Estimating Water Temperatures in Small Streams in Western Oregon Using Neural Network Models Prepared in cooperation with the OREGON WATERSHED ENHANCEMENT BOARD U.S. GEOLOGICAL SURVEY Water-Resources Investigations Report 02-4218 Estimating Water Temperatures in Small Streams in Western Oregon Using Neural Network Models By John C. Risley, U.S. Geological Survey, Edwin A. Roehl, Jr., Advanced Data Mining, LLC, and Paul A. Conrads, U.S. Geological Survey U.S. GEOLOGICAL SURVEY Water-Resources Investigations Report 02-4218 Prepared in cooperation with the OREGON WATERSHED ENHANCEMENT BOARD Portland, Oregon 2003 U.S. DEPARTMENT OF THE INTERIOR GALE A. NORTON, Secretary U.S. GEOLOGICAL SURVEY Charles G. Groat, Director Any use of trade, product, or firm names in this publication is for descriptive purposes only and does not imply endorsement by the U.S. Government. 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 10615 S.E. Cherry Blossom Drive Building 810 Portland, Oregon 97216-3159 Box 25286, Federal Center Email: [email protected] Denver, CO 80225-0286 Internet: http://oregon.usgs.gov CONTENTS Abstract ................................................................................................................................................................ 1 Introduction .......................................................................................................................................................... 1 Background ................................................................................................................................................. 1 Purpose and Scope ...................................................................................................................................... 2 Study Area................................................................................................................................................... 3 Previous Investigations ............................................................................................................................... 3 Acknowledgments....................................................................................................................................... 6 Data Collection..................................................................................................................................................... 6 Water Temperature...................................................................................................................................... 6 Stream Habitat Surveys............................................................................................................................... 8 Basin Characteristics................................................................................................................................... 8 Climate ........................................................................................................................................................ 9 Model Development............................................................................................................................................. 11 Background Theory..................................................................................................................................... 11 Clustering Analysis ..................................................................................................................................... 12 Model Framework....................................................................................................................................... 15 Training....................................................................................................................................................... 19 Validation.................................................................................................................................................... 21 Model Application................................................................................................................................................ 30 Shade Adjustment ....................................................................................................................................... 30 Climate Adjustment .................................................................................................................................... 31 Future Improvements .................................................................................................................................. 34 Summary and Conclusions................................................................................................................................... 35 References Cited .................................................................................................................................................. 36 Appendix A. Site list for water temperature and habitat survey data collection ................................................. 38 Appendix B. Model input variable tables and sensitivity analyses..................................................................... 42 Appendix C. Model operation instructions ......................................................................................................... 56 Contents iii FIGURES Figure 1. Map showing western Oregon study region ...................................................................................... 4 Figure 2. Graphs showing mean monthly precipitation and air temperature at Astoria, Brookings, Crater Lake, Eugene, Medford, North Bend, and Salem, Oregon .................................. 5 Figure 3. Map showing locations of stream temperature stations, climate stations, and snowpack measurement stations in western Oregon ......................................................................... 7 Figure 4. Diagram showing feed-forward neural network architecture with three inputs, five hidden-layer nodes, and a single output ..................................................................................... 12 Figure 5. Graph showing density of water temperature records ....................................................................... 13 Figure 6. Graph showing results of clustering analysis .................................................................................... 14 Figure 7. Map showing distribution of the three groups of stream temperature stations within the study area .......................................................................................................................... 16 Figure 8. Graph showing mean of normalized 24-hour moving average hourly water temperature time series from each of the three groups...................................................................... 17 Figure 9. Diagram showing components of artificial neural network water temperature models .................... 18 Figure 10. Map showing location of model validation sites ............................................................................... 22 Figure 11. Graphs showing measured and simulated 24-hour moving average hourly water temperatures for selected sites in western Oregon............................................................................. 25 Figure 12. Graphs showing measured and simulated hourly water temperatures for selected sites in western Oregon...................................................................................................................... 27 Figure 13. Graphs showing simulated 24-hour moving average hourly water temperatures for varying shade conditions for selected sites in western Oregon ......................................................... 32 iv Figures TABLES Table 1. Stream habitat and basin variables used as model inputs and their statistics .................................... 9 Table 2. Climate time series data assembled for the model simulations ......................................................... 10 Table 3. Statistical results for the training and testing of simulations for each model .................................... 20 Table 4. Location, stream habitat, and basin characteristics data for the validation stream sites.................... 23 Table 5. Comparison of static, 24-hour moving average, and hourly model errors for the simulation period (June 21, 1999, to September 20, 1999) for the validation stream sites............... 24 Table 6. Existing and adjusted shade and vegetation variable values for selected stream sites ...................... 31 Table 7. Mean of simulated hourly temperatures for varying shade conditions for selected stream sites ...... 31 Table 8. Departure of 1999 mean monthly water temperatures from the period of record at selected stations in western Oregon............................................................................................... 34 Tables v CONVERSION FACTORS AND VERTICAL DATUM Conversion Factors Multiply By To obtain cubic meter per second (m3/s) 35.31 cubic foot per second (ft3/s) millimeter (mm) 0.03937 inch meter (m) 3.281 foot (ft) kilometer (km) 0.5400 mile (mi) square kilometer (km2) 0.3861 square mile (mi2) cubic meter (m3) 1.308 cubic yard (yd3) Temperature in degrees Celsius (°C) may be converted to degrees Fahrenheit (°F) as follows: °F=1.8 °C+32 Vertical Datum In this report, vertical coordinates are referenced to the North American Vertical Datum of 1988 (NAVD