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Geomorphic Change Caused by Outburst Floods And

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Geomorphic Change Caused by Outburst Floods And GEOMORPHIC CHANGE CAUSED BY OUTBURST FLOODS AND DEBRIS FLOWS AT MOUNT RAINIER, WASHINGTON, WITH EMPHASIS ON TAHOMA CREEK VALLEY By Joseph S. Walder and Carolyn L. Driedger U.S. GEOLOGICAL SURVEY Water-Resources Investigations Report 93-4093 Prepared in cooperation with the NATIONAL PARK SERVICE Vancouver, Washington 1994 U.S. DEPARTMENT OF THE INTERIOR BRUCE BABBITT, Secretary U.S. GEOLOGICAL SURVEY Gordon Eaton, Director For additional information write to: Copies of this report can be purchased from: Joseph S. Walder U.S. Geological Survey U.S. Geological Survey Cascades Volcano Observatory Books and Open-file Reports 5400 MacArthur Boulevard Federal Center, Box 25425 Vancouver, Washington 98661 Denver, Colorado 80225 11 CONTENTS Page Abstract ................................................... 1 Introduction ................................................ 3 Purpose and scope ......................................... 6 Description of field area ..................................... 6 Methods of investigation ..................................... 15 Acknowledgments .......................................... 15 Relation between outburst floods and debris flows ...................... 16 Tahoma Creek valley ....................................... 16 Dry-weather debris flows .................................. 19 Wet-weather debris flows .................................. 20 Nisqually River, Kautz Creek and West Fork White River .............. 25 Recent geomorphic change in Tahoma Creek valley ...................... 26 Erosional zone ............................................ 26 Measurement of change ................................... 41 Slope retreat ........................................... 46 Depositional zone .......................................... 48 Comparison to change in other glacierized drainages .................. 50 Cause of outburst floods ........................................ 55 Relation between outburst floods and meteorological variables ........... 55 Hypothesis for the origin of outburst floods ........................ 64 Possible future geomorphic change ................................ 69 Tahoma Creek ............................................ 69 Nisqually River, Kautz Creek and West Fork White River .............. 71 Summary and conclusions ....................................... 72 References cited ............................................. 73 Appendix A: Characteristics of floods and debris flows in studied drainages during the period 1985 to 1992 ................................ 78 Appendix B: Data on stage, conductivity and turbidity ................... 85 111 ILLUSTRATIONS Page FIGURE 1. Index map showing location of Mount Rainier and studied streams and glaciers ............................. 4 2. Oblique aerial photograph taken October 2, 1984, showing stagnant parts of South Tahoma Glacier ............... 5 3. Photograph showing debris-covered snout of Tahoma Glacier/South Tahoma Glacier on August 21, 1913 ....... 7 4-7. Maps showing: 4. Topography of drainages of Kautz Creek and Nisqually River, and locations of gaging stations .... 9 5. Topography of drainage of West Fork White River ... 10 6. Topography of Tahoma Creek drainage and locations of sites discussed in the text ................... 11 7. Detail of topography of upper reach of Tahoma Creek and part of South Tahoma Glacier ............. 12 8-9. Photographs showing: 8. Tahoma Creek flowing in a U-shaped channel strongly affected by passage of debris flows ...... 13 9. Bouldery debris-flow levee along Tahoma Creek ..... 13 10. Drawing showing profile of the thalweg of Tahoma Creek . 14 11. Histogram showing frequency of debris flows at Tahoma Creek since 1965 ........................ 17 12-13. Photographs showing: 12. Deposits on Westside Road left by debris flow of September 8, 1992 ........................ 18 13. Zone of ice collapse in upper stagnant-ice area following outburst flood of June 29, 1987 ....... 18 14. Hydrograph of debris flow of July 26, 1988 at Tahoma Creek 19 15-19. Vertical aerial photographs showing: 15. Lower stagnant-ice area along Tahoma Creek on September 28, 1988 ....................... 22 16. Lower stagnant-ice area, following large slope failure on October 28, 1988 ...................... 23 17. Slump block in bottom of Tahoma Creek gorge on October 11, 1990 ......................... 24 18. Upper reach of Tahoma Creek on August 16, 1967 ... 27 19. Upper reach of Tahoma Creek and terminus region of South Tahoma Glacier on September 18, 1967 .... 28 20. Oblique aerial photograph showing South Tahoma Glacier and upper reach of Tahoma Creek on October 12, 1972 ... 30 21. Vertical aerial photograph showing region near terminus of South Tahoma Glacier on September 29, 1976 ......... 31 IV ILLUSTRATIONS-Continued Page FIGURE 22-25. Oblique aerial photographs showing: 22. South Tahoma Glacier and uppermost reach of Tahoma Creek on August 17, 1981 ............ 32 23. South Tahoma Glacier and upper reach of Tahoma Creek on September 4, 1986 ........... 33 24. Upper reach of Tahoma Creek on September 28, 1987, looking upstream .................... 34 25. Upper reach of Tahoma Creek on September 28, 1987, looking downstream .................. 35 26. Photograph showing region where Tahoma Creek incised stagnant ice ............................ 36 27-29. Vertical aerial photographs showing: 27. Regions of slope failure during September 1992 debris flows along Tahoma Creek, on September 29, 1992 . 38 28. Deeply incised reach of Tahoma Creek on October 28, 1988 ......................... 39 29. Bank failure associated with September 1992 debris flows along Tahoma Creek, on September 29, 1992 . 40 30-32. Maps showing: 30. Topography of upper reach of Tahoma Creek and part of South Tahoma Glacier, 1970 ........... 42 31. Topography of upper reach of Tahoma Creek and part of South Tahoma Glacier, 1991 ........... 43 32. Topographic change between 1970 and 1991 in upper reach of Tahoma Creek and stagnant part of South Tahoma Glacier ................... 44 33-38. Photographs showing: 33. Tension crack at surface of lower stagnant ice zone of South Tahoma Glacier ..................... 47 34. Slump features in lower stagnant-ice zone along Tahoma Creek ........................... 47 35. Forested area in the floodplain of Tahoma Creek damaged by debris flows ................... 49 36. Area near terminus of Nisqually Glacier on September 3, 1955 ........................ 52 37. Area near terminus of Nisqually Glacier on August 30, 1956 ......................... 53 38. Area near terminus of Nisqually Glacier on September 10, 1975 ....................... 54 ILLUSTRATIONS-Continued Page FIGURE 39-44. Graphs showing: 39. Probability distribution functions for daily rainfall at Paradise Ranger Station, Mount Rainier, months May through November, 1986 through 1991 ...... 57 40. Probability distribution functions for daily maximum temperature at Paradise Ranger Station, Mount Rainier, months May through November, 1986 through 1991 ........................ 57 41. Probability distribution functions for daily rainfall at Paradise Ranger Station, Mount Rainier, months May through November, 1986 through 1991, including only days with measurable rainfall ...... 57 42. Probability distribution functions for daily maximum temperature at Paradise Ranger Station, Mount Rainier, months May through November, 1986 through 1991, including only rainless days ... 57 43. Conditional probability of debris flow at Tahoma Creek as a function of daily rainfall, including only days with measurable rainfall, 1986 through 1991 ...... 60 44. Conditional probability of debris flow at Tahoma Creek as a function of daily maximum temperature, including only rainless days, from 1986 through 1991 ...... 60 45-46. Drawings showing: 45. Idealized statistical model fitted by logistic regression . 62 46. Idealized glacier-bed cavities ................... 65 47-48. Photographs showing: 47. Rock ledges exhumed by thinning of South Tahoma Glacier ................................ 66 48. Deposits along Tahoma Creek near river km 9.0 left by debris flow of September 8, 1992 ........... 84 49-53. Graphs showing: 49. Stage and rainfall measured at station 12081590, Nisqually River, during 1987 .................. 89 50. Stage and electrical conductivity measured at station 12081595, Nisqually River, during 1987 ... 90 51. Turbidity, stage and rainfall measured at station 12081900, Kautz Creek, during 1987 ........... 91 52. Stage, electrical conductivity and air temperature measured at station 12081910, Kautz Creek, during 1987 ............................ 92 53. Stage measured at station 12081990, Tahoma Creek, during 1987 ............................ 93 vi TABLES Page TABLE 1. Results of Kolmogorov-Smirnov (K-S) test for rainfall data from Paradise Ranger Station .................... 58 2. Results of Kolmogorov-Smirnov (K-S) test for maximum-temperature data from Paradise Ranger Station . 59 3. Values of coefficients for logistic regression ............ 63 4. Types of data collected at stream-gaging sites ........... 86 CONVERSION FACTORS Multiply metric units By To obtain inch-pound units millimeter 0.039 inch meter 3.28 foot kilometer 0.62 mile square kilometer 0.39 square mile cubic meter 35.3 cubic foot meter per second 3.28 foot per second cubic meter per second 35.3 cubic foot per second Temperature in degrees Fahrenheit (°F) as follows:°F = 1.8x°C + 32 Vll GEOMORPHIC CHANGE CAUSED BY OUTBURST FLOODS AND DEBRIS FLOWS AT MOUNT RAINIER, WASHINGTON, WITH EMPHASIS
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