Prepared in cooperation with the National Park Service Sources and Sinks of Nitrogen and Phosphorus in a Deep, Oligotrophic Lake, Lake Crescent, Olympic National Park, Washington Scientific Investigations Report 2012–5107 U.S. Department of the Interior U.S. Geological Survey Cover: Photograph looking southeast over Lake Crescent, Washington. (Photograph taken by Steve Fradkin, National Park Service.) Sources and Sinks of Nitrogen and Phosphorus in a Deep, Oligotrophic Lake, Lake Crescent, Olympic National Park, Washington By P.W. Moran, S.E. Cox, S.S. Embrey, R.L. Huffman, T.D. Olsen, and S.C. Fradkin Prepared in cooperation with the National Park Service Scientific Investigations Report 2012–5107 U.S. Department of the Interior U.S. Geological Survey U.S. Department of the Interior SALLY JEWELL, Secretary U.S. Geological Survey Suzette M. Kimball, Acting Director U.S. Geological Survey, Reston, Virginia: 2013 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 http://www.usgs.gov or call 1–888–ASK–USGS. For an overview of USGS information products, including maps, imagery, and publications, visit http://www.usgs.gov/pubprod To order this and other USGS information products, visit http://store.usgs.gov Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Although this report is in the public domain, permission must be secured from the individual copyright owners to reproduce any copyrighted materials contained within this report. Suggested citation: Moran, P.W., Cox, S.E., Embrey, S.S., Hufffman, R.L., Olsen, T.D., and Fradkin, S.C., 2013, Sources and sinks of nitrogen and phosphorus to a deep, oligotrophic lake, Lake Crescent, Olympic National Park, Washington: U.S. Geological Survey Scientific Investigations Report 2012–5107, 56 p., http://pubs.usgs.gov/sir/2012/5107/. iii Contents Abstract ..........................................................................................................................................................1 Introduction.....................................................................................................................................................1 Purpose and Scope ..............................................................................................................................4 Description of Lake Crescent and the Watershed ...................................................................................4 Geologic and Glacial History ..............................................................................................................4 Climate ....................................................................................................................................................4 Land Cover and Land Use ....................................................................................................................8 Shoreline Development .......................................................................................................................8 Hydrology ...............................................................................................................................................8 Previous Limnology and Water-Quality Studies ............................................................................10 Trophic Status ......................................................................................................................................10 Water Temperature and Dissolved Oxygen ....................................................................................10 Water-Quality Characteristics and Nutrients.................................................................................10 Aquatic Ecology ..................................................................................................................................11 Methods of Investigation ............................................................................................................................11 Geographic Information System Methods .....................................................................................11 Water-Quality Data Collection ..........................................................................................................12 Hydrologic Data Collection ...............................................................................................................13 Water-Quality Data .............................................................................................................................13 Groundwater Data .............................................................................................................................13 Lake Sediment Coring ........................................................................................................................14 Quality Control, Method Detection Limits, and Reporting Levels ...............................................16 Sources and Sinks of Nitrogen and Phosphorus ...................................................................................17 Hydrology of the Lake Crescent Watershed ..................................................................................17 Water Chemistry .................................................................................................................................17 Groundwater Chemistry .....................................................................................................................23 Lake Sedimentation ............................................................................................................................25 Mass Balances....................................................................................................................................27 Water Balance ....................................................................................................................................27 Precipitation................................................................................................................................27 Evaporation .................................................................................................................................28 Gaged Basins..............................................................................................................................28 Ungaged Basins .........................................................................................................................28 Average Ungaged Area Runoff Scenario .....................................................................29 High Ungaged Area Runoff Scenario ............................................................................30 Low Ungaged Runoff Area Scenario .............................................................................30 Groundwater ...............................................................................................................................30 Water Balance Summary ..................................................................................................................31 Nutrient Balance .................................................................................................................................32 Nutrient Transport in Streams .................................................................................................32 Nutrients from Ungaged Basins ..............................................................................................36 Precipitation................................................................................................................................36 Groundwater and Septic Systems ..........................................................................................39 iv Contents—Continued Sources and Sinks of Nitrogen and Phosphorous—Continued Nutrient Balance—Continued Other Sources.............................................................................................................................40 Litterfall ...............................................................................................................................40 Pollen ................................................................................................................................40 Vehicle Emissions .............................................................................................................42 Nitrogen Fixation ...............................................................................................................43 Dry Deposition ...................................................................................................................44 Nutrient Budget ..................................................................................................................................45 Uncertainties .......................................................................................................................................46 Summary........................................................................................................................................................47 Recommendations .......................................................................................................................................49 Acknowledgments .......................................................................................................................................50