Cover photograph: North Umpqua River above Copeland Creek and Old Man Rock, summer 1994. (Photograph by Chauncey W. Anderson, U.S. Geological Survey.) Water-Quality and Algal Conditions in the North Umpqua River Basin, Oregon, 1992–95, and Implications for Resource Management By CHAUNCEY W. ANDERSON and KURT D. CARPENTER U.S. Department of the Interior U.S. Geological Survey Water-Resources Investigations Report 98–4125 Prepared in cooperation with Douglas County Portland, Oregon 1998 U.S. DEPARTMENT OF THE INTERIOR BRUCE BABBITT, Secretary U.S. GEOLOGICAL SURVEY Thomas J. Casadevall, Acting 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 addtional information write to: Copies of this report can be purchased from: District Chief U.S. Geological Survey U.S. Geological Survey, WRD Branch of Information Services 10615 S. E. Cherry Blossom Drive Box 25286 Portland, Oregon 97216-3159 Federal Center E-mail: [email protected] Denver, CO 80225 CONTENTS Abstract........................................................................................................................................................................................................1 Introduction .................................................................................................................................................................................................2 Background ...................................................................................................................................................................................2 Purpose and Scope ........................................................................................................................................................................2 Study Area.....................................................................................................................................................................................3 Climate...................................................................................................................................................................................3 Geology..................................................................................................................................................................................3 Hydroproject Area .................................................................................................................................................................5 Wild and Scenic Reach ..........................................................................................................................................................9 Steamboat Creek ....................................................................................................................................................................9 Little River Watershed.........................................................................................................................................................10 Water-Quality Issues and Aquatic Ecosystem Concepts ............................................................................................................10 Water-Quality Standards......................................................................................................................................................10 Benthic Algae.......................................................................................................................................................................12 Methods .....................................................................................................................................................................................................13 U.S. Geological Survey Data Collection, 1993–95 ....................................................................................................................13 Streamflow and Monitors............................................................................................................................................................14 Water and Sediment ....................................................................................................................................................................14 Algae ...........................................................................................................................................................................................17 Quality Assurance .......................................................................................................................................................................19 Water and Sediment.............................................................................................................................................................19 Algae....................................................................................................................................................................................20 Results .......................................................................................................................................................................................................21 Hydrologic Conditions................................................................................................................................................................21 Temporal and Spatial Variability.........................................................................................................................................22 Flow Balance .......................................................................................................................................................................23 Major Ions, Trace Elements, and Organic Compounds ..............................................................................................................26 Nutrients......................................................................................................................................................................................27 Algal Conditions .........................................................................................................................................................................29 Periphyton Biomass .............................................................................................................................................................31 Phytoplankton Chlorophyll a...............................................................................................................................................31 Periphyton Species Composition .........................................................................................................................................31 Autecological Guilds ...........................................................................................................................................................33 Spatial Variability.........................................................................................................................................................33 Seasonal Variability......................................................................................................................................................33 Cluster Analysis...................................................................................................................................................................34 Ordination of Sites, Algal Taxa, and Environmental Variables ..........................................................................................35 Water Temperature, Dissolved Oxygen, and pH ........................................................................................................................36 Relations of Water Quality and Algal Conditions to Resource Management...........................................................................................40 Forestry .......................................................................................................................................................................................40 Hydropower ................................................................................................................................................................................42 Effects of Reservoirs on Water Quality...............................................................................................................................42 Effects of Reservoirs on Algal Abundance and Distribution...............................................................................................44 Suggestions for Future Studies ...................................................................................................................................................45 Background Conditions .......................................................................................................................................................45 Nutrient Status and Limitation.............................................................................................................................................46 Geomorphology ...................................................................................................................................................................47