Prepared in cooperation with the city of Portland, the city of Gresham, the city of Milwaukie, Clackamas County’s Water Environment Services, and Multnomah County Hydrology of the Johnson Creek Basin, Oregon Scientific Investigations Report 2009–5123 U.S. Department of the Interior U.S. Geological Survey Cover: Top: Photograph of Crystal Springs Creek at Reed College, Portland, Oregon, July 6, 2005. Middle: Photograph of Holgate Lake at Portland, Oregon, March 13, 2006. Bottom: Photograph of Johnson Creek at Portland, Oregon, December 25, 2006. Photographs taken by Karl K. Lee, U.S. Geological Survey. Hydrology of the Johnson Creek Basin, Oregon By Karl K. Lee and Daniel T. Snyder Prepared in cooperation with the city of Portland, the city of Gresham, the city of Milwaukie, Clackamas County’s Water Environment Services, and Multnomah County Scientific Investigations Report 2009–5123 U.S. Department of the Interior U.S. Geological Survey U.S. Department of the Interior KEN SALAZAR, Secretary U.S. Geological Survey Suzette M. Kimball, Acting Director U.S. Geological Survey, Reston, Virginia: 2009 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. 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Suggested citation: Lee, K.K., and Snyder, D.T., 2009, Hydrology of the Johnson Creek basin, Oregon: U.S. Geological Survey Scientific Investigations Report 2009–5123, 56 p. iii Contents Abstract ...........................................................................................................................................................1 Introduction.....................................................................................................................................................2 Hydrologic Setting ................................................................................................................................2 Land Use .................................................................................................................................................4 Previous Investigations........................................................................................................................4 Purpose and Scope ..............................................................................................................................5 Methods...........................................................................................................................................................5 Groundwater ..........................................................................................................................................5 Surface Water .......................................................................................................................................8 Water Quality .........................................................................................................................................9 Meteorologic Data ................................................................................................................................9 Groundwater Hydrology................................................................................................................................9 Recharge ................................................................................................................................................9 Groundwater Discharge ....................................................................................................................10 Springs and Seepage ................................................................................................................11 Long-Term Streamflow Data ....................................................................................................17 Use of Environmental Tracers to Identify Groundwater Discharge ..................................18 Groundwater Flow Direction .............................................................................................................20 Variation in Groundwater Levels and Storage ...............................................................................22 Response of the Groundwater System to Precipitation Extremes ............................................29 High and Low Groundwater Discharge: Crystal Springs Creek .........................................29 Use of Hydrologic Data to Predict Streamflow of Crystal Springs Creek .........................................................................................30 Flooding from High Groundwater Level–Holgate Lake ........................................................32 Use of Hydrologic Data to Anticipate Flooding from Holgate Lake ..........................34 Surface-Water Hydrology ..........................................................................................................................35 Annual Flow .........................................................................................................................................35 Spatial Trends .............................................................................................................................35 Temporal Trends .........................................................................................................................36 Low Flow...............................................................................................................................................36 Spatial Trends .............................................................................................................................37 Temporal Trends .........................................................................................................................38 High Flow ..............................................................................................................................................41 Spatial Trends .............................................................................................................................41 Temporal Trends .........................................................................................................................44 Implications for Water Quality ...................................................................................................................47 Stream Temperature ...........................................................................................................................47 Sediment and Other Contaminants ..................................................................................................49 Potential Future Studies..............................................................................................................................50 Summary .......................................................................................................................................................50 Acknowledgments .......................................................................................................................................52 References Cited..........................................................................................................................................52 iv Plate Plate 1. Map showing location of groundwater and surface-water sites in the Johnson Creek basin, Oregon. Figures Figure 1. Map showing location of the Johnson Creek basin, Oregon ……………………… 3 Figure 2. Graph showing streamflow measurements of Crystal Springs Creek at Reed College, measurements and estimates of streamflow at the mouth of Crystal Springs Creek, and measurements of Errol Spring Creek, Portland, Oregon …… 11 Figure 3. Graph showing relation between average measured streamflow at the mouth of Crystal Springs Creek, Portland, Oregon, and consecutive 7-day average low streamflow of Johnson Creek at Milwaukie, Oregon, August to October 1989, 1997–2006 ………………………………………………………… 12 Figure 4. Graph showing seepage measurements during low flow in 1988, 1997–2000, 2006, and specific conductance measurements during low flow in 1998, 1999, and 2006, Johnson Creek, Oregon ………………………………………………… 15 Figure 5. Graph showing annual, 3-year average, and cumulative departure from average precipitation at Portland Airport, Oregon, 1911–2006 …………………… 16 Figure 6. Graph showing gain in consecutive 7-day average low streamflow between Johnson Creek at Regner Road at Gresham, Oregon, and Johnson Creek at Sycamore, Oregon, and between Johnson Creek at Sycamore and Johnson Creek at Milwaukie, Oregon ……………………………………………………… 17 Figure 7. Graph showing temperature at river mile (RM) 7.8, RM 5.5, and RM 3.2, Johnson Creek, Oregon …………………………………………………………… 19 Figure 8. Map showing estimated water table elevation, Johnson Creek basin, Oregon …… 21 Figure 9. Hydrographs showing water levels in selected long-term observation wells, Johnson Creek basin, Oregon …………………………………………………… 24 Figure 10. Graphs showing water level elevation