EPA/600/R-13/006 | January 2013 | www.epa.gov/research AAnn EEccoollooggiiccaall CChhaarraacctteerriizzaattiioonn aanndd LLaannddssccaappee AAsssseessssmmeenntt ooff tthhee HHuummbboollddtt RRiivveerr BBaassiinn R E S E A R C H A N D D E V E L O P M E N T An Ecological Characterization and Landscape Assessment of the Humboldt River Basin Prepared by Leah Hare1, Daniel Heggem1, Robert Hall2, Peter Husby3 1U.S. Environmental Protection Agency Office of Research and Development National Exposure Research Laboratory Environmental Sciences Division Las Vegas, NV 89119 2U.S. Environmental Protection Agency Region 9 WTR2 San Francisco, CA 94105 3U.S. Environmental Protection Agency Region 9 Laboratory Richmond, CA 94804 Although this work was reviewed by EPA and approved for publication, it may not necessarily reflect official Agency policy. Mention of trade names and commercial products does not constitute endorsement or recommendation for use. U.S. Environmental Protection Agency Office of Research and Development Washington, DC 20460 ii Table of Contents List of Tables .............................................................................................................................................................. v List of Figures ......................................................................................................................................................... vii List of Appendices ..................................................................................................................................................... xi List of Acronyms and Abbreviations...................................................................................................................... xiii Acknowledgements ................................................................................................................................................. xiv Executive Summary.................................................................................................................................................... 1 1.0 Introduction ........................................................................................................................................................ 3 1.1. Objectives ..................................................................................................................................................... 3 1.2. Broad-Scale Environmental Condition ......................................................................................................... 4 1.3. Overview ....................................................................................................................................................... 6 2.0 The Biophysical Setting ...................................................................................................................................... 7 2.1. Land Cover and Topography ........................................................................................................................ 7 2.2. Streams ........................................................................................................................................................ 10 2.3. Watershed ................................................................................................................................................... 11 3.0 Methodology ...................................................................................................................................................... 13 3.1. Regional Classification ............................................................................................................................... 13 3.2. EPA-Delineated Sub-watersheds ................................................................................................................ 14 3.3. Landscape Metrics ...................................................................................................................................... 16 3.4. Soil and Landform Metrics ......................................................................................................................... 17 3.5. EMAP Measurements ................................................................................................................................. 17 3.6. Data Sources ............................................................................................................................................... 18 3.7. Data Analysis .............................................................................................................................................. 18 4.0 Land Cover/Use ................................................................................................................................................ 19 4.1. Forests ......................................................................................................................................................... 19 4.2. Shrubland/Grasslands ................................................................................................................................. 20 4.3. Agriculture .................................................................................................................................................. 21 4.4. Grazing ........................................................................................................................................................ 22 4.5. Population Growth and Urban Development .............................................................................................. 25 4.6. Roads .......................................................................................................................................................... 26 4.7. Mining ......................................................................................................................................................... 27 4.8. Riparian Land Cover/Use ........................................................................................................................... 31 iii 5.0 Land Cover Comparison ................................................................................................................................. 33 6.0 Soil Cover .......................................................................................................................................................... 35 6.1. R Factor ....................................................................................................................................................... 35 6.2. C Factor ....................................................................................................................................................... 36 6.3. K Factor ...................................................................................................................................................... 37 6.4. P factor ........................................................................................................................................................ 38 6.5. LS Factor ..................................................................................................................................................... 38 6.6. A Value ....................................................................................................................................................... 39 7.0 Ecological Indicators ........................................................................................................................................ 41 7.1. Dissolved Oxygen ...................................................................................................................................... 41 7.2. pH ............................................................................................................................................................... 42 7.3. Total Kjeldahl Nitrogen .............................................................................................................................. 42 7.4. Total Phosphorus ........................................................................................................................................ 42 7.5. IBI ............................................................................................................................................................... 43 7.6. TDS ............................................................................................................................................................. 43 8.0 Landscape and Water Relationships .............................................................................................................. 45 8.1. Regression Models ...................................................................................................................................... 45 8.2. Model Application ...................................................................................................................................... 45 9.0 Conclusion ......................................................................................................................................................... 47 References ............................................................................................................................................................... 51 Data .........................................................................................................................................................................