SIR 2020–5059: Hydrology and Geomorphology of the Taiya River
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Prepared in cooperation with the National Park Service Hydrology and Geomorphology of the Taiya River Near the West Creek Tributary, Southeast Alaska 1,000 100 10 1 Discharge, in cubic meters per second 0.1 Jan. Feb. Mar. Apr. May June July Aug. Sep. Oct. Nov. Dec. Scientific Investigations Report 2020–5059 U.S. Department of the Interior U.S. Geological Survey Cover: Background image: Midriver view of the Taiya River downstream from the Dyea Road bridge and upstream from the historical Dyea downtown area, looking downstream, Alaska (photograph by Janet Curran, U.S. Geological Survey, August 30, 2017). Inset images, left to right: Hydrograph showing maximum, mean, and minimum daily discharge and peak discharge for period of record for U.S. Geological Survey streamgage on Taiya River, Alaska; relative elevation model of Taiya River main stem valley bottom for 2003 conditions, Alaska. Hydrology and Geomorphology of the Taiya River Near the West Creek Tributary, Southeast Alaska By Janet H. Curran Prepared in cooperation with the National Park Service Scientific Investigations Report 2020–5059 U.S. Department of the Interior U.S. Geological Survey U.S. Department of the Interior DAVID BERNHARDT, Secretary U.S. Geological Survey James F. Reilly II, Director U.S. Geological Survey, Reston, Virginia: 2020 For more information on the USGS—the Federal source for science about the Earth, its natural and living resources, natural hazards, and the environment—visit https://www.usgs.gov or call 1–888–ASK–USGS. For an overview of USGS information products, including maps, imagery, and publications, visit https://store.usgs.gov. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Although this information product, for the most part, is in the public domain, it also may contain copyrighted materials as noted in the text. Permission to reproduce copyrighted items must be secured from the copyright owner. Suggested citation: Curran, J.H., 2020, Hydrology and geomorphology of the Taiya River near the West Creek Tributary, southeast Alaska: U.S. Geological Survey Scientific Investigations Report 2020–5059, 57 p., https://doi.org/10.3133/sir20205059. Associated data for this publication: Curran, J.H., 2020, Geomorphic surface and channel boundaries for the lower 7.5 kilometers of the Taiya River Valley, southeast Alaska, 2018: U.S. Geological Survey data release, https://doi.org/10.5066/P9XP1SE7. ISSN 2328-0328 iii Acknowledgments The staff of the National Park Service graciously facilitated field access and provided access to geospatial data. Jami Belt of the National Park Service provided significant project coordination and field assistance. Rob Schenkert of the U.S. Geological Survey (USGS) and Devon Burton of the National Park Service (NPS) assisted with field activities. This project benefitted from discussions with Jami Belt, Karl Gurcke, Dave Schirokauer, and Paul Burger of the NPS and Robin Beebee, Jim O’Connor, and Louis Sass of the USGS. Joel Cusick of the NPS assisted with geospatial data acquisition. Karl Gurcke facilitated access to historical photographs and reports from the archives of the Klondike Gold Rush National Historical Park. Contents Acknowledgments ......................................................................................................................................iii Abstract ...........................................................................................................................................................1 Introduction.....................................................................................................................................................2 Purpose and Scope ..............................................................................................................................5 Previous Studies ...................................................................................................................................5 Description of Study Area ............................................................................................................................7 Geology and Geography ......................................................................................................................7 Climate and Hydrology .........................................................................................................................8 Methods.........................................................................................................................................................10 Streamflow Data and Flood History Compilation ...........................................................................10 Discrete Suspended Sediment Data Collection ............................................................................11 Geomorphic Mapping and Analysis ................................................................................................12 Hydrogeomorphically Dependent Park Resources .......................................................................18 Surface-Water Hydrology and Suspended Sediment ...........................................................................18 Streamflow Since the 1960s ..............................................................................................................18 Decadal-Scale Change .............................................................................................................18 Comparisons Between West Creek and Taiya River Discharge ........................................20 Large Floods Since the 1800s............................................................................................................20 Suspended Sediment .........................................................................................................................24 Geomorphology ............................................................................................................................................24 Valley and Main Stem Channel Geomorphology ...........................................................................28 Active Main Stem ......................................................................................................................28 Abandoned Fluvial Surfaces ....................................................................................................33 Alluvial Fans ................................................................................................................................33 Emergent Tidal Flats ..................................................................................................................34 Historical Channel Change ................................................................................................................34 Channel Change 1894–1948 ......................................................................................................34 Channel Change Since 1948 .....................................................................................................34 Sediment Sources...............................................................................................................................38 Off-Main-Stem Channels ...................................................................................................................41 iv Selected Hydrogeomorphically Dependent Resources ........................................................................46 River Recreation..................................................................................................................................46 Boreal Toad Habitat ............................................................................................................................46 Sites Near Eroding Banks .................................................................................................................46 Hydrogeomorphic Implications for Taiya River Resources ..................................................................48 Evolution of Valley Bottom Surfaces and Channels ......................................................................48 Streamflow and Sediment Timing and Seasonality ......................................................................50 Wetland Water Sources ....................................................................................................................50 Monitoring Considerations ................................................................................................................51 Summary and Conclusions .........................................................................................................................52 References Cited..........................................................................................................................................54 Appendix 1. Geographic Information System Digital Files ................................................................57 Figures 1. Taiya River Basin and Lynn Canal, southeast Alaska, and Taiya River Basin and West Creek subbasin drainage basins, Klondike Gold Rush National Historical Park, mapping area, and selected streamgages, southeast Alaska ....................................3 2. Main stem Taiya River valley bottom and mapping area, Alaska .........................................6 3. Elevation and locations of features within the most developed part of the main stem Taiya River valley bottom, Alaska .....................................................................................9