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Landform Mapping at North Cascades National Park Service Complex, Washington

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Landform Mapping at North Cascades National Park Service Complex, Washington National Park Service U.S. Department of the Interior Natural Resource Stewardship and Science Geomorphology of the Upper Skagit Watershed Landform Mapping at North Cascades National Park Service Complex, Washington Natural Resource Technical Report NPS/NCCN/NRTR—2012/568 ON THE COVER From upper right to lower left: Photograph of the north face of Mt. Spickard from Silver Glacier taken by Stephen Dorsch of the NPS; Perry Creek taken by Nicole Bowerman of the NPS; The south slope of Desolation Peak with Mt. Hozomeen visible to the north taken by Sharon Brady of the NPS; The north face of Jack Mountain and the Nohokomeen Glacier from south face of Desolation Peak. Photograph by: Sharon Brady, NPS Geomorphology of the Upper Skagit Watershed Landform Mapping at North Cascades National Park Service Complex, Washington Natural Resource Technical Report NPS/NCCN/NRTR—2012/568 Jon Riedel Sharon Brady Stephen Dorsch Nicole Bowerman Jeanna Wenger National Park Service North Cascades National Park 7280 Ranger Station Road Marblemount, Washington 98267 April 2012 U.S. Department of the Interior National Park Service Natural Resource Stewardship and Science Fort Collins, Colorado The National Park Service, Natural Resource Stewardship and Science office in Fort Collins, Colorado publishes a range of reports that address natural resource topics of interest and applicability to a broad audience in the National Park Service and others in natural resource management, including scientists, conservation and environmental constituencies, and the public. The Natural Resource Technical Report Series is used to disseminate results of scientific studies in the physical, biological, and social sciences for both the advancement of science and the achievement of the National Park Service mission. The series provides contributors with a forum for displaying comprehensive data that are often deleted from journals because of page limitations. All manuscripts in the series receive the appropriate level of peer review to ensure that the information is scientifically credible, technically accurate, appropriately written for the intended audience, and designed and published in a professional manner. This report received informal peer review by subject-matter experts who were not directly involved in the collection, analysis, or reporting of the data. Views, statements, findings, conclusions, recommendations, and data in this report do not necessarily reflect views and policies of the National Park Service, U.S. Department of the Interior. Mention of trade names or commercial products does not constitute endorsement or recommendation for use by the U.S. Government. This report is available from the North Coast and Cascades Network (http://science.nature.nps.gov/im/units/nccn/reportpubs.cfm) and the Natural Resource Publications Management website (http://www.nature.nps.gov/publications/nrpm/). Please cite this publication as: Riedel, J., Brady, S., Dorsch, S., Bowerman, N., and Wenger, J. 2012. Geomorphology of the Upper Skagit watershed: Landform mapping at North Cascades National Park Service Complex, Washington. Natural Resource Technical Report NPS/NCCN/NRTR—2012/568. National Park Service, Fort Collins, Colorado. NPS 168/113511, April 2012 ii Contents Page Contents ......................................................................................................................................... iii Figures............................................................................................................................................. v Tables ............................................................................................................................................ vii Abstract .......................................................................................................................................... ix 1 - Introduction ............................................................................................................................... 1 1.1 Applications of Landform Mapping Data ........................................................................... 1 1.2 Project History .................................................................................................................... 2 2 - Study Area ................................................................................................................................. 5 2.1 Geographic Setting ............................................................................................................... 5 2.2 Geologic Setting ................................................................................................................... 8 2.2.2 Geologic Units ........................................................................................................... 9 2.3 Glacial History .................................................................................................................. 11 2.4 Climate .............................................................................................................................. 15 2.5 Hydrologic Setting ............................................................................................................ 17 2.6 Vegetation ......................................................................................................................... 20 3 - Landform Mapping at NOCA .................................................................................................. 23 3.1 National Hierarchical Framework for Ecological Units ................................................... 23 3.1.1 Subsection (1:250,000) ............................................................................................ 23 3.1.2 Landtype Association (1:62,500) ............................................................................. 24 3.1.3 Landtype Phase (Landform) (1:24,000) .................................................................. 25 3.2 Landform Age ................................................................................................................... 26 3.2.1 Linking Landform Age to Soil Genesis .................................................................... 26 4 – Methods................................................................................................................................... 29 iii Contents (continued) Page 4.1 Preliminary Methods .................................................................................................. 29 4.1.1 Field Methods .......................................................................................................... 29 4.1.2 Digitizing Methods ................................................................................................... 29 4.2 Areas Surveyed............................................................................................................ 30 5 - Results and Discussion ............................................................................................................ 31 5.1 General Watershed Overview ........................................................................................... 31 5.1.1 High Elevation Landforms ....................................................................................... 33 5.2 Valley Characteristics of West Ross Lake Sub-Watersheds............................................. 34 5.3 Valley Characteristics of East Ross Lake Sub-Watersheds .............................................. 53 5.4 Upper Skagit Watershed Landslide Inventory .................................................................. 62 6 - Future Work ............................................................................................................................. 67 7 - Literature Cited ........................................................................................................................ 69 Appendix A: Landslide Inventories for the Upper Skagit Watershed .......................................... 73 iv Figures Page Figure 1. Map showing the location of Skagit River and adjacent watersheds within North Cascades National Park Service Complex (NOCA)............................................................. 6 Figure 2. Landform map (1:24,000) showing the distribution of landforms in the Upper Skagit Watershed as well as the locations of the sub-watersheds and peaks referred to in the text. ...................................................................................................................... 7 Figure 3. Major fault systems and terranes in the North Cascades. ............................................... 9 Figure 4. Bedrock map showing the Upper Skagit Watershed (note location of Ross Lake) and some of the adjoining watersheds ................................................................................ 10 Figure 5. Map of the known extent of the Cordilleran Ice Sheet during the Fraser Glaciation. ..................................................................................................................................... 12 Figure 6. Reconstruction of Big Beaver Glacier during about 25,000 years ago, showing the approximate extent of Glacial Lake Skymo. ............................................................ 14 Figure 7. Digital elevation model showing permanent snowfields and glaciers in and around the Upper Skagit Watershed, as well as weather monitoring stations mentioned in the text......................................................................................................................................
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