ruses science for a changing world Prepared in cooperation with the Alaska Energy Authority u Effects of Ice Formation on Hydrology and Water Quality in the Lower Bradley River, Alaska Implications for Salmon Incubation Habitat Water-Resources Investigations Report 98-4191 U.S. Department of the Interior U.S. Geological Survey Cover photograph: Ice pedestals at Bradley River near Tidewater transect, February 28, 1995. Effects of Ice Formation on Hydrology and Water Quality in the Lower Bradley River, Alaska Implications for Salmon Incubation Habitat by Ronald L. Rickman U.S. GEOLOGICAL SURVEY Water-Resources Investigations Report 98-4191 Prepared in cooperation with the ALASKA ENERGY AUTHORITY Anchorage, Alaska 1998 U.S. DEPARTMENT OF THE INTERIOR BRUCE BABBITT, Secretary U.S. GEOLOGICAL SURVEY Thomas J. Casadevall, Acting Director Use of trade names in this report is for identification purposes only and does not constitute endorsement by the U.S. Geological Survey. For additional information: Copies of this report may be purchased from: District Chief U.S. Geological Survey U.S. Geological Survey Branch of Information Services 4230 University Drive, Suite 201 Box 25286 Anchorage, AK 99508-4664 Denver, CO 80225-0286 http://www-water-ak.usgs.gov CONTENTS Abstract ................................................................. 1 Introduction ............................................................... 1 Location of Study Area.................................................. 1 Bradley Lake Hydroelectric Project ........................................ 2 Pink Salmon Life History ................................................ 2 Winter Flow Conditions ................................................. 2 Purpose and Scope...................................................... 4 Acknowledgments...................................................... 4 Description of Study Area .................................................... 4 Bear Island Transect .................................................... 6 Tidewater Transect ..................................................... 6 Tree Bar Reach Transect................................................. 6 Below Fish Camp Transect............................................... 11 Upper Riffle Reach Transect.............................................. 11 Lower Riffle Reach Transect.............................................. 11 Middle Fork Bradley River below North Fork Bradley River .................... 14 Methods and Materials....................................................... 14 Observation of Spawning Area Locations and Escapement Estimates.............. 14 Measurements of Surface Water ........................................... 14 Measurements of Intragravel Water ........................................ 16 Observations and Estimates of Fine-Sediment Deposition....................... 18 Results and Discussion ...................................................... 18 Escapement Estimates and Spawning Locations............................... 18 Ice Formation and Streamflow ............................................ 18 Hydrologic Properties ................................................... 23 Surface-Water Hydrostatic Head and Water Depth ........................ 23 Surface-Water Velocity. ............................................. 24 Wetted Perimeter................................................... 36 Field Water-Quality Data ................................................ 37 Temperature ...................................................... 37 Dissolved Oxygen.................................................. 38 Specific Conductance ............................................... 40 Fine-Sediment Deposition and Streambed Permeability......................... 40 Fine-Sediment Deposition............................................ 40 Dissolved-Oxygen Interchange........................................ 42 Stranding............................................................. 43 Discharge from the North and Lower Middle Forks Bradley River ................ 45 Summary ................................................................. 47 Conclusions ............................................................... 48 References Cited ........................................................... 49 Contents III FIGURES 1. Map showing location of Bradley Lake Hydroelectric Project area. ............. VI 2. Photograph showing aerial view of the study area from Bear Island to Lower Riffle Reach. .................................................. 4 3. Map showing lower Bradley River study cross-section transects ............... 5 4. Longitudinal profile of the study reach ................................... 7 5-10. Photographs showing Bradley River at the: 5. Bear Island transect looking upstream ................................. 8 6. Tidewater transect................................................. 9 7. Tree Bar Reach transect, looking upstream ............................. 10 8. Below Fish Camp transect, looking upstream ........................... 12 9. Upper Riffle Reach transect, looking upstream .......................... 13 10. Lower Riffle Reach transect......................................... 15 11. Diagram showing definitions of water depth and hydrostatic head as used in this report.................................................... 17 12. Graph of estimated escapement for pink salmon, 1986 to 1997................. 19 13. Graph showing daily mean discharges for Bradley River near Tidewater. ........ 20 14. Photograph of water flowing out of holes drilled through the ice during a period of forming ice ................................................ 22 15-20. Graphs showing selected physical properties of Bradley River relative to discharge: 15. At Bear Island transect............................................. 25 16. Near Tidewater transect ............................................ 26 17. At Tree Bar Reach transect.......................................... 27 18. Below Fish Camp transect .......................................... 28 19. At Upper Riffle Reach transect....................................... 29 20. At Lower Riffle Reach transect ...................................... 30 21-22. Graphs showing: 21. Lines of equal velocity for selected ice-forming and ice-free conditions for Bradley River at Tree Bar Reach .................................. 32 22. Selected surface-water velocity distributions for the six transects in the lower Bradley River ............................................... 33 23-24.Boxplots showing: 23. Surface- and intragravel-water dissolved-oxygen concentrations at the six transects of the lower Bradley River................................ 39 24. Dissolved-oxygen percent interchange at the six transects of the lower Bradley River .................................................... 44 25. Graphs showing instantaneous discharge measurements and daily mean discharges for the Middle Fork Bradley River below North Fork Bradley River ... 46 IV Contents TABLES 1. Summary of ice formation at stream-gaging station Bradley River near Tidewater . 19 2. Ice conditions for which mean velocity is likely to exceed 0.5 foot per second for various discharges................................................. 31 3. Mean intragravel-water temperature and thermal input from January 1 to April 1........................................................... 37 4. Standard settling velocities for quartz particles and corresponding minimum shear velocities required to keep particles in suspension ...................... 41 5. Mean and range of shear velocities for the six study transects in the lower Bradley River .................................................. 42 6. Gravel bar slopes at the six study transects ................................ 43 7. Monthly minimum discharge measured at stream-gaging station Middle Fork Bradley River below North Fork Bradley River and estimated monthly maximum discharge needed from the fish-water bypass to meet minimum flow requirements in the lower Bradley River...................... 45 CONVERSION FACTORS, ABBREVIATED WATER-QUALITY UNITS AND VERTICAL DATUM ______________________Multiply_______by__________To obtain___________________ inch (in.) 25.4 millimeter foot (ft) 0.3048 meter mile (mi) 1.609 kilometer foot per second (ft/s) 0.3048 meter per second foot per minute (ft/min) 0.3048 meter per minute cubic foot per second (ft3/s) 0.02832 cubic meter per second foot per second squared (ft/s2) 0.3048 meter per second squared In this report, temperature is reported in degrees Celsius (°C), which can be converted to degrees Fahrenheit (°F) by the following equation: °F=1.8(°C) + 32 ABBREVIATED WATER-QUALITY UNITS mL, milliliter mg/L, milligram per liter mm, millimeter uS/cm, microsiemen per centimeter at 25 degrees Celsius VERTICAL DATUM Sea level: In this report, "sea level" refers to the National Geodetic Vertical Datum of 1929 A geodetic datum derived from a general adjustment of the first-order level nets of the United States and Canada, formerly called Sea Level Datum of 1929. Contents V MILES 5 KILOMETERS 151°00' 150°50' 150°35' EXPLANATION A USGS Stream-gaging station 15239060 Dam Middle Fork Bradley River below North Fork Bradley River 15239070 Bradley River near Tidewater / Nort \~ 15239050 ', __. Bradley River \Mi*l<4laMiddle ForkCr.A, N below dam Bradley Riverv Middle Forkx diversion dam i > ~ Bradley Lake dam f and fish-water bypass 15238990 Bradley River near' _^^ 5 KILOMETERS Figure 1. Location of the