Eutrophication Potential of Payette Lake, Idaho
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EUTROPHICATION POTENTIAL OF PAYETTE LAKE, IDAHO By PAUL F. WOODS U.S. GEOLOGICAL SURVEY Water-Resources Investigations Report 97-4145 Prepared in cooperation with the IDAHO DIVISION OF ENVIRONMENTAL QUALITY Boise, Idaho 1997 science for a changing world U.S. DEPARTMENT OF THE INTERIOR BRUCE BABBITT, Secretary U.S. GEOLOGICAL SURVEY Gordon P. Eaton, Director The use of firm, trade, and brand names in this report is for identification purposes only and does not constitute endorsement by the U.S. Geological Survey. For additional information write to: Copies of this report can be purchased from: District Chief U.S. Geological Survey U.S. Geological Survey Information Services 230 Collins Road Box 25286 Boise, ID 83702-4520 Federal Center Denver, CO 80225 CONTENTS Abstract ................................................................................................................................................................................. 1 Introduction .................................................................................................................................................................^ 2 Description of study area ...................................................................................................................................................... 4 Hydrologic budgets ............................................................................................................................................................... 5 Data collection and analysis ........................................................................................................................................ 5 Streamflow................................................................................................................................................................... 6 Hydrologic budgets...................................................................................................................................................... 7 Nutrient budgets..................................................................................................................................................................... 8 Data collection and analysis ........................................................................................................................................ 8 Nutrient budgets........................................................................................................................................................... 9 Effects of fire on nutrient budgets................................................................................................................................ 11 Limnology.... ..............................................................................................................................................................^ 12 Data collection and analysis ........................................................................................................................................ 12 Limnetic zone................................................................................................................................................... 12 Littoral zone...................................................................................................................................................... 13 Limnetic zone.............................................................................................................................................................. 15 Water temperature............................................................................................................................................. 15 Water-column transparency.............................................................................................................................. 15 Specific conductance......................................................................................................................................... 17 pH.........................................................._ 18 Dissolved oxygen.............................................................................................................................................. 18 Phosphorus........................................................................................................................................................ 21 Nitrogen...........................................................................................................^ 23 Limiting nutrient............................................................................................................................................... 25 Chlorophyll-a.................................................................................................................................................... 25 Phytoplankton................................................................................................................................................... 26 Trophic state...................................................................................................................................................... 27 Sediment nutrients............................................................................................................................................ 28 Littoral zone................................................................................................................................................................. 29 Periphyton production....................................................................................................................................... 29 Aquatic macrophytes........................................................................................................................................ 30 Effects of fire on lake water quality............................................................................................................................. 30 Nutrient load/lake response model........................................................................................................................................ 31 Model description....................................................................................................._^ 31 Model calibration and verification............................................................................................................................... 32 Simulation results........................................................................................................................................................ 33 Summary and conclusions..................................................................................................................................................... 36 References cited..................................................................................................................................................................... 38 FIGURES 1. Map showing location of study area........................................................................................................................ 3 2. Graph showing relation of depth to lake surface area and volume for Payette Lake.............................................. 6 3. Map showing locations of limnetic and littoral sampling stations and model segments, and bathymetry of Payette Lake............................................................................................................................................................ 14 4-12. Graphs showing: 4. Lines of equal temperature, in degrees Celsius, at stations 1-4 during selected months of 1995-96, Payette Lake.................................................................................................................................................. 16 5. Depths of euphotic zone and secchi-disc transparency at stations 1 -4 during 1995-96, Payette Lake....... 17 Contents Hi 6. Lines of equal dissolved-oxygen concentration, in milligrams per liter, at stations 1-4 during selected months of 1995-96, Payette Lake................................................................................................................ 19 7. Lines of equal dissolved oxygen, as percent saturation, at stations 1 -4 during selected months of 1995-96, Payette Lake................................................................................................................................. 20 8. Concentrations of total phosphorus and dissolved orthophosphorus in the euphotic zone and lower hypolimnion at stations 1-4 during 1995-96, Payette Lake ....................................................................... 22 9. Concentrations of total nitrogen, dissolved inorganic nitrogen, and dissolved ammonia in the euphotic zone and lower hypolimnion at stations 1-4 during 1995-96, Payette Lake.............................................. 24 10. Ratios of dissolved inorganic nitrogen to dissolved orthophosphorus at stations 1 -4 during 1995-96, Payette Lake.................................................................................................................................................. 26 11. Chlorophyll-a concentrations at stations 1-4 during 1995-96, Payette Lake ............................................. 26 12. Phytoplankton biovolume at stations 1-4 during 1995-96, Payette Lake................................................... 28 TABLES 1. Annual coefficients for unit runoff and nutrient export for three gaged inflow stations