Late Quaternary Sediment Source and Deposition History of Lake Ozette
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Report to: National Park Service U.S. Department of the Interior Olympic National Park Port Angeles, Washington Late Quaternary Sediment Source and Deposition History of Lake Ozette 7/1/2009 Andy Ritchie and Dr. Joanne Bourgeois Earth & Space Sciences Department University of Washington TABLE OF CONTENTS LIST OF FIGURES ........................................................................................................................ ii LIST OF TABLES ......................................................................................................................... iii Executive Summary .......................................................................................................................... Acknowledgments............................................................................................................................. 1 INTRODUCTION & RESEARCH OBJECTIVES ................................................................ 1 1.1 Background & Objectives ............................................................................................... 1 1.2 Physical Setting ............................................................................................................... 1 1.2.1 Geography ................................................................................................................... 1 1.2.2 Climate ........................................................................................................................ 4 1.2.3 Limnology & Lake Ecology ....................................................................................... 5 1.2.4 Geology ....................................................................................................................... 6 1.2.5 Watershed Land Use and Disturbance History ......................................................... 10 2 METHODS ........................................................................................................................... 12 2.1 Shoreline and watershed land use history ..................................................................... 12 2.1.1 Shoreline analysis ..................................................................................................... 13 2.1.1.1 Preliminary shoreline analysis .......................................................................... 14 2.1.1.2 Quantitative Shoreline Analysis ....................................................................... 15 2.1.1.3 Umbrella Creek Delta Analysis ........................................................................ 16 2.1.2 Watershed Land-use Analysis ................................................................................... 18 2.1.2.1 Ozette Watershed land use analysis .................................................................. 18 2.1.2.2 Umbrella Creek detailed sub-basin land use analysis ....................................... 19 2.2 Sediment Accumulation History ................................................................................... 19 2.2.1 Reconnaissance surveys ............................................................................................ 20 2.2.1.1 Sediment grab-sampling ................................................................................... 20 2.2.1.2 Seismic profiling ............................................................................................... 22 2.2.2 Lake sediment core acquisition ................................................................................. 24 2.2.2.1 Coring platform construction ............................................................................ 24 2.2.2.2 Sediment core collection ................................................................................... 26 2.2.3 Sediment core processing and storage ...................................................................... 26 2.2.3.1 Lake sediment X-ray analysis ........................................................................... 27 2.2.3.2 Lake sediment radioisotope analysis ................................................................ 27 2.2.3.2.1 210-Pb analysis for short-term accumulation rates ..................................... 27 2.2.3.2.2 14-C analysis for long-term accumulation rates ......................................... 28 2.2.3.3 Lake sediment stable isotope analysis .............................................................. 29 3 RESULTS ............................................................................................................................. 30 3.1 Quantification and description of shoreline and watershed changes ............................ 30 3.1.1 Preliminary shoreline analysis .................................................................................. 30 3.1.2 Quantitative Shoreline Analysis ............................................................................... 34 3.1.3 Umbrella Creek Delta Analysis ................................................................................ 38 3.1.4 Ozette Watershed Land Use History......................................................................... 41 3.1.5 Umbrella Creek detailed sub-basin analysis ............................................................. 48 3.2 Lake Ozette sediment accumulation history ................................................................. 51 3.2.1 Short-term accumulation rates (210Pb isotope analysis) ............................................ 51 3.2.2 Long-term accumulation rates (14C isotope analysis) ............................................... 63 3.3 δ13C and δ15N isotope values in Lake Ozette ................................................................ 67 4 DISCUSSION ....................................................................................................................... 73 4.1.1 Shoreline and watershed changes ............................................................................. 73 4.1.2 The sedimentary record in Lake Ozette .................................................................... 75 4.1.3 Spatial distribution and timing of changes in sediment accumulation in relation to watershed disturbance. .......................................................................................................... 79 4.1.4 Stable isotope signatures in Lake Ozette. ................................................................. 79 5 REFERENCES ..................................................................................................................... 82 APPENDIX A: Acoustic profiles ................................................................................................. 90 APPENDIX B: Core X-radiograph negatives............................................................................... 90 LIST OF FIGURES Figure 1. Ozette watershed location map with sub-basins. ............................................................. 2 Figure 2. Geologic Map of the Ozette basin ................................................................................... 8 Figure 3. Lake Ozette shoreline directly SW of the Ozette River outlet, in 1953 and 2003. ...... 15 Figure 4: Umbrella Creek delta analysis polygons. ...................................................................... 18 Figure 5: Seismic profile, grab sample, and Kasten core locations .............................................. 21 Figure 6: A portion of original seismic data, scanned at 100 dpi. ................................................ 22 Figure 7: A portion of the center of the FFT of the scanned chart depicted in Figure 9 .............. 23 Figure 8: Resulting de-striped image corresponding to the same area as Figure 6. ..................... 23 Figure 9. Coring platform constructed to collect sediment cores from Lake Ozette. ................... 25 Figure 10. Composite X-ray negative of core OZ1005-5. ............................................................ 27 Figure 11. Changes in Lake Ozette vegetation and shoreline from 1953 to 2003. ....................... 31 Figure 12. Vegetation changes from 1953-2003 at Lake Ozette at the Ozette River outlet. ........ 32 Figure 13. Shoreline changes at the mouth of Umbrella Creek on Lake Ozette. ......................... 33 Figure 14. Change in shoreline unvegetated area, ........................................................................ 34 Figure 15. Unvegetated beach area in 1953 and 2003 .................................................................. 35 Figure 16. Comparison of south Allen’s Beach from 1953 to 2003 ............................................. 36 Figure 17. Vegetation changes at Olsen’s Beach from 1953 to 2003 ........................................... 37 Figure 18. Umbrella Creek Delta in 1953. 1953 (orange) and 2003 (red) shorelines are shown. 38 Figure 19. Umbrella Creek Delta in 2003. 1953 (orange) and 2003 (red) shorelines are shown. 39 Figure 20. Change in proximal and whole Umbrella Creek subaerial delta area since 1952. ...... 40 Figure 21. Primary forest fraction remaining from photo year1953 – 2006 by sub-watershed.... 41 Figure 22. Primary forest fraction remaining from 1953 – 2006 by ownership category. ........... 43 Figure 23. Cumulative and annualized harvest as percent of ownership area .............................. 44 Figure 24. Cumulative harvest as percent of watershed area for major Ozette tributaries. .......... 45 Figure 25. Road Density through time for entire watershed (gray) and subwatersheds (black). 46 Figure 26. Road density by ownership for private