the result of multiple instances of base-level lowering on the South Fork Eel River. iii ACKNOWLEDGEMENTS First and foremost, I wish to thank Harvey Kelsey, an amazing graduate advisor. I am hugely appreciative of the time and enthusiasm you have devoted to this project and my scholastic endeavors. Ben Crosby was most helpful with my MATLAB questions and proposal reviews. Thank you to Bill Weaver for his advice on this manuscript and several proposals and abstracts. Pacific Watershed Associates deserves many thanks for all of their support; they made this thesis possible. Thank you to Redwood Forest Foundation Incorporated and Campbell Timberland Management for allowing and facilitating land access for field research. This research was supported by a student grant from the Geological Society of America and a data collection grant from the National Center for Airborne Laser Mapping. Additional data and GIS tools were downloaded from http://opentopography.org/ and http://geomorphtools.org/. David Lamphear and Diane Montoya graciously helped me dive into the world of GIS and LiDAR. Bonnie Bennett, Ronna Bowers, Mary Barr, Koa Lavery, Kyle French, Jason Buck, and especially Evan Saint-Pierre were kind enough to help me collect field data. I am so appreciative of my family for their various forms of support during this process. And to all of my friends- thank you for your patience and the good times! iv TABLE OF CONTENTS ABSTRACT ....................................................................................................................... iii ACKNOWLEDGEMENTS ............................................................................................... iv TABLE OF CONTENTS .................................................................................................... v LIST OF TABLES ............................................................................................................ vii LIST OF FIGURES ......................................................................................................... viii LIST OF APPENDICES ..................................................................................................... x INTRODUCTION .............................................................................................................. 1 STUDY AREA ................................................................................................................... 3 DATA AND METHODS ................................................................................................... 5 LiDAR-Generated Digital Elevation Models .................................................... 5 Stream Profile Analysis...................................................................................... 6 Identification of Knickpoints and Knickzones ................................................... 8 RESULTS ......................................................................................................................... 10 South Fork Eel River ........................................................................................ 10 Standley Creek ................................................................................................. 10 Bear Pen Creek ................................................................................................. 12 Knickpoints and Knickzones: Frequency and Distribution ............................. 14 Terraces ............................................................................................................ 16 South Fork Eel River Basin-Wide Steepness Indices ...................................... 16 DISCUSSION ................................................................................................................... 18 Trends in Knickzone Length and Gradient with Drainage Area ...................... 18 v Are Major Knickzones Characterized by Narrower Valleys? .......................... 19 Elevation Groupings of Major Knickpoints ..................................................... 20 Generation of Major Knickzones: Internal or External Control? ..................... 21 Terraces Support Transient Knickzone Migration ........................................... 22 Multiple Events of Base-level Lowering on the South Fork Eel ..................... 23 CONCLUSION ................................................................................................................. 25 REFERENCES CITED ..................................................................................................... 27 TABLES ........................................................................................................................... 29 FIGURES .......................................................................................................................... 31 APPENDICES .................................................................................................................. 54 vi LIST OF TABLES TABLE PAGE 1 Knickpoint Frequency in the Standley and Bear Pen Creek Drainage Basins Eel River ..................................................................................30 vii LIST OF FIGURES FIGURE PAGE 1 Location Map of the South Fork Eel River ........................................................32 2. Hillshades of the South Fork Eel River Basin ....................................................33 3. Hillshades and GIS-derived drainage network for Standley and Bear Pen Creeks Utilizing 10-m and 1-m DEMs ...............................................................34 4. Schematic Figure Depicting Knickpoints and Knickzones ................................35 5. Longitudinal Profile and Hillshade of the South Fork Eel River ........................36 6. Longitudinal Profile and Hillshade of Standley Creek .......................................37 7. Longitudinal Profile, Hillshade, and Slopeshade of North Fork Standley Creek ....................................................................................................38 8. Longitudinal Profile, Hillshade, and Slopeshade of Long Gulch .......................39 9. Longitudinal Profile, Hillshade, and Slopeshade of Standley Creek Tributary 2 ..........................................................................................................40 10. Longitudinal Profile, Hillshade, and Slopeshade of Standley Creek Tributary 4 ..........................................................................................................41 11. Longitudinal Profile, Hillshade, and Slopeshade of Bear Pen Creek .................42 12. Longitudinal Profile, Hillshade, and Slopeshade of North Fork Bear Pen Creek ...................................................................................................43 13. Longitudinal Profile, Hillshade, and Slopeshade of Cinnamon Bear Gulch ......44 14. Longitudinal Profile, Hillshade, and Slopeshade of Bear Pen Creek Tributary 1 ..........................................................................................................45 15. Longitudinal Profile, Hillshade, and Slopeshade of Bear Pen Creek Tributary 5 ..........................................................................................................46 16. Plots of Knickpoint Attributes ............................................................................47 viii 17. Knickpoint Frequency Denoted by Stream Order ..............................................48 18. Major Knickzone Distribution in the Standley and Bear Pen Creek Drainage Basins ..................................................................................................................49 19. Pre-incision Base Levels and Associated Terraces .............................................50 20. Normalized Steepness Indices Throughout the South Fork Eel River Basin .....51 21. Characteristics of Major