Prepared in cooperation with Pierce County Public Works and Utilities, Surface Water 

Management; and King County Department of Natural Resources and Parks, Water and Land 

Resources Division

Geomorphic Analysis of the River Response to Sedimentation 

Downstream of Mount Rainier, Washington

U.S. Department of the Interior

U.S. Geological Survey

Open-File Report 2012–1242
Cover: Photograph taken from Emmons Vista in Mount Rainier National Park, Washington, 

showing view of Mount Rainier, Emmons Glacier, and the headwaters of the White River. 

(Photograph taken by C.S. Magirl, U.S. Geological Survey, August 14, 2011.)
Geomorphic Analysis of the River Response to 

Sedimentation Downstream of Mount Rainier, Washington

By Jonathan A. Czuba, Christopher S. Magirl, Christiana R. Czuba, Christopher A. Curran, Kenneth H. Johnson, 

Theresa D. Olsen, Halley K. Kimball, and Casey C. Gish

Prepared in cooperation with Pierce County Public Works and Utilities, Surface Water Management; and 

King County Department of Natural Resources and Parks, Water and Land Resources Division

Open-File Report 2012–1242

U.S. Department of the Interior

U.S. Geological Survey
U.S. Department of the Interior

KEN SALAZAR, Secretary

U.S. Geological Survey

Marcia K. McNutt, Director

U.S. Geological Survey, Reston, Virginia: 2012

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Suggested citation:

Czuba, J.A., Magirl, C.S., Czuba, C.R., Curran, C.A., Johnson, K.H., Olsen, T.D., Kimball, H.K., and Gish, C.C., 2012, 

Geomorphic analysis of the river response to sedimentation downstream of Mount Rainier, Washington: U.S. 

Geological Survey Open-File Report 2012-1242, 134 p.

Any use of trade, product, or firm names is for descriptive purposes only and does not imply 

endorsement by the U.S. Government.

Although this report is in the public domain, permission must be secured from the individual 

copyright owners to reproduce any copyrighted material contained within this report.
iii

Contents

Abstract ......................................................................................................................................................................... 1

Introduction.................................................................................................................................................................... 2

Purpose and Scope ................................................................................................................................................... 3

Description of Study Area .......................................................................................................................................... 4

Fluvial Geomorphology .............................................................................................................................................. 5

Sediment Load ....................................................................................................................................................... 5

Sediment Measurement ......................................................................................................................................... 6

Aggradation and Incision........................................................................................................................................ 6

Debris Flows........................................................................................................................................................... 7

Wood...................................................................................................................................................................... 8

Conceptual Model of Sediment Delivery from Mount Rainier ........................................................................................ 9

Weathering and Rockfall............................................................................................................................................ 9

Glaciation................................................................................................................................................................... 9

Mount Rainier Debris Flows ......................................................................................................................................10

Sediment Transport in River Network .......................................................................................................................11

Serial Sediment Delivery...........................................................................................................................................12

Geomorphic Characteristics of Mount Rainier Rivers ...................................................................................................12

River Centerlines and Stationing...............................................................................................................................12

Longitudinal River Profiles ........................................................................................................................................13

Sediment Equilibrium................................................................................................................................................14

Bed-Material Sediment Size......................................................................................................................................15

Hydrologic Trends and Geomorphic Response at Gaging Stations..............................................................................16

Analyzing Hydrologic Gage Data ..............................................................................................................................16

Long-Term Hydrologic Runoff...................................................................................................................................16

Peak-Flow Events .....................................................................................................................................................17

Implications of 20th-Century Hydrology on Sediment Production and Transport ......................................................18

Geomorphic Response to Hydrologic Events............................................................................................................18

Sediment Loads of Mount Rainier Rivers .....................................................................................................................19

Previous Sediment-Load Estimates ..........................................................................................................................20

Historical Changes in Plan Form and Profiles in Mountainous River Reaches .........................................................22

Change in Active-Channel Width for Rivers Draining Mount Rainier.....................................................................22

Active-Channel Elevation Relative to Forested-Terrace Elevation ........................................................................24

Change in Elevation of River Profiles ....................................................................................................................25

Sediment Contributions from the Flood Plain due to Expansion of the Active Channel.........................................25

The Link between Superglacial Debris and Downstream Aggradation..................................................................26

The Link between the 1963 Debris Avalanche and Upper White River Aggradation.............................................27

Sediment Supply from Cascade Uplands outside Mount Rainier National Park .......................................................27

Methodology for Assessing Sediment-Production Potential ..................................................................................28

Roads ................................................................................................................................................................28

Landslides .........................................................................................................................................................29

Soil Creep..........................................................................................................................................................29

Calibration .........................................................................................................................................................29

Sediment-Production Potential Results .................................................................................................................30
iv

Sediment Loads of Mount Rainer Rivers—Continued

Estimates of Sediment Loads using Historical and New Data...................................................................................31

Load Estimates of the Upper Nisqually River ........................................................................................................31

Seasonality in Suspended-Sediment Concentration in Mount Rainier Rivers .......................................................32

Suspended-Sediment Load of the Puyallup River from 1978 to 1994 ...................................................................32

Sediment-Load Estimates of the White River from Recent Measurements ...........................................................33

Collection of Sediment Data and Calculation of Sediment Loads ......................................................................33

Suspended-Sediment Load and Bedload of the White River.............................................................................34

Estimated Bedload-Transport relation for the White, Puyallup, and Carbon Rivers...............................................35

Synthesis of Sediment Load of Mount Rainier Rivers ...............................................................................................37

Best Estimate of Current Sediment Loads.............................................................................................................37

Regional Context...................................................................................................................................................38

Relative Sediment Contributions from Mount Rainier and Other Sources.............................................................39

Modeling Bed-Material Sediment Transport by Rivers..................................................................................................39

Model Framework .....................................................................................................................................................40

The Unified Gravel-Sand (TUGS) Model...............................................................................................................40

Geomorphic Data ..................................................................................................................................................40

Channel Geometry.............................................................................................................................................41

Streamflow Data ................................................................................................................................................41

Sediment Data...................................................................................................................................................41

Model-Conditioning Process..................................................................................................................................42

Geomorphic Setting ..................................................................................................................................................42

Nisqually River ......................................................................................................................................................43

Carbon River .........................................................................................................................................................43

Puyallup River .......................................................................................................................................................43

White River............................................................................................................................................................44

Model Performance...................................................................................................................................................44

Model Comparison to Physical Measurements .....................................................................................................44

Model Limitations ..................................................................................................................................................45

Model Simulations of the Nisqually, Carbon, Puyallup, and White Rivers.................................................................46

Model Simulation of Long-Term Streamflow Record .............................................................................................46

Capacity of Rivers to Transport Sediment.............................................................................................................47

Spatial and Temporal Geomorphic Change due to Altered Sediment Supply .......................................................48

Potential Effect of Changing Hydrologic Conditions on Future Bed Elevations .....................................................50

Synthesis of Modeling Bed-Material Transport by Rivers..........................................................................................52

Implications for River Management ..............................................................................................................................54

Aggradation Potential in the River Network...............................................................................................................54

Potential Sediment-Management Locations..............................................................................................................55

Opportunities for Future Research............................................................................................................................56

Summary and Conclusions...........................................................................................................................................57

Acknowledgments ........................................................................................................................................................61

References Cited..........................................................................................................................................................61

Appendix A. Auxillary Tables ......................................................................................................................................131
v

Figures

Figure 1. Map showing rivers, basin boundaries, U.S. Geological Survey streamflow-gaging stations, and tributaries 

draining Mount Rainier, Washington, along with river stationing used in the this study ............................................... 73

Figure 2. Conceptual model of processes affecting sediment delivery from Mount Rainier, Washingto. ................... 74

Figure 3. Images of the headwaters of the White River at the terminus of the Emmons Glacier, Mount Rainier, 

Washington ................................................................................................................................................................ 75

Figure 4. Graph showing river elevation profiles for main-stem rivers and tributaries of the (A) Puyallup, 

(B) White, (C) Carbon, (D) Nisqually, and (E) Cowlitz Rivers, Washington.................................................................. 76

Figure 5. Graph showing bed-material size gradations of the Puyallup, Carbon, White, and upper 

Nisqually Rivers, Washington ...................................................................................................................................... 78

Figure 6. Maps showing bed-material size gradations of the Nisqually, Carbon, Puyallup, and White Rivers, 

Washington ................................................................................................................................................................ 79

Figure 7. Graphs showing (A) Hydrologic conditions during the 20th century in the Mount Rainier, Washington, 

catchment as reflected in 10-year moving-average daily-discharge values, normalized by the mean annual flow,

for U.S. Geological Survey streamflow-gaging stations Puyallup River at Puyallup (12101500) and the Cowlitz River

at Packwood (14226500); and (B) 10-year moving average of sea surface temperatures in the northern Pacific Ocean 

as reflected with the Pacific Decadal Index ................................................................................................................. 80

Figure 8. Graph showing annual peak flows for U.S. Geological Survey streamflow-gaging stations on unregulated 

section of the main-stem rivers draining Mount Rainier, Washington: (A) the Puyallup River near Orting gage 

(12093500), (B) the Carbon River near Fairfax gage (12094000), (C) the Cowlitz River at Packwood gage 

(14226500), and (D) the Nisqually River near National gage (12082500) ................................................................... 81

Figure 9. Graph showing stage for median flow and daily discharge as measured at the U.S. Geological Survey 

streamflow-gaging station Nisqually River near National (12082500).......................................................................... 82

Figure 10. Map showing active-channel width in 2009 of rivers draining Mount Rainier, Washington. ...................... 83

Figure 11. Graph showing active-channel width from 1965, 1994, and 2009 of rivers draining Mount Rainier, 

Washington ............................................................................................................................................................. 84

Figure 12. Map showing change in active-channel width from 1965 to 1994 for rivers draining Mount Rainier, 

Washington ............................................................................................................................................................. 85

Figure 13. Map showing change in active-channel width from 1994 to 2009 for rivers draining Mount Rainier, 

Washington ............................................................................................................................................................. 86

Figure 14. Graph showing the difference in elevation between the forested terrace adjacent to the active

channel and the active channel for the (A) Carbon River, (B) Nisqually River, (C) Puyallup River, and 

(D) White River, Washington ....................................................................................................................................... 87

Figure 15. Graph showing active-channel width of rivers draining Mount Rainier, Washington, in 2009 versus 

(A) total glacier retreat from 1913 to 1994 of river’s primary glacier source and (B) percentage of mantling of 

superglacial debris on river primary glacier source. All glacier data by Nylen (2004). ................................................. 88

Figure 16. Map showing location of 27 subcatchments analyzed to calculate sediment-production potential and 

the three additional subcatchments used for calibration.............................................................................................. 89

Figure 17. Graph showing relation between the predictions of sediment-production potential from five calibration 

subcatchments and the measured total sediment load. Error bars represent uncertainty in the sediment-load 

predictions ............................................................................................................................................................. 90

Figure 18. Map showing predicted sediment-production yield from roads, landslides, and soil creep for

mountainous subcatchments outside Mount Rainier National Park that contribute to the Puyallup, Carbon, and 

White Rivers and the upper Nisqually River ................................................................................................................ 91
vi

Figure 19. Graph showing suspended-sediment concentration versus discharge as collected in 1974–1976

by Nelson (1978) at U.S. Geological Survey streamflow-gaging station White River below Clearwater River 

near Buckley (12097850)............................................................................................................................................. 92

Figure 20. Graph showing suspended-sediment concentration for water years 1978–1994 at U.S. Geological 

Survey streamflow-gaging station Puyallup River at Puyallup (12101500).................................................................. 92

Figure 21. Graph showing annual suspended-sediment load and daily streamflow at U.S. Geological Survey 

streamflow-gaging station Puyallup River at Puyallup (12101500).............................................................................. 93

Figure 22. Graph showing regression equations used to estimate suspended-sediment concentration and fine 

suspended-sediment concentration from turbidity at U.S. Geological Survey streamflow-gaging station White River at 

R Street near Auburn (12100490)................................................................................................................................ 94

Figure 23. Graph showing regression equation used to estimate bedload from streamflow at U.S. 

Geological Survey streamflow-gaging station White River at R Street near Auburn (12100490)................................. 94

Figure 24. Graph showing time series of streamflow and suspended-sediment concentration at U.S. Geological 

Survey streamflow-gaging station White River at R Street near Auburn (12100490) .................................................. 95

Figure 25. Graph showing time series of streamflow, cumulative suspended-sediment load, cumulative fine 

suspended-sediment load, and cumulative bedload for water year 2011 at U.S. Geological Survey 

streamflow-gaging station White River at R Street near Auburn (12100490) .............................................................. 95

Figure 26. Graph showing suspended-sediment loads for 3-month periods at the U.S. Geological Survey 

streamflow-gaging station White River at R Street near Auburn (12100490) .............................................................. 96

Figure 27. Graph showing bedload measurements from 1986 and 2010-2011 at U.S. Geological Survey streamflowgaging stations Carbon River near Orting (12094300, referred to as Carbon River at Crocker by Sikonia, 1990), 

Puyallup River near Orting (12093500), and White River at R Street near Auburn (12100490) .................................. 96

Figure 28. Graph showing estimated annual bedload for water years 1984-2011 at U.S. Geological Survey 

streamflow-gaging stations Carbon River near Orting (12094300, referred to as the Carbon River at Crocker by 

Sikonia, 1990), Puyallup River near Orting (12093500), and White River at R Street near Auburn (12100490) ......... 97

Figure 29. Graph showing sediment load values of the Nisqually River flowing into Alder Lake and the lower 

Puyallup River compared to sediment-load data reported from other rivers throughout the Pacific Northwest............ 98

Figure 30. Graph showing geomorphic variables of the Nisqually River: (A) slope, (B) measured active-channel 

width, (C) D90 and D50 size of bed-surface sediment, and (D) percent sand of bed-surface sediment. Error bars 

represent one standard deviation of the particle-size distribution ................................................................................ 99

Figure 31. Graph showing geomorphic variables of the Carbon River: (A) slope, (B) measured active-channel width, 

(C) D90 and D50 size of bed-surface sediment, and (D) percent sand of bed-surface sediment .............................. 100

Figure 32. Graph showing geomorphic variables of the Puyallup River: (A) slope, (B) measured active-channel width, 

(C) D90 and D50 size of bed-surface sediment, and (D) percent sand of bed-surface sediment .............................. 101

Figure 33. Graph showing geomorphic variables of the White River: (A) slope, (B) measured active-channel width, 

(C) D90 and D50 size of bed-surface sediment, and (D) percent sand of bed-surface sediment. ............................. 102

Figure 34. Graph showing comparison of simulated daily sediment loads to measured sediment loads for the 

Carbon River at State Route 162/Pioneer Way, Puyallup River at Calistoga Street, and White River at R Street..... 103

Figure 35. Graph showing daily streamflow and simulated annual bed-material sediment loads for the 

(A) Nisqually River at State Route 7, (B) Carbon River at State Route 162/Pioneer Way, (C) Puyallup River at 

Calistoga Street, and (D) White River at R Street...................................................................................................... 104

Figure 36. Graph showing capacity of the Nisqually River to transport sediment: (A) bed-material sediment-transport 

capacity (after model conditioning) and stream power and (B) unit bed-material sediment-transport capacity (after 

model conditioning) and unit stream power ............................................................................................................... 105

Figure 37. Graph showing capacity of the Carbon River to transport sediment: (A) bed-material sediment-transport 

capacity (after model conditioning) and stream power and (B) unit bed-material sediment-transport capacity (after 

model conditioning) and unit stream power ............................................................................................................... 105
vii

Figure 38. Graph showing capacity of the Puyallup River to transport sediment: (A) bed-material sediment-transport 

capacity (after model conditioning) and stream power and (B) unit bed-material sediment-transport capacity (after 

model conditioning) and unit stream power ............................................................................................................... 106

Figure 39. Graph showing capacity of the White River to transport sediment: (A) bed-material sediment-transport 

capacity (after model conditioning) and stream power and (B) unit bed-material sediment-transport capacity (after 

model conditioning) and unit stream power ............................................................................................................... 106

Figure 40. Graph showing effect of pulse grain size, pulse volume, and streamflow on the characteristic transport 

time (A1-D1), sediment load (A2-D2), and bed volume (A3-D3) for the Nisqually (A1-A3), Carbon (B1-B3), Puyallup 

(C1-C3), and White Rivers (D1-D3)........................................................................................................................... 107

Figure 41. Graph showing characteristic transport time for sediment pulses to arrive downstream for different pulse 

grain size, pulse volume, and streamflow for the (A) Nisqually, (B) Carbon, (C) Puyallup, and (D) White Rivers...... 108

Figure 42. Graph showing Nisqually River response to sediment pulse input for (A) characteristic residence 

time for D50 sediment to move through each 400-m node and (B) the maximum increase in bed volume as a 

percentage of input pulse volume.............................................................................................................................. 109

Figure 43. Graph showing Carbon River response to sediment pulse input for (A) characteristic residence time for 

D50 sediment to move through each 400-m node and (B) the maximum increase in bed volume as a percentage of 

input pulse volume..................................................................................................................................................... 109

Figure 44. Graph showing Puyallup River response to sediment pulse input for (A) characteristic residence time for 

D50 sediment to move through each 400-m node and (B) the maximum increase in bed volume as a percentage of 

input pulse volume..................................................................................................................................................... 110

Figure 45. Graph showing White River response to sediment pulse input for (A) characteristic residence time for D50 

sediment to move through each 400-m node and (B) the maximum increase in bed volume as a percentage of input 

pulse volume ........................................................................................................................................................... 110

Figure 46. Graph showing potential future bed-elevation change for the Nisqually River after 25 years for (A) a 

baseline condition and (B) a future condition; and after 50 years for (C) a baseline condition and (D) a future 

condition ........................................................................................................................................................... 111

Figure 47. Graph showing potential future bed-elevation change for the Carbon River after 25 years for (A) a 

baseline condition and (B) a future condition; and after 50 years for (C) a baseline condition and (D) a future

condition ........................................................................................................................................................... 112

Figure 48. Graph showing potential future bed-elevation change for the Puyallup River after 25 years for (A) a 

baseline condition and (B) a future condition; and after 50 years for (C) a baseline condition and (D) a future 

condition ........................................................................................................................................................... 113

Figure 49. Graph showing potential future bed-elevation change for the White River after 25 years for (A) a 

baseline condition and (B) a future condition; and after 50 years for (C) a baseline condition and (D) a future 

condition ........................................................................................................................................................... 114

Figure 50. Graph showing lower White River, Washington, (A) approximate bed elevations from measurements 

(raw model input) and from steady state simulations (after model conditioning) and (B) change in elevation after 

the model-conditioning process with quasi-equilibrium conditions............................................................................. 115

Figure 51. Map of Mount Rainier, Washington, showing where potential sediment-management actions would be 

most effective based on geomorphic conditions that suggest sediment accumulates naturally, including both longand mid-term transient-storage reaches. Also shown are best estimates for long-term sediment-load values for

rivers in the study ...................................................................................................................................................... 116
viii

Tables

Table 1. U.S. Geological Survey streamflow-gaging stations in the State of Washington used for hydrologic and 

geomorphic analysis in this study. ............................................................................................................................. 117

Table 2. Twenty largest peak-flow events at the U.S. Geological Survey streamflow-gaging station Nisqually River 

near National (12082500) between 1989 and 2009 and the resulting change in stage, for median flow, at the gage 

after to peak-flow event. ............................................................................................................................................ 118

Table 3. Sample of 81 meteorological, hydrologic, and atmospheric parameters collected and correlated to the 

change in stage for the 20 largest peak-flow events measured at the Nisqually River gage. .................................... 119

Table 4. Published sediment-load estimates for rivers in the Mount Rainier National Park, Washington, watershed and 

for the Pacific Northwest............................................................................................................................................ 120

Table 5. Summary of active-channel width measured in 1965, 1994, and 2009 and the change in width between 

dates, for rivers draining Mount Rainier, Washington. ............................................................................................... 122

Table 6. Estimated sediment load contribution to river main stems due to increases in active-channel width, for rivers 

draining Mount Rainier, Washington, 1965–2009...................................................................................................... 124

Table 7. Summary of sediment-production potential for Cascade Range subcatchments outside Mount Rainier 

National Park, Washington. ....................................................................................................................................... 125

Table 8. Sediment load calculations and measurements completed as part of this study, for rivers draining Mount 

Rainier, Washington. ................................................................................................................................................. 127

Table 9. Scaling factors and U.S. Geological Survey streamflow-gaging stations used in developing long-term 

streamflow records for model simulations for the Nisqually, Carbon, Puyallup, and White Rivers, Washington........ 128

Table 10. Comparison of simulated sediment load into Alder Lake by the Nisqually River to measured sediment 

volumes of the delta of the Nisqually River in Alder Lake, Washington, from Czuba and others (2012).................... 129

Table 11. Simulated bed-material sediment loads for the Nisqually River at State Route 7, Carbon River at State 

Route 162/Pioneer Way, Puyallup River at Calistoga Street, and White River at R Street, Washington. Streamflow at 

the White River at R Street is controlled by Mud Mountain Dam. .............................................................................. 130
ix

Conversion Factors, Datums, and Abbreviations and Acronyms

Conversion Factors

Inch/Pound to SI

Multiply By To obtain

Length

inch (in.) 2.54 centimeter (cm)

inch (in.) 25.4 millimeter (mm)

foot (ft) 0.3048 meter (m)

mile (mi) 1.609 kilometer (km)

Flow rate

cubic foot per second (ft3/s) 0.02832 cubic meter per second (m3/s)

SI to Inch/Pound

Multiply By To obtain

Length

centimeter (cm) 0.3937 inch (in.)

millimeter (mm) 0.03937 inch (in.)

meter (m) 3.281 foot (ft) 

kilometer (km) 0.6214 mile (mi)

Area

square meter (m2) 10.76 square foot (ft2) 

square kilometer (km2) 0.3861 square mile (mi2)

Volume

cubic meter (m3) 35.31 cubic foot (ft3)

cubic meter (m3) 1.308 cubic yard (yd3) 

Flow rate

cubic meter per second (m3/s) 35.31 cubic foot per second (ft3/s)

cubic meter per day (m3/d) 35.31 cubic foot per day (ft3/d)

cubic meter per year (m3/yr) 35.31 cubic foot per year (ft3/yr)

cubic meter per second per meter

[(m3/s)/m]

10.76 cubic foot per second per foot

[(ft3/s)/ft]

Power

watts (W) 3.4121 British thermal unit per hour (Btu/h)

watts per meter (W/m) 1.04 British thermal unit per hour 

per foot [(Btu/h)/ft]
x

watts per square meter (W/ m2) 0.317 British thermal unit per hour 

per square foot [(Btu/h)/ ft2]

Concentration

milligrams per liter (mg/L) 0.0001335 ounce per gallon (oz/gal)

Mass

metric ton (tonnes) 1.102 ton, short (2,000 lb)

metric ton per day (tonnes/d) 1.102 ton per day (ton/d) 

tonnes per year per square

kilometer [(tonnes/yr)/km2]

2.8547 ton per year per square mile 

[(ton/yr)/mi2]

metric ton per year (tonnes/yr) 1.102 ton per year (ton/yr) 

Density

kilogram per cubic meter (kg/m3) 0.06242 pound per cubic foot (lb/ft3)

metric ton per cubic meter 

(tonnes/ m3)

0.03121 ton per cubic yard (ton/ft3)

metric ton per cubic meter 

(tonnes/ m3)

0.8428 ton per cubic yard (ton/yd3)

Temperature in degrees Celsius (°C) may be converted to degrees Fahrenheit (°F) as follows:

°F=(1.8×°C)+32

Vertical coordinate information is referenced to the North American Vertical Datum of 1988 (NAVD 88).

Horizontal coordinate information is referenced to the North American Datum of 1983 (NAD 83).

Elevation, as used in this report, refers to distance above the vertical datum.
xi

Abbreviations and Acronyms

ADCP acoustic Doppler current profiler

BAGS Bedload Assessment in Gravel-bedded Streams model

CRKM Carbon River kilometer

CwRKM Cowlitz River kilometer

D50 median particle size

D90 size of sediment for which 90 percent of the sample is finer

DEM digital elevation model

DNR Department of Natural Resources

DRG digital raster graphic

DOQ digital orthophoto quadrangles 

EDI equal-discharge increment

FISP Federal Interagency Sedimentation Project

GIS geographic information system

GPS global positioning system

LiDAR light detection and ranging

MEWI multiple equal-width increment

MORA Mount Rainier National Park

NAIP National Agriculture Imagery Program

NRKM Nisqually River kilometer

NWIS National Water Information System

PDO Pacific Decadal Oscillation

PRKM Puyallup River kilometer

RTK real-time kinematic

TUGS the Unified Gravel-Sand model

UTM10 Universal Transverse Mercator zone 10

USGS U.S. Geological Survey

WRKM White River kilometer

WSDOT Washington State Department of Transportation
xii

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1

Geomorphic Analysis of the River Response to 

Sedimentation Downstream of Mount Rainier, Washington

By Jonathan A. Czuba, Christopher S. Magirl, Christiana R. Czuba, Kenneth H. Johnson, Theresa D. Olsen, 

Christopher A. Curran, Halley K. Kimball, and Casey C. Gish

“...know that Mount Rainier sits above us a pile of shattered rock surrendering minute by 

minute to the inexorable seduction of gravity.” (Barcott, 1997)

Abstract 

A study of the geomorphology of rivers draining Mount Rainier, Washington, was completed to 

identify sources of sediment to the river network; to identify important processes in the sedimentdelivery system; to assess current sediment loads in rivers draining Mount Rainier; to evaluate if there 

were trends in streamflow or sediment load since the early 20th century; and to assess how rates of 

sedimentation might continue into the future using published climate-change scenarios. 

Rivers draining Mount Rainier carry heavy sediment loads sourced primarily from the volcano 

that cause acute aggradation in deposition reaches as far away as the Puget Lowland. Calculated yields 

ranged from 2,000 tonnes per square kilometer per year [(tonnes/km2)/yr] on the upper Nisqually River 

to 350 (tonnes/km2)/yr on the lower Puyallup River, notably larger than sediment yields of 50–200 

(tonnes/km2

)/yr typical for other Cascade Range rivers. These rivers can be assumed to be in a general 

state of sediment surplus. As a result, future aggradation rates will be largely influenced by the 

underlying hydrology carrying sediment downstream. The active-channel width of rivers directly 

draining Mount Rainier in 2009, used as a proxy for sediment released from Mount Rainier, changed 

little between 1965 and 1994 reflecting a climatic period that was relatively quiet hydrogeomorphically. 

From 1994 to 2009, a marked increase in geomorphic disturbance caused the active channels in many 

river reaches to widen. Comparing active-channel widths of glacier-draining rivers in 2009 to the 

distance of glacier retreat between 1913 and 1994 showed no correlation, suggesting that geomorphic 

disturbance in river reaches directly downstream of glaciers is not strongly governed by the degree of 

glacial retreat. In contrast, there was a correlation between active-channel width and the percentage of 

superglacier debris mantling the glacier, as measured in 1971. A conceptual model of sediment delivery 

processes from the mountain indicates that rockfalls, glaciers, debris flows, and main-stem flooding act 

sequentially to deliver sediment from Mount Rainier to river reaches in the Puget Lowland over decadal 

time scales. Greater-than-normal runoff was associated with cool phases of the Pacific Decadal 

Oscillation. Streamflow-gaging station data from four unregulated rivers directly draining Mount 

Rainier indicated no statistically significant trends of increasing peak flows over the course of the 20th

century.

The total sediment load of the upper Nisqually River from 1945 to 2011 was determined to be 

1,200,000±180,000 tonnes/yr. The suspended-sediment load in the lower Puyallup River at Puyallup, 

Washington, was 860,000±300,000 tonnes/yr between 1978 and 1994, but the long-term load for the 

Puyallup River likely is about 1,000,000±400,000 tonnes/yr. Using a coarse-resolution bedloadtransport relation, the long-term average bedload was estimated to be about 30,000 tonnes/yr in the
2

lower White River near Auburn, Washington, which was four times greater than bedload in the Puyallup 

River and an order of magnitude greater than bedload in the Carbon River. Analyses indicate a general 

increase in the sediment loads in Mount Rainier rivers in the 1990s and 2000s relative to the time period 

from the 1960s to 1980s. Data are insufficient, however, to determine definitively if post-1990 increases 

in sediment production and transport from Mount Rainier represent a statistically significant increase 

relative to sediment-load values typical from Mount Rainier during the entire 20th century.

One-dimensional river-hydraulic and sediment-transport models simulated the entrainment, 

transport, attrition, and deposition of bed material. Simulations showed that bed-material loads were 

largest for the Nisqually River and smallest for the Carbon River. The models were used to simulate 

how increases in sediment supply to rivers transport through the river systems and affect lowland 

reaches. For each simulation, the input sediment pulse evolved through a combination of translation, 

dispersion, and attrition as it moved downstream. The characteristic transport times for the median 

sediment-size pulse to arrive downstream for the Nisqually, Carbon, Puyallup, and White Rivers were 

approximately 70, 300, 80, and 60 years, respectively. 

Introduction

Mount Rainier, located in western Washington, rises to 4,392 meters (m) above sea level and 

contains the largest volume of glacial ice in the conterminous United States (Krimmel, 2002). The 

mountain is a recurrently active stratovolcano, having erupted during at least 10 distinct episodes in the 

past 2,600 years (Sisson and Vallance, 2008). The combination of glacial ice, active volcanism, and 

weathering promotes production of large volumes of colluvial debris. The volcano’s proximity to sea 

level at Commencement Bay in Puget Sound—some Mount Rainier glaciers are as close as 85 km from 

Puget Sound (fig. 1)—results in a relatively steep network of mountainous rivers conducive to sediment 

transport between eruptive episodes. 

Rivers and contributing catchments draining Mount Rainier (fig. 1) have presented acute 

challenges to flood-plain management in Pierce and King Counties. The upper Nisqually River, 

upstream of Alder Lake, has been subject to flooding and channel migration (Beason and Kennard, 

2007; GeoEngineers, 2007). Similarly, the Puyallup River basin, which includes the Carbon and White 

Rivers, has been flood prone for the past two decades (Pierce County, 2012). Several large floods since 

1990 raised concern among river managers that regional flood magnitudes may be increasing (Pierce 

County, 2012). Sediment accumulation in some river reaches and concomitant reductions in floodconveyance capacity (Czuba and others, 2010) have fostered the potential for significant economic 

impacts from future flooding, particularly where flood-plain development is extensive (Pierce County, 

2012).

Over geological time scales, Mount Rainier cycles between increased sediment production 

during eruptive periods and smaller, but still significant, sediment production during inter-eruptive 

periods (Crandell, 1971; Scott and others, 1995). Similar sediment-production cycles are well 

documented on other Pacific Northwest stratovolcanoes (Major and others, 2000; Pierson and others, 

2011). From the early 20th century to the present, Mount Rainier has been in an inter-eruptive period. 

Although limited eruptive activity may have occurred in 1894 (Sisson and Vallance, 2008), the 

generation of sediment beyond normal inter-eruptive magnitudes was not documented. During intereruptive periods, rivers draining Mount Rainier carry heavy sediment loads relative to rivers not 

draining volcanoes (Czuba and others, 2011). High sedimentation rates have been documented in the 

lowland reaches of rivers draining Mount Rainier, and it has long been recognized that sediment 

production from Mount Rainier increases overall sediment load (Fahnestock, 1963; Crandell, 1971; 
3

Mills, 1976; Nelson, 1978; Dunne, 1986; Prych, 1988; Sikonia, 1990; Scott and others, 1995; Hoblitt 

and others, 1998; Czuba and others, 2010). 

Until the late 1980s, large volumes of sediment commonly were removed through in-channel 

dredging from select reaches of the river network in the Puget Lowland (Prych, 1988; Czuba and others, 

2010; Herrera Environmental Consultants, 2010), partially offsetting sediment input from the upper 

drainage basin. Sediment removal largely ceased in the Puyallup River basin by the middle 1990s partly 

to prevent adverse effects on the aquatic habitat containing federally listed salmonids, including 

Chinook salmon [Oncorhynchus tshawytscha] and steelhead [O. mykiss], which are listed as threatened 

in Puget Sound, as well as coho salmon [O. kisutch], listed as a species of concern (National Oceanic 

and Atmospheric Administration, 2010a). Other factors that contributed to the cessation of gravel 

removal in the region included the challenges of obtaining necessary permits, the reductions in rivermaintenance budgets, and the recognition that flood-reduction benefits from gravel removal are

temporary (Pierce County, 2012). 

Recent observations of increased hydrogeomorphic activity in rivers draining Mount Rainier, 

including several debris flows (Copeland, 2009; Lancaster and others, 2012), large floods, and 

aggradation in the rivers within the national park (Beason, 2007), suggest that production and transport 

of alluvial material from the volcano may be increasing. Inevitably, sediment delivered to rivers 

draining the volcano will be transported downstream, but the timing of arrival of new sediment and the 

magnitude of impacts on downstream channel form are unknown. Pierce County recently developed a 

flood-hazard-management plan and an environmental-impact statement to guide flood-management 

efforts in future decades (Pierce County, 2012). To assist with development of the plan, Pierce and King 

Counties requested that the U.S. Geological Survey (USGS) conduct a cooperative study of the 

geomorphology of rivers draining Mount Rainier. 

Purpose and Scope

This report documents an assessment of historical and current fluvial sediment loads in rivers 

draining Mount Rainier; the sources of sediment within the watershed; important sediment-production 

and sediment-delivery processes within the watershed; long-term trends of increasing discharge or 

sediment loads; and the anticipated magnitude of sedimentation 25 and 50 years into the future using 

published climate-change predictions. The focus of the study is on the Puyallup, Carbon, White, and 

upper Nisqually Rivers, although all rivers draining Mount Rainier are considered as is the sedimentdelivery potential from contributing watersheds.

Specific data sets used for the study included light detection and ranging (LiDAR) digitalelevation models (DEMs) from multiple sources; meteorological data collected since 1986; hydrologic, 

geologic, and land-use data from within the watershed; and available sediment-load data collected from 

the Puyallup, White, and Carbon Rivers. Literature reviews of sediment loads in regional rivers, glacial 

data sets from Mount Rainier, and future-climate predictions affecting peak-flow hydrology also were 

used. Aerial imagery from 1965, 1994, and 2009 of the upper reaches of all rivers directly draining 

Mount Rainier glaciers were analyzed to determine late 20th-century trends in active-channel width. 

Geographic, topographic, and hydrologic data were used to assess the potential for sediment production 

from subcatchments in the upper Nisqually River basin and the greater Puyallup River basin. Finally, 

one-dimensional sediment-transport models were developed for the main-stem river network to assess 

how sediment produced on the volcano moves downstream over time. These models were used to 

compare sediment-delivery rates on each river; evaluate where ecologically sensitive river-management 

practices like setback levees or gravel scalping might more efficiently increase flood-conveyance 
4

capacity; and predict how lowland reaches of analyzed rivers will respond to current and future 

sediment pulses.

Description of Study Area

Mount Rainier is a 500,000-year old recurrently active stratovolcano (Sisson and others, 2001) 

located in the Cascade Range, a north-trending volcanic arc formed by the subduction of the Juan de 

Fuca plate under the North American plate (Pringle, 2008). The Cascade Range is between 6 and 15 

million years old (Reiners and others, 2002). The Puget Lowland is a physiographic fore-arc basin 

located west of the Cascade Range, and Mount Rainier volcanism is centered west of the crest of the 

Cascade Range. The Nisqually and Puyallup River basins drain the southern, western, and northern 

flanks of Mount Rainier and empty into Puget Sound (fig. 1). The Cowlitz River drains the eastern flank 

of Mount Rainier and empties into the Columbia River. The retreat of the Puget Lobe of the Cordilleran 

Ice Sheet from the Puget Lowland about 16,000–17,000 years ago (Porter and Swanson, 1998) reset the 

network of rivers draining the Cascade Range. As a result, the Nisqually and Puyallup River networks 

in the Puget Lowland are still adjusting to the effects of the ice sheet, incising where they cross glacial 

till deposits and aggrading where river slope decreases in former embayments of Puget Sound (Collins 

and Montgomery, 2011). 

The climate of the study area is predominantly wet and temperate (National Oceanic and 

Atmospheric Administration, 2010b). The prevailing wind direction is from the south or southwest 

during the rainy season (October to June) and from the northwest during the relatively dry summer from 

July to September. During the winter, cold air from the Canadian interior occasionally flows southward,

covering the region. The average January maximum temperature in the Puget Lowland is about 6°C 

(43°F) and the minimum is about -1°C (30°F). During July, the average maximum temperature is about 

24°C (75°F) and the minimum is about 10°C (50°F). Annual precipitation in the Puget Lowlands is 

about 1,000 mm (40 in.), and the winter-season snowfall is about 380 mm (15 in.). Precipitation

increases with elevation; annual rainfall in the Cascade Range in high-elevation catchments typically is

1,550–2,500 mm (60–100 in.) and total annual snowfall is between 10 and 15 m (400–600 in.) at 

elevations of 1,200–1,600 m (4,000–5,500 ft) (National Oceanic and Atmospheric Administration, 

2010b).

The Muddy Fork Cowlitz and the Ohanapecosh Rivers (fig. 1) are unregulated by dams or 

diversions downstream to Packwood, Washington. The Nisqually River and its tributaries flow into 

Alder Lake (fig. 1), which is ponded behind Alder Dam trapping much of the river sediment load 

(Nelson, 1974). The Carbon River is unregulated. The Puyallup River has a low-head diversion dam for 

power production upstream of Orting (fig. 1), but the facility is designed to pass peak flows with no 

effect on peak-flow magnitude. Flood management for the lower Puyallup River valley is provided by 

Mud Mountain Dam, which was completed on the White River (fig. 1) in 1948 (U.S. Army Corps of 

Engineers, 2009). The U.S. Army Corps of Engineers operates Mud Mountain Dam to control flooding 

on the lower Puyallup River. During peak events on the Puyallup River, flow on the White River is 

retained by Mud Mountain Dam, causing water to pool in the reservoir and depositing large volumes of 

sand and coarser sediment, which can accumulate to depths of as much as 12 m (Rick Emry, U.S. Army 

Corps of Engineers, written commun., 2010). When the flood peak on the lower Puyallup River has 

abated, sediment (as large as 0.5 m) is sluiced through the dam, preventing aggradation of the channel 

invert of the White River (Rick Emry, U.S. Army Corps of Engineers, written commun., 2010). Mud 

Mountain Dam traps a portion of the arriving White River bedload, and Dunne (1986) postulated that 

most coarse-grained bedload was retained in reservoir storage, at least through the 1970s. But bedload 

storage in the reservoir will decrease through time as the trap efficiency of the coarsest sediment 
5

decreases. The current trap efficiency of bedload within the reservoir is unknown, but observations of 

rapid changes in the river stage just downstream of the dam since the 1970s (Czuba and others, 2010) 

and observations of little change to the water-surface elevation of the White River through the reservoir 

reach suggests that a sizeable proportion of bedload now passes Mud Mountain Dam. Along the lower 

White River, a low-head diversion dam upstream of Auburn occasionally diverts flow to Lake Tapps 

during low flow, but this structure passes bedload and does not affect peak-flow magnitude. Water from 

Lake Tapps is returned to the White River downstream of Auburn.

Mean annual discharge for the Puyallup River at Puyallup gage (USGS streamflow-gaging 

station No. 12101500) is 94 m3

/s (3,320 ft3/s) for the period of record (table 1) with dominant 

hydrologic inputs from winter rainfall and snowmelt in the spring and summer. Late summer and 

autumn discharge is sustained by groundwater and glacial melt from Mount Rainier; the headwaters of 

all main-stem rivers draining Mount Rainier originate from the glaciers. The largest peak-flow events in 

the basin are associated with heavy autumn or winter precipitation associated with atmospheric rivers, 

strong synoptic systems from the Pacific Ocean that tap into tropical moisture sources (Neiman and 

others, 2011). At the Puyallup River at Puyallup, the flood of record of 1,610 m3/s (57,000 ft3/s) 

occurred in December 1933, prior to construction of Mud Mountain Dam. For this lower Puyallup River 

site, 6 of the 10 largest annual peak events have occurred since 1980, including 1,360 m3/s (48,200 ft3/s) 

on January 8, 2009 (2nd largest peak in the record), and 1,120 m3

/s (39,700 ft3/s) on November 7, 2006 

(10th largest peak in the record). These recent large peak events occurred despite flow regulation by 

Mud Mountain Dam. The November 2006 event was more significant farther upstream, and peaks of 

record of 411 m3/s (14,500 ft3/s), 609 m3/s (21,500 ft3/s), and 617 m3/s (21,800 ft3/s) were established 

for the Carbon River at Fairfax gage (12094000), the Puyallup River near Orting gage (12093500), and 

the Nisqually River near National gage (12082500), respectively. Widespread flooding also affected the 

region in February 1996 when discharge peaked at 1,320 m3/s (46,700 ft3/s) on the Puyallup River at 

Puyallup (third largest peak in the record) and 600 m3/s (21,200 ft3/s) on the Nisqually River near 

National. Smaller peak-flow events usually occur in late spring and early summer with the seasonal 

snowmelt. Hydrologic data at USGS streamflow-gaging stations are typically reported by water year 

(WY), which starts October 1 of the previous calendar year and extends to September 30.

Fluvial Geomorphology

Rivers carry water, sediment, and wood, all of which influence channel form (Leopold and 

others, 1964). The entrainment, transport, and deposition of sediment is spatially and temporally 

complex, and assessing or predicting how sediment moves downstream and the morphologic responses 

to sediment transport in a particular river can require extensive scientific effort. Understanding fluvial 

processes requires a standard terminology of mechanistic function and insight into the interaction 

between sediment-transport modes. This section discusses the terminology and function of river 

processes as they relate to sediment transport, sediment deposition, and the influence of wood in river 

systems draining Mount Rainier. The reader familiar with concepts in geomorphology can skip this 

section without loss of continuity in the report.

Sediment Load

The sediment load carried by a river, also referred to as sediment flux or total sediment 

discharge, is defined as the rate of transfer of non-dissolved, inorganic particles flowing past a given 

cross section within the stream. Sediment load typically is reported in units of mass per time, and the 

total sediment load is composed of suspended-sediment load and bedload. Suspended-sediment load is 

the fraction of fine sediment carried by turbulent eddies within the flowing river that can settle out in 
6

quiet backwaters of the river corridor or when discharge decreases. Bedload is the fraction of moving 

sediment too heavy to be carried in suspension that moves along the river bottom by rolling, sliding, or 

saltation. 

At low and moderate streamflow, overall bedload is small and the riverbed remains largely 

static. As streamflow increases, particles on the riverbed mobilize, resulting in increased bedload. 

Concurrently, the load of suspended sediment increases with increasing discharge, as does the 

characteristic median size of particles in suspension. Particles from both suspended-sediment load and 

bedload make up the bed material of the river bottom, and the particle-size threshold between 

suspended-sediment load and bedload is related to discharge. Bed-material load is the fraction of 

moving sediment that deposits on and composes the river bed, including all bedload and the coarser 

fraction of the suspended-sediment load.

As individual particles move downstream, collisions with other particles and the bed cause 

breakage or surface ablation in a process termed “attrition” (Collins and Dunne, 1989). Through attrition

and selective transport, river-bed material and bedload particle size decreases in the downstream 

direction (Sklar and others, 2006). In many rivers, there is a gravel-sand transition that forms by particle 

fining or changes in channel hydraulics (Hoey and Bluck, 1999; Ferguson, 2003; Singer, 2008; Labbe 

and others, 2011).

Sediment Measurement

Suspended-sediment load and bedload are sampled using specific protocols to minimize errors 

and enable comparability between different river systems (Edwards and Glysson, 1999). Even when 

using these protocols, large variability in sediment loads in the flowing river make precise and 

comprehensive sediment-load measurements difficult to obtain (Horowitz, 2003). Heterogeneous 

distributions of suspended-sediment load and bedload are common in most river systems and vary by 

position, hydrologic conditions in the catchment, geomorphic conditions in the local river reach, and 

discharge. 

Similarly, heterogeneity creates uncertainties when assessing the characteristic size of bed 

material. The most common approach to determining bed material size is with a Wolman pebble count 

(Wolman, 1954), but differences in application of the technique, as well as variability in bed surfaces, 

can create deviations in sample populations. The most effective technique to improve accuracy in 

measuring both sediment load and bed material is to collect replicate samples in sufficient quantities to 

enable the evaluation of the variation of the total population of interest.

Aggradation and Incision

Aggradation is the general trend of sediment accumulation in a particular river reach, which, in 

turn, causes an increase in the river-bed elevation, as well as the stage for a given discharge. Incision, or 

degradation, is the general trend of net sediment removal from a river reach, which lowers the riverbed 

elevation and decreases the stage for a given discharge. Lane (1955) introduced a qualitative relation 

that the product of discharge and slope is proportional to product of bedload and representative of bedmaterial size for a given river. It follows from Lane’s relation that conceptually, increases in bedload or 

bed-material size with no concurrent change in hydrologic discharge or river slope results in 

aggradation. Conversely, decreases in bedload under constant hydrologic discharge and slope results in 

net local incision. Similarly, if bedload and bed-material size are constant, decreases in discharge would 

result in aggradation and increases in discharge would result in incision. Though Lane’s simple relation 

has limitations, and has been improved and clarified by other researchers (see Schmidt and Wilcock, 
7

2008; Dust and Wohl, 2012), the underlying concept remains a useful and effective tool for 

understanding geomorphic response of alluvial river systems.

Alluvial sections of gravel-bed rivers subject to increased bedload and aggradation often respond 

with channel widening and braiding (Lyons and Beschta, 1983; Knighton, 1989; Madej and Ozaki, 

1996; Miller and Benda, 2000; Lisle, 2008; Pierson and others, 2011), particularly if the aggradation is 

caused by a pulse of finer-grained sediment translating through the reach (Lisle, 2008). Conversely, 

decreasing sediment loads typically result in channel incision and narrowing (Knighton, 1989; Lisle, 

2008; Madej and others, 2009). Leopold and Maddock (1953), using the flume data of Gilbert and 

Murphy (1914), stated that for constant velocity and discharge, an increase in channel width is 

associated with an increase in bedload. These particular channel responses of braided mountain rivers 

are pertinent to the present study because of the availability of aerial imagery showing channel form and 

the relative dearth of direct bedload measurements close to the mountain.

A graded river represents an alluvial system that balances sediment supply and the sedimenttransport capacity to move bed material, whereby there is no long-term aggradation or incision (Leopold 

and others, 1964). Transport capacity to move bed material is often assumed to be proportional to the 

available stream power of a river, which is proportional to the product of discharge and slope (Bagnold, 

1966). In rivers where sediment supply from the contributing catchment is less than the transport 

capacity, the long-term tendency of the river is to incise. Such rivers are often referred to as “supplylimited” or under conditions of “sediment deficit” (Schmidt and Wilcock, 2008); bedrock-controlled 

rivers fall into this category (Montgomery and Buffington, 1997). Conversely, if the sediment supply 

from the contributing catchment exceeds the transport capacity of the river, the river is categorized as 

“transport-limited” or under conditions of “sediment surplus” (Schmidt and Wilcock, 2008). No river is 

ever in a condition of pure sediment surplus or pure sediment deficit. Instead, the specific condition of 

the river falls in a spectrum between the two states, and varies in space and time. Rivers in sediment 

deficit can switch to sediment surplus after a large storm causes widespread landslides and a temporary 

oversupply of sediment (Brummer and Montgomery, 2006). Conversely, rivers in a state of sediment 

surplus can become sediment starved if sediment influx from the catchment decreases for a period of 

time. Additionally, rivers can be in sediment surplus in one particle-size class and in sediment deficit in 

another size class (Schmidt and Wilcock, 2008).

Debris Flows

A debris flow is a rapidly moving slurry of water of 70–90 percent sediment (by weight) with 

rheological properties that enable the efficient downstream transport of large volumes of sediment 

(Pierson and Costa, 1987; Costa, 1988). Granular collisions in the flow and a matrix of water and finegrained sediment give debris flows the competence to buoy large boulders and transport them several 

kilometers downstream. The sediment-transport competence of debris flows far exceeds water flow of 

similar depth and discharge, and debris flows are a predominant, formative geomorphic process in many 

mountainous rivers (Dietrich and Dunne, 1978; Reneau and Dietrich, 1991; Benda and Dunne, 1997;

Brummer and Montgomery, 2006).

Debris flows typically spawn from loose, unconsolidated colluvium or alluvium on hillslopes 

between 30 and 45 degrees. Heavy rainfall or the rapid melting of snow or glaciers can increase pore 

pressure of water in the soil column greater than a failure threshold, thus initiating movement of the 

hillslope (Iverson, 2000; Montgomery and others, 2002). If the clay content and water saturation is 

sufficient, the hillslope failure can continue to move downslope entering tributary and main-stem 

drainage networks. In steeper tributaries, debris flows scour and recruit additional sediment growing in 

volumetric size, through a process termed “bulking up.” In wider stream sections or reaches where the 
8

valley widens, debris flows deposit sediment and shrink in volume. The travel distance of the debris 

flow, as a slurry capable of carrying boulders, is a function of the total volume of the debris flow and the 

relative clay content (Iverson and others, 1998; Griswold and Iverson, 2008). Debris flows with high 

clay content can more effectively hold water in the matrix and extend travel distance (Scott and others, 

1995). After the debris flow deposits its coarse sediment, the remaining water/fine-sediment matrix can 

move downstream as hyperconcentrated flow, containing 40–70 percent sediment by weight (Beverage 

and Culbertson, 1964; Pierson, 2005). Although rheologically distinct from debris flows, 

hyperconcentrated flows have the competence to transport significant quantities of sediment 

downstream.

The term “debris flow” refers to any rapid mass movement of rocky debris mobilized by water. 

The term “mudflow” has been defined as a debris flow that contains more than 50 percent sand-, silt-, or 

clay-sized particles (Varnes, 1978). The differences in rheological properties and transport competence 

between debris flows and mudflows are so subtle that contemporary researchers have tended exclusively 

to use the term debris flow. Nevertheless, the term persists: Both the Osceola and the Electron 

Mudflows were named by early researchers, and news outlets are more likely to refer to debris flows as 

mudflows, an intuitive term for the general public. The term “lahar” is an Indonesian word that is used 

as a general designation to denote a debris flow that originates from an active volcano, whether 

triggered by an eruption or not (Crandell, 1971; Pierson and Scott, 1985; Vallance and Scott, 1997). In a 

strict technical sense, all debris flows originating from the flanks of Mount Rainier, regardless of size, 

are lahars. In 2003, however, to clarify communication protocol with emergency services, the public, 

and the press, Mount Rainier National Park made the administrative decision to use the term lahar only 

when describing large debris flows that were likely to leave the park boundary. The park service now 

reserves the term debris flow for smaller events that remain within the park. This report follows a 

similar convention. 

Wood

Historically, all rivers in the Pacific Northwest carried large quantities of wood that shaped 

channel form and ecological function (Abbe and Montgomery, 1996; O’Connor and others, 2003; Fox 

and Bolton, 2007; Collins and others, 2012). Within Mount Rainier National Park, where logging was 

never permitted, there appears to be a relative stasis between the position of old-growth forests and the 

active channel of rivers draining Mount Rainier (Kennard and others, 2011). Although the lower 20 km 

of the Nisqually River approaching Puget Sound flows through a relatively intact riparian corridor 

where the function of large wood in the river is similar to pre-development conditions (Collins and 

others, 2012) and riparian wood is still widespread within Mount Rainier National Park, the quantity of 

wood in all other main-stem river reaches draining Mount Rainier has been significantly reduced. This 

reduction in wood is particularly acute near population centers. In a forensic analysis of damaging 

regional floods of November 1906, Chittenden (1907) recommended the removal and control of drift 

wood as part of a three-pronged strategy to control floods (the other two components being river 

straightening and the construction of an extensive levee system). When the lower White River was 

leveed and straightened between 1914 and 1919 by the Inter-County River Improvement Commission, 

360,000 m3 of logs and drift wood from the flood plain and underlying alluvium were removed and 

burned (Roberts, 1920). Although the quantity of wood present in lowland sections of the Puyallup, 

Carbon, and White Rivers is significantly less than before development, wood is still recruited from the 

adjacent flood plain. Though this wood provides ecological benefit, it can also raise stage during floods 

(Brummer and others, 2006) or direct flow toward revetments causing damage and increase the risk of 
9

failure of flood-management structures and subsequent flooding. Although important, the impacts and 

function of wood to Mount Rainier rivers was not a focus in this study.

Conceptual Model of Sediment Delivery from Mount Rainier

Conceptually, sediment is transported from Mount Rainier to the Puget Lowland through a 

sequence of glacial and fluvial processes (fig. 2). High on the mountain, glaciers entrain sediment 

through bedrock erosion and carry colluvium deposited by rockfalls. Englacial sediment is transported 

by glaciers to lower elevations and deposited in moraines. Debris flows mobilize sediment from 

moraines as well as from superglacial deposits transporting sediment downstream into the river network. 

Finally, floods work to transport coarse-grained and fine-grained sediment down main-stem rivers to the 

Puget Lowland and Puget Sound.

Weathering and Rockfall

Chemical and physical weathering on Mount Rainier promotes the production of large volumes 

of sediment from the flanks of the stratovolcano. Near the summit, hydrothermal alteration of the 

extrusive igneous bedrock (Frank, 1995) produces weak, clay-rich material susceptible to sector 

collapse and large lahars (Scott and others, 1995; Reid and others, 2001; Sisson and others, 2001). 

Between eruptive episodes or large-scale sector collapse, the chemical weathering of the mountain 

bedrock causes rockfalls from exposed headwalls that deposit predominantly on glaciers. Small 

rockfalls are common throughout the summer, supplying new sediment to glaciers. Large rockfalls can 

mobilize into debris avalanches that move down the glacier as granular flows. 

In June 2011, a series of large debris avalanches, which started as rockfalls, blanketed the upper 

Nisqually Glacier. Because of the elevation of the deposit and the danger in the fall zone, no forensic 

data of the June 2011 debris avalanche were directly collected, but the aerial extent of the debris 

avalanche, as visible on 2011 National Agricultural Imagery Program (NAIP) imagery (U.S. 

Department of Agriculture, 2011), indicated the debris avalanche traveled a distance of more than 2 km 

down the face of the upper glacier and covered about 500,000 m2 of ice. If the deposit is assumed to be 

1–2 m thick, the total volume of sediment added to the Nisqually Glacier was between 0.5 and 1.0 

million m3. 

Larger rockfalls and debris avalanches have been documented (Crandell and Fahnestock, 1965; 

Frank, 1985; Scott and Vallance, 1995). The largest rockfall/debris avalanche in the Mount Rainier 

historical record occurred in December 1963, when 11 million m3 fell during at least seven separate 

avalanches that traveled a distance of more than 6 km down Emmons Glacier and left a sizeable deposit 

on the valley floor in front of the glacier terminus (Crandell and Fahnestock, 1965) (fig. 3). A 

photograph of the region downslope of the Emmons Glacier terminus taken in the summer following the 

debris avalanche shows the extent of the debris coverage (fig. 3B), and a photograph taken from a 

similar vantage point five years later shows the progression of the rockfall-sourced sediment down the 

White River (fig. 3C). By the summer of 2011, vegetation had grown on much of the 1963 debrisavalanche surface, and fluvial processes appeared to have significantly reworked the deposit and 

transported a portion downstream (fig. 3D). 

Glaciation

In the geologic record, aggradation in fluvial networks is often associated with periods of glacial 

advance (Schumm, 1965; O’Connor and others, 2001). In many systems, however, studies of proglacial 
10

sedimentation show complex patterns of aggradation and incision (Maizels, 1979; Leonard, 1997), and 

debris released by proglacial or postglacial regions of retreating glaciers have triggered increased 

sediment loads and downstream aggradation (Church and Ryder, 1972; O’Connor and Costa, 1993; 

Hallet and others, 1996).

Mount Rainier glaciers have been the focus of numerous studies (for example, Harrison, 1956; 

Sigafoos and Hendrick, 1961; Fahnestock 1963; Veatch, 1971; Crandell and Miller, 1974; Sigafoos and 

Hendricks, 1972; Metcalf, 1979; Mills, 1979; Burbank, 1981; Driedger and Kennard, 1986; Heine, 

1998; Nylen, 2004; Sisson and others, 2011). The movement of glaciers over bedrock promotes 

sediment entrainment through plucking and abrasion. Mills (1979) estimated the Nisqually Glacier 

produced a fine-grained suspended-sediment load of about 60,000 tonnes/yr, predominantly sourced 

from abrasion and released during the summer melt season. Metcalf (1979) calculated the suspendedsediment load from subglacial abrasion of Nisqually Glacier to be 30,000 tonnes/yr. Sediment sourced 

from abrasion processes is believed to be the primary cause of “glacial flour,” the high-sediment 

concentration in glacier-draining streams observed during warm summer months (Fahnestock, 1963; 

Mills, 1979). Englacial sediment, sediment carried within or on top of the flowing ice matrix, also 

represents a significant volume of total glacial sediment load. Englacial sediment on Mount Rainier is 

predominantly sourced from rockfalls and debris avalanches that occur high on the mountain. 

Glacier retreat in the Pacific Northwest during the 20th century has been widely documented 

(Spicer, 1986; Pelto and Riedel, 2001; Pelto, 2006), and glacier response on Mount Rainier has mostly 

reflected the regional trends (Nylen, 2004; Sisson and others, 2011). Nylen (2004) determined that, 

between 1913 and 1971, glacier cover on Mount Rainier decreased 18.5 percent and glacier volume 

decreased 22.7 percent. From 1970 to 2008, Mount Rainier lost another 14 percent by volume of glacier 

ice and perennial snow (Sisson and others, 2011). Most glaciers on the mountain have retreated since 

1980, with the largest documented glacier retreat on the southern flank of the volcano. Rockfall debris 

on Emmons Glacier (mostly from the 1963 event) caused a modest advance and thickening of the 

glacier since 1970 (Sisson and others, 2011). Similar debris mantling has insulated the Carbon and 

Winthrop Glaciers, mitigating tendencies toward glacier retreat (Nylen, 2004; Sisson and others, 2011).

The flux of sediment carried downslope by an active glacier is the product of the glacier velocity 

and the sediment in or on the flowing ice matrix. Seasonal temperature and snowfall are the primary 

climatic variables influencing glacial dynamics and whether the glacier is in a state of advance or 

retreat. Englacier sediment is deposited in lateral and terminal moraines near the glacier terminus. Most 

lateral and terminal moraines on Mount Rainier are located at low elevations and are subject to 

mobilization into debris flows.

Mount Rainier Debris Flows

On Mount Rainier, debris flows are initiated by rapid summer melting of glaciers and 

subsequent outburst flooding that mobilize sediment (Walder and Driedger, 1994) or by intense rainfall 

that saturates loose, unconsolidated soils on steep slopes near the glacier terminus (Copeland, 2009; 

Lancaster and others, 2012). Most of the large rainfall-induced debris flows documented in the historical 

record occurred in October or November, presumably with little antecedent snowpack. No debris flows 

have been recorded from December to May, when snowpack is thicker (Nick Legg, Oregon State 

University, written commun., 2011). These historical observations, however, also may reflect the fact 

that fewer visitors are in the park during the winter months, particularly along the Carbon and White 

Rivers. The retreat of most glaciers on Mount Rainier during the 20th century exposed fresh colluvium 

suggesting a correlation between recent observed debris-flow activity and glacial retreat with intense 
11

rainfall from strong autumnal atmospheric rivers acting as a primary triggering mechanism (Copeland, 

2009; Lancaster and others, 2012). 

The largest historical debris-flow event was the 1947 Kautz Creek debris flow, which mobilized 

about 40 million m3 of material following heavy rainfall in October (Crandell, 1971). Following the 

1947 event, periodic debris flows continued to occur in the Kautz drainage about every 10 years 

(Driedger and Fountain, 1989; Nick Legg, Oregon State University, written commun., 2011). The 

greatest level of sustained debris-flow activity on Mount Rainier occurred in Tahoma Creek with at least 

28 individual debris-flow events from 1967 through 2006 (Walder and Driedger, 1994; Copeland, 

2009). Debris flows in the Nisqually River basin triggered by summer glacial melt were common in the 

1990s (Walder and Driedger, 1994; Copeland, 2009). In the 2000s, the entire mountain experienced a 

spate of debris-flow activity associated with heavy autumn rainfall in 2003, 2005, and 2006 (Copeland, 

2009). 

On the southern side of Mount Rainier, documented debris flows have initiated from steep 

slopes in recently deglaciated terrain (Copeland, 2009; Lancaster and others, 2012). Few direct 

observations of debris flows are available from the northern and western sides of the mountain, but 

reconnaissance of the Carbon River near the glacier terminus, conducted as part of this study, showed 

debris flows had traveled at least 2 km downstream of the Carbon Glacier within the past 10 years and 

that extensive debris-flow levees were present within 300 m of the glacier. A wide active channel and 

widespread burial of flood-plain forests along the upper Carbon River just downstream of the glacier 

suggest recent and significant trends in sedimentation. Evidence along the upper Carbon River indicates 

that debris flows are an active part of the transport process, despite minimal 20th-century glacial retreat. 

Debris flows efficiently transport sediment from steeper sections of the fluvial network near the 

glaciers to lower elevation fluvial reaches (fig. 2). This debris-flow transport is important to the overall 

delivery process because the upstream reaches of the glacier-draining rivers do not have the hydrologic 

stream power sufficient to mobilize larger particles. Without debris flows, the majority of debris in 

terminal and lateral moraines would remain near the glacier. Debris flows carry sediment into 

downstream fluvial reaches where flow competence increases and stream power is sufficient to mobilize 

gravel, cobbles, and boulders into the river sediment load.

Sediment Transport in River Network

Once sediment is delivered to the primary fluvial network, transport to downstream reaches and 

the geomorphic response of the river channel form is dictated by the balance of hydrology and sediment 

load (Lane, 1955). High-gradient fluvial reaches, with slopes greater than about 0.02 m/m, are subject to 

active aggradation and incision with the potential to move into forested terraces of the flood plain 

adjacent the active river channel (fig. 2). Because these steeper reaches tend to be within the national

park boundary, the presence of old-growth forests resists channel migration and avulsions of the river 

into the forested flood plain (Kennard and others, 2011). 

Downstream of the national park, rivers flow through mountainous reaches with slopes between 

0.002 and 0.02 m/m. The background hydrology in these reaches, coupled with the relatively steep 

slopes, tends to efficiently transport sediment with relatively little long-term aggradation or incision. 

Some river reaches, however, can experience active-channel migration and avulsions, particularly where 

forestry and development have removed large anchor trees (Collins and others, 2012). 

Upon exiting the mountain front, rivers draining Mount Rainier enter the Puget Lowland where 

slope decreases, promoting long-term aggradation and the build-up of alluvial fans (Dragovich and 

others, 1994; Collins and Montgomery, 2011). Changes to river corridors from engineering and 

development, as well as flow regulation, further complicate river responses in the lowland.
12

Sediment deposited in main-stem rivers of the Mount Rainier fluvial network is transported 

downstream by infrequent large and frequent intermediate-sized flows (fig. 2). Although the 

geomorphic work done by intermediate flows is less than the work done by large events, intermediate 

flows accomplish work through event frequency and serve as an important contributor to the total 

sediment load (Langbein and Leopold, 1964). Large, infrequent floods transport and deposit the largest 

particles in the bed, which establishes the geomorphic framework of bars and pools in the river corridor. 

Channel migration, widening, and avulsions tend to occur during larger flood events. Smaller, morefrequent peak-flow events do not exert the channel-forming influence on river morphology as the larger 

events, but these intermediate flows transport a significant portion of the total sediment load. The 

combination of frequent moderate-magnitude flows and infrequent large floods are responsible for 

transporting large volumes of sediment to depositional reaches in river systems draining other 

stratovolcanoes (Major, 2004; Pierson and others, 2011).

Serial Sediment Delivery

The heavy sediment loads in rivers draining Mount Rainier depend on contributions of four 

dominant sediment-delivery processes working in unison: (1) rockfalls, (2) glaciers, (3) debris flows, 

and (4) floods. Rockfalls and debris avalanches onto glaciers at the highest elevations of the mountain, 

promoted by weathering and hydrothermal alteration of the volcano bedrock structure, initiate the 

delivery of sediment downstream. This rockfall sediment is carried by the downslope movement of 

glaciers. Debris flows then episodically transport sediment from glacial moraines to downstream 

reaches of the river network. Heavy rainfall and concomitant large floods transport sediment to lowland 

reaches where the coarser material deposits in aggrading reaches and the finer sediment is eventually 

transported to Puget Sound. If any of these processes slow or cease, the sediment loads delivered to 

lowland reaches would decrease over time. Conversely, if these processes increase concurrently, then 

sediment delivery to lowland reaches would increase. More research is needed to better understand the 

relative contributions of each process in overall sediment delivery, specifically related to timing of 

delivery and limiting processes in the sequence. For example, there is likely a phase delay in the timing 

of one dominant sediment-delivery process to the next which can affect sediment arrival downstream, 

and sediment can reside for periods of time in temporary sediment reservoirs (for example, glacial 

moraines or flood-plain storage). However, in general, these four processes act to meter sediment 

delivery to lowland reaches.

Geomorphic Characteristics of Mount Rainier Rivers

Mount Rainier rivers have been influenced by the geology of the Cascade Range and Puget 

Lowland as well as the large sediment loads supplied by the volcano.

River Centerlines and Stationing

Using available LiDAR DEMs and aerial images (appendix A, table A1), digitization of the 

active channel and centerline was completed for each main-stem river in the study (Puyallup, Carbon, 

White, Nisqually, and Cowlitz Rivers). River centerlines also were digitized to provide consistent river 

stationing along the dominant flow path of the active channel. These digitization products were used to 

compute longitudinal elevation profiles and active-channel widths for each river and to construct onedimensional river-hydraulic/sediment-transport models. Details of the digitization are discussed further 

in section “Model Framework.” River kilometer stationing along each main-stem river was established 

from upstream to downstream, with river-kilometer 0 starting near the terminus of the glacier for each 
13

main-stem river (fig. 1). Stationing for each main-stem river was differentiated using the following 

naming convention: Nisqually River (NRKM), Puyallup River (PRKM), Carbon River (CRKM), White 

River (WRKM), and Cowlitz River (CwRKM). River centerlines (fig. 1) were digitized from the 

apparent flow path using LiDAR data in order to compute an elevation profile of each tributary entering 

main-stem rivers.

Longitudinal River Profiles

Longitudinal profiles of Mount Rainier rivers and tributaries show the prominent high-gradient 

nature of the drainage network from the stratovolcano to lowland reaches (fig. 4). For example, the 

Puyallup River grades steeply from its source glacier, the Puyallup Glacier, through an upper alluvial 

reach to a relatively steep bedrock canyon at the mountain front of the Cascade Range located from 

about PRKM 27 to 35 (fig. 4A). After flowing through an alluvial reach near the volcano, the Carbon 

River cuts through a similar bedrock canyon at a similar elevation from about CRKM 27 to 33 (fig. 4C). 

The White River near Mud Mountain Dam (WRKM 71.0) also cuts through a bedrock constriction, 

though the length of the White River bedrock reach is shorter than those along the Puyallup and Carbon 

Rivers (fig. 4B). These bedrock canyons, common on Cascade Range rivers exiting the mountain front 

and entering the Puget Lowland, are geologic reflections of the influence of the Puget Lobe of the 

Cordilleran Ice Sheet (Collins and Montgomery, 2011). 

Downstream of the bedrock canyons, the Carbon and the Puyallup Rivers have incised into 

Pleistocene glacial till for a short distance before joining near the city of Orting within the Puget 

Lowland, where the rivers’ longitudinal profiles change (Collins and Montgomery, 2011). Following 

former embayments of Puget Sound (Booth, 1994), the slopes of lowland rivers decrease, promoting 

high sedimentation rates and long-term aggradation. From Orting to just downstream of the confluence 

with the White River, the Puyallup River flows down an elongated alluvial fan of coarse-grained 

sediment built during the Holocene predominantly by Mount Rainier sediment (Dragovich and others, 

1994; Collins and Montgomery, 2011). Close to Commencement Bay, the Puyallup River flows across a 

flatter flood plain that Collins and Montgomery (2011) explained to be an alluvial reach where the river 

tends to have bed topography higher than the adjacent flood plain. Before development, these Puget 

Lowland rivers were prone to avulsions and active channel migration across the width of the flood plain.

When compared to profiles of other rivers draining Mount Rainier, the slope of the longitudinal 

profile of the White River is relatively modest (fig. 4B). Upstream of Mud Mountain Dam, the White 

River follows a structural feature in the Cascade Range that likely predates the volcano. Moreover, the 

White River was repeatedly impacted by lahars during the Holocene including the Osceola Mudflow, a 

large lahar that mobilized 3.8 km3 of sediment during a sector collapse of the volcano 5,600 years ago 

(Vallance and Scott, 1997). In addition to inundating the river corridor up to dozens of meters deep in 

flowing lahar, the event also rerouted the course of the White River from its early Holocene path, where 

South Prairie Creek now flows, to its current path through the glacial-till plain between Enumclaw and 

Auburn, Washington. Downstream of Auburn, the White River enters the former course of the Stuck 

River (from about WRKM 110 to the confluence with the Puyallup River), where slope decreases, 

fostering high sedimentation rates (Dunne, 1986; Prych, 1988; Czuba and others, 2010). The inset in 

figure 4A shows the pronounced reduction in slope of the White River along the former Stuck River 

about 7–10 km upstream of the confluence.

The Carbon River, upstream of its bedrock canyon, flows through an alluvial reach (fig. 4C). 

This alluvial reach has a relatively wide flood plain, and the slope of the Carbon River here is less than 

the geomorphically comparable section of the Puyallup River (fig. 4A). Most tributaries of the Carbon 

River enter at steep slopes likely reflecting the geomorphic response to Pleistocene alpine glaciation 
14

(Crandell and Miller, 1974). In contrast, South Prairie Creek enters the Carbon River at a slope much 

less than the main stem, reflecting the fact that this valley carried the White River before 5,600 years 

ago (Crandell, 1963).

The Nisqually River exhibits a long profile that grades into the reach of river where Alder Dam 

was constructed in 1945 (Czuba and others, 2012) (fig. 4D). Glacier-draining tributaries Kautz and 

Tahoma Creeks similarly grade into the main-stem Nisqually River, but tributaries draining catchments 

away from the volcano do not necessarily grade smoothly into the main stem, likely reflecting a smaller 

sediment supply or a delayed geomorphic response to changes in base level (Leopold and Bull, 1979) 

from Pleistocene alpine glaciation (Crandell and Miller, 1974). Curiously, Mineral Creek enters the 

Nisqually River with a supine slope, possibly reflecting a geologically recent episode of sedimentation 

along the main-stem Nisqually River. After entering the valley floor, Big Creek flows along a recent 

relict channel of the Nisqually River and exhibits little difference in slope relative to the main stem. 

The Muddy Fork Cowlitz River steeply flows from the Cowlitz Glacier to the lower Cowlitz 

Valley in about 20 km (fig. 4E). As a result, much of the river corridor is bedrock controlled from the 

national park to Packwood, Washington, with a few alluvial reaches. The alluvial reaches closest to the 

volcano have a braided channel form indicative of some degree of sediment load, though these reaches 

are not as wide or as spatially extensive as braided sections of the Nisqually River or Carbon River. The 

Ohanapecosh River follows a similarly steep longitudinal profile from the glacier to its confluence with 

the main-stem Cowlitz River. If the Cowlitz River was aggrading with new sediment, the reach of river 

near Packwood, about 25 km downstream of the glacier where river slope decreases, would likely show 

aggradation. Czuba and others (2010), however, reported that the reach of the Cowlitz River near 

Packwood has been incised by about 0.5 m since 1990. Though more research is needed to quantify 

sediment loads on the Cowlitz River system, observations indicate the Cowlitz and Ohanapecosh Rivers 

are not experiencing the same magnitude of rapid sedimentation documented on other rivers draining 

Mount Rainier.

Sediment Equilibrium

Where the Puyallup, Carbon, and White Rivers exit the mountain front and enter the shallow 

gradients of the Puget Lowland, long-term trends of aggradation and fill in former embayments of Puget 

Sound are prominent and widespread (Dragovich and others, 1994; Collins and Montgomery, 2011). In 

upstream mountainous reaches, however, aggradation is less pronounced and more localized.

Large lahars from Mount Rainier and a near-continuous supply of fluvial sediment between 

lahar episodes shaped the fluvial geomorphology of the White, Puyallup, and Nisqually Rivers. Most 

lahar episodes are marked in the geologic record by significant increases in sedimentation. In the 

Nisqually River flood plain, upstream of Alder Lake, Crandell (1971) documented a complex pattern of 

gravel- and sand-rich terraces of both lahar and fluvial origin that are likely associated with eruptive 

phases of the volcano. But the current upper Nisqually River is inset below these terraces indicating that 

the river has graded to a late-Holocene equilibrium, integrating long-term inputs of sediment from intereruptive periods and lahar episodes. Similarly, the White River flood plain contains an assemblage of 

lahar and fluvial terraces, the most prominent of which is the Osceola Mudflow (Vallance and Scott, 

1997). Smaller but significant lahar episodes affected the White River valley between 2,600 and 2,200 

years ago and between 1,500 and 1,000 years ago (Sisson and Vallance, 2008). Although late 

Pleistocene alpine glaciation likely scoured the White River valley near Mount Rainier, sediment 

supplied by lahar episodes refilled the White River valley toward a post-Pleistocene graded state that

roughly balances current hydrology and sediment supply. The upper Puyallup River valley appears to 

still be under the influence of the 600-year-old Electron Mudflow (Scott and Vallance, 1995) that filled 
15

much of the flood-plain valley, constricting the current river with resistant lahar terraces and 

suppressing the formation of wide alluvial sections. 

The perceived sediment-equilibrium conditions in the White and Puyallup Rivers, as well as in 

the Nisqually River, contrast with documented disequilibrium conditions between sediment yields from 

Cascade Range drainages in British Columbia, Canada (Church and Slaymaker, 1989). The upper 

Carbon River, however, may still reflect the influence of Pleistocene alpine glaciation. The Carbon 

River, upstream of its bedrock canyon reach (upstream of CRKM 27), flows through a wide alluvial 

reach with few topographically high terraces. Few large lahars have impacted the Carbon River during 

the Holocene (Crandell, 1971; Scott and others, 1995), and the relatively wide alluvial flood plain 

coupled with the lack of high constraining terraces may indicate that the upper Carbon River valley is 

still adjusting its sediment load to a river valley carved by Pleistocene alpine glaciers. 

Bed-Material Sediment Size

Czuba and others (2010) reported characteristic bed-material size along the Puyallup, Carbon, 

and White Rivers within the Puget Lowland (fig. 5). The beds of these lowland rivers contained 

predominantly sand, gravels, and cobbles, though boulders made up a portion of the bed for the 

Puyallup and Carbon Rivers, where the rivers exit the mountain front and first enter the lowland. A 

gravel-sand transition was present in the Puyallup River approximately 6.4 km (PRKM 76.1) from the 

river mouth at Commencement Bay. A similar gravel-sand transition was found on the White River 

approximately 5.6 km (WRKM 111.1) upstream of the confluence with the Puyallup River. 

For this study, using the Wolman pebble-count method (Wolman, 1954), bed-material size was 

measured along the main stems of the Puyallup, Carbon, White, and upper Nisqually Rivers into Mount 

Rainier National Park. For the pebble-count method, a 30-m tape measure was laid along the apex of 

gravel bars, and particles were counted every 0.3 m (100 particles counted for each survey), with all 

particles less than 2 mm grouped into the sand category. At each measurement site, at least three 

surveys were made and the combined data defined the grain-size distribution.

Boulder- to cobble-sized material was present in all main-stem river reaches within Mount 

Rainier National Park (fig. 5). As much as one-quarter of the bed material in the Nisqually and Carbon 

Rivers within 3 km of the glacier terminus was boulder sized. Boulder-sized material also was

widespread along the upper Puyallup River. The White River upstream of Mud Mountain Dam had 

fewer boulders than the Puyallup and Carbon Rivers. Gravel-sized particles were present in all river 

reaches except the most downstream sections of the lower Puyallup and lower White Rivers where sand 

is dominant. Downstream of the national park boundary, the upper Puyallup and Carbon Rivers had 

larger bed-material sediment than the Nisqually and White Rivers at similar distances from the 

mountain (fig. 5). This difference may reflect greater sediment loads coming from the Nisqually and 

White Rivers relative to the Puyallup and Carbon Rivers, as pulses of sediment translating through a 

river corridor have particle-size distributions smaller than the extant bed (Lisle, 2008).

The percentage of sand in the bed material can indicate sediment surplus conditions and also is 

an important parameter to assess bedload-transport potential. Sand percentage of the bed was mapped 

for each river of interest (fig. 6). Sand was prevalent throughout the river network, and there was 

widespread sand on the upper Nisqually River and upper White River. The upper Carbon River also had 

a large percentage of sand. Although sand was present along the upper Puyallup River, the relative 

percentage was less than the percentage of sand on other rivers. Similarly, the White River downstream 

of the West Fork White River and upstream of Mud Mountain Dam had a relatively small percentage of 

sand, possibly reflecting larger hydrologic transport capacity of the White River downstream of the 

West Fork White River.
16

The particle size coarser than 90 percent of the particles at a site (D90) also was mapped 

showing the relatively large D90 values near Mount Rainier and general trends of fining in the 

downstream direction (fig. 6). However, D90 sizes remained relatively large along the White, Carbon, 

and Puyallup Rivers several kilometers downstream of the mountain front, reflecting large stream power 

and significant transport potential well into the lowland reaches. 

Hydrologic Trends and Geomorphic Response at Gaging Stations

The hydrologic flow regime of the Mount Rainier watershed governs the transport capacity of 

the river network. Data from streamflow-gaging stations on Mount Rainier rivers (table 1) were 

analyzed to assess trends in hydrologic flow regime, specifically trends in runoff as well as trends in 

peak-flow events. Data were also analyzed to determine if geomorphic responses of aggradation and 

incision at a particular gaging station could be correlated with hydrogeomorphic conditions of 

individual storms affecting a particular catchment.

Analyzing Hydrologic Gage Data

Daily discharge values recorded at the Puyallup River at Puyallup gage (12101500) and on the 

upper Cowlitz River at Packwood gage (14226500) were used to analyze general long-term flow 

conditions of rivers draining Mount Rainier. The gaging record for the Nisqually River near National 

(12082500), which drains the southern flank of Mount Rainier, began in 1942 and indicates that runoff 

trends in the Nisqually River were similar to general trends for the Puyallup and Cowlitz Rivers.

Long-term daily-discharge values were examined for correlation with trends in the Pacific 

Decadal Oscillation (PDO). The PDO is a sea-surface temperature pattern that develops in the northern 

Pacific Ocean and typically persists for 20–30 years (Mantua and others, 1997). The PDO index,

produced and made available by the Joint Institute for the Study of the Atmosphere and Ocean 

(University of Washington, 2012), is a metric representing the monthly sea-surface temperature. A 

positive PDO index indicates warmer than normal sea-surface temperatures in the northern Pacific 

Ocean, and a negative PDO index indicates cooler than normal temperatures. The El Niño-Southern 

Oscillation (ENSO), a large-scale climate pattern of sea-surface temperatures in the tropical Pacific 

Ocean that typically cycles every 5 years, also influences precipitation and runoff in the Pacific 

Northwest (Redmond and Koch, 1991; McCabe and Dettinger, 1999); however, averaged over decades, 

the PDO largely reflects the influence of ENSO forcing (Newman and others, 2003). Because the PDO 

more strongly influences winter precipitation in the Pacific Northwest than the ENSO alone (McCabe 

and Dettinger, 2002), only correlations between runoff and the PDO index were considered here, but 

future studies can more fully assess teleconnections between runoff, PDO, and ENSO.

Peak-flow events for unregulated river reaches were analyzed to assess long-term trends and 

identify periods of time with several large events. A Mann-Kendall trend test on the peak-flow 

magnitude, where time is the dependent variable, was conducted to determine if statistically significant 

peak-flow trends were detectable, where a p-value less than 0.05 indicates there was a statistically 

significant trend with time (Helsel and Hirsch, 1992).

Long-Term Hydrologic Runoff

The 10-year moving average of daily discharge recorded at the lower Puyallup River and the 

Cowlitz River, normalized against the long-term mean annual flow, showed the general hydrologic 

runoff trends of the two rivers through the 20th century (fig. 7). Flood-management actions at Mud 

Mountain Dam do not affect the 10-year moving average of discharge in the lower Puyallup River 
17

because water is not retained in the reservoir for extended periods. Diversions and returns to and from 

Lake Tapps affected summer flows in the lower Puyallup River to some extent during the 20th century 

(Herrera Environmental Consultants, 2005), but for the purposes of this study, it is assumed that these 

effects are small compared to the 10-year average of total runoff. The Cowlitz River near Packwood is 

unregulated. Distinct wet and dry hydrologic periods appeared in the flow record with the period of time 

from 1911 to 1947 having normal or below normal flows; the period from 1947 to 1978 representing a 

wet hydrologic period; and the period from 1978 to about 1994 representing another dry hydrologic 

period. From the middle 1990s to about 2005, runoff was normal. Since about 2005, runoff appears to 

have increased.

Comparing the hydrologic flow conditions of the Puyallup and Cowlitz Rivers against the PDO 

index plotted on a scale, with positive and negative values reversed from the usual convention, shows a 

relation (fig. 7). Analysis of the data indicated that the coefficient of determination (R2

) between runoff 

and the PDO index was about 0.65. Researchers have identified a distinct 20th-century cool period from 

1947 to 1976 in the PDO index (Mantua and others, 1997), which corresponds to a period of greater 

runoff in Mount Rainier rivers. In contrast, researchers also identified two prominent 20th-century warm 

periods in the PDO from 1925 to 1946 and from 1977 to at least the middle 1990s. The runoff of the 

Puyallup and Cowlitz Rivers during these periods was smaller than normal. It appears that the PDO 

influences the general hydrologic runoff of rivers draining Mount Rainier and that cool PDO phases will 

result in the potential for larger overall runoff.

Peak-Flow Events

Mass and others (2011) argued that large rain events have increased in catchments along the 

Washington coast. But Mass and others (2011) and Wallick and others (2011) also observed decreasing 

trends in flood magnitude in Oregon and northern California. In analysis of long-term streamflowgaging data, Hirsch and Ryberg (2011) found no statistically significant correlation between peak flows 

in the northwestern quadrant of the United States and the magnitude of global atmospheric carbon.

Plotting the annual peak flow for the available record on the unregulated sections of the 

Puyallup, Carbon, Cowlitz, and Nisqually Rivers reaffirms observations (Pierce County, 2012) that 

several large floods have affected the region since about 1990 (fig. 8). Large floods in western 

Washington are caused predominantly by atmospheric rivers (Neiman and others, 2011), which tend to 

affect geographically limited regions. Because the positional focus of any given atmospheric river can 

shift due to subtle differences in atmospheric steering winds, whether or not Mount Rainier is affected 

by a strong atmospheric river from one year to the next appears to be governed by stochastic 

probabilities. Though possible that the PDO might influence the strength of atmospheric rivers, the data 

set from Mount Rainier gages is too limited to detect a direct correlation.

A more fundamental question posed by Allan (2011) and Min and others (2011) is whether 

precipitation events will become more severe with global climate change. The data from the Nisqually 

River near National has been identified as an example of an increasing trend in peak flows. Applying 

the Mann-Kendall trend test to the Nisqually River data resulted in a p-value of 0.014, confirming that 

for WYs 1942–2011, annual peak flows increased along the upper Nisqually River. Applying the MannKendall test to longer streamflow records from the Cowlitz, Carbon, and upper Puyallup Rivers, 

however, resulted in p-values of 0.067, 0.067, and 0.512, respectively, indicating there are no 

statistically significant trends of increasing peak flows for these rivers. Regionally, the 1930s were a 

period of large floods. The Nisqually River gaging station began operation in 1942 and the streamflow 

data record does not capture the larger peak flows of the early 20th century, likely explaining the 

contrast in results of trend analysis compared to the other gages. Considering the available peak-flow 
18

data from unregulated Mount Rainier gages and the possibility that increasing trends verified on the 

Nisqually River may be an artifact of a short gaging record, the data indicate that there has not been a 

statistically significant trend of increasing peak flows during the 20th century in the rivers draining 

Mount Rainier.

Implications of 20th-Century Hydrology on Sediment Production and Transport 

Based on runoff and peak-flow data, time periods in the gaging record were categorized into 

more-active or less-active periods (in hydrological terms) to provide context for later discussion of 

sediment-load and sediment-production analyses. The period of time from the late 1940s to about 1960 

had great-than-normal runoff (fig. 7) and some large peak-flow events (fig. 8). This period was more 

active hydrologically. The notable 1947 Kautz debris flow (Crandell, 1971) contributed significant 

sediment to the main-stem Nisqually River; this sediment was transported to Alder Lake during the 

1950s (Czuba and others, 2012). In contrast, conditions were less active from the middle 1960s to the 

middle 1970s, a period with slightly greater-than-normal runoff but few large peak-flow events to 

produce new sediment from the catchment. Conditions became even less active from 1978 to about 

1994, when hydrologic runoff was less than normal and there were few peak flows. Large peak flows 

started to affect the region again in the 1990s, with the February 1996 flood ushering in a more active 

period. Recently, increased hydrologic activity occurred from 2006 to 2009 with the combination of 

greater-than-normal runoff and large peak-flow events (Beason and Kennard, 2007; Mastin and others, 

2010). 

Geomorphic Response to Hydrologic Events

Flood-induced incision or aggradation of a particular river reach is governed by the mass balance 

of sediment entering and exiting the reach and the resulting storage of bed material. Using gage 

analysis, Czuba and others (2010) found the Nisqually River near National had experienced significant 

changes in the stage-discharge relation since 1942. Plotting stage for the median flow for the Nisqually 

River along with the daily discharge from 1986 to 2011 showed an apparent relation between stage 

changes recorded at the gage and during peak flow events (fig. 9). During some large peak-flow events 

(notably, the February 1996 storm), the median-flow stage at the gaging station decreased significantly. 

In contrast, other peak-flow events (for example, during the November 2006 storm) were associated 

with a net increase in median-flow stage at the gage. Still other peak-flow events were associated with 

little or no change in median-flow stage.

To assess what may influence the geomorphic response at the Nisqually River gage, individual 

shifts in stage for the 20 largest peak flows from 1989 to 2009 (table 2) were compared to 81 

atmospheric, hydrologic, and meteorological data sets collected in the catchment before, during, and 

after the particular flood event. Flows occurring from April to October, likely representing snowmelt 

events, were excluded. Peak-flow date and time were determined using the maximum unit-discharge 

value that occurred during the storm period. The change in stage at the gaging station related to a 

particular peak-flow event was calculated by subtracting the stage at median flow at the gaging station

before and after the event (Czuba and others, 2010). 

Changes in stage at the Nisqually River gage were compared to National Oceanic and 

Atmospheric Administration atmospheric-sounding data from the Quillayute, Washington (University 

of Wyoming, 2011), before and during the peak event. Sounding parameters, including precipitable 

water, wind, temperature, pressure, and indices of instability (table 3) were compared to observed 

changes in stage. Changes in stage were also compared to snowpack telemetry (SNOTEL) data from 

Paradise, Washington (National Resources Conservation Service, 2011). SNOTEL data included the 
19

snow-water equivalent and air temperature before, during, and after the peak-flow event. Finally, stage 

changes also were compared to Longmire, Washington, and Paradise weather-station data from the 

National Climatic Data Center (CLIMATEDATA disk Volume 21.3 and 20.2, 2010, produced by 

EarthInfo®, Inc.), which included precipitation. Sounding data for the 48 hours preceding the peak flow 

were compiled and analyzed. Of the available SNOTEL sites, the Paradise site was the closest to the 

Nisqually River gage and was centrally located within the upper catchment. Similarly, daily rainfall data

measured at weather stations at Longmire and Paradise within the upper Nisqually River catchment 

were analyzed. In all, 81 parameters were available in sufficient quantities to test for correlation (table 

3).

Of the 81 parameters evaluated, only 4 parameters had a coefficient of determination (R2) larger 

than 0.20 (indicated in bold in table 3), signifying little correlation between parameters and measured 

changes in river stage. Even for the four parameters with a coefficient of determination larger than 0.20, 

the correlation between the parameter and stage change was weak. The strongest correlation was 

between minimum temperature one day after the peak and stage change (R2 = 0.56), and two other postevent temperature parameters also showed a weak correlation (average temperature and maximum 

temperature the day after the peak). Of the evaluated data parameters from the day of the storm, only the 

sounding-recorded severe weather threat (SWEAT) index (a stability index which incorporates 

instability, wind shear, and wind speed; National Oceanic and Atmospheric Administration, 2012) 

showed a weak correlation to stage change (R2 = 0.29). Notably, several parameters which were 

anticipated to correlate with gage response, including total precipitation, precipitation intensity, 

antecedent moisture conditions, and snow-water equivalent in the watershed, were found to have no 

correlation.

The failure of the exercise to find even reasonably moderate correlations with hydrologic or 

atmospheric parameters may be due to the time delay between a particular hydrologic perturbation and 

the response measured at the Nisqually River gage. The Nisqually River gage is about 14 km 

downstream of the national park boundary and 32 km downstream of the Nisqually Glacier. Even for a 

large flood, the sediment mobilized from the within the watershed likely would be deposited in the main 

stem upstream of the gage and require a series of additional peak-flow events to transport to the river

reach near the gage. A gage location closer to the disturbed section of the catchment or a compensation 

for a time delay in the movement of sediment likely would be needed to find a better correlation 

between hydrologic parameters and gage response. The lack of correlation in the analysis may also be 

related to the fact that stage at a given gage, which is related to the hydraulic control in the river just 

downstream from the gage, may not exclusively reflect sediment conditions in the watershed. Instead, 

hydraulic control could be affected by other factors including vegetation, wood assemblages, or 

localized sediment accumulation not associated with conditions in the watershed.

Sediment Loads of Mount Rainier Rivers

Knowledge of sediment loads in regional rivers is important to a wide spectrum of resource 

managers dealing with aquatic habitat, flood-hazard management, and planning issues (see Herrera 

Environmental Consultants, 2010; Pierce County, 2012). For flood-risk management along Mount 

Rainier rivers, bedload data are most useful, but knowledge of suspended-sediment load also is helpful 

because of impacts on water quality and aquatic habitat as well as the fact that bedload is typically 4–10 

percent of suspended-sediment load (Nelson, 1971; Nelson, 1974). Suspended-sediment load data, being 

easier to collect, are more readily available. Furthermore, determining the source of sediment within the 

catchment is important to help guide planning and river-management responses to current and future 

sedimentation trends (Dietrich and others, 1982; Reid and Dunne, 1996).
20

Owing to ample supply from Mount Rainier, sediment loads in the Puyallup and upper Nisqually 

Rivers are large relative to other rivers in western Washington (Czuba and others, 2011). The Skagit and 

Nooksack Rivers, draining the stratovolcanoes Glacier Peak and Mount Baker, respectively, also have 

large sediment-discharge values (Czuba and others, 2011). However, data sets characterizing sediment 

load in western Washington rivers are limited, particularly given the large temporal variability in loads. 

Order of magnitude changes in sediment load from one year to the next are common in most river 

systems (Horowitz; 2003; Milliman and Farnsworth, 2011), and limited studies from Washington show 

that rivers draining Mount Rainier have similar degrees of variability (Nelson, 1974, 1978; Dunne, 

1986). Ideally, sediment load would be measured continuously for many years to quantify the total load 

from the system and to identify trends (for example, Horowitz, 2010). No long-term sediment-discharge 

data are available for rivers in western Washington, and those data that are available typically represent 

one to five discontinuous years from the 1960s to 2000s (Czuba and others, 2011).

Several approaches were applied in this study to help evaluate the magnitude of sediment load 

from rivers draining Mount Rainier and determine the source of sediment from within the catchment. 

Published studies of sediment loads and unpublished historical USGS sediment data within the Mount 

Rainier watershed and along regional rivers were collected as part of a literature review. Trends in 

active-channel width of rivers and streams draining glaciers on Mount Rainier were evaluated using 

aerial images and LiDAR DEMs. Coarse estimates of sediment-production potential from 

subcatchments were generated for the mountainous, forested portion of the Puyallup River basin 

(including the White and Carbon Rivers) and the upper Nisqually River outside the boundary of Mount 

Rainier National Park. Data from complementary USGS cooperative studies were used to determine 

recent sediment loads along the lower White River. Hundreds of historical USGS data records, mostly 

collected from the 1970s to the 1990s, were assembled and analyzed to determine the magnitude of 

suspended-sediment load and bedload and to assess seasonality of rivers draining Mount Rainier. 

Finally, these multiple data sets and analyses were synthesized to estimate current sediment loads of 

rivers within the study area, determine sources of sediments within the catchment, and assess trends in 

sediment production from Mount Rainier since 1990.

Although aerial imagery and local field observations suggest some small proportion of the 

sediment load exiting the park originates from mountainous areas away from the stratovolcano, no effort 

was made to differentiate the sources of sediment within the boundaries of Mount Rainier National 

Park. For the purposes of this study, reference to Mount Rainier generated sediment applies to sediment 

sourced from the locations inside the administrative boundary of Mount Rainier National Park.

Previous Sediment-Load Estimates

Published sediment-load and yield measurements from rivers draining Mount Rainier, 

contributing drainages, and other rivers and basins in the coastal Pacific Northwest were assembled to 

assess known sediment production from Mount Rainier and to compare sediment production between 

catchments (table 4). Researchers have generated sediment-load estimates using different methods 

including measurements from the river (Fahnestock, 1963; Nelson, 1974, 1978; Wise and others, 2007); 

measurements of sedimentation in a basin (Walder and Driedger, 1994); calculations based on existing 

data sets (Mills, 1976; Downing, 1983; Dunne, 1986; Abbe and others, 2007); calculations based on 

empirical models (Herrera Environmental Consultants, 2010); and calculations of catchment-based 

sediment budgets (Laurie, 2002; Ketcheson and others, 2003). In analyzing the regional data, sediment 

yield (sediment load normalized by drainage area) allows a comparison between basins.

Within the White River basin, Dunne’s (1986) estimate of 450,000 tonnes/yr of total sediment 

load in the reach upstream of Mud Mountain Dam likely is the best available estimate, because it builds 
21

on the work of Nelson (1978) who collected more than 700 sediment measurements between June 1974 

and June 1976. Nelson reported a total load of 390,000 tonnes in the first year of the study and 1.3 

million tonnes in the second year, reflecting the temporal variability of sediment load within the system. 

Dunne (1986) used hydrologic data extended to 1966 to refine the overall load estimate, but reiterated 

the variability in the system. Dunne’s estimate also spans a time period of less-active hydrogeomorphic 

conditions, with smaller than normal sediment loads. The sediment-load data of the White River near 

Emmons Glacier of Fahnestock (1963) were collected only during the summer, potentially missing 

important sediment transport occurring in autumn and winter. The other estimates of sediment load from 

the White River basin were based on sediment budgets of smaller catchments in the basin and were 

larger than Dunne’s calculations.

Few sediment-load estimates are available for the lower Puyallup River, though Wise and others 

(2007) reported that the sediment load in 2000 was 1,250,000 tonnes. Downing’s (1983) estimate of 

total load on the lower Puyallup River was significantly smaller. Czuba and others (2011) synthesized 

the results of Wise and others (2007) and Downing (1983) to report a total load in the Puyallup River at 

Puget Sound of 890,000 tonnes/yr, but the precision of this number is poor owing to the limited data.

Within the greater Mount Rainier basin, Nelson (1974) published the most complete and

extensive study of sediment loads, measuring suspended-sediment concentration from 1971 to 1972 at 

16 sites in the Nisqually and Deschutes River basins. Using multi-year hydrologic data, Nelson 

estimated suspended-sediment load for each site. Nelson’s load estimates do not include bedload, but 

Nelson assumed bedload was less than 10 percent of the total load. Within the study area, Nelson’s 

(1974) estimates for the Nisqually River near National and for Mineral Creek near Mineral showed 

about an order of magnitude decrease in sediment yield for drainages away from the volcano (table 4). 

Nelson’s (1974) data also were collected in a hydrologically quiet period with relatively few large, 

sediment-producing storms, and likely underestimates long-term sediment loads. Mills (1976) used 

bathymetric data to estimate sediment load of the Nisqually River into Alder Lake of 902,000 tonnes/yr. 

Czuba and others (2012) later refined Mills’ estimate of sediment filling Alder Lake and extended the 

bathymetric record to 2011. Load estimates for the upper Nisqually River for this study, based on the 

data collected by Czuba and others (2012), are discussed later in this section. Owing to the episodic 

nature of sediment transport in Mount Rainier basins, generating a long-term sediment-load estimate for 

the Nisqually River from Alder Lake sediment volumes is more accurate than other methods because 

the largest sediment events are captured in the record. The Nisqually River basin, in particular, has been 

subject to significant sediment inputs from the volcano that have been well documented (Crandell, 

1971; Walder and Driedger, 1994; Beason, 2007).

The largest sediment yield values are found on rivers and tributaries close to Mount Rainier 

where loads are large and the contributing basin area is small. For example, Tahoma Creek had a 

sediment yield of 14,000 (tonnes/km2

)/yr and the White River, just downstream of Emmons Glacier,

had a yield of 12,000 (tonnes/km2)/yr. In river reaches downstream of the park boundary, sediment 

yields on rivers draining the glaciated volcano tend to be on the order of about 1,000 (tonnes/km2)/yr. 

Sediment yields from mountainous catchments not draining Mount Rainier tend to be about 100 

(tonnes/km2)/yr. Sediment yields from catchments in the Puget Lowland tend to be on the order of 10 

(tonnes/km2)/yr.

Data from Milliman and Farnsworth (2011) for rivers draining coastal mountainous regions of 

the Pacific Northwest were analyzed to place the sediment-load and sediment-yield estimates from this 

study into a regional context. In general, coastal Pacific Northwest rivers have sediment yields between 

100 and 500 (tonnes/km2

)/yr, though some rivers have yields more than 1,000 (tonnes/km2)/yr. Rivers in 

coastal British Columbia, Canada, also tend to have large sediment yields (table 4). 
22

Historical Changes in Plan Form and Profiles in Mountainous River Reaches 

The active-channel widths of mountainous reaches of rivers draining Mount Rainier were 

determined from aerial imagery from 1965, 1994, and 2009 to identify temporal and spatial changes in 

the width of the active channel. The difference between active-channel widths between 1965 and 1994 

and between 1994 and 2009 provided an estimate of the lateral expansion and contraction of the active 

channel resulting from hydrogeomorphic disturbance of the catchment (such as debris flows and floods) 

and vegetation encroachment, respectively. Along main-stem rivers, the mean elevation of the active 

channel was compared to the mean elevation of the first forested terrace adjacent the active channel to 

assess the qualitative degree of channel filling within particular reaches. Historical river-elevation 

profiles from 1910 and from the 1950s to 1990s were compared to current river elevations with the goal 

of identifying regions of changing channel storage through aggradation or incision. The uncertainty of 

the historical contours was greater than most of the computed changes in elevation. To get a gross 

estimate of sediment contributions to the active channel from the flood plain owing to channel 

widening, the change in active channel width was multiplied by forested terrace height. 

Change in Active-Channel Width for Rivers Draining Mount Rainier

Paper copies of 1965 black and white aerial photographs of Mount Rainier and the surrounding 

landscape from the University of Washington library were scanned, imported into ArcGIS®, and 

georeferenced to the 2009 imagery using common features (for example, roads, structures, islands, and 

lakes). Features closest to the river corridor, rather than the surrounding landscape, were used for 

georeferencing to ensure the greatest accuracy of the river features. Georeferenced aerial imagery for

1994 was obtained from digital orthophoto quadrangles (DOQs; U.S. Geological Survey, 2012a) and for 

2009 from the National Agricultural Imagery Program (NAIP; U.S. Department of Agriculture, 2011).

In some instances, imagery was not available for the entire river course in 1965 and 1994. 

Digitization of the imagery was completed at a scale of 1:3,000. The active channel, defined as 

the section of the river corridor relatively free of vegetation that conveys most of the water and sediment 

during high flow, was digitized for each of the three sets of aerial images. Areas of dense vegetation 

within the bounds of the active channel were digitized as island features and did not count towards 

active-channel width. Each digitized data set was reviewed for quality, accuracy, and consistency 

following the recommendations of Wallick and others (2011). A river centerline was then digitized 

through the approximate center of the active channel, representing the dominant pathway of the river 

during high flow. For every 1-km length along the 2009 centerline, the average active-channel width for 

each of the three imagery sets (1965, 1994, and 2009) was computed by dividing the active-channel area 

by the length of the segment of channel centerline for that year. Resolution of the 1994 imagery was 2 

meters, and resolution of the 2009 imagery was 1 meter. Resolution of the georeferenced 1965 imagery 

was not measured but likely was about 10 m. In comparing changes in channel width between imagery 

sets, differences greater than 25 m were assumed to be significant.

The rivers included in the active-channel width analysis (table 5) are shown in figure 10 along 

with the values of the 2009 active-channel width averaged over 1-km segments. In general, only the 

mountainous reaches of study rivers closest to Mount Rainier, where changes to active-channel width 

are prominent and where bank armoring is rare, were analyzed. The active-channel widths were 

averaged over various sub-reaches and summarized in figure 11. Of the river reaches analyzed, the 

Nisqually and Carbon Rivers had the widest active channels. The White River upstream of the Mount 

Rainier National Park boundary and the West Fork White River downstream of the national park 

boundary also showed wide active-channel widths. The active-channel widths of the Puyallup and 
23

Cowlitz Rivers and their tributaries generally were smaller, except for the Mowich River and the 

Cowlitz River downstream of the Muddy Fork Cowlitz River.

The change in active-channel width between 1965 and 1994, averaged by 1-km reaches (fig. 12), 

suggests that this period was relatively free of hydrogeomorphic events capable of disturbing the active 

channel. The exception is Tahoma Creek, where the active-channel width increased by more than 175 

m. This change is consistent with the record of known debris flows on Mount Rainier, as 1967 was the 

beginning of a series of debris flows on Tahoma Creek (Copeland, 2009). During this time period, 

Kautz Creek was recovering from the 1947 debris flow, evidenced by the decrease in active-channel 

width by more than 100 m and the growth of vegetation.

The change in active-channel width between 1994 and 2009 (fig. 13) suggests that this was a 

period when the catchment was subjected to greater hydrogeomorphic disturbance, including debris 

flows, large floods, and increased sediment transport, resulting in increases in active-channel width of 

over 25 m on many rivers and tributaries downstream of the volcano. The largest increases in activechannel width during this time period were on the Carbon and Nisqually Rivers. The upper Carbon 

River near the glacier increased in active-channel width by more than 100 m. Significant active-channel 

widening on the Carbon River also occurred downstream of CRKM 10 with more than 100 m of 

increase in an alluvial section of the river near CRKM 24. The Nisqually River, downstream of Kautz 

Creek, widened along most of its length by up to 200 m. Channel widening was particularly pronounced 

between NRKM 20 and 30. The Nisqually River was subjected to two large peak-flow events in 1996 

and 2006, which caused significant geomorphic change (Beason and Kennard, 2007; Pierce County, 

2012), and to a significant source of new sediment into the river network from debris-flow activity 

(Copeland, 2009). Along the White River, increases in active-channel width occurred, but the 

magnitude of change was more modest than changes observed on the Nisqually and Carbon Rivers. 

Increases in active-channel width of 25–50 m were apparent along much of the main-stem White River 

and the West Fork White River. The Puyallup River system also increased in channel width, particularly 

along the main stem up to the Puyallup Glacier and along the Mowich River, although the changes here 

were less than changes along the White River. Notably, the South Fork Puyallup River had no 

detectable changes in active-channel width dating back to 1965. The Muddy Fork Cowlitz River 

experienced limited increases in active-channel width, but much of this river flows through a bedrockcontrolled canyon and the channel likely would not respond as dramatically to increases in sediment 

load as other rivers. Similarly, the Ohanapecosh River is bedrock controlled, but the few alluvial reaches 

of the Ohanapecosh River showed little or no expansion. In general, the limited channel-width 

expansion from rivers draining the eastern flank of Mount Rainier, compared to trends along the 

Nisqually, White, and Carbon Rivers, suggests smaller increases in sediment production since 1994. 

Of the rivers draining Mount Rainier glaciers, all but the Muddy Fork Cowlitz and the 

Ohanapecosh Rivers, which both flow through some length of bedrock control, have long alluvial 

deposition zones just downstream of the glacier. Assuming that the underlying hydrology of each of the 

draining streams is similar (a reasonable assumption given the mountain is a stratovolcano mostly 

symmetric around its vertical axis), then active-channel width can be considered a proxy for recent 

trends in geomorphic disturbance and sediment load. Increases in channel width are often associated 

with aggradation (Lyons and Beschta, 1983; Madej and Ozaki, 1996; Lisle, 2008; Pierson and others, 

2011) and increased bedload (Leopold and Maddock, 1953). In addition, for mountain rivers, large 

width-to-depth ratios and braiding are indicative of significant bedload (Schumm, 1977). Although 

increases in channel width can also reflect geomorphic disturbance of large floods that remove riparian 

vegetation, particularly in logged river corridors (see Lyons and Beschta, 1983), the old-growth forests 

within Mount Rainier National Park effectively resist avulsions and channel widening (Kennard and 
24

others, 2011). In general, alluvial river reaches with wider active channels are assumed to transport 

more bedload than rivers with narrower active channels, a concept shown in theory (Parker and others, 

2007) and applied in practice (Lauer and others, 2008). 

Active-channel width for the White, West Fork White, Carbon, Puyallup, and Nisqually Rivers 

did not increase appreciably after these rivers exited Mount Rainier National Park. The Cowlitz River 

near Packwood showed a large active-channel width in 2009, but comparative imagery from 1994 or 

1965 was not analyzed as part of this study precluding an assessment of change through time. However, 

Collins and others (2012) attributed the wide active channel of the Cowlitz River to logging in and near 

the flood plain. Based on qualitative assessment of available imagery, tributaries entering the main 

stems of the four study rivers originating from logged mountainous catchments not draining Mount 

Rainier did not have noticeably wide active-channel widths. This suggests, qualitatively, that the 

predominant source of sediment to the river networks is Mount Rainier. 

Active-Channel Elevation Relative to Forested-Terrace Elevation

Comparison of mean elevation of the active channel to the mean elevation of the first forested 

terrace adjacent the active channel was evaluated only where the terrace had continuously supported a 

forest since 1965 (based on aerial imagery). For each analyzed location, a cross-section line was created 

in ArcGIS orthogonal to the channel flow direction and spanning the terrace and active channel. 

Elevation data were extracted every 4 m along the cross section in both the active channel and forested 

terrace, and no elevation data were taken from a 20-m buffer at the margin between the active channel 

and the forested terrace. For all cross sections, at least 10 individual elevation points were included in 

the calculation of mean elevation. All elevation data were extracted from LiDAR-based DEMs 

(appendix A, table A1). Although the absolute accuracy of the LiDAR DEMs was about 1 m, relative 

local differences in the elevation along a cross section of 0.5 m or greater likely were detectable. 

Because the forested terraces contained some volume of accumulated organic material on the ground, 

elevation estimates from the forest likely were higher than the bare ground. The average elevation along 

the cross section from the active channel, defined using the 2009 active-channel centerline digitization, 

was subtracted from average elevation of the forested terrace to compute the terrace elevation. Positive 

terrace-elevation values indicate the forested terrace was higher than the active channel (fig. 14). 

Negative terrace-elevation values indicate the active channel was above the forested terrace. 

The terrace elevations of the Carbon River in 2009 were 1-2 m for most of its length (fig. 14A) 

and lower than terrace elevations measured along the Nisqually and Puyallup Rivers, suggesting that the 

braided Carbon River was in a state of aggradation likely associated with more-active hydrogeomorphic 

conditions prevalent since 1996. The Nisqually River from NRKM 8–12 was less than 1 m below the 

forested terrace indicating recent aggradation and confirming observations by the National Park Service 

(Beason and Kennard, 2007). The farthest upstream extent of the Nisqually River had elevated terraces 

on the order of 10 m. This section of the river flows through large, prominent fluvial terraces deposited 

during eruptive periods (Crandell, 1971), confirming that contemporary sediment loads in the Nisqually 

River are significantly smaller than sediment loads typical during eruptive phases. Downstream of 

Kautz Creek, the terrace elevation of the Nisqually River generally was between 1 and 3 m. Compared 

to the other rivers analyzed, terrace elevations of the Puyallup River were larger, generally between 3 

and 6 m (fig. 14C). The larger terrace elevations likely were due to smaller sediment loads in the 

Puyallup River (as assessed using active-channel width in 2009) and by the presence of the Electron 

Mudflow, which constricted the upper Puyallup River flood plain and increased transport capacity. The 

White River between WRKM 8 and 18 had an active-channel elevation essentially even with the 

forested-terrace elevation. A number of cross sections in this reach had channel elevations above the 
25

forested terrace. These data support the observation of Kennard and others (2011) describing severe 

aggradation and the role of old-growth forest to maintain channel position during periods of increased 

sedimentation. Downstream of the national park boundary, the terrace elevation of the White River was 

more typical of terrace elevations observed along the Nisqually River, but possible areas of aggradation 

were observed near WRKM 30 and 50.

Change in Elevation of River Profiles

Historical river-elevation profiles were compared to current river-elevation profiles with the goal 

of identifying regions of changing channel storage through aggradation or incision. Historical data sets

that were analyzed included a 1910 survey of river corridors from a water power study (Henshaw and 

Parker, 1913) and USGS topographic quadrangles digital raster graphics (DRGs) from the 1950s to 

1990s (U.S. Geological Survey, 2012a). The 1910 survey was available as paper maps with outlines of 

the channel and elevation contours drawn at 1.5-m intervals above mean sea level (Henshaw and Parker, 

1913). The paper maps were scanned and georeferenced to the North American Datum of 1929 

(NAD29, horizontal). Channel outlines and contour lines were then digitized in ArcGIS from the 

rectified maps and attributed with contour elevations assuming that the vertical datum of mean sea level 

of the historical contours was equivalent to NGVD29. The contours were then projected and converted 

to the North American Datum of 1983 (NAD83, horizontal) and the North American Vertical Datum of 

1988 (NAVD88; vertical) in meters. The 2.5-m resolution USGS 1:24,000 topographic quadrangles 

digital raster graphics (DRGs) from the 1950s to 1990s (U.S. Geological Survey, 2012a) were available 

as individual tiles with 6- or 12-m elevation contours. Channel centerlines and contours near the rivers 

were digitized from the maps and projected and converted to NAD83 and NAVD88 in meters. The 

uncertainty of the historical contours was much greater than most of the computed changes in elevation. 

Therefore, the results from this analysis were not used and are not discussed further.

Sediment Contributions from the Flood Plain due to Expansion of the Active Channel

Sediment budgets in fluvial systems sometimes consider contributions from channel widening or 

avulsions (Trimble, 1999; Lauer and Parker, 2008) when knowledge of short-term or localized sediment 

responses is important. Over longer (geologic) time scales, however, these calculations often are 

discounted because fluvial sediment recruited from the flood plain is not new sediment to the system, 

instead it is fluvial sediment exiting or entering temporary storage. For some river reaches in the study 

area, knowledge of the local recruitment of sediment is useful for river-management decisions. To 

estimate sediment released from the flood plain owing to recent channel widening, changes in activechannel width are needed along with channel- and bank-elevation data before and after the time period 

of interest. For mountainous reaches of main-stem rivers draining Mount Rainier studied here, the 

changes in active-channel width between 1965 and 1994 and between 1994 and 2009 were known, and 

the topography of the braided channel and first forested terrace in 2009 was determined using LiDAR 

data. Pre-change topography of the river corridor in either 1965 or 1994, however, was unavailable. 

Because of the lack of pre-change elevation data, the analysis included here does not represent a 

calculation of sediment exchange with the flood plain. Additionally, the analysis here does not account 

for sediment contributions from river migration into bluffs of glacial till that bound river flood plains in 

the Puget Lowland. Recruitment of sediment from glacial-till bluffs can be significant. Rather, this 

analysis approximates the order of magnitude of sediment volume potentially released from the flood 

plain due to channel widening. The analysis only considers main-stem, alluvial reaches of the Nisqually, 

Puyallup, Carbon, and White Rivers where active-channel width was measured and active-channel 

width was not constricted by bedrock
26

In a widening river, the volume of sediment recruited from the flood plain is the product of the 

increase in active-channel width, the terrace elevation, and the length of the reach. If the channel 

elevation did not change over the period of interest, this calculation would estimate the sediment 

recruited into the active channel. In an incising system, additional sediment would be recruited from the 

flood plain, as well as the active channel as it erodes deeper into its bed, and the previous calculation 

would underestimate the total recruited sediment volume. For this analysis, it is assumed that few river 

reaches are appreciably incising—most incising rivers tend to narrow. If the channel aggraded over the 

period of interest, new sediment would deposit on the channel bed and the previous calculation would 

overestimate the contribution of sediment to the river. Because it is likely that most river reaches close 

to Mount Rainier are in a state of relative stasis or slight aggradation, the following calculations likely 

overestimate the sediment load recruited to the active channel through channel widening. 

An estimate of the contribution of sediment due to active-channel widening was computed by 

multiplying terrace elevations by measured increases in active-channel width over the length of a reach. 

Annualized rates of change in active-channel width between 1965 and 1994 and between 1994 and 2009 

bracket generalized lateral expansion of the active channel and represent a range of widening measured 

during the late 20th century. Bedrock-controlled reaches were not considered in the analysis. The 

annualized rates of positive change in active-channel width were multiplied by positive terrace thickness 

to estimate volumetric sediment contribution from the flood plain due to an expansion of the active 

channel (table 6). Additionally, the contribution to the river sediment load from the measured range of 

channel widening was determined by multiplying mobilized sediment volumes by the anticipated range 

of bulk density, 1.5–1.8 tonnes/m3 (Wu and Wang, 2006). Finally, to compare results between rivers, 

volume estimates for each river were normalized by the length of river analyzed.

The rivers with the largest contributions of sediment from the flood plain to the active channel 

per unit length of channel are the Nisqually and Puyallup Rivers, likely due to the greater terrace 

thickness of the Nisqually and Puyallup Rivers relative to the White and Carbon Rivers. These estimates 

likely are overestimates of the sediment contribution from the flood plain because they only include 

recruitment from the flood plain (loss of flood-plain storage), not added storage of sediment in the flood 

plain, and the calculations ignore sediment storage within the active channel, which, for an aggrading 

system, could be significant. Nonetheless, the estimates establish an upper bound of the flood-plain 

contributions to the total sediment load.

The Link between Superglacial Debris and Downstream Aggradation

Observations of aggradation on rivers downstream of Mount Rainier (Beason, 2007; Czuba and 

others, 2010), coupled with documented 20th century retreat of glaciers on Mount Rainier (Harrison, 

1956; Nylen, 2004; Sisson and others, 2011), have led researchers to consider the hypothesis that the 

two observations are linked. Nylen (2004) analyzed historical data sets to determine geospatial trends of 

glaciers on Mount Rainier including glacier retreat from 1913 to 1994, total area of each glacier as 

measured in 1971, and the percentage of total areal coverage of superglacial debris mantling each 

glacier in 1971. To determine if some physical characteristic of Mount Rainier glaciers explains 

differences in active-channel width of the rivers just downstream of the respective glacier, linear 

regressions were calculated between active-channel width and the three glacier parameters reported by 

Nylen (2004). In addition, a linear regression of active-channel width versus total drainage area of the 

catchment was analyzed to assess if catchment size, and thus, contributing hydrology, would explain the 

observed response in active-channel width. 

Active-channel widths calculated with 2009 imagery (fig. 11) were averaged for each draining 

tributary from the glacier terminus to the first prominent tributary that enters from a different glacier 
27

(fig. 15). The regression showed little correlation between active-channel width and total drainage area 

(R2 = 0.15). Similarly, there was only a weak correlation between active-channel width and total glacier 

area (R2 = 0.33). The strongest correlation was between active-channel width and the total area of debris 

mantling the glacier as measured in 1971 (R2 = 0.78). This correlation indicated that active-channel 

width, that is, recent geomorphic disturbance, was influenced by the presence of superglacial sediment 

mantling the glacier. For example, the mantling of 43 percent of the Carbon Glacier by sediment 

(Nylen, 2004) seemed to promote an average active-channel width of more than 200 m in the 

downstream reach. Conversely, the Puyallup River, which had an average active-channel width of about 

50 m is fed by the Puyallup Glacier which was mantled with debris over 7 percent of its total area. 

Surprisingly, there was no correlation (R2 = 0.0009) between active-channel width and the amount of 

glacier retreat during the 20th century. These data suggest that geomorphic disturbance of rivers 

draining Mount Rainier, as measured in 2009, was influenced by debris mantling on the glacier and little 

influenced by the magnitude of 20th-century glacier retreat. 

The Link between the 1963 Debris Avalanche and Upper White River Aggradation

Aggradation in the White River just inside the national park boundary has been the cause of 

flooding to State Route 410 and a source of concern for officials at the Washington State Department of 

Transportation, the National Park Service, and Pierce County (Abbe and others, 2005). Analysis from 

this study shows that the reach of the White River from 8 to 18 km downstream of Emmons Glacier was 

in a state of acute aggradation in 2009 with an active-channel elevation that was flush with the forested 

terrace (fig. 14D). Both upstream and downstream of this aggraded reach, the forested terrace was about 

2 m above the active channel. Assuming this 10-km reach of localized aggradation is a pulse of 

sediment moving down the river corridor and that this pulse is 2-m deep and as wide as the activechannel width in this reach (about 125 m, fig. 11), the total volume of sediment in this pulse is about 2.5 

million m3. 

Although one debris flow was documented from the Inter Glacier during November 2006 

(Copeland, 2009), no debris flows have been documented from Emmons Glacier. Floods have affected 

the upper White River (Abbe and others, 2005). The 1963 sequence of rockfalls and debris avalanches 

deposited 11 million m3 of material over Emmons Glacier that extended well beyond the glacier 

terminus (Crandell and Fahnestock, 1965). More importantly, photographic evidence (fig. 3) showed 

that some portion of the debris was reworked and moved downstream into the fluvial network in the 

years following the rockfalls. Crandell (1971) and Czuba and others (2012) showed that about 25 

percent of the large 1947 Kautz Creek debris flow transported downstream to Alder Lake. Assuming a 

similar ratio of sediment mobilization from the 1963 debris-avalanche deposit, it appears that the pulse 

of sediment causing the aggradation in the White River along State Route 410 may be predominantly 

sourced from the 1963 rockfall. 

Sediment Supply from Cascade Uplands outside Mount Rainier National Park

Though aerial imagery suggested that the predominant source of sediment to rivers in the study 

area was Mount Rainier, mountainous catchments outside the national park, many of which are actively 

logged, also contribute to sediment load. To assess the potential for contribution from these other 

mountainous catchments, coarse-resolution, watershed-scale sediment-production potential was 

estimated. This sediment-production potential does not represent a sediment budget; rather, it assesses 

the potential for a subcatchment to generate sediment based on its topography, drainage network, 

landslide activity, and road density. Sediment contributions to the lower Puyallup River system from 
28

urban and lowland catchments were not considered. These lowland catchments tend not to produce 

large, naturally occurring sediment loads (Nelson, 1971, 1974).

In comprehensive sediment budgets, all processes that may produce sediment are considered,

including wind erosion, rilling, tunnel erosion, animal burrowing, tree throw, dry ravel, land-use soil 

erosion, soil creep, landslides, and production from roads (Reid and Dunne, 1996). Full sediment 

budgets also account for transient storage and routing within the catchment. For this study, the potential 

for sediment delivery to the subcatchment outlets from roads, landslides, and soil creep in logged areas 

was assessed. These processes have been shown to be the dominant processes for sediment production 

from catchments (Dietrich and Dunne, 1978; Roberts and Church, 1986). These sediment-production 

estimates were then calibrated to known sediment-production rates from five subcatchments. Only 

contributing area from outside Mount Rainier National Park was considered. All sediment production 

inside the park boundary was assumed to originate from the volcano, and no effort was made to 

independently differentiate the magnitude of sediment production for forested lands inside the park from 

sediment sourced from the volcano.

Methodology for Assessing Sediment-Production Potential

Following the general recommendation of Dietrich and others (1982) and Reid and Dunne 

(1996), the sediment-production potential for subcatchments contributing to the Puyallup River basin 

and the upper Nisqually River basin was calculated. A total of 27 subcatchments that contribute to the 

White River upstream of Auburn, the Carbon River, the Puyallup River upstream of its confluence with 

the Carbon River, and the Nisqually River upstream of Alder Lake were delineated using USGS 

StreamStats (accessed September 4, 2012, at http://streamstats.usgs.gov/Washington.html) (fig. 16). 

Named tributary subcatchments were included as well as contributing areas from catchments along the 

corridor of each main-stem river. Large catchments along each main stem were delineated into smaller 

subcatchments. Three additional subcatchments outside the study area—Issaquah Creek, the Mashel 

River, and the upper Deschutes River— also were delineated to enable calibration of the methodology 

with published sediment-load data sets. Key basin hydrologic parameters for each subcatchment were 

recorded from StreamStats, including drainage area, elevation, relief, precipitation, and percentage of 

catchment with slopes greater than 30 percent.

Roads

Sediment production from roads was estimated using data from Reid and Dunne’s (1984) study 

of sediment production from roads in logged areas of the Clearwater River basin in the Olympic 

Mountains. Geographic information system (GIS) data of road networks within the subcatchments were 

downloaded from the Washington State Department of Natural Resources (DNR). The data indicated

the location of roads, road length, general usage characteristics, and provided information on road 

surfacing (unpaved, paved, gravel, crushed rock, pitrun, natural material, and unknown). For each length 

of road in a given subcatchment, sediment production was estimated by applying yield data of Reid and 

Dunne (1984) to the road-usage category. Roads labeled as unpaved, crushed rock, gravel, pitrun, and 

native material were assumed to generate sediment yields of 3.8 (tonnes/km)/yr. Paved roads were 

assumed to generated sediment yields of 2.0 (tonnes/km)/yr. Abandoned roads were assumed to 

generate a sediment yield of 0.51 (tonnes/km)/yr. Roads not classified by usage were assumed to be 

abandoned. This combination of sediment yield by road type produced results that most reasonably 

approximated sediment production in subcatchments where sediment loads were known from published 

studies. Uncertainty in the estimate of sediment production from roads was estimated to be 50 percent.
29

Landslides

Updated GIS data of mapped landslides within the study area, supplied by DNR (Isabelle 

Sarikhan, Washington Department of Natural Resources, written commun., 2012), were used to assess 

the sediment production by landslides from each subcatchment. DNR conducts mapping of forested 

lands to assist foresters and land managers in identifying unstable slopes under the Landslide Hazard 

Zonation Project (accessed September 4, 2012, at 

http://www.dnr.wa.gov/BusinessPermits/Topics/LandslideHazardZonation/Pages/Home.aspx). For the 

mapped watersheds, the total extent of active-landslide area was available as well as the types of 

landslides (deep seated and shallow as well as active and inactive). No effort was made to differentiate 

sediment-production rates from individual landslides by category. Nelson and Booth (2002) completed a 

sediment budget of the Issaquah Creek catchment (a western Cascade Range catchment with 

topographic and hydrologic characteristics similar to the subcatchments just outside Mount Rainier 

National Park) and determined that 3,264 tonnes/yr was sourced from landslides. According to DNR 

landslide mapping, Issaquah Creek contained 18 km2 of landslides. Therefore, the sediment yield from 

landslide-contributing areas in the Issaquah Creek subcatchment was 182 (tonnes/km2

)/yr. This 

landslide sediment-production yield was multiplied by the landslide area in other mapped 

subcatchments to determine sediment production by landslides. For subcatchments not mapped for 

landslides by DNR, the total active-landslide area was first estimated by building a linear regression of 

data from mapped subcatchments relating total active-landslide area to the percent of the basin with 

slopes greater than 30 percent. This regression relation was used to estimate total landslide area in 

unmapped subcatchments using StreamStats data of basin area with slopes greater than 30 percent. This 

estimated landslide area was multiplied by the Nelson and Booth (2002) landslide yield to predict 

sediment production by landslides in unmapped subcatchments. Uncertainty in the estimate of sediment 

production from landslides was estimated to be 50 percent where landslides were mapped by DNR, and 

75 percent where no mapping was available. Because of resource limitations in this study, a more 

detailed and comprehensive analysis of sediment production from landslide potential was not possible, 

but future research attempting a more fully developed sediment budget would benefit from more 

rigorous estimates of landslide potential (Montgomery and Dietrich, 1994; Montgomery and others, 

1998).

Soil Creep

Roberts and Church (1986) assimilated data from literature collected in the Pacific Northwest to 

estimate that the rate of sediment delivery from logged slopes by soil-creep processes was 6–40 m3/yr

per kilometer of channel length along higher-order streams in the catchment. Assuming a bulk density 

of 1.65 tonnes/m3 (Wu and Wang, 2006), sediment load from soil creep was estimated to be 10–66 

(tonnes/km)/yr from logged slopes. To apply these soil-creep estimates to subcatchments of this study, 

the assumption was made that soil creep predominantly occurs on slopes greater than 30 percent. Using 

the National Hydrography Dataset, the total length of natural streams within each subcatchment

categorized as perennial was calculated in ArcGIS and multiplied by the soil-creep estimates of Roberts 

and Church (1986), factoring in the total catchment area with slopes greater than 30 percent. 

Uncertainty in the estimate of sediment production from soil creep was 74 percent, a value directly 

taken from the published range of Roberts and Church (1986). 

Calibration

Calculations of sediment-production potential were calibrated using known sediment-load data 

from the five calibration subcatchments. Two of the calibration subcatchments, Mineral Creek and the 
30

Little Nisqually River, were within the study area. Two other calibration catchments, Mashel River and 

the Deschutes River near La Grande, Washington, were just west of the study area. The fifth calibration 

subcatchment, Issaquah Creek, drains the Cascade Range into Lake Sammamish about 50 km north of 

the White River. Total sediment load from Mineral Creek (15,000 tonnes/yr), Mashel River (16,000 

tonnes/yr), and Deschutes River near La Grande (21,000 tonnes/yr) were determined by multiplying 

Nelson’s (1974) suspended-sediment load estimates, based on measurements taken in 1971–1972, by 

107 percent to account for bedload, estimated by Nelson to be between 4 and 10 percent of the total 

load. The total sediment-load estimates of the Little Nisqually River were based on measurements of 

accumulated delta sediment in Alder Lake (Czuba and others, 2012). Estimates of total sediment load 

for Issaquah Creek were taken from Nelson and Booth (2002). It was found that the sum of the raw 

estimates of sediment product from roads, landslides, and soil creep was less than the known sediment 

production from the calibration subcatchments. Multiplying the predicted raw sediment production by a 

scaling factor of 2.5 produced a minimum residual error (Helsel and Hirsch, 1992) between predicted 

sediment production and the known sediment production. This scaling factor was applied to the raw 

estimates of sediment production from each subcatchment to generate final estimates. The uncertainty in 

the estimates of total sediment production from each subcatchment was determined by summing the 

uncertainties of each individual sediment-producing component. 

Sediment-Production Potential Results

The correlation between the predictions of sediment production from subcatchments with the 

measured sediment loads was not strong, but it was reasonable given the uncertainty in the process (fig. 

17). The prediction of sediment production from Issaquah Creek was larger than published sedimentload data, and the prediction of sediment production from the Deschutes River near La Grande was less 

than the published value. Predictions of the other three calibration subcatchments were better. 

Estimating sediment load from a catchment using indirect approaches typically results in large 

uncertainty (Reid and Dunne, 1996). The methodology mostly fails to capture the contribution of large, 

infrequent storm events that have major hydrogeomorphic effects on the catchment (Reneau and 

Dietrich, 1991; Benda and Dunne, 1997). These large, infrequent storms can cause widespread landslide 

activity and release significant volumes of sediment into the river network (Wemple and others, 2001; 

Turner and others, 2010). Nevertheless, the approach is useful to assess relative contributions of 

sediment between subcatchments during typical hydrologic water years. The methodology is also useful 

to assess how much of the total sediment loads measured on main-stem reaches of the Puyallup and 

Nisqually River is sourced from the Cascade uplands as opposed to Mount Rainier National Park under 

typical conditions.

Within the study area, subcatchments draining into the White River contributed the largest 

quantity of sediment load (table 7). A total of 130,000±89,000 tonnes/yr was predicted to be delivered 

to the White River, mostly from the contributing subcatchment along the middle section of the White

River and from the Greenwater and Clearwater Rivers (fig. 18). These subcatchments had considerable 

sediment contributions from soil-creep processes, related to the relatively large contributing area of 

slopes greater than 30 percent. Sediment production from landslides also was significant, and DNR 

mapped large areas of landslide activity within these subcatchments. Sediment yield from White River 

subcatchments ranged from 77 to 240 (tonnes/km2

)/yr and averaged 140 (tonnes/km2)/yr for the White 

River basin, consistent with published yield measurements of western Cascade uplands (Nelson, 1971; 

Nelson, 1974; Nelson and Booth, 2002). Sediment production values from the Nisqually, Puyallup, and 

Carbon River basins were all less than the sediment production from the White River basin. The 

sediment production was smallest from the Carbon River basin (42,000±28,000 tonnes/yr) and the 
31

Puyallup River basin (42,000±29,000 tonnes/yr), and the sediment production from the Nisqually River 

Basin was 50,000±33,000 tonnes/yr. Yields were 84, 120, and 86 (tonnes/km2

)/yr for the Nisqually, 

Puyallup, and Carbon River basins, respectively. Summing the sediment production from 

subcatchments in the Puyallup, Carbon, and White Rivers basins, which collect into the lower Puyallup 

River, resulted in a total sediment production of 210,000±150,000 tonnes/yr and a yield of 120 

(tonnes/km2

)/yr.

Estimates of Sediment Loads using Historical and New Data

Long-term sediment-load estimates of the upper Nisqually River were calculated using the 

reservoir-sediment data of Czuba and others (2012). Variation of sediment concentration and load by 

season is assessed using high-resolution data collected by Nelson (1978) along the upper White River. 

The suspended-sediment load in the lower Puyallup River from 1978–1994 was calculated using 

available suspended-sediment concentration data collected by the USGS and available through the 

National Water Information System (NWIS). Recent (April 2010–March 2012) sediment-load estimates 

along the lower White River, using turbidity as a suspended-sediment-concentration surrogate, also 

were calculated. Finally, a rough bedload-transport relation was constructed from available bedload 

measurements and used to infer relative magnitude of bedload in the White, Carbon, and Puyallup 

Rivers where they exit the mountain front and first enter the Puget Lowland.

Load Estimates of the Upper Nisqually River

Czuba and others (2012) calculated the rate of accumulated sediment in Alder Lake from the 

Nisqually River from 1945 to 2011 (66 years) to be 660,000±60,000 m3/yr. Czuba and others (2012) 

also reported the rate of accumulated sediment in Alder Lake from the Little Nisqually River over a 

period of 66 years to be 4,700±1,600 m3/yr. To estimate the total sediment load of the Nisqually and 

Little Nisqually Rivers into Alder Lake, a correction for trap efficiency of the reservoir is needed.

No direct assessment of the trap efficiency of Alder Lake is available. Trap efficiency is a 

function of reservoir size relative to the volumetric inflow, dam operations, hydrology, and the 

characteristic particle size of the delivered sediment load (Brune, 1953). Trap efficiency of bedload for 

large reservoirs is nearly 100 percent if the delta front is far from the dam, and trap efficiency decreases 

with decreasing sediment size. For suspended-sediment load, aerial imagery and turbidity data 

downstream of Alder Lake suggest some portion of the fine-grained load passes the dam. Nelson (1974) 

reported the suspended-sediment load in the Nisqually River upstream and downstream of the dam to be 

300,000 and 42,000 tonnes/yr, respectively. Assuming these differences in load represent a proxy for 

trap efficiency, the Alder Lake trap efficiency, as indirectly measured by Nelson in 1971–1972, was 

0.87. Using the empirical estimates of Brune (1953), trap efficiency was estimated using the nondimensional ratio of reservoir capacity to annual inflow. The reservoir capacity of Alder Lake as 

constructed was 287 million m3

; the reservoir capacity in 2011 was about 245 million m3 (Czuba and 

others, 2012). The combined mean annual flow of the Nisqually River near National gage (12082500) 

and Mineral Creek near Mineral gage (12083000) is 32.3 m3

/s (1,140 ft3/s). Using Brune’s (1953) 

empirical model, the trap efficiency of Alder Lake is about 0.94. For the purposes of this analysis, the 

trap efficiency of Alder Lake for Nisqually River load was estimated to be 0.90±0.05. Owing to small 

annual inflow, the Alder Lake trap efficiency for the Little Nisqually River load was estimated to be 1.0.

Accounting for trap efficiency, the total sediment load of the Nisqually River into Alder Lake 

between 1945 and 2011 was estimated to be 740,000±100,000 m3/yr. Similarly, the total sediment load 

of the Little Nisqually River into Alder Lake was estimated to be 4,700±1,600 m3

/yr. The bulk density 
32

of accumulated sediment in Alder Lake was estimated to be between 1.5 and 1.8 tonnes/m3 (Wu and 

Wang, 2006). Therefore, the total sediment load in the Nisqually River between 1945 and 2011 was 

1,200,000±180,000 tonnes/yr, and the total sediment load in the Little Nisqually River between 1945 

and 2011 was 7,800±2,600 tonnes/yr. The total annual sediment yields of the Nisqually and Little 

Nisqually Rivers were 2,000±300 and 120±39 (tonnes/km2)/yr, respectively, an order of magnitude 

difference in yield. The total annual sediment load passing Alder Dam and delivered downstream 

between 1945 and 2011 was estimated to be 120,000±18,000 tonnes/yr. This pass-through load 

predominantly consists of fine-grained sediment that transports through the reservoir and is likely 

delivered to the Nisqually River delta in Puget Sound. Because the middle to late 20th century was a 

less-active hydrogeomorphic time period for Mount Rainier, the average load of the Nisqually River 

into Alder Lake from 1956 to 1985 also was calculated using available bathymetric data from Czuba 

and others (2012) and the previously mentioned methodology. The total load of the upper Nisqually

River from 1956 to 1985 was 860,000±370,000 tonnes/yr, or about 70 percent of the long-term annual 

load.

Seasonality in Suspended-Sediment Concentration in Mount Rainier Rivers

Suspended-sediment concentration was sampled between 1974 and 1976 by Nelson (1978; U.S. 

Geological Survey, 2012b) at the White River below Clearwater near Buckley gage (12097850). These 

data were grouped into four 3-month seasons, or hydrologic quarters, and show the strong seasonality of 

suspended-sediment concentration of the glacier-draining White River throughout the year (fig. 19). 

During the summer quarter (July–September), warm temperatures result in glacial melt, increasing finesediment load and producing high suspended-sediment concentrations. The early flood-season quarter 

(October–December) also has high suspended-sediment concentrations. By the late flood-season quarter 

(January–March), much of the fine sediment has been flushed from the river corridor, which results in 

lower overall suspended-sediment concentrations. The snowmelt freshet quarter (April–June) has the 

lowest concentrations of suspended sediment. The observed seasonality in suspended-sediment 

concentration at the White River below Clearwater River near Buckley gage (12097850) is consistent 

with observations of seasonality in suspended-sediment concentration at other glacial-fed catchments in 

western Washington, specifically the Skagit River (Czuba and others, 2011).

Suspended-Sediment Load of the Puyallup River from 1978 to 1994

Horowitz (2003) presented a methodology to calculate annual sediment load at gages where 

suspended sediment is only periodically measured. Using the Horowitz approach, all available 

suspended-sediment and concurrently measured discharge data collected from the lower Puyallup River 

from WYs 1978–1994 were compiled and segregated by hydrologic quarters (summer, early flood 

season, late flood season, and snowmelt freshet). These data were then log transformed. For each data 

group, both a linear and second-order polynomial regression was applied. A “smearing correction,” to 

compensate for bias in converting the data set from log space to arithmetic space (Duan, 1983), also was 

applied. For each data group, these steps produced four candidate regression models for the final load 

estimates: (1) linear uncorrected, (2) linear “smearing” corrected, (3) polynomial uncorrected, and (4) 

polynomial “smearing” corrected (Horowitz, 2003). Of the four candidate models, the one that produced

a total load estimate closest to the measured load from the known data set was used to predict 

suspended-sediment concentrations using the full hydrologic record from WYs 1978–1994. For the 

Puyallup River data set, a linear uncorrected model best represented the two flood-season quarters and a 

polynomial “smearing” corrected model best represented the summer and snowmelt freshet quarters.
33

Suspended-sediment concentration was measured 84 times between WY 1978 and 1994 at the 

Puyallup River at Puyallup gage (U.S. Geological Survey, 2012b) (fig. 20). Data were measured 

periodically throughout the year, with 5–6 samples typically collected per year; 20 samples were 

collected in the summer quarter, 16 samples were collected in the early flood-season quarter, 23 samples 

were collected in the late flood-season quarter, and 25 samples were collected in the snowmelt freshet 

quarter. The data showed seasonality in suspended-sediment concentration, although the signal was not 

as strong as the seasonality demonstrated for the White River below Clearwater River near Buckley

gage (fig. 19). 

Yearly suspended-sediment load calculations for the lower Puyallup River for the period from 

1978 to 1994 were as large as 1.7 million tonnes in WY 1991 and as small as 220,000 tonnes in WY 

1994 (fig. 21). This near-order-of-magnitude variation in annual loads is typical for rivers and is 

strongly related to the hydrological conditions from year to year. The mean suspended-sediment load

during this 17-year time period was estimated to be 860,000±300,000 tonnes/yr, where the uncertainty 

represents interannual variability. The period of time between 1978 and 1994 was a less-active 

hydrogeomorphic period. Loads were likely larger during more-active hydrogeomorphic time periods, 

such as from 1996 to 2009.

Sediment-Load Estimates of the White River from Recent Measurements

Suspended-sediment concentration and bedload measurements were collected along the lower 

White River from April 2010 to March 2012. These data were used to estimate the total sediment load 

for the lower White River.

Collection of Sediment Data and Calculation of Sediment Loads

Fluvial sediment data were collected over a range of flows at the White River at R Street near 

Auburn gage (12100490) from April 2010 to March 2012. Suspended-sediment concentration data were 

collected using the equal discharge increment (EDI) method and bedload data were collected using the 

multiple equal width increment (MEWI) method (Edwards and Glysson, 1999). Suspended-sediment 

concentration data were collected using a variety of depth-integrated samplers approved by the Federal 

Interagency Sedimentation Project (FISP) and routinely used by USGS personnel (Davis, 2005). 

Bedload data were collected using a modified Helley-Smith sampler (also referred to as an Elwha 

sampler) with a 20- by 10-cm opening and a 1.40 expansion ratio as described by Childers and others 

(2000). All sediment samples were analyzed at the USGS sediment laboratory at the Cascades Volcano 

Observatory in Vancouver, Washington, to determine either the concentration and percentage of fines 

(less than 0.0625 mm) of suspended-sediment samples or the particle-size distribution for bedload

samples.

Turbidity was continuously monitored during the period of sediment sampling, with the 

exception of intermittent periods when instrument failure or excessive fouling occurred. Turbidity was 

measured using a YSITM 6136 optical turbidity sensor enclosed within a protective pipe that was freely 

suspended from a bridge rail. This mounting arrangement allowed turbidity measurements in an actively 

flowing part of the river channel and decreased the likelihood of debris build-up around the sensor face 

or on the mounting hardware, which could foul sensor readings. Turbidity data were recorded at 15-

minute intervals and were included in the transmission of real-time data of the streamflow-gaging

station. USGS protocols for the operation and maintenance of continuous water-quality instruments 

were followed as outlined by Wagner and others (2006), and the time-series data were processed and 

reviewed according to established USGS policy for continuous water-quality data. Standard USGS 
34

guidelines were followed for using turbidity as a surrogate measurement for suspended-sediment 

concentration (Rasmussen and others, 2009), enabling the calculation of suspended-sediment loads.

Regression equations were developed for estimating a time series of the concentration of 

suspended sediment and the fraction of fine-grained (less than 0.625 mm) suspended sediment based on 

EDI concentrations and either turbidity or streamflow (during periods when turbidity data were not 

available) recorded at the time of sample collection. The chosen form of the regression equations was 

selected based on the coefficient of determination (R2

) from several regression equations that were 

developed using various logarithmic transformations. Upper and lower confidence intervals for 

regression models were determined at the 95-percent level. A time series of suspended-sediment 

concentration was computed by applying the appropriate regression equation using turbidity or 

streamflow time-series data. Suspended-sediment load was computed by multiplying suspendedsediment concentration with streamflow. A regression equation was developed for estimating bedload 

based on the mass of MEWI samples and the recorded streamflow. Instantaneous bedload discharge 

(tonnes/d) was computed from a regression equation using instantaneous streamflow.

Suspended-Sediment Load and Bedload of the White River

At the White River at R Street near Auburn gage (12100490), six measurements of suspendedsediment concentration (appendix A, table A2) and five measurements of bedload (appendix A, table 

A3) were made between June 2, 2010, and January 20, 2011. The regression equations used to estimate 

suspended-sediment concentration from turbidity and bedload from streamflow are shown in figures 22 

and 23, respectively. Suspended-sediment concentration and suspended-sediment loads were computed 

between April 1, 2010, and March 31, 2012 (fig. 24). The sediment measurements made during this 

time period represent conditions through a range of measured streamflow, from 22 to 202 m3/s (773–

7,150 ft3/s), and the average discharge at the Puyallup River at Puyallup gage (12101500) for this time 

period was 115 percent of the mean annual flow. The concentration of suspended sediment generally 

peaked around the same time as streamflow; however, the magnitude of the concentration of suspended 

sediment was not consistent with streamflow (fig. 24).

For WY 2011, at White River at R Street, the suspended-sediment load was 527,000 tonnes, of 

which 222,000 tonnes or 42 percent was fines (less than 0.0625 mm). The bedload was 65,000 tonnes, 

of which 45,000 tonnes or 70 percent was gravel and cobbles (greater than 2 mm). A relatively small 

number of storm events during the winter flood season transported the majority of load during the water 

year (fig. 25). The total sediment load was 590,000 tonnes, composed of 37 percent fines (less than 

0.0625 mm), 55 percent sand (0.0625–2 mm), and 8 percent gravel and cobbles (greater than 2 mm). 

Approximately 11 percent of the total sediment load was transported as bedload. For the longer 24-

month period of monitoring from April 2010 to March 2012, the average suspended-sediment load was 

370,000 tonnes/yr, the average bedload was 46,000 tonnes/yr, and the total sediment load was 420,000 

tonnes/yr.

Calculations of loads for the White River from each seasonal quarter from April 2010 through 

March 2012 show the variation by season and variation between years (fig. 26). For WY 2011, the late 

flood-season quarter (January–March) had the largest loads of about 250,000 tonnes and the summer 

and early flood-season quarters (July–September and October–December, respectively) had the smallest 

loads of the year, about 35,000 tonnes. During the two-year period of data, the late flood-season loads 

for a given water year were greater than the early-season loads, but during many years of data 

collection, the average loads for these two flood-season quarters would likely be similar because the 

largest floods typically affect the region between November and January. For the measured data, loads 

were comparable between the early flood-season quarter (October–December) and the snowmelt freshet 
35

quarter (April–June). The loads during the summer season (July–September) were the smallest during 

the year because of less discharge, even though the suspended-sediment concentration was highest in 

the summer from the presence of glacial flour (fig. 19).

Estimated Bedload-Transport relation for the White, Puyallup, and Carbon Rivers

Within the aggrading reaches of the Puyallup and White Rivers, where they exit the mountain 

front and enter the Puget Lowland, knowledge of bedload is important to flood-risk managers making 

river-management decisions to maintain flood-conveyance capacity. Czuba and others (2010) found that 

between 1984 and 2009, 418,000 m3 of new sediment accumulated in the White River between R Street

and the Lake Tapps return, a 12.2-km reach mostly confined by levees and revetments where the slope 

is small relative to the upstream reach. The annualized mass accumulation rate in this reach was 28,000 

tonnes/yr, assuming a bulk density of 1.65 tonnes/m3 (Wu and Wang, 2006). Czuba and others (2010) 

also reported that 1,020,000 m3 of sediment accumulated between 1984 and 2009 along the Puyallup 

River from the gage near Orting (12093500) to the confluence with the Carbon River, a 12.9-km reach 

where the slope does not change substantially relative to the upstream reach. Most measured 

aggradation occurred within two setback-levee reaches (completed in 1998 and 2006), and Czuba and 

others (2010) attributed the enhanced aggradation to river response to the setback levees. The 

annualized mass accumulation rate in this reach was 67,000 tonnes/yr. No appreciable aggradation was 

found along the Carbon River between 1984 and 2009, though comparative 1984 cross sections did not 

extend far up the Carbon River corridor (Czuba and others, 2010). 

Relatively few bedload measurements have been collected in Puget Lowland rivers, but Sikonia 

(1990) did collect bedload data in the Puyallup, Carbon, and White Rivers in 1986. Sikonia’s bedload 

measurements from the lower Carbon, Puyallup, and White Rivers near the mountain front in the Puget 

Lowland were collected at the Carbon River near Orting gage (12094300, referred to as the Carbon 

River at Crocker by Sikonia, 1990), the Puyallup River near Orting gage (12093500), and the White 

River at R Street near Auburn gage (12100490) (Sikonia, 1990; U.S. Geological Survey, 2012b).

Combining these data collected by Sikonia with bedload data measured on the White River at R Street 

by the USGS in 2010 and 2011 (appendix A, table A2) allowed the generation of a generalized bedloaddischarge relation applicable to the Puyallup, Carbon, and White Rivers where these rivers exit the 

mountain front. Despite the fact that these data were taken from separate rivers, bedload-discharge data 

fit into a close grouping, which was approximated with a single power-law function (fig. 27). Lack of 

bedload data precluded the development of a similar bedload power-law function for the upper 

Nisqually River. The power-law function developed for the lowland rivers was not applicable to the 

upper Nisqually River due to differences in hydraulic geometry, proximity to the volcano, and 

geomorphic setting. Bedload data were comparable between lowland rivers because each river at the 

mountain front has similar slopes (fig. 4A), channel widths (Czuba and others, 2010), and characteristic 

particle sizes (fig. 6) at the locations of bedload data collection. This combined bedload-discharge 

relation cannot be used as a precise predictor of bedload on each river; however, the simple model can 

be used to assess order-of-magnitude bedload potential between each river and serve as a useful 

analytical tool to predict how changes in future hydrology might impact overall bedload transport.

Using the bedload-transport relation (fig. 27), daily estimates of bedload from WY 1984 to 2011 

were computed at the White River at R Street (drainage area 1,230 km2

), the Puyallup River near Orting 

(drainage area 450 km2; measured at the Calistoga Street bridge), and the Carbon River just upstream of 

South Prairie Creek (drainage area 250 km2; measured at the State Route 162 bridge) using daily 

streamflow data from the closest available long-term gaging station data scaled for contributing 

drainage area (fig. 28). The average bedload for WYs 1984–2009 was 29,000±18,000 tonnes/yr for the 
36

White River near Auburn, 7,800±7,200 tonnes/yr for the Puyallup River near Orting, and 2,700±2,800 

tonnes/yr for the Carbon River near Orting; the stated accuracy is the standard deviation of bedload 

variation by year. Because the same bedload-transport relation is assumed to apply to all three rivers, the 

cumulative bedload reported here reflects the differences in the underlying peak-flow hydrology. 

Despite regulation at Mud Mountain Dam, the White River showed a larger potential to transport 

bedload than the Puyallup and Carbon Rivers. High flows released from Mud Mountain Dam were 

sufficient, when summed over a given water year, to move significant volumes of bedload. In contrast, 

the overall hydrologic flows in the Puyallup River were notably smaller than flows in the White River, 

reflecting the smaller catchment area. Bedload estimates for the Carbon River were smaller than the 

estimates for the Puyallup River, further reflecting the influence of a smaller contributing drainage area. 

The bedload model indicated that from 1984 to 2011, the White River transported about four times more 

bedload than the Puyallup River and about 11 times more bedload than the Carbon River. Particular 

water years stood out as significant in moving bedload, including 1996, 2007, and 2009. For example, 

the hydrologic conditions in WY 1996 were such that the model predicted that 37,000 tonnes of bedload 

moved down the Puyallup River, nearly five times the long-term average value. 

Comparing bedload estimates from the bedload equation to suspended-sediment load from the 

lower Puyallup River, long-term bed-material accumulation in the lower White River, recent 

measurements of annual bedload in the lower White River, and long-term bed-material accumulation in 

the Puyallup River allows an assessment of how the simple model predicts bedload in the system. 

Typically, about 4–10 percent of total load is bedload (Nelson, 1971; Nelson, 1974). The suspendedsediment load in the lower Puyallup River from 1978 to 1994 was 860,000±300,000 tonnes/yr (fig. 21). 

The sum of estimated annual bedload from 1978 to 1994 in the three rivers draining into the lower 

Puyallup River was 33,000 tonnes/yr, which is 3.7 percent of the total load for the same time period. 

This comparison suggests the bedload equation may underpredict actual bedload, but overall, the 

predictions are reasonable. Comparing predicted bedload in the White River with accumulation in the 

reach between R Street and Lake Tapps (Czuba and others, 2010) showed good agreement between the 

two, assuming that much of the White River bedload passing R Street deposits in the reach of decreased 

slope upstream of the Lake Tapps return and the finer sediment is carried downstream. The predicted 

bedload at the White River at R Street for WY 2011 was 49,000 tonnes (fig. 28), which was smaller 

than the reported bedload of 64,500 tonnes (fig. 25) but a reasonable estimate given the uncertainty in 

both values. Comparison of the bedload prediction with the measured sediment-accumulation rate of 

67,000 tonnes/yr in the Puyallup River (Czuba and others, 2010) showed poor agreement. Though the 

bedload equation likely underpredicted actual bedload in the Puyallup River, the order-of-magnitude 

difference between predicted bedload in the Puyallup River and the long-term sediment accumulation 

suggests that perhaps pulses of sediment were mobilized from larger flood events (notably, the 1996 and 

2006 floods) in the catchment that resulted in increased bedload transport. More likely, it is possible that 

setback-levee reaches trapped a larger proportion of the total load as bed material, including finegrained sediment not typically part of the bedload. Under this second scenario, the bedload relation 

could reasonably predict bedload for the Puyallup River, but the volume of sediment collected in the 

setback-levee reaches includes bedload and a sizeable portion of the suspended load. In considering the 

whole of available comparative data, it appears that, though imprecise, this simple bedload equation 

reasonably predicts bedload for the Puyallup, Carbon, and White Rivers where these rivers exit the 

mountain front.

Projections of future climate-change impacts in Washington State during the 21st century predict 

increases in streamflow for October–March of 11.6 percent for 2010–2034 and of 18.1 percent for 

2035–2059 (compared with the mean streamflow during 1917–2006; Elsner and others, 2010). 
37

Assuming the bedload relation (fig. 27) represents future bedload conditions and that the system 

remains in a state of sediment surplus, during the next 25 years, an increase in streamflow of 11.6 

percent would result in an increase in bedload of 30 percent. During the following 25-year period (25–

50 years in the future), an increase in streamflow of 18.1 percent would result in an increase in bedload 

of 48 percent. If the average bedload of the White River at R Street near Auburn from 1984 to 2009 was 

28,000 tonnes/yr (Czuba and others, 2010), then average bedload will be approximately 36,000 

tonnes/yr from 2010–2034 and 41,000 tonnes/yr from 2035–2059. Close monitoring of aggradation and 

bedload in aggrading reaches of lowland rivers in coming decades will aid resource managers in 

assessing changes in flood-conveyance capacity, particularly given that subtle increases in peak-flow 

hydrology has the potential to significantly increase bedload.

Synthesis of Sediment Load of Mount Rainier Rivers

Without the resources to directly measure long-term sediment loads or in the absence of 

reservoirs that trap a large portion of the load, a combination of analyses of existing data sets, published 

literature, and strategic sediment sampling allows an approximate estimation of long-term sediment 

loads. This section synthesizes disparate analyses and data sets previously discussed to generate best 

estimates for total sediment load in rivers in the study area.

Best Estimate of Current Sediment Loads

The best estimates of long-term sediment loads within the study area were for the Nisqually 

River system (table 8). Using sediment accumulation volumes (Czuba and others, 2012) and estimates 

of trap efficiency, the total sediment load of the upper Nisqually River into Alder Lake was found to be 

1,200,000±180,000 tonnes/yr during the time period 1945–2011. Trap efficiency in Alder Lake is 

0.90±0.05, and 120,000±18,000 tonnes/yr of load passes Alder Dam. Based on active-channel widths, 

the relative contribution of sediment loads from Tahoma Creek, Kautz Creek, and the main-stem 

Nisqually River, the three primary tributaries in the Nisqually River watershed draining Mount Rainier, 

were similar. During much of the 20th century and up to 2011, the Nisqually River was subjected to 

several large peak-flow events and significant debris-flow activity on Mount Rainier (Crandell, 1971; 

Walder and Driedger, 1994; Beason and Kennard, 2007; Lancaster and others, 2012). Total sediment 

load in the Nisqually River was large in the years following the 1947 Kautz Creek debris flow and from 

the 1990s to the present. However, loads decreased from 1956 to 1985 to 860,000±370,000 tonnes/yr as 

overall peak flows were modest in magnitude and an apparent decrease in debris-flow activity. 

Although the spate of debris flows that impacted Tahoma Creek started in 1967, evidence suggests that 

much of this sediment remained in Tahoma Creek through 1985 (Walder and Driedger, 1994). Analysis 

of changes in active-channel width from 1965 to 1994 supports conclusions that the Nisqually River 

catchment was in a state of less-active hydrogeomorphic activity from the 1960s to the 1980s. Starting 

in 1990, hydrogeomorphic activity in the Nisqually River catchment increased. In the 1990s, several 

summer outburst debris flows supplied significant volumes of sediment to the Nisqually River basin 

inside Mount Rainier National Park. From 1996 to 2009, a series of large floods and debris flows from 

Mount Rainier increased overall sediment load in the main-stem Nisqually River, increased activechannel width along several river reaches outside the park boundary, and led to marked periods of both 

incision and aggradation at the Nisqually River near National gaging station (Czuba and others, 2010). 

For the lower Puyallup River, the suspended-sediment load between 1978 and 1994 was 

estimated to be 860,000±300,000 tonnes/yr (table 8) based on periodic suspended-sediment 

measurements collected by the USGS. This load estimate is likely smaller than the long-term load 

during much of the 20th century based on loads calculated for the Nisqually River. Though not 
38

determined, it is likely that large peak flows and sediment released from Mount Rainer starting in the 

1990s increased the sediment load of the Puyallup River to about 1.0 million tonnes/yr, an estimate 

partially confirmed by Wise and others (2007) who found 1.25 million tonnes of sediment flowed down 

the lower Puyallup River in 2000. Dunne’s (1986) estimate of total sediment load on the White River of 

450,000 tonnes/yr was likely a reasonable estimate of annualized loads from the 1960s to 1980s, 

although the White River load since the 1990s was likely about 500,000 tonnes/yr, a value that agrees 

with estimates of sediment load from April 2010 to March 2012 made during this study (table 8). Based 

on active-channel width analysis, the West Fork White, White, Carbon, and Mowich Rivers supplied 

significant sediment to the river network between 1994 and 2009. In contrast, the main-stem and South 

Puyallup Rivers (fig. 1) supplied less sediment. Few sediment-load data for the Carbon River are 

available.

Bedload estimates for the Puyallup, Carbon, and White Rivers, where these rivers exit the 

mountain front and first enter the Puget Lowland, suggested that overall bedload-transport capacity 

along the White River, owing in part to the size of drainage area, is larger than along both the Puyallup 

and Carbon Rivers. In contrast, the Carbon River has a relatively small bedload-transport capacity due 

to a relatively small contributing drainage area.

No load estimates for the Cowlitz River drainage were made as part of this study, though gage 

analysis of the Cowlitz River at Packwood (Czuba and others, 2010), the relative absence of debris-flow 

activity from the upper Muddy Fork Cowlitz and Ohanapecosh Rivers draining Mount Rainier (Nick 

Legg, Oregon State University, written commun., 2011), and relatively modest changes in activechannel width from 1994 to 2009 suggest that the overall sediment load of the Cowlitz River is less than 

the overall sediment load of other rivers draining the volcano.

Insufficient data are available to determine definitively if post-1990 increases in sediment 

production and transport from Mount Rainier represent a statistically significant trend relative to 

sediment-production values typical from Mount Rainier during the 20th century. The more complete 

data sets collected since the 1940s—that is, sediment accumulation in Alder Lake, sediment-load data 

collected from the 1970s to the present, and hydrologic data from gaging stations around the 

mountain—indicate that sediment loads from 1990 to the present are likely greater than sediment loads 

in comparable river reaches from the 1960s to the 1980s. However, the data sets are too limited to 

determine if the increased post-1990 sediment loads are significantly larger than sediment loads from 

the 1940s to 1960s. The hydrologic data of total runoff and peak flows indicate that flows of the 1940s–

1960s were similar to flows since 1990. Moreover, the sediment accumulation data from Alder Lake 

indicates sediment loads in the Nisqually River from 1945 to 1956 were similar to sediment loads

measured from 1985 to 2011. Given these data, it appears that post-1990 sediment loads in rivers 

draining Mount Rainier are not unusual or significantly larger than loads typical during the entire 20th

century.

Regional Context

Comparing the sediment-load estimates from this study to other rivers shows that rivers draining 

Mount Rainier generally carry larger sediment loads than similarly sized rivers in the Pacific Northwest 

not draining volcanos (fig. 29). The Nisqually River, with a long-term yield of 2,000±300 

(tonnes/km2)/yr, carries a load that is in the upper range of variation from other rivers reflecting both 

significant response to hydrogeomorphic disturbance to the catchment and proximity to the source 

material. Nelson (1971, 1974) found that rivers draining the Cascade Range in western Washington 

away from volcanoes typically carry sediment yields ranging from 50 to 250 (tonnes/km2

)/yr. Milliman 

and Farnsworth (2011) reported a larger range of yield values from larger Pacific Northwest river 
39

systems directly draining to the Pacific Ocean. Sediment yields for these coastal rivers ranged from 

about 50 to 1,000 (tonnes/km2

)/yr, with the larger values associated with rivers draining steep 

mountainous terrain with active tectonic uplift. The lower Puyallup River had a smaller load than the 

Nisqually River from 1978 to 1994, and, being farther from the source volcano, had a smaller yield of 

350±120 (tonnes/km2

)/yr. As such, the sediment loads for the Puyallup River from 1978 to 1994 were 

more comparable to other Pacific Northwest rivers.

Relative Sediment Contributions from Mount Rainier and Other Sources

Anecdotal observations of active-channel width on rivers crossing from the national park into 

logged lands outside the park (where no discernible width increases were observed downstream of the 

park boundary) suggested that most of the sediment load supplied to the rivers draining Mount Rainier 

originated from the volcano. Assessments of sediment-production potential from this study confirm 

these anecdotal observations. For example, the contribution to overall sediment load from the Nisqually 

River basin outside the national park was estimated to be 50,000±33,000 tonnes/yr (table 7). Because 

the data used to calibrate sediment-production potential were largely based on sediment-load data 

collected in the 1970s, it is best to compare this estimate to the Nisqually River load estimated between 

1956 and 1985, which was determined to be 860,000±370,000 tonnes/yr. Using this value as the 

estimate for the total load during the middle 20th century, then about 83–98 percent of the total 

sediment load in the upper Nisqually River can be attributed to sources within Mount Rainier National 

Park. Comparison of the sediment-production potential in the White River basin, which was determined 

to be 130,000±89,000 tonnes/yr, to Dunne’s (1986) estimate of sediment load in the upper White River 

(450,000 tonnes/yr) indicates that about 51–91 percent of the total sediment load in the White River 

originates from inside the national park. Similarly, comparison of the combined sediment-production 

potential for the White, Puyallup, and Carbon River basins (210,000±150,000 tonnes/yr) to the sediment 

load estimate for the lower Puyallup River from 1978 to 1994 (860,000 tonnes/yr) indicates that about 

58–93 percent of the total load in the lower Puyallup River can be attributed to sources inside Mount 

Rainier National Park. No attempt was made to determine the sediment production from specific 

sources inside the national park (that is, forested areas versus the volcanic cone), but aerial imagery 

suggested most sediment originates directly from the stratovolcano.

Modeling Bed-Material Sediment Transport by Rivers

One-dimensional river-hydraulic and sediment-transport models were developed for the 

Nisqually, Carbon, Puyallup, and White Rivers, simulating the entrainment, transport, abrasion, and 

deposition of sediment. Major inputs to the models included channel-geometry, streamflow, and 

sediment data. Results of model simulations were compared to physical measurements, where available, 

to assess the efficacy of these models in predicting sediment transport at spatial (0.4–100 km) and 

temporal (one day to hundreds of years) scales. Model simulations address four questions regarding the 

quantity, spatial and temporal distribution, downstream effect, and future outlook of sediment transport 

by rivers draining Mount Rainier: (1) How much sediment is transported by each river and how has this 

quantity varied through time? (2) How is sediment distributed in space and time through each river as it 

is transported downstream? (3) What is the timing and magnitude of geomorphic change in downstream 

reaches due to altered sediment delivery to rivers and varying hydrology? (4) How might changing 

hydrologic conditions during the next 25–50 years affect bed elevations?
40

Model Framework

Models for each of the four rivers were developed using the Unified Gravel-Sand (TUGS) model 

with channel-geometry, streamflow, and sediment data as major inputs (Cui, 2007a). A modelconditioning process was used to adjust bed elevations and bed grain-size distributions in order to 

establish quasi-equilibrium. The upstream extent of each model was chosen where the river had a slope 

of approximately 0.02 m/m to avoid modeling sediment transport on steep slopes and to model reaches 

of the river where fluvial processes are the dominant mechanism for sediment transport rather than 

debris flows. For each river, morphodynamic parameters were averaged every 0.4 km into model nodes.

At the downstream end of each model, the bed elevation was fixed and the water-surface elevation was 

set by the normal flow assumption.

The model of the Nisqually River extended from just upstream of Tahoma Creek to Alder Lake 

(NRKM 14.2–41.0) and included tributary streamflow and sediment inputs from Big and Mineral 

Creeks (NRKM 28.2 and 37.4, respectively). The model of the Carbon River extended from Chenuis 

Creek to the Puyallup River (CRKM 8.2–50.2) and included tributary streamflow and sediment inputs 

from Evans, South Prairie, and Voight Creeks (CRKM 21.4, 41.4, and 44.2, respectively). The model of 

the Puyallup River extended from the Mowich River to Commencement Bay of Puget Sound (PRKM 

16.2–82.2) and included tributary streamflow and sediment inputs from the Carbon and White Rivers 

(PRKM 54.2 and 65.8, respectively). The model of the White River extended from within Mount 

Rainier National Park to the Puyallup River (WRKM 13.4–116.6) and included tributary streamflow 

and sediment inputs from Huckleberry Creek, West Fork White River, Greenwater River, and 

Clearwater River (WRKM 33.4, 39.4, 45.0, and 61.8, respectively). Additionally, for the model of the 

White River downstream of Mud Mountain Dam (WRKM 71.0), the streamflow reflected dam 

operations.

The Unified Gravel-Sand (TUGS) Model

The TUGS model (Cui, 2007a) is a one-dimensional river-hydraulic and sediment-transport 

model that was used to simulate the entrainment, transport, abrasion, and deposition of sediment for 

each of the four rivers. The major components of the TUGS model include: (1) a flow calculation, 

which provides local shear stress, through a rectangular channel using a standard-backwater formulation

when the Froude number (Fr) is less than 0.8 and a quasi-normal flow approximation when Fr is greater 

than or equal to 0.8; (2) a local sediment-transport capacity calculation from local shear stress using the 

surface-based bedload equation of Wilcock and Crowe (2003); and (3) a bed-change calculation using 

the grain-size-based Exner equations of sediment continuity, which includes the abrasion of gravel 

during transport as proposed by Parker (1991a, 1991b). The full details of the TUGS model are provided 

in Cui (2007a). The TUGS model has been used to examine the dynamics of grain-size distributions of 

gravel/sand deposits in the Sandy River, Oregon (Cui, 2007b), and to predict changes to the sediment 

transport regime of the Waipaoa River, New Zealand, that may occur in response to forecasted climate 

changes in the 21st century (Gomez and others, 2009).

Geomorphic Data

The major geomorphic data inputs to the TUGS models included channel-geometry, streamflow, 

and sediment data. The channel-geometry data included channel widths and elevations. The streamflow 

data were obtained from USGS streamflow-gaging stations and the data were scaled for use upstream 

and downstream of the gaging-station locations. The sediment data included surface and subsurface 

sediment grain-size distributions and sediment loads.
41

Channel Geometry

The active channel, defined as the section of the river corridor relatively free of vegetation that 

conveys the majority of the water and sediment during high flow, was digitized from the 2009 National 

Agricultural Imagery Program (NAIP) imagery at 1:3000 scale (U.S. Department of Agriculture, 2011). 

Areas of dense vegetation within the bounds of the active channel were digitized as island features and 

did not count towards the computation of active-channel width. Mapping of channel features was 

affected by the quality and resolution of available imagery. Some areas of imagery had varying degrees 

of glare, shadows, or local obstructions of channel features, and errors were introduced by imprecise 

line placement. To minimize errors and increase the overall precision of the interpretive mapping, all 

delineated features were quality controlled by other members of the project team. A river centerline was 

digitized through the center of the active channel, representing the dominant pathway of the river during 

high flow. The active-channel width for each 400-m node was computed by dividing the total activechannel area in a given node by the length of the segment (400 m). Active-channel widths were not 

altered in the model-conditioning process or in any model simulations.

A longitudinal profile approximating the water-surface elevation was generated by sampling the 

elevation of LiDAR data along the river centerline. Elevation points were sampled from the underlying 

LiDAR data at 10-m increments along the river centerlines and averaged every 400 m to determine an 

average elevation for each model node. The available LiDAR data sets (appendix A, table A1) were 

projected and converted to the North American Datum of 1983 (NAD 83) Universal Transverse 

Mercator zone 10 (UTM 10) in meters and the North American Vertical Datum of 1988 (NAVD 88) in 

meters. For elevations of the lower 10.5 km of the Puyallup River and lower 2.5 km of the White River,

channel-elevation data surveyed by Czuba and others (2010) were used because the LiDAR data in 

these areas represent low-slope backwater conditions that were not representative of the channel slope.

Streamflow Data

Long-term streamflow records for each river were compiled using time series of daily discharge 

from USGS streamflow-gaging stations (table 1). The streamflow data measured at gages were scaled to 

upstream and downstream reaches using 2-year recurrence-interval peak discharges (table 9; U.S. 

Geological Survey, 2011). Missing streamflow data from Carbon River near Fairfax gage, for WYs

1978–1991, were estimated by multiplying streamflow data from the Puyallup River near Orting gage 

by 0.6, which is the average ratio of the streamflows from the two gages during the period when both 

gages were operating. Streamflow data for the Puyallup River between the Carbon and White Rivers

(PRKM 54.2–65.4) were obtained by adding the streamflow data from the Puyallup River near Orting

gage to 1.65 times the streamflow data from the Carbon River near Fairfax gage (sum of streamflows 

above the confluence of the Puyallup and Carbon River; table 9). Streamflow data for the White River 

downstream of Mud Mountain Dam (WRKM 71.0–116.6) were derived using data from a combination 

of the White River near Buckley gage, for WYs 1939–2003, and the White River above Boise Creek at 

Buckley gag, for WYs 2004–2011 (table 9).

Sediment Data

All sediment data were grouped into discrete size ranges, with breaks between ranges defined 

using the sedimentological phi-scale (2, 4, 8, 16, 32, 64, 128, 256, 512, and 1,024 mm). The grain-size 

distribution for sand and fines had a median particle size (D50) of approximately 0.4 mm, was assumed 

to be identical everywhere, and was based on physical measurements of the sand distribution in the 

lower Puyallup River system (Czuba and others, 2010). The volumetric abrasion coefficient for coarse 

sediment (greater than 2 mm) was set at 0.02/km based on abrasion values for basaltic colluvium from 
42

the Satsop River basin in the southern Olympic Mountains in Washington State (Collins and Dunne, 

1989).

Surface grain-size distributions were measured using the Wolman pebble-count method 

(Wolman, 1954) between October 2010 and August 2011 (NRKM 2–41.0, CRKM 2–25, PRKM 8–22, 

and WRKM 4–93) and also were obtained from previous studies (Czuba and others, 2010: CRKM 38–

50.2, PRKM 36–82.2, and WRKM 110–116.6; Herrera Environmental Consultants, 2010: WRKM 100–

109). Surface grain-size distributions measured at each site were assigned to the nearest model node and 

were used to interpolate grain-size distributions for all other nodes.

The distribution of sediment load by grain size, which varied with streamflow, was input to the 

model at the upstream boundary and at tributaries and was determined using the software program 

Bedload Assessment in Gravel-bedded Streams (BAGS; Pitlick and others, 2009). BAGS computed 

bedload transport by grain size for a range of flows using the Wilcock and Crowe (2003) bedloadtransport equation from channel-width, slope, surface grain-size distribution, and streamflow data at the 

input location. The TUGS model was modified to supply sediment by grain size at the input location 

using the BAGS output and streamflow data.

The subsurface grain-size distribution at each node was computed by combining 30 percent of 

the surface grain-size distribution with 70 percent of the bedload grain-size distribution (from BAGS) 

following the formulation of Toro-Escobar and others (1996). The subsurface sand fraction was set 

equal to the surface sand fraction. Sand covered the bed of the lower Puyallup and White Rivers (PRKM 

75.8–82.2 and WRKM 111.0–116.6) when the bed material was measured by Czuba and others (2010). 

The TUGS model is capable of modeling a sand-covered bed (Cui, 2007a, 2007b; Gomez and others, 

2009). However, the downstream boundary conditions (tidal water-surface elevation for the Puyallup 

River and the Puyallup River water-surface elevation for the White River) required to maintain a sandcovered bed were simplified to normal flow water-surface elevations resulting in inaccuracies for the 

downstream end of the Puyallup and White River models.

Model-Conditioning Process

The model-conditioning process allowed imprecise bed elevations and bed grain-size 

distributions to adjust until model output stabilized at a quasi-equilibrium condition. The modelconditioning process also has been referred to as a zero process and is discussed further by Cui and 

Wilcox (2008) and Cui and others (2006a, 2006b). First, input sediment loads from BAGS were reduced 

until the long-term bed-elevation change was minimized at the upstream model boundary and at 

tributaries. Second, the entire long-term streamflow record was simulated repeatedly with bed elevations 

(and therefore local slope) and grain-size distributions from the end of one simulation used as input to 

the next simulation. Model simulations were repeated until each model reached quasi-equilibrium, when 

the model simulated short-term fluctuations in bed elevation, but minimal long-term change. At the end 

of the model-conditioning process, the general downstream variation of the model-conditioned (or 

simulated) slope and grain-size distribution matched the raw-input (or measured) data, but the modelconditioned slope and grain-size distribution were locally adjusted. The conditioned models define the 

geomorphic starting point for all simulations.

Geomorphic Setting

The geomorphic setting of the Nisqually, Carbon, Puyallup, and White Rivers can be described 

by the channel-geometry and bed-sediment characteristics of these rivers. The primary geomorphic 

variables describing the channel geometry are the model-conditioned (or simulated) slope and raw-input 
43

(or measured) width. The primary geomorphic variables describing the bed sediment are the modelconditioned (or simulated) D50 size, D90 size, and percent sand of bed-surface sediment.

Nisqually River

The Nisqually River (NRKM 14.2–41.0) was characterized by three geomorphic reaches: an 

upper alluvial reach (NRKM 14.2–28.2), a constricted reach (NRKM 28.6–32.6), and a lower alluvial 

reach (NRKM 33.0–41.0) (fig. 30). The Nisqually River (NRKM 14.2–41.0) had a slope that decreased 

from approximately 0.02 to 0.008 m/m and a width that varied between 150 and 250 m. There were two 

short constrictions in the width of the Nisqually River between NRKM 28.6 and 32.6 that were 

associated with a local decrease in slope. The model-conditioned D90 size, D50 size, and percent sand 

of bed-surface sediment decreased from approximately 160 to 100 mm, 60 to 40 mm, and increased 

from approximately 40 to 60 percent, respectively. The model-conditioned D90 and D50 sizes of bedsurface sediment were smaller than measured data and the model-conditioned percent sand of bedsurface sediment was within the variability of the measured data.

Carbon River

The Carbon River (CRKM 8.2–50.2) was characterized by three geomorphic reaches: an upper 

alluvial reach (CRKM 8.2–20.2), a canyon reach (CRKM 20.6–37.0), and a lower alluvial reach 

(CRKM 37.4–50.2) (fig. 31). The upper alluvial reach (CRKM 8.2–20.2) had a slope that gradually 

decreased from 0.02 to 0.015 m/m and a width that varied between 150 and 300 m. The active channel 

was more than 400 m wide at CRKM 10.6. The canyon reach (CRKM 20.6–37.0) was constrained by a 

bedrock canyon to a width of approximately 30 m. The lower alluvial reach (CRKM 37.4–50.2) had a 

slope that decreased from 0.01 to 0.004 m/m and a width that varied between 60 and 180 m. The modelconditioned D90 size, D50 size, and percent sand of bed-surface sediment decreased from 

approximately 200 to 120 mm, 80 to 60 mm, and increased from approximately 20 to 30 percent, 

respectively, and generally were within the variability of the measured data.

Puyallup River

The Puyallup River (PRKM 16.2–82.2) was characterized by four geomorphic reaches: an upper 

alluvial reach (PRKM 16.2–21.0), a canyon reach (PRKM 21.4–33.4), a middle alluvial reach 

downstream of the canyon (PRKM 33.8–48.2), and a lower alluvial reach downstream of Calistoga 

Street (PRKM 48.6–82.2) (fig. 32). The upper alluvial reach (PRKM 16.2–21.0) had a slope of 

approximately 0.017 m/m and a width that increased from approximately 60 to 200 m. The canyon 

reach (PRKM 21.4–33.4) was constrained by a bedrock canyon to a width of approximately 30 m. The 

middle alluvial reach downstream of the canyon (PRKM 33.8–48.2) had a slope that decreased from 

0.01 to 0.005 m/m and a width that varied between 100 and 200 m. The narrow width of 45 m at PRKM 

41.0 corresponds to the bedrock constriction at the Puyallup River near Orting gage (12093500), and the 

wide section at PRKM 42.6 of 280 m corresponding to the setback-levee reach (Czuba and others, 

2010). The lower alluvial reach downstream of Calistoga Street (PRKM 48.6–82.2) had a slope that 

decreased from 0.005 to 0.0006 m/m and a width that generally varied between 40 and 100 m. The 

model-conditioned D90 size, D50 size, and percent sand of bed-surface sediment decreased from 

approximately 430 to 60 mm, 180 to 35 mm, and increased from approximately 25 to 50 percent, 

respectively, and generally were within the variability of the measured data except for the percent sand 

downstream of PRKM 50.0.
44

White River

The White River (WRKM 13.4–116.6) was characterized by four geomorphic reaches: an upper 

alluvial reach (WRKM 13.4–44.6), a middle alluvial reach separated into two reaches upstream and 

downstream of Mud Mountain Dam (WRKM 45.0–70.6; 71.0–101.0, respectively), and a lower alluvial 

reach (WRKM 101.4–116.6) (fig. 33). The upper alluvial reach (WRKM 13.4–44.6) had a slope that 

decreased from 0.02 to 0.01 m/m and a width that generally varied between 50 to 150 m. The 

Greenwater River joined the White River at the upstream end of the middle alluvial reach (WRKM 

45.0–101.0), which had a nearly constant slope of 0.008 m/m and a width that generally varied from 50 

to 150 m. The lower alluvial reach (WRKM 101.4–116.6) had a slope that decreased from 0.008 to 

0.002 m/m and a width of approximately 50 m. The model-conditioned slope of the White River was 

larger than the raw input between WRKM 111.0–116.6 because the tendency of the model, during the 

model-conditioning process, was to increase the slope of the river in order to more efficiently transport 

sediment through this reach. The model-conditioned D90 size, D50 size, and percent sand of bedsurface sediment decreased from approximately 140 to 55 mm, 60 to 25 mm, and generally varied 

between 30 and 40 percent, respectively, and generally were within the variability of the measured data 

except for the percent sand downstream of WRKM 45.0.

Model Performance

Model performance was assessed based on a comparison of simulated sediment loads to physical 

measurements. In addition to these comparisons, the limitations of the models are discussed to aid in the 

interpretation of model results.

Model Comparison to Physical Measurements

The Nisqually River deposits its bed-material load (sand, gravel, and cobbles) in the delta of the 

Nisqually River in Alder Lake. The finer washload (silt and clay) is either deposited in the main body of 

Alder Lake or transported through the dam outlet. Changes in the volume of sediment deposited in the 

delta of the Nisqually River in Alder Lake were estimated between 1945 and 1956, 1985, and 2011 by 

Czuba and others (2012). A simulation of the conditioned Nisqually River model between WYs 1946 

and 2011 shows that the simulated sediment loads of the Nisqually River into Alder Lake were within 

the uncertainty bounds of the measurements of changes in delta volume (table 10). The model of the 

Nisqually River tended to simulate slightly higher transport into Alder Lake than was measured, except 

for WYs 1946–1956, which was attributed to the 1947 Kautz Creek debris flow that was not 

incorporated into the model simulations.

Concurrent measurements of suspended load and bedload from the Carbon River at State Route 

162/Pioneer Way, Puyallup River at Calistoga Street, and White River at R Street were compared to 

model-simulated loads. Measured loads were separated into a sand load (sum of the fraction less than 2 

mm from the suspended load and bedload samples) and a gravel load (fraction greater than 2 mm from 

the bedload samples) for comparison to model simulations of sand load and gravel load because the 

Wilcock and Crowe (2003) equation (used in the TUGS model) simulates the transport of sand and 

gravel as bed-material load. Bed-material load is the fraction of the total sediment load affecting bed 

elevations, which is the focus of this study. For comparison, the simulated loads in m3

/d were converted 

to tonnes/d assuming a density of 1.6 tonnes/m3 (Wu and Wang, 2006).

The measurements of sediment load were made during two periods: 1986 and 2010–2011. The 

simulated loads in comparison to the measured loads generally were in good agreement for the 

combined sand and gravel, and sand (fig. 34). The model overpredicted gravel load at low loads 
45

compared to the measured loads (fig. 34), which in part may be due to the timing of the physical 

measurements on the falling limb of the hydrograph.

Model Limitations

The comparisons of the simulated loads to physical measurements provide a measure of the 

accuracy of the models at predicting sediment loads, and ultimately model performance. In order to 

fully understand the model results, this section discusses some of the limitations inherent in the TUGS 

model itself and in the model as applied to the Nisqually, Carbon, Puyallup, and White Rivers.

It is difficult to assess the efficacy of the models based on a few measurements. Additionally, for 

the sediment-load measurements, the appropriateness of the comparisons of the measured data to the 

simulated results are uncertain, given their different spatial and temporal resolutions. For each 

measurement, several samples were collected at 5–20 points along a cross section of the river, each 

sample was collected over several seconds, and the resulting samples were combined to obtain a rate of 

sediment transport. Measurements at high-streamflow conditions often occur when the flow is rapidly 

changing with the streamflow rising, peaking, and receding all within a day. In the model, each node 

represents the average conditions over a bed area that is an active-channel-width wide by 400-m long. 

Therefore, any change in elevation at a node represents the average change over this area, which can 

vary significantly within this area. For example, the measured change in elevation from 1984-2009 at 

one cross section on the Puyallup River was between -1 m and 3 m, with an average elevation increase 

of approximately 1 m (cross section P120 in Czuba and others 2010). The model also used daily 

streamflow, which underestimates peak streamflows, and averages out any variation in streamflow 

within a day.

The active-channel widths were fixed for all model simulations. The widths, measured from the 

2009 aerial imagery, were likely larger than the long-term average active-channel widths due to recent 

large flows (fig. 11). Though past and future hydrologic conditions were simulated with fluctuating 

sediment loads, bed elevations, and hydrology, fixed channel widths limited the models’ predictive 

accuracy relative to some of the dynamics of sediment transport through time. Additionally, for all 

model simulations, streamflow and sediment were confined to the active channel, and the models did 

not simulate overbank flow or conveyance through the vegetated flood plain. Improved models would 

account for these factors.

The model-conditioning process established quasi-equilibrium conditions for these rivers as a 

starting point for model simulations. However, some reaches may not be in quasi-equilibrium, whereby

they are storing sediment locally and not efficiently transporting sediment downstream (such as in 

setback-levee reaches). Additionally, any modifications to various reaches in the future that were not 

considered in the future model simulations would violate the quasi-equilibrium assumption (such as 

setback levees and gravel removal implemented after 2009). In particular, the conditioning process 

significantly changed the slope of the lower White River near Auburn from its current low-slope value 

to a relatively steep future condition. As a result of the conditioning, the model poorly predicts longterm aggradation along the lower White River.

The downstream boundary conditions (water-surface elevations) required to maintain a sandcovered bed of the lower Puyallup and White Rivers (PRKM 75.8–82.2 and WRKM 111.0–116.6) were 

simplified to normal flow water-surface elevations in the model simulations, and, therefore, simulated 

changes in bed elevations in these reaches are not accurate. Furthermore, the significant increase in the 

model-conditioned slope from the measured slope of the lower White River (WRKM 111.0–116.6) 

highlights that this reach does not effectively transport sediment downstream, implying that sediment 
46

deposits just upstream of and within this reach. Model simulations were not accurate for this reach of 

the lower White River.

The model of the White River simplifies the dynamics of the transport through Mud Mountain 

Dam. In the model, there is a change in streamflow at Mud Mountain Dam where water and sediment 

freely passes through a channel-width constriction of 40 m. The model simulates sediment passing 

immediately through, instead of temporarily accumulating in and later sluicing out of the reservoir. It 

was assumed that most sediment is sluiced through the reservoir between winter storms or during spring 

and summer snowmelt; therefore, the transport of sediment through the reservoir is only delayed a few 

months, which would not significantly affect annual sediment loads downstream. However, it is 

currently unknown how effective Mud Mountain Dam has been at trapping sediment since its 

construction in 1948 and how this trap efficiency might have changed over time.

Another limitation of the models is that they do not account for additional sediment load 

supplied by channel migration into flood plain deposits or glacial-till bluffs. The erosion of sediment 

from the toe of glacial-till bluff can be significant, particularly along the lower Carbon River.

Given these limitations, the models generally were able to simulate predicted loads and were 

able to provide insight into questions regarding the quantity, spatial and temporal distribution, 

downstream effect, and future outlook of sediment transport by rivers draining Mount Rainier.

Model Simulations of the Nisqually, Carbon, Puyallup, and White Rivers

Model simulations address four questions regarding sediment transport by rivers draining Mount

Rainier: (1) How much sediment is transported by each river and how has this quantity varied through

time? (2) How is sediment distributed in space and time through each river as it is transported 

downstream? (3) What is the timing and magnitude of geomorphic change in downstream reaches due 

to altered sediment delivery to rivers and varying hydrology? (4) How might changing hydrologic 

conditions during the next 25–50 years affect bed elevations?

Model Simulation of Long-Term Streamflow Record

A simulation of the long-term streamflow record for each river provides an estimate of sediment 

transport by each river and how this quantity might have varied through time. Daily streamflow and 

simulated annual bed-material sediment load for each river are shown for the Nisqually River at State 

Route 7 (NRKM 41.0), Carbon River at State Route 162/Pioneer Way (CRKM 41.0), Puyallup River at 

Calistoga Street (PRKM 48.6), and White River at R Street (WRKM 104.6) (fig. 35). At these locations, 

average-annual streamflow was largest to smallest for the Nisqually, White, Puyallup, and Carbon 

Rivers. Streamflow of the White River was not as variable as streamflow of the other rivers because the 

White River at R Street location is downstream of Mud Mountain Dam, which moderates peak 

streamflow. Similar to streamflow, the simulated annual bed-material sediment load was largest for the 

Nisqually River (690,000 m3

/yr) and was smaller for the White (530,000 m3/yr), Puyallup (83,000 

m3/yr), and Carbon (15,000 m3/yr) Rivers (table 11). The simulated bed-material sediment loads ranged 

over an order of magnitude: 340,000–1,500,000 m3/yr for the Nisqually; 2,800–77,000 m3/yr for the 

Carbon; 28,000–260,000 m3

/yr for the Puyallup; and 250,000–900,000 m3/yr for the White Rivers (table 

11). Streamflow is the driving force of sediment transport and the differences between streamflows 

explain the differences between sediment loads for these rivers. The simulated annual bed-material 

sediment load was, on average, 8, 16, 8, and 16 percent gravel and coarser for the Nisqually, White, 

Puyallup, and Carbon Rivers, respectively (table 11). This suggests that of the sediment measured in the 

delta of the Nisqually River in Alder Lake, 8 percent is gravel and coarser sediment.
47

Capacity of Rivers to Transport Sediment

Locations along rivers that are most prone to sedimentation are those where the capacity of the 

river to move sediment decreases. Two metrics for characterizing the ability of rivers to move sediment 

are sediment-transport capacity and stream power (figs. 36–39). Sediment-transport capacity (m3/d) 

directly quantifies the amount of bed-material sediment that can be transported by the river for a given 

flow and was calculated for the 2-year recurrence-interval flow (table 11; U.S. Geological Survey, 

2011). Stream power is the rate at which energy is expended per unit downstream length by the flowing 

water. Stream power (Ω; watts [W]/m) was computed as:

Ω = ρgQS,

where ρ is the density of water (1,000 kg/m3

), g is the acceleration due to gravity (9.81 m/s

2

), Q 

is the 2-year recurrence-interval streamflow (m3/s), and S is the local river slope (m/m). Additionally, 

dividing the sediment-transport capacity and stream power by the active-channel width (referred to as 

unit sediment-transport capacity [(m3/d)/m] and unit stream power, respectively) shows the strength of 

the river acting on a unit area to transport sediment (figs. 36–39). Unit stream power (ω; W/m2) was 

computed as:

ω = Ω/B = ρgQS/B,

where B is the local active-channel width (m).

Sediment-transport capacity and stream power quantify the strength of the river acting on the 

bed of the river, irrespective of how the channel width concentrates these forces on the bed. Unit 

sediment-transport capacity and unit stream power quantify the strength of the river acting on a unit area 

of the bed, and for the same sediment-transport capacity or stream power, the unit metrics identify 

where the strength of the river is high due to a narrow channel or low due to a wide channel. Reaches 

with low sediment-transport capacity and stream power are reaches that are prone to sedimentation. 

Reaches with low unit sediment-transport capacity and unit stream power are weak at transporting 

sediment per unit bed area.

The capacity of the Nisqually River to transport sediment decreased in the upper alluvial reach 

(NRKM 14.2–28.2) to a minimum at NRKM 28.2, was variable in the constricted reach (NRKM 28.6–

32.6), and was greater in the lower alluvial reach (NRKM 33.0–41.0) than in the upper alluvial reach 

(fig. 36). The lower alluvial reach of the Nisqually River is downstream of Mineral Creek, which is 

tributary to the Nisqually River, and therefore increases the capacity of the river to transport sediment. 

The strength of the Nisqually River to transport sediment per unit width was lowest between NRKM 

21.8 and 28.2 and highest in the constricted reach (NRKM 28.6–32.6) (fig. 36).

The capacity of the Carbon River to transport sediment was lowest in the upper alluvial reach 

(CRKM 8.2–20.2), slightly higher in the lower alluvial reach (CRKM 37.4–50.2), and highest in the 

canyon reach (CRKM 20.6–37.0) (fig. 37). The strength of the Carbon River to transport sediment per 

unit width was lowest at CRKM 10.6 where the active channel width was widest and exhibited similar 

patterns as the capacity of the Carbon River to transport sediment (fig. 37).

The capacity of the Puyallup River to transport sediment generally decreased downstream 

(PRKM 16.2–82.2) except for the canyon reach (PRKM 21.4–33.4) where the capacity was highest (fig. 

38). The lowest capacity at PRKM 65.4 was just upstream of the confluence with the White River (fig. 

38). The strength of the Puyallup River to transport sediment per unit width locally was low at PRKM 

42.6, a setback-levee reach (Czuba and others, 2010). Elsewhere along the Puyallup River, the stream 

power per unit width exhibited similar patterns to transport sediment (fig. 38).

The capacity of the White River to transport sediment decreased in the upper alluvial reach 

(WRKM 13.4–44.6), increased in the middle alluvial reach upstream of Mud Mountain Dam (WRKM 

45.0–70.6), decreased in the middle alluvial reach downstream of Mud Mountain Dam (WRKM 71.0–
48

101.0), and decreased most significantly in the lower alluvial reach (WRKM 101.4–116.6) (fig. 39). The 

strength of the White River to transport sediment per unit width was lowest throughout most of the 

upper alluvial reach (WRKM 13.4–44.6), just upstream of the confluence with the Clearwater River 

(WRKM 54.6–61.8), and throughout the lower alluvial reach (WRKM 101.4–116.6) (fig. 39).

Spatial and Temporal Geomorphic Change due to Altered Sediment Supply

A set of model simulations were used to assess the timing and magnitude of geomorphic change 

in downstream reaches due to altered sediment supply and varying hydrology, and to assess how 

sediment is distributed in space and time through each river as it is transported downstream. Model 

simulations were used to investigate how increases in sediment supply to rivers, as pulses distributed 

during the first year of simulation, are transported through the river systems and affect lowland reaches. 

The set of model simulations for each river consisted of 36 different conditions: 3 hydrologic 

conditions, 2 pulse volumes, and 6 pulse grain sizes. The set of model simulations had varied hydrology 

[repeating 10-year periods of daily discharge of high (WYs 1995–2004), medium (WYs 1975–1984), 

and low (WYs 1985–1994) flow], pulse volume (100,000 and 500,000 m3 supplied to the upstream end 

of the model throughout the first simulation year), and pulse grain size (uniform distribution where 100 

percent is finer than 4, 8, 16, 32, and 64 mm, and a distribution of sand; generally all sizes were less 

than the D50 bed-surface grain size). For each hydrologic condition, simulated results of bed 

elevations/volumes and sediment loads of a baseline condition (without an input sediment pulse) were 

subtracted from the simulated results of a sediment-pulse condition (with different pulse volumes and 

grain size) to isolate the response of the input sediment pulse.

For each simulation, the input sediment pulse evolved through a combination of translation, 

dispersion, and attrition as it moved down the river system. A characteristic time for each pulse to arrive 

at each location along the river was computed as the time for half of the pulse to transport past that 

location, specifically, the median of the cumulative distribution of the increase in sediment load at each 

location through time. The magnitude of geomorphic change at each location along each river due to the 

input sediment pulse was quantified as the maximum increase through time in bed volume and sediment 

load compared to the baseline condition.

The characteristic transport time for each simulated pulse to move through the river depended 

strongly on the grain size of the pulse compared to that of the bed surface (normalized grain size). 

Sediment pulses finer than the D50 of the bed surface transport faster than pulses that are more similar 

to the D50 of the bed surface, and pulses coarser than the D50 of the bed surface transport slower with 

in-place attrition dominating pulse evolution (Cui and others, 2003; Cui and Parker, 2005; Sklar and 

others, 2009). The characteristic transport time, change in sediment load, and change in bed volume for 

each pulse condition was summarized for each river at one location: Nisqually River at State Route 7

(NRKM 41.0), Carbon River at State Route 162/Pioneer Way (CRKM 41.0), Puyallup River at 

Calistoga Street (PRKM 48.6), and White River at R Street (WRKM 104.6) (fig. 40).

As the pulse grain size gets larger, it takes longer to transport this sediment downstream because 

fewer events occur that are capable of transporting this sediment, and when this sediment arrives 

downstream, the increased sediment load is smallest for the largest size classes. The influence of pulse 

grain size on bed volume locally varies, with no clear trend at the one summary location for each river. 

As the pulse volume increases, it takes longer to transport this sediment downstream because more 

sediment needs to be moved before half of the pulse is transported, and the bed volume and sediment 

load increases because there is more sediment that can ultimately deposit and transport as the sediment 

moves downstream. As the magnitude or frequency of sediment-transporting streamflow increases, 
49

sediment transports downstream quicker and the loads are larger. The influence of streamflow on bed 

volume is small compared to other factors, with no clear trend at these locations.

The characteristic transport time for the D50 sediment size to arrive at a downstream location for 

the Nisqually River at State Route 7, Carbon River at State Route 162/Pioneer Way, Puyallup River at 

Calistoga Street, and White River at R Street is approximately 70, 300, 80, and 60 years, respectively

(fig. 41). For this reason, increased sediment input to the upper rivers beginning in 1967 (Copeland, 

2009) would have affected the Puget Lowland sooner in the Puyallup River than the Carbon River, 

which may explain the pattern of average channel-elevation change between 1984 and 2009 measured 

by Czuba and others (2010, fig. 10).

The characteristic transport time (fig. 41) is a cumulative function of the time it takes for a 

sediment pulse to arrive downstream, which integrates the travel time of the pulse through upstream 

reaches. The difference in the characteristic transport times between downstream and upstream model 

nodes yields the characteristic residence time of the pulse through each 400-m node. Each sedimentpulse simulation (36 for each river) shows similar reaches with high and low residence times, but the 

absolute values scale with grain size. Because the characteristic residence time of the sediment pulse 

strongly depends on the grain size of the pulse, the characteristic residence time of all pulse simulations 

was normalized to the characteristic D50 sediment size of the bed-surface sediment by dividing the 

characteristic residence time by the pulse grain size and multiplying it by the D50 of the bed-surface 

sediment. The 36 normalized characteristic residence times for each river were averaged (figs. 42a–45a) 

and show the characteristic time for sediment to move through each 400-m node as the sediment is 

locally stored and transported downstream. The light-gray lines are the average value plus or minus one 

standard deviation of the 36 normalized characteristic residence times for each river (figs. 42a–45a).

The characteristic residence time for the Nisqually River was long in the upper alluvial reach 

(NRKM 14.2–28.2) at approximately 1 year, and longest between NRKM 21.8 and 28.2 at 

approximately 1.1 year (fig. 42A). The constricted reach (NRKM 28.6–32.6) had the shortest residence 

time at the constriction because this reach is capable of quickly transporting sediment downstream (fig. 

42A). The lower alluvial reach (NRKM 33.0–41.0) had a residence time of approximately 0.7 year, 

which was shorter than in the upper alluvial reach (fig. 42A).

The characteristic residence time for the Carbon River was longest in the upper alluvial reach 

(CRKM 8.2–20.2) at approximately 38 years, with a maximum residence time of 113 years at CRKM 

10.2 (fig. 43A). The canyon reach (CRKM 20.6–37.0) was capable of transporting sediment 

downstream quickly, with a residence time near zero for sediment (fig. 43A). The lower alluvial reach 

(CRKM 37.4–50.2) had a residence time of approximately 7 years, which was highest just downstream 

of the canyon (CRKM 37.4–41.0) and decreased farther downstream (CRKM 41.4–50.2) (fig. 43A).

The characteristic residence time for the Puyallup River in the upper alluvial reach (PRKM 

16.2–21.0) was approximately 2.8 years (fig. 44A). The canyon reach (PRKM 21.4–33.4), like the 

canyon reach of the Carbon River (CRKM 20.6–37.0), was capable of transporting sediment 

downstream quickly and had a minimal residence time (fig. 44A). The middle alluvial reach 

downstream of the canyon (PRKM 33.8–48.2) had a residence time of approximately 4.3 years, and was 

longest at PRKM 42.2 at approximately 8.7 years (fig. 44A). The lower alluvial reach downstream of 

Calistoga Street (PRKM 48.6–82.2) had a residence time of approximately 3.1 years (fig. 44A).

The characteristic residence time for the White River was longest in the upper alluvial reach 

(WRKM 13.4–44.6) at approximately 0.5 years (fig. 45A). Where the Greenwater River enters the 

White River in the middle alluvial reach (WRKM 45.0–101.0), the residence time was reduced to 

approximately 0.2 years as the White River was more competent to transport sediment (fig. 45a). The 

lower alluvial reach (WRKM 101.4–116.6) had a residence time of approximately 0.5 years (fig. 45A).
50

The large spike near WRKM 71.0 is a discontinuity in the model at Mud Mountain Dam and does not 

represent a real response in the river.

The maximum increase in bed volume from each sediment pulse input was divided by the pulse 

volume because pulse volume had the greatest influence on bed-volume change. The maximum increase 

in bed volume normalized by the pulse volume shows what percentage of the original pulse volume will 

temporarily deposit at each model node as the sediment moves downstream (figs. 42b–45b). The 

greatest changes in bed volume due to the pulse inputs were closest to the input location, and generally 

decreased downstream. In general, the maximum increase in bed volume due to the sediment-pulse 

input was on the order of a few percent of the input-pulse volume for the lowland reaches of each river.

The maximum increase in bed volume, owing to the sediment-pulse input, for the Nisqually 

River was greatest in the upper alluvial reach (NRKM 14.2–28.2) at approximately 12 percent. The 

maximum increase in bed volume in the constricted reach (NRKM 28.6–32.6) was approximately 2.3 

percent. The lower alluvial reach (NRKM 33.0–41.0) had maximum increases in bed volume of 

approximately 2 percent (fig. 42B).

The maximum increase in bed volume, owing to the sediment-pulse input, for the Carbon River 

was greatest in the upper alluvial reach (CRKM 8.2–20.2) at approximately 18 percent, with a 

maximum between CRKM 8.2 and 10.6 of 50 percent (fig. 43B). The maximum increase in bed volume 

in the canyon reach (CRKM 20.6–37.0) was near zero as this reach was capable of quickly transporting 

sediment downstream (fig. 43B). The lower alluvial reach (CRKM 37.4–50.2) had a maximum increase 

in bed volume of approximately 1.2 percent (fig. 43B).

The maximum increase in bed volume, owing to the sediment-pulse input, for the Puyallup 

River was greatest in the upper alluvial reach (PRKM 16.2–21.0) at approximately 19 percent (fig. 

44B). The canyon reach (PRKM 21.4–33.4), like the canyon reach of the Carbon River (CRKM 20.6–

37.0), was capable of quickly transporting sediment downstream with minimal increase in bed volume 

(fig. 44B). The middle alluvial reach downstream of the canyon (PRKM 33.8–48.2) had maximum 

increases in bed volume of approximately 6 percent and farther downstream, the lower alluvial reach 

downstream of Calistoga Street (PRKM 48.6–82.2) had increases of approximately 1.5 percent (fig. 

44B).

The maximum increase in bed volume, owing to the sediment-pulse input, for the White River 

was greatest in the upper alluvial reach (WRKM 13.4–44.6) at approximately 5.3 percent (fig. 45B). 

Downstream of the confluence with the Greenwater River, in the middle alluvial reach (WRKM 45.0–

101.0), the maximum increase in bed volume, owing to the pulse, was approximately 0.5 percent, and in 

the lower alluvial reach (WRKM 101.4–116.6) the maximum increase in bed volume was 

approximately 0.3 percent (fig. 45B).

Potential Effect of Changing Hydrologic Conditions on Future Bed Elevations

Potential changes in hydrologic conditions during the next 25–50 years were simulated to assess 

possible future effects on bed elevations. Projections of future climate conditions in Washington State 

during the 21st century include increased temperatures, increased precipitation and runoff for October–

March, and decreased precipitation and runoff for April–September (compared with the mean during 

WYs 1917–2006; Elsner and others, 2010). Potential bed-elevation change was simulated for 50 years 

for WYs 2010–2059 based on projected changes in runoff from Elsner and others (2010) by repeating 

the 25-year period of daily streamflow for WYs 1982–2006 during the simulation period. The daily 

streamflows for the first 25-year period were increased by 11.6 percent for October–March and 

decreased by 18.1 percent for April–September (Elsner and others, 2010). The daily streamflows for the 
51

second 25-year period were increased by 18.1 percent for October–March and decreased by 26.3 percent 

for April–September (Elsner and others, 2010).

The model-conditioning process established a river with geomorphic characteristics that 

effectively transports sediment through the system with minimal long-term change in bed elevations. As 

a result, the model is incapable of simulating changes to a river reach undergoing conditions of rapid 

aggradation or incision. When run under the baseline condition, the conditioned model simulates 

minimal bed-elevation change after 25 and 50 years (figs. 46–49). The projected future hydrologic 

conditions were assumed to include a rate of sediment delivery close to the sediment-transport capacity 

of the upstream end of each river, without excessive aggradation or incision at the upstream end of the 

model. This assumption was necessary because there is no model of how sediment production from 

Mount Rainier will change for future climate conditions. The future conditions show potential bedelevation change after 25 and 50 years given the projected changes in streamflow resulting from 

changes in climate conditions (figs. 46–49). It is uncertain how the supply of sediment will change with 

changing streamflow, increased temperatures, and increased storm intensity. Therefore, a sensitivity 

analysis of the change in potential bed elevation due to the altered streamflow was included by 

simulating both a 10-percent increase and decrease in sediment supply.

For the Nisqually River, the average difference in bed elevations between a 10-percent increase 

and decrease in sediment supply was 0.7 m after 50 years (fig. 46). The locations where bed-elevation 

changes were predicted to be the greatest are NRKM 14.6–18.6 with deposition of approximately 0.18 

and 0.41 m of sediment after 25 and 50 years, respectively, compared to approximately 0.07 and 0.08 m 

for the baseline condition, respectively; and NRKM 24.2–31.0 with deposition of approximately 0.16 

and 0.39 m after 25 and 50 years, respectively, compared to incision of approximately 0.01 and 0 m for 

the baseline condition, respectively.

For the Carbon River, the average difference in bed elevations between a 10-percent increase 

and decrease in sediment supply was 0.04 m after 50 years (fig. 47). Bed-elevation changes of the 

Carbon River 25 and 50 years into the future were predicted to be minimal. The locations where bedelevation changes were predicted to be the greatest are CRKM 15.8–17.8 with deposition of 

approximately 0.03 and 0.05 m of sediment after 25 and 50 years, respectively, compared to 

approximately 0.02 and 0.03 m for the baseline condition, respectively; CRKM 37.4–41.4 with incision 

of approximately 0.05 and 0.11 m after 25 and 50 years, respectively, compared to approximately 0.06 

and 0.10 m for the baseline condition, respectively; and CRKM 46.6–50.2 with deposition of 

approximately 0.0 and 0.03 m after 25 and 50 years, respectively, compared to incision of 

approximately 0.04 and 0.05 m for the baseline condition, respectively.

For the Puyallup River, the average difference in bed elevations between a 10-percent increase 

and decrease in sediment supply was 0.14 m after 50 years (fig. 48). The locations where bed-elevation 

changes were predicted to be the greatest are PRKM 39.4–82.2 with deposition of approximately 0.10 

and 0.21 m of sediment after 25 and 50 years, respectively, compared to approximately 0.04 and 0.06 m 

for the baseline condition, respectively.

For the White River, the average difference in bed elevations between a 10-percent increase and 

decrease in sediment supply was 1.96 m upstream of Mud Mountain Dam (WRKM 71.0) (fig. 49). The 

locations where bed-elevation changes were predicted to be the greatest were WRKM 25.8–52.2 with 

deposition of approximately 0.22 and 0.56 m of sediment after 25 and 50 years, respectively, compared 

to incision of approximately 0.09 and 0.16 m for the baseline condition, respectively; WRKM 53.4–67.0 

with deposition of approximately 0.47 and 0.86 m after 25 and 50 years, respectively, compared to 

approximately 0.04 and 0.02 m for the baseline condition, respectively; and WRKM 71.4–82.2 with 

deposition of approximately 0.31 and 0.44 m after 25 and 50 years, respectively, compared to 
52

approximately 0.19 and 0.21 m for the baseline condition, respectively. Results are not shown for the 

section of the White River downstream of about WRKM 94. The model-conditioning process resulted in 

a predicted slope along the lower White River that was much larger than the current condition.

Therefore, the conditioned model for the lower White River is unable to simulate long-term aggradation.

The simulations of changes in bed elevation assume that future climate changes will increase 

runoff (as described by Elsner and others, 2010) and that the supply of sediment will continue to be 

large enough for the rivers to transport sediment near capacity. However, with simultaneous projections 

for increased temperatures (Elsner and others, 2010; Mote and Salathé, 2010) and more intense 

precipitation (Salathé, 2006), sediment generation and delivery to the rivers may be higher for 

comparable flows, leading to increased sediment transport and deposition in these river systems. If 

future sediment transport increases, then future bed-elevation change may be closer to the bed-elevation 

change from the model-simulation results for the future condition with a 10-percent increase in sediment 

supply. Additionally, the simulated bed-elevation changes are averaged over a large area, and it is likely 

that there will be localized variability in bed elevations larger than simulated average changes.

Synthesis of Modeling Bed-Material Transport by Rivers

One-dimensional river-hydraulic and sediment-transport models were developed using the 

unified gravel-sand (TUGS) model (Cui, 2007a) for the Nisqually, Carbon, Puyallup, and White Rivers 

simulating the entrainment, transport, abrasion, and deposition of sediment with channel-geometry, 

streamflow, and sediment data as major inputs. The upstream extent of each model was chosen where 

the river had a slope of approximately 0.02 m/m. A model-conditioning process was used to adjust bed 

elevations and bed grain-size distributions in order to establish quasi-equilibrium prior to model 

simulations. Results of model simulations were compared to physical measurements and it was 

concluded that the models generally were able to simulate predicted loads and were able to provide 

insight into questions regarding the quantity, spatial and temporal distribution, downstream effect, and 

future outlook of sediment transport by rivers draining Mount Rainier.

Simulations of the entire long-term streamflow record for the Nisqually River at State Route 7

(NRKM 41.0), Carbon River at State Route 162/Pioneer Way (CRKM 41.0), Puyallup River at 

Calistoga Street (PRKM 48.6), and White River at R Street (WRKM 104.6) resulted in simulated annual 

bed-material sediment loads consistent with streamflow that was largest for the Nisqually River 

(690,000 m3/yr) and was smaller for the White (530,000 m3/yr), Puyallup (83,000 m3/yr), and Carbon 

(15,000 m3

/yr) Rivers. The simulated bed-material sediment loads were 340,000–1,500,000 m3/yr for 

the Nisqually River, 2,800–77,000 m3/yr for the Carbon River, 28,000–260,000 m3/yr for the Puyallup

River, and 250,000–900,000 m3

/yr for the White River. The simulated annual bed-material sediment 

load was, on average, 8, 16, 8, and 16 percent gravel and coarser for the Nisqually, White, Puyallup, and 

Carbon Rivers, respectively, which suggests that of the sediment measured in the delta of the Nisqually 

River in Alder Lake, 8 percent is gravel and coarser sediment. 

Model simulations investigated how increases in sediment supply to rivers, as pulses distributed 

during the first year of simulation, are transported through the river systems and affect lowland reaches. 

The set of model simulations for each river consisted of 36 different conditions: 3 hydrologic 

conditions, 2 pulse volumes, and 6 pulse grain sizes. The set of model simulations had varied 

hydrology, repeating 10-year periods of daily discharge of high (WYs 1995–2004), medium (WYs

1975–1984), and low (WYs 1985–1994) flow, pulse volume (100,000 and 500,000 m3 supplied to the 

upstream end of the model throughout the first simulation year), and pulse grain size (uniform 

distribution where 100 percent is finer than 4, 8, 16, 32, and 64 mm, and a distribution of sand). For 

each hydrologic condition, simulation results of a baseline condition (without an input sediment pulse) 
53

were subtracted from a sediment-pulse condition (with different pulse volumes and grain size) to isolate 

the response of the input sediment pulse. For each simulation, the input sediment pulse evolved through 

a combination of translation, dispersion, and attrition as it moved down the river system. The magnitude 

of geomorphic change at each location along each river due to the input sediment pulse was quantified 

as the maximum increase through time in bed volume and sediment load compared to the baseline 

condition.

The characteristic transport time for each simulated pulse to move through the river strongly 

depended on the grain size of the pulse compared to that of the bed surface. Sediment pulses finer than 

the median size of the bed surface transported faster than pulses that are closer to the median size of the 

bed surface, and pulses coarser than the median size of the bed surface transported slowly with in-place 

attrition dominating pulse evolution (Cui and others, 2003; Cui and Parker, 2005; Sklar and others, 

2009). The characteristic transport time for the median sediment size to arrive downstream for the 

Nisqually River at State Route 7, Carbon River at State Route 162/Pioneer Way, Puyallup River at 

Calistoga Street, and White River at R Street was approximately 70, 300, 80, and 60 years, respectively. 

Increased sediment input to the upper rivers beginning in 1967 (Copeland, 2009) would have affected 

the Puget Lowland sooner in the Puyallup River than in the Carbon River because of their different time 

scales for downstream transport and change, which may explain the pattern of change in average 

channel elevation between 1984 and 2009 measured by Czuba and others (2010, fig. 10).

In general, model simulations showed the following: (1) an increase in pulse grain size led to an 

increase in the characteristic transport time (later time of arrival) and a decrease in sediment load; (2) an 

increase in pulse volume led to an increase in the characteristic transport time, bed volume, and 

sediment load; and (3) an increase in streamflow led to a decrease in characteristic transport time and an 

increase in sediment load. As the pulse grain size gets larger, it takes longer to transport this sediment 

downstream because fewer flows occur that are capable of transporting this sediment, and when this 

sediment does arrive, the increased sediment load is smallest for the largest size classes. As the pulse 

volume increases, it takes longer to transport this sediment downstream because more sediment needs to 

be moved before half of the pulse is transported, and the bed volume and sediment load increases 

because there is more sediment that can ultimately deposit and transport as the sediment moves 

downstream. As the magnitude or frequency of sediment-transporting streamflow increases, sediment 

moves downstream more rapidly and the loads are larger. The greatest changes in bed volume due to the 

pulse inputs were closest to the input location, and generally decreased downstream.

Potential changes in hydrologic conditions during the next 25–50 years (Elsner and others, 2010) 

were simulated to assess possible future effects on bed elevations. The projected future hydrologic 

conditions were assumed to include a rate of sediment delivery close to the sediment-transport capacity 

of the upstream end of each river, without excessive aggradation or incision at the upstream end of the 

model. It is uncertain how the supply of sediment will change with changing streamflow, increased 

temperatures, and increased storm intensity. Therefore, a sensitivity analysis of the change in potential 

bed elevation due to the altered streamflow was included that takes into account a 10-percent increase 

and decrease in sediment supply. The maximum predicted bed-elevation changes for each river (within 

the modeling domain) after 50 years were about 0.5 m for the Nisqually River, 0.1 m for the Carbon 

River, 0.4 m for the Puyallup River, and 1.0 m for the White River assuming these rivers are currently 

in a quasi-equilibrium state, which may not be the case for select reaches of these rivers. The modelconditioned slope of the White River was larger than the raw input between WRKM 111.0–116.6 

because the tendency of the model, during the model-conditioning process, was to increase the slope of 

the river in order to more efficiently transport sediment through this reach. This highlights that the lower 

White River (WRKM 111.0–116.6) does not effectively transport sediment downstream and that model 
54

simulations of potential future bed-elevation change probably are low for this reach. The simulations of 

changes in bed elevation assume that future climate changes will simply increase the runoff (as 

described by Elsner and others, 2010) and that the supply of sediment will continue to be large enough 

for the rivers to transport near capacity. However, with simultaneous projections of increased 

temperatures (Elsner and others, 2010; Mote and Salathé, 2010) and more intense precipitation (Salathé, 

2006), sediment generation and delivery to the rivers may be higher for the same flow leading to 

increased sediment input and deposition in these river systems.

Implications for River Management

Although the data are insufficient to state with statistical significance that there is a long-term 

increasing trend of sediment production from Mount Rainier, predictions of increasing hydrologic 

runoff with climate change suggest that aggradation rates in the 21st century may increase. More 

relevant to river managers working in the catchment, however, is the fact that large sediment loads have 

affected the region’s rivers since at least the early 20th century (Roberts, 1920) and will continue to 

affect rivers downstream of Mount Rainier as long as an active stratovolcano is located within the 

watershed and sediment-transporting floods occur.

River managers challenged with balancing objectives of flood protection and ecological 

productivity are forced to manage sediment generated from an effectively continuous source. Sediment 

is transported from Mount Rainier to the Puget Lowland through a sequence of glacial and fluvial 

processes working synchronously to deliver material downstream. Once sediment arrives and deposits 

in the Puget Lowland, there are limited structural methods for managing sediment to reduce flood risk. 

Potential sediment-management actions, including setback levees and gravel removal, would be most 

effective in reaches that tend to accumulate sediment naturally; these reaches were identified based on 

geomorphic conditions. Furthermore, river management is complicated given future predictions of more 

intense precipitation in western Washington during the 21st century (Salathé, 2006; Mote and Salathé, 

2010) with the potential for more hydrogeomorphic disturbance to mountainous catchments and larger 

floods that likely will lead to increased sediment production and delivery from Mount Rainier.

Aggradation Potential in the River Network

The White River has a slope of approximately 0.0060 m/m as it exits the mountain front 

(WRKM 103.0) that decreases to approximately 0.0009 m/m before joining the Puyallup River (WRKM 

116.6). The sediment-transport model-conditioning process predicted quasi-equilibrium conditions for 

the lower White River, whereby a minimum slope of 0.0023 m/m would be needed to efficiently 

transport all bedload through the reach. This suggests that the lower White River will continue to 

aggrade until it reaches a slope of approximately 0.0023 m/m. In order for the lower White River to 

achieve this slope, bed elevations would have to increase by more than 8 m between R Street (WRKM 

104.6) and the Lake Tapps Return (WRKM 110.6) (fig. 50). With the current levee-width spacing, the 

volume of sediment required for the river to reach this quasi-equilibrium state is 4,600,000 m3. If

bedload deposited in the White River at the same rate measured between 1984 and 2009 (16,700 m3/y; 

Czuba and others, 2010), this reach of the White River would grade to these equilibrium conditions in

about 275 years, assuming deposition patterns of incoming bedload remains constant. This assumption 

is unrealistic because as slope increases, the reach would more efficiently pass bedload. Nonetheless, 

this simple analytical exercise illustrates the challenges in managing this reach of the White River. 

Analysis of the sediment-transport models and the bedload-transport relation (figs. 27 and 28) 

indicates that the Carbon River delivers about an order of magnitude less bedload to the Puget Lowland 
55

than the White River. The bedload transport of the lower Carbon River is small for two reasons: (1) the 

contributing catchment area is small relative to other main-stem rivers, and (2) the upper Carbon River 

flows through a wide flood-plain valley still adjusting to the geomorphic influence of Pleistocene alpine 

glaciation (Church and Slaymaker, 1989). The upper Carbon River has not been subject to multiple, 

large lahars and associated elevated fluvial sediment loads like the other river systems around Mount 

Rainier (Scott and others, 1995). As a result, the upper Carbon River likely is retaining a larger

proportion of sediment than the neighboring rivers, reflected in the long characteristic residence time of 

sediment (fig. 43). This reduced bedload potential of the Carbon River also helps explain the findings of 

Czuba and others (2010) that little to no aggradation occurred in the lower Carbon River near Orting 

between 1984 and 2009.

The Puyallup River delivers about four times less bedload than the White River. The Puyallup 

River was affected by multiple large lahars, including the recent Electron Mudflow, that constricted the

upper Puyallup River into a more confined flood-plain corridor. The active-channel width analysis (fig. 

13) indicates that recent post-1990 sediment delivery to the upper Puyallup River system has been less 

than sediment delivered to other main-stem rivers.

Given the bedload-transport capacity and new sediment supply from Mount Rainier, the White 

River near Auburn likely will continue to aggrade significantly in the coming decades. The Puyallup 

River will experience less severe aggradation, and the Carbon River will experience the least 

aggradation. Although the Puyallup River near Orting aggraded significantly between 1984 and 2009 

(Czuba and others, 2010), this aggradation likely reflected the presence of two setback levee projects, 

which trapped a larger proportion of the total sediment load.

The upper Nisqually River has a geomorphic character similar to that of the upper White River. 

The river has been subjected to large fluvial sediment loads during the 20th century, but because it has 

graded to an equilibrium state influenced by heavy sediment loads during multiple eruptive periods, the 

reach transports much of the available bedload. The sediment-transport model suggests there is some 

potential for aggradation along the upper Nisqually River downstream of the national park boundary if 

large sediment pulses arrive from Mount Rainier. 

Potential Sediment-Management Locations

The methods used for managing sediment to reduce flood risk in the lower Puyallup, White, and 

Carbon Rivers have changed through time (Pierce County, 2012). From the 1900s through 1960s, major 

modifications were made to the river channels to increase flow conveyance, including straightening of 

channels, levee and revetment construction, and removal of sediment and large wood. During the early 

and middle 20th century, gravel dredging was common, and hundreds of thousands of cubic meters of 

sediment were removed (Prych, 1988; Czuba and others, 2010; Herrera Environmental Consultants, 

2010). With improved awareness of the ecological effects of gravel removal, gravel scalping became the 

preferred sediment-removal approach. More recently, setback-levee projects have been used to reduce 

flooding risk (Czuba and others, 2010; Pierce County, 2012).

Potential sediment-management actions, including setback levees and gravel removal, would be 

more effective in reaches that tend to accumulate sediment naturally. These reaches have less capacity 

to transport sediment with decreasing channel slope or increasing active-channel width. Additionally, 

reaches with long characteristic sediment residence times offer a longer window of opportunity to 

manage the accumulated sediment. Based on the residence time of sediment, locations along each river 

were roughly characterized into four transport categories: sediment sinks, long-term transient-storage 

reaches, mid-term transient-storage reaches, and transport reaches. Sediment sinks are areas that 

significantly aggrade or store sediment over long periods of time (greater than 100 years). Long-term 
56

transient-storage reaches have long residence times for sediment (between 50 and 100 years) and midterm transient storage reaches have moderate residence times for sediment (between 5–50 years). 

Transport reaches transport sediment downstream relatively quickly with short resident times (less than 

5 years) and bed-elevation changes in these reaches tend to be small.

Sediment sinks include the Nisqually River delta in Alder Lake and the Puyallup River delta in 

Commencement Bay of Puget Sound. Long-term transient-storage reaches include the Mud Mountain 

Dam reservoir (WRKM 63.7–71.0), setback-levee reaches (specifically, PRKM 41.9–44.1 and PRKM 

45.6–47.4), the county-line reach of the White River (WRKM 104.5–110.8), and the upper alluvial 

reach of the Carbon River (CRKM 13.7–24.6) (fig. 51). Mid-term transient-storage reaches include the 

upper and lower alluvial reaches of the Nisqually River (NRKM 23.0–28.4 and NRKM 32.8–37.2, 

respectively), the lower alluvial reach of the Carbon River (CRKM 34.4–45.8), the upper and middle 

alluvial reaches of the Puyallup River (PRKM 16.0–21.3 and PRKM 34.0–49.7 downstream of the 

bedrock canyon, respectively, and not including setback-levee reaches), and the middle alluvial reach 

upstream of Mud Mountain Dam on the White River (WRKM 54.3–62.4) (fig. 51). Transport reaches 

make up the remainder of the river network.

Opportunities for Future Research

Rivers draining Mount Rainier can be assumed to be in a general state of sediment surplus, a 

reasonable assumption given recent aggradation trends in Mount Rainier National Park (Beason and 

Kennard, 2007), aggradation rates measured in the Puget Lowland (Czuba and others, 2010), and the 

widespread distribution of sand throughout the fluvial network. As a result, future aggradation rates will 

be largely governed by the underlying hydrology that transports sediment downstream. If a series of 

large floods occurs in the coming decades, increased rates of aggradation are likely. The rivers in the 

network transport sediment in quantities proportional to the underlying hydrologic conditions, and the 

sediment load can vary by an order of magnitude from year to year (Nelson, 1978). River managers 

tasked with flood management in lowland reaches could monitor the size and duration of peak flows 

during a winter flood season to get an early indication of aggradation potential. A more direct method of 

monitoring aggradation includes analyzing flood-conveyance capacity at existing gages (Czuba and 

others, 2010) or establishing an array of stage gages along an aggrading reach to compare trends in 

water-surface elevation for a given discharge. 

Cross-section analysis (Prych, 1988; Czuba and others, 2010) is an effective way to measure 

aggradation. Long-term monitoring of georeferenced cross sections in aggradation- and flood-prone 

reaches of the region’s rivers would provide early warning of reduced flood-conveyance capacity.

Within the framework of ongoing monitoring, the White River near Auburn is the reach most prone to 

aggradation and compromised channel-conveyance capacity, thus requiring more frequent monitoring.

The Puyallup River near Orting has been subject to significant aggradation recently, but setback levees 

and a smaller relative sediment supply from upstream means that this reach would require less-frequent 

monitoring than the lower White River. The upper Nisqually River, upstream of the Nisqually River 

near National gage, is prone to aggradation, and monitoring cross sections here would provide useful

geomorphic data. Although the Carbon River near Orting seems to be a transport reach with less 

aggradation (Czuba and others, 2010), cross-section monitoring in the lower Carbon River could 

provide early warning of geomorphic change due to increased bedload arriving from upstream sources.

Finally, cross sections established along the White River downstream of the national park boundary 

could be used to monitor the movement of sediment pulses moving away from Mount Rainier. 

Recent advances in sediment-surrogate technologies (Gray and Gartner, 2009; Gray and others, 

2010) coupled with strategic sediment sampling enables the near-continuous measurement and reporting 
57

of sediment load in rivers. The estimated suspended-sediment load for the Puyallup River at Puyallup 

gage (12101500) and at locations within the watershed may be inaccurate due to the sparse and aging 

data sets and the variable nature of sediment transport. Recent application of this technology has greatly 

improved the ability to quantify and reduce uncertainty of sediment-delivery estimates by the Skagit 

River (Czuba and others, 2011). Application of these technologies would improve the understanding of 

sediment transport and delivery from rivers draining Mount Rainier. Strategic deployment of sedimentsurrogate technologies (such as turbidity) at key locations within the watershed would improve the 

monitoring and assessment of geomorphic disturbance (such as landslides and debris flows) as major 

contributors of sediment to the river system. Measured high turbidity events could be combined with 

field reconnaissance, aerial photography, and geographic information systems to accurately map sources 

of sediment and quantify the amount of sediment delivered to the river system (Sobieszczyk and others, 

2007).

As the lower White River downstream of R Street continues to aggrade (Czuba and others, 

2010), quantifying the amount of sediment transporting past R Street becomes important. Application of 

passive hydrophones as a bedload surrogate technology (Gray and others, 2010) would provide a near 

continuous estimate of bedload transport that can be used to anticipate the volume of sediment deposited 

in the lower White River and subsequent aggradation. Combining the continuous monitoring of bedload 

past R Street with a stage-monitoring network in the downstream aggrading reach would not only 

provide timely insight into potentially hazardous accumulation of sediment but also would provide 

important insight of the hydrological mechanics of sediment delivery from upstream and deposition 

patterns within the river.

A key component to understanding sediment transport in the White River is a better 

understanding of the movement of bedload through Mud Mountain Dam. Analysis of topography in the 

reservoir delta and modeling of the sediment-transport capacity through the structure would give 

important insight into the current bedload trap efficiency of the dam and how bedload transport rates 

downstream of the dam may change in the future. Ongoing monitoring of sediment accumulation and 

delivery downstream also would provide early warning of sediment pulses moving downstream. 

Because of the unique operations of the dam, the structure also may be a location where gravel could be 

removed in an ecologically sensitive fashion.

The sediment-production-potential analysis of this study offers a coarse estimate of the sediment 

generation from mountainous watersheds outside Mount Rainier National Park, but the accuracy of the 

analysis was limited. The construction of a full sediment budget would help to better identify 

watersheds prone to sediment production. Estimates of sediment production from landslides would 

benefit from landslide mapping and assessments of landslide potential from established models 

(Dietrich and others, 1995; Montgomery and others, 1998). Additionally, new sediment-fingerprinting 

techniques that identify sources of sediment within sediment budgets (Collins and others, 2010; Evrard 

and others, 2011; Gellis and Walling, 2011) may be effective at identifying source area from sediment 

loads in rivers or from sediment accumulations in reservoirs.

Summary and Conclusions

A comprehensive study of the geomorphology of rivers draining Mount Rainier was completed 

using published climate-change scenarios to assess current sediment loads, identify sources of sediment 

to the river network, identify important processes in the sediment-delivery system, evaluate if there were 

trends in streamflow or sediment load since the early the 20th century, and assess how rates of 

sedimentation might continue into the future. 
58

The longitudinal profiles of the Nisqually, Puyallup, Carbon, and White Rivers reflect similar 

geomorphic evolution since the end of the Pleistocene. Each of these rivers drains Mount Rainier first 

through alluvial mountainous reaches, and then through one or more bedrock-controlled reaches, and 

finally through reaches incised into glacial till deposited by the Puget Lobe of the Cordilleran Ice Sheet 

before entering wide, alluvial flood plains of the Puget Lowland. The rivers were shaped by heavy 

sediment loads from the volcano. Because of ample sediment supply during the Holocene, the 

Nisqually, Puyallup, and White Rivers have all graded to a quasi-equilibrium balancing their dominant 

sediment loads with the underlying hydrology. Although there are aggradation zones of transient 

accumulation along each river, most of these river corridors efficiently transport sediment from the 

mountain to deposition zones on alluvial fans in the Puget Lowland. However, geologic evidence along 

the upper Carbon River suggests this drainage was rarely affected by large lahars. As a result, the active 

flood plain in the upper Carbon River is unusually wide and the river slope is less than at comparable 

locations on other rivers. It appears that the Carbon River is still in disequilibrium following Pleistocene 

alpine glaciation and stores more sediment than it passes. The Muddy Fork Cowlitz River and the 

Ohanapecosh Rivers mostly cut through long bedrock-controlled reaches for about 10 kilometers before 

joining in the main-stem Cowlitz River near Packwood. Qualitative assessments of the geomorphology 

of the Cowlitz River indicate that large recent floods have impacted the Cowlitz River basin, but the 

overall sediment load likely is less than loads in the other four main-stem rivers draining Mount Rainier.

The total sediment load of the upper Nisqually River from 1945 to 2011 was determined to be 

1,200,000±180,000 tonnes per year (tonnes/yr), and the total sediment load passing Alder Dam during 

the same time period was calculated to be 120,000±18,000 tonnes/yr. From 1956 to 1985, the total 

sediment load in the upper Nisqually River was determined to be 860,000±370,000 tonnes/yr, a 

significant decrease relative to the total load from 1945 to 2011 and indicative of a less-active 

hydrogeomorphic period affecting Mount Rainier from the 1960s to 1980s. Using available suspendedsediment measurements, the suspended-sediment load in the lower Puyallup River at Puyallup was 

found to be 860,000±300,000 tonnes/yr between 1978 and 1994. It is likely that increased streamflow 

and sediment released from the catchment starting in the 1990s increased the sediment load of the 

Puyallup River to about 1.0 million tonnes/yr. The White River likely carries a long-term sediment load 

of about 500,000 tonnes/yr. Calculations from this study showed that the White River at R Street carried 

a total load of 590,000 tonnes in water year 2011 and an annualized total load of 420,000 tonnes/yr from 

April 2010 to March 2012. 

Bedload was measured to be 64,500 tonnes during water year 2011 along the lower White River 

and averaged 46,000 tonnes/yr on the White River from April 2010 to March 2012. Bedload versus 

discharge values were found to be similar on the Carbon, Puyallup, and White Rivers where these rivers 

exit the mountain front and first enter the Puget Lowland. Using a coarse-resolution bedload-transport 

relation developed from data for all three rivers and applying to measured daily discharge data from 

each river, the long-term average bedload from 1984 to 2009 was estimated to be 29,000±18,000 

tonnes/yr for the White River near Auburn, 7,800±7,200 tonnes/yr for the Puyallup River near Orting, 

and 2,700±2,800 tonnes/yr for the Carbon River near Orting. 

An analysis of 27 mountainous subcatchments contributing to the Nisqually, Puyallup, Carbon, 

and White Rivers outside Mount Rainier National Park was made to estimate sediment-production 

potential due to roads, landslides, and soil-creep processes. The upper White River contributed the 

greatest load of sediment (130,000±89,000 tonnes/yr) while subcatchments to the Nisqually, Puyallup, 

and Carbon Rivers delivered 50,000±33,000 tonnes/yr, 42,000±29,000 tonnes/yr, and 42,000±28,000 

tonnes/yr, respectively. The dominant source of sediment loads was Mount Rainier. For the sediment 

load in the upper Nisqually River, about 83–98 percent was estimated to originate from within Mount 
59

Rainier National Park. For the upper White River, about 51–91 percent of the total sediment load was 

estimated to originate from within the national park. For the lower Puyallup River, with contributions 

from the White, Carbon, and upper Puyallup River, about 58–93 percent of the total sediment load was 

estimated to originate from within the national park. 

The active-channel width of rivers directly draining Mount Rainier in 2009, used as a proxy for 

bedload and sediment released from Mount Rainier, was locally as wide as 365 m. The Nisqually River, 

from the national park boundary to Alder Lake, had the largest average active-channel width in 2009 

(231 m) and the Carbon River upstream of the national park boundary had the next widest reach (208 

m). In general, active-channel widths of glacier-draining rivers were less in 1965 and 1994 than widths 

measured in 2009. For most rivers, active-channel width changed little between 1965 and 1994 

reflecting a climatic period that was relatively quiet hydrogeomorphically. From 1994 to 2009, a marked 

increase in hydrogeomorphic disturbance within the watershed caused the active channels in many river 

reaches to widen. Widening was particularly pronounced in the upper Nisqually River system, the upper 

Carbon River, the White River, the West Fork White River, and the Mowich River. Little or no 

disturbance was recorded in the Muddy Fork Cowlitz River, its tributaries, and the Ohanapecosh River. 

The South Fork Puyallup River also had little change. Comparison of the elevation of the active channel 

to the first forested terrace adjacent the river showed areas of recent aggradation along much of the 

Carbon River, along the upper Nisqually River, and along the White River. 

Comparing active-channel widths of glacier-draining rivers in 2009 to the distance of glacier 

retreat between 1913 and 1994 showed no correlation, suggesting that geomorphic disturbance in river 

reaches directly downstream of glaciers is not strongly governed by the degree of glacial retreat. In 

contrast, a correlation was found between active-channel width as measured in 2009 and the percentage 

of superglacier debris mantling the upstream glacier as measured in 1971. A conceptual model of 

sediment-delivery processes from the mountain suggests that rockfalls, glaciers, debris flows, and mainstem flooding sequentially act to deliver sediment from Mount Rainier to river reaches in the Puget 

Lowland over decadal time scales. If one or more of these processes slow or cease, the overall sediment 

delivery to lowland reaches would eventually decrease. Conversely, if all of these processes increased 

concurrently, sediment delivery to lowland reaches would increase. 

Streamflow trends in rivers draining Mount Rainier were linked to the Pacific Decadal 

Oscillation, which has phases that persist for 20–30 years. Greater-than-normal runoff was associated 

with cool phases of the Pacific Decadal Oscillation. However, a link between the Pacific Decadal 

Oscillation and individual peak-flow events was not found. Moreover, streamflow-gaging data from 

four unregulated rivers directly draining Mount Rainier (the upper Nisqually, Cowlitz, Puyallup, and 

Carbon Rivers) indicated no statistically significant trends of increasing peak flows over the course of 

the 20th century. 

Data sets collected since the 1940s—that is, sediment accumulation in Alder Lake, analysis of 

changes in active-channel width, sediment-load data collected from the 1970s to the present, and 

hydrologic data from gaging stations—indicate that sediment loads from 1990 to the present likely are 

greater than sediment loads in comparable river reaches from the 1960s to 1980s. Data are insufficient, 

however, to determine definitively if post-1990 increases in sediment production and transport from 

Mount Rainier represent a statistically significant increase relative to sediment-load values typical from 

Mount Rainier during the entire 20th century.

One-dimensional river-hydraulic and sediment-transport models for the Nisqually, Carbon, 

Puyallup, and White Rivers simulated the entrainment, transport, abrasion, and deposition of sediment

with channel-geometry, streamflow, and sediment data as major inputs. Results of model simulations 

were compared to physical measurements indicating the models generally were able to simulate 
60

predicted loads and provide insight into aggradation potential along rivers draining Mount Rainier. But 

coarse data sets and issues arising from uncertainties associated with the downstream boundary 

condition of some rivers, particularly the White River, created inaccuracies in some predictions of 

aggradation. Nonetheless, the model proved useful for comparisons between rivers. 

Simulations showed that bed-material loads were largest for the Nisqually (690,000 cubic meters 

per year [m3/yr]) and White Rivers (530,000 m3/yr) and smallest for the Puyallup (83,000 m3/yr) and 

Carbon Rivers (15,000 m3

/yr) Rivers. The characteristic transport time for each simulated pulse to move 

through the river strongly depended on the grain size of the pulse compared to that of the bed surface. 

Sediment pulses finer than the median size of the bed surface transport faster than pulses that are closer 

to the median size of the bed surface, and pulses coarser than the median size of the bed surface 

transport slowly with in-place attrition dominating pulse evolution. The characteristic transport times for 

the median sediment size to arrive downstream for the Nisqually, Carbon, Puyallup, and White Rivers 

were approximately 70, 300, 80, and 60 years, respectively. In general, model simulations showed that 

an increase in pulse grain size led to an increase in the characteristic transport time (longer time of 

arrival) and a decrease in sediment load. An increase in pulse volume led to an increase in the 

characteristic transport time, bed volume, and sediment load. An increase in streamflow led to a 

decrease in characteristic transport time and an increase in sediment load. The greatest changes in bed 

volume due to the pulse inputs were closest to the input location, and generally decreased in the 

downstream direction.

Potential changes in hydrologic conditions during the next 25 to 50 years were assessed to 

predict future effects on aggradation. When compared to the current bedload-transport relation for the 

White River, predicted future changes in hydrologic conditions suggested that bedload transport would 

increase in the White River by 30 percent in 25 years and by 48 percent in 50 years. Of the river reaches 

analyzed, the aggradation potential was determined to be the greatest in the lower White River near 

Auburn, where the slope significantly decreases, incoming sediment load is large, and background 

hydrology effectively transports bedload through the reach. The lower Puyallup River near Orting also 

has a large aggradation potential, but the anticipated aggradation here likely will be less than 

aggradation along the lower White River owing to a smaller contributing catchment and less relative 

sediment mobilization from Mount Rainier. The Nisqually River, upstream of Alder Lake, has less 

aggradation potential compared to the lower White River. The lower Carbon River near Orting, owing

to its small catchment and small relative sediment-conveyance potential along its upper flood plain, has 

the smallest potential for future aggradation.

The White River near Auburn has a slope of approximately 0.0060 meters per meter (m/m) as it 

exits the mountain front and decreases to approximately 0.0009 m/m before it enters the Puyallup River. 

In order to efficiently transport sediment through this reach, the lower White River will continue to 

aggrade until it reaches a slope of approximately 0.0023 m/m, when it will be capable of transporting 

coarse bedload to the Puyallup River. In order for the lower White River to achieve this slope, bed 

elevations will have to increase by as much as 8 m. The volume of sediment required for the river to 

reach this quasi-equilibrium state is 4,600,000 m3

, assuming that containment levees are spaced in their 

current position and are raised with the aggrading bed. Assuming that all bedload past R Street deposits

in the White River at a rate of 16,700 m3

/yr, with no gravel removal and no changes in current 

depositional patterns, the county-line reach of the White River would grade to equilibrium conditions in

about 275 years.

Rivers draining Mount Rainier can be assumed to be in a general state of sediment surplus. As a 

result, future aggradation rates will be largely influenced by the underlying hydrology carrying sediment 

downstream. Early indications of increasing aggradation can be inferred through monitoring of the size 
61

and duration of floods during a given winter season using the existing gaging network. Modeling from 

the study identified reaches within the river network where sediment residence times were large; rivermanagement actions in these reaches, including setback-levee projects and gravel removal, would be

more effective than in transport reaches. Long-term river-management decisions can be improved with 

the monitoring of suspended-sediment load, bedload, and aggradation in river reaches in the Puget 

Lowland as well as monitoring of key sediment-delivery processes on the mountain, including glacial 

dynamics and debris-flow activity.

Acknowledgments

Sarah Henneford, U.S. Geological Survey, digitized many of the historical surveys and helped 

collect bed-material sediment data. Matt Marineau and Mark Mastin, U.S. Geological Survey, collected

bed-material sediment and channel cross-section data. Art Horowitz, U.S. Geological Survey, offered 

insight concerning calculation of sediment loads using historical data. Yantao Cui, Stillwater Sciences, 

provided the source code for the TUGS model. Wes Lauer, Seattle University, provided important 

feedback on the content of the report. Cascade Water Alliance provided funding for turbidity monitoring 

on the lower White River. The U.S. Army Corps of Engineers provided funding for sediment sampling 

on the lower White River. 

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Figure 1. Map showing rivers, basin boundaries, U.S. Geological Survey streamflow-gaging stations, and 

tributaries draining Mount Rainier, Washington, along with river stationing used in the this study.
74

Figure 2. Conceptual model of processes affecting sediment delivery from Mount Rainier, Washington.
75

Figure 3. Images of the headwaters of the White River at the terminus of the Emmons Glacier, Mount Rainier, 

Washington: (A) July 18, 1959 (published by Sigafoos and Hendricks, 1961; numbered points indicate 

botanical study locations), (B) 1964 (photo by D.R. Crandell), (C) August 29, 1969 (published by Sigafoos and 

Hendricks, 1972), and (D) August 14, 2011 (photo by C.S. Magirl).
76

Figure 4. Graph showing river elevation profiles for main-stem rivers and tributaries of the (A) Puyallup, 

(B) White, (C) Carbon, (D) Nisqually, and (E) Cowlitz Rivers, Washington.
77

Figure 4. Graph showing river elevation profiles for main-stem rivers and tributaries of the (A) Puyallup, 

(B) White, (C) Carbon, (D) Nisqually, and (E) Cowlitz Rivers, Washington.—continued
78

Figure 5. Graph showing bed-material size gradations of the Puyallup, Carbon, White, and upper Nisqually 

Rivers, Washington.
79

Figure 6. Maps showing bed-material size gradations of the Nisqually, Carbon, Puyallup, and White Rivers, 

Washington: (A) percentage of sand in bed-surface sediment and (B) D90 size of bed-surface sediment (only 

including sizes greater than 2 mm).
80

Figure 7. Graphs showing (A) Hydrologic conditions during the 20th century in the Mount Rainier, Washington, 

catchment as reflected in 10-year moving-average daily-discharge values, normalized by the mean annual 

flow, for U.S. Geological Survey streamflow-gaging stations Puyallup River at Puyallup (12101500) and the 

Cowlitz River at Packwood (14226500); and (B) 10-year moving average of sea surface temperatures in the 

northern Pacific Ocean as reflected with the Pacific Decadal Index.
81

Figure 8. Graph showing annual peak flows for U.S. Geological Survey streamflow-gaging stations on 

unregulated section of the main-stem rivers draining Mount Rainier, Washington: (A) the Puyallup River near 

Orting gage (12093500), (B) the Carbon River near Fairfax gage (12094000), (C) the Cowlitz River at 

Packwood gage (14226500), and (D) the Nisqually River near National gage (12082500). 
82

Figure 9. Graph showing stage for median flow and daily discharge as measured at the U.S. Geological Survey 

streamflow-gaging station Nisqually River near National (12082500).
83

Figure 10. Map showing active-channel width in 2009 of rivers draining Mount Rainier, Washington.
84

Figure 11. Graph showing active-channel width from 1965, 1994, and 2009 of rivers draining Mount Rainier, 

Washington.
85

Figure 12. Map showing change in active-channel width from 1965 to 1994 for rivers draining Mount Rainier, 

Washington.
86

Figure 13. Map showing change in active-channel width from 1994 to 2009 for rivers draining Mount Rainier, 

Washington.
87

Figure 14. Graph showing the difference in elevation between the forested terrace adjacent to the active channel 

and the active channel for the (A) Carbon River, (B) Nisqually River, (C) Puyallup River, and (D) White River, 

Washington. Error bars represent one standard deviation of elevation data from forested terrace. All elevation 

data taken from available light detection and ranging digital elevation models.
88

Figure 15. Graph showing active-channel width of rivers draining Mount Rainier, Washington, in 2009 versus (A) 

total glacier retreat from 1913 to 1994 of river’s primary glacier source and (B) percentage of mantling of 

superglacial debris on river primary glacier source. All glacier data by Nylen (2004).
89

Figure 16. Map showing location of 27 subcatchments analyzed to calculate sediment-production potential and the 

three additional subcatchments used for calibration. (MORA stands for Mount Rainier National Park.)
90

Figure 17. Graph showing relation between the predictions of sediment-production potential from five calibration 

subcatchments and the measured total sediment load. Error bars represent uncertainty in the sediment-load 

predictions. The diagonal line represents perfect agreement between predictions and actual loads.
91

Figure 18. Map showing predicted sediment-production yield from roads, landslides, and soil creep for 

mountainous subcatchments outside Mount Rainier National Park that contribute to the Puyallup, Carbon, and 

White Rivers and the upper Nisqually River.
92

Figure 19. Graph showing suspended-sediment concentration versus discharge as collected in 1974–1976 by 

Nelson (1978) at U.S. Geological Survey streamflow-gaging station White River below Clearwater River near 

Buckley (12097850). 

Figure 20. Graph showing suspended-sediment concentration for water years 1978–1994 at U.S. Geological 

Survey streamflow-gaging station Puyallup River at Puyallup (12101500).
93

Figure 21. Graph showing annual suspended-sediment load and daily streamflow at U.S. Geological Survey

streamflow-gaging station Puyallup River at Puyallup (12101500).
94

Figure 22. Graph showing regression equations used to estimate suspended-sediment concentration and fine 

suspended-sediment concentration from turbidity at U.S. Geological Survey streamflow-gaging station White 

River at R Street near Auburn (12100490).

Figure 23. Graph showing regression equation used to estimate bedload from streamflow at U.S. Geological 

Survey streamflow-gaging station White River at R Street near Auburn (12100490).
95

Figure 24. Graph showing time series of streamflow and suspended-sediment concentration at U.S. Geological 

Survey streamflow-gaging station White River at R Street near Auburn (12100490). The time when suspendedsediment and bedload measurements were made are indicated on the streamflow hydrograph.

Figure 25. Graph showing time series of streamflow, cumulative suspended-sediment load, cumulative fine 

suspended-sediment load, and cumulative bedload for water year 2011 at U.S. Geological Survey streamflowgaging station White River at R Street near Auburn (12100490).
96

Figure 26. Graph showing suspended-sediment loads for 3-month periods at the U.S. Geological Survey 

streamflow-gaging station White River at R Street near Auburn (12100490). Error bars represent the 95 

percent confidence intervals for the quarterly estimate.

Figure 27. Graph showing bedload measurements from 1986 and 2010-2011 at U.S. Geological Survey

streamflow-gaging stations Carbon River near Orting (12094300, referred to as Carbon River at Crocker by 

Sikonia, 1990), Puyallup River near Orting (12093500), and White River at R Street near Auburn (12100490).
97

Figure 28. Graph showing estimated annual bedload for water years 1984-2011 at U.S. Geological Survey

streamflow-gaging stations Carbon River near Orting (12094300, referred to as the Carbon River at Crocker by 

Sikonia, 1990), Puyallup River near Orting (12093500), and White River at R Street near Auburn (12100490).
98

Figure 29. Graph showing sediment load values of the Nisqually River flowing into Alder Lake and the lower 

Puyallup River compared to sediment-load data reported from other rivers throughout the Pacific Northwest.
99

Figure 30. Graph showing geomorphic variables of the Nisqually River: (A) slope, (B) measured active-channel 

width, (C) D90 and D50 size of bed-surface sediment, and (D) percent sand of bed-surface sediment. Error 

bars represent one standard deviation of the particle-size distribution.
100

Figure 31. Graph showing geomorphic variables of the Carbon River: (A) slope, (B) measured active-channel 

width, (C) D90 and D50 size of bed-surface sediment, and (D) percent sand of bed-surface sediment. Error 

bars represent one standard deviation of the particle-size distribution.
101

Figure 32. Graph showing geomorphic variables of the Puyallup River: (A) slope, (B) measured active-channel 

width, (C) D90 and D50 size of bed-surface sediment, and (D) percent sand of bed-surface sediment. Error 

bars represent one standard deviation of the particle-size distribution.
102

Figure 33. Graph showing geomorphic variables of the White River: (A) slope, (B) measured active-channel width, 

(C) D90 and D50 size of bed-surface sediment, and (D) percent sand of bed-surface sediment. Error bars 

represent one standard deviation of the particle-size distribution.
103

Figure 34. Graph showing comparison of simulated daily sediment loads to measured sediment loads for the 

Carbon River at State Route 162/Pioneer Way, Puyallup River at Calistoga Street, and White River at R Street.
104

Figure 35. Graph showing daily streamflow and simulated annual bed-material sediment loads for the (A) Nisqually 

River at State Route 7, (B) Carbon River at State Route 162/Pioneer Way, (C) Puyallup River at Calistoga 

Street, and (D) White River at R Street.
105

Figure 36. Graph showing capacity of the Nisqually River to transport sediment: (A) bed-material sedimenttransport capacity (after model conditioning) and stream power and (B) unit bed-material sediment-transport 

capacity (after model conditioning) and unit stream power.

Figure 37. Graph showing capacity of the Carbon River to transport sediment: (A) bed-material sediment-transport 

capacity (after model conditioning) and stream power and (B) unit bed-material sediment-transport capacity 

(after model conditioning) and unit stream power.
106

Figure 38. Graph showing capacity of the Puyallup River to transport sediment: (A) bed-material sedimenttransport capacity (after model conditioning) and stream power and (B) unit bed-material sediment-transport 

capacity (after model conditioning) and unit stream power.

Figure 39. Graph showing capacity of the White River to transport sediment: (A) bed-material sediment-transport 

capacity (after model conditioning) and stream power and (B) unit bed-material sediment-transport capacity 

(after model conditioning) and unit stream power.
107

Figure 40. Graph showing effect of pulse grain size, pulse volume, and streamflow on the characteristic transport 

time (A1-D1), sediment load (A2-D2), and bed volume (A3-D3) for the Nisqually (A1-A3), Carbon (B1-B3), 

Puyallup (C1-C3), and White Rivers (D1-D3).
108

Figure 41. Graph showing characteristic transport time for sediment pulses to arrive downstream for different pulse 

grain size, pulse volume, and streamflow for the (A) Nisqually, (B) Carbon, (C) Puyallup, and (D) White Rivers.
109

Figure 42. Graph showing Nisqually River response to sediment pulse input for (A) characteristic residence time 

for D50 sediment to move through each 400-m node and (B) the maximum increase in bed volume as a 

percentage of input pulse volume.

Figure 43. Graph showing Carbon River response to sediment pulse input for (A) characteristic residence time for 

D50 sediment to move through each 400-m node and (B) the maximum increase in bed volume as a 

percentage of input pulse volume.
110

Figure 44. Graph showing Puyallup River response to sediment pulse input for (A) characteristic residence time for 

D50 sediment to move through each 400-m node and (B) the maximum increase in bed volume as a 

percentage of input pulse volume.

Figure 45. Graph showing White River response to sediment pulse input for (A) characteristic residence time for 

D50 sediment to move through each 400-m node and (B) the maximum increase in bed volume as a 

percentage of input pulse volume.
111

Figure 46. Graph showing potential future bed-elevation change for the Nisqually River after 25 years for (A) a 

baseline condition and (B) a future condition; and after 50 years for (C) a baseline condition and (D) a future 

condition.
112

Figure 47. Graph showing potential future bed-elevation change for the Carbon River after 25 years for (A) a 

baseline condition and (B) a future condition; and after 50 years for (C) a baseline condition and (D) a future 

condition.
113

Figure 48. Graph showing potential future bed-elevation change for the Puyallup River after 25 years for (A) a 

baseline condition and (B) a future condition; and after 50 years for (C) a baseline condition and (D) a future 

condition.
114

Figure 49. Graph showing potential future bed-elevation change for the White River after 25 years for (A) a 

baseline condition and (B) a future condition; and after 50 years for (C) a baseline condition and (D) a future 

condition.
115

Figure 50. Graph showing lower White River, Washington, (A) approximate bed elevations from measurements 

(raw model input) and from steady state simulations (after model conditioning) and (B) change in elevation after 

the model-conditioning process with quasi-equilibrium conditions.
116

Figure 51. Map of Mount Rainier, Washington, showing where potential sediment-management actions would be 

most effective based on geomorphic conditions that suggest sediment accumulates naturally, including both 

long- and mid-term transient-storage reaches. Also shown are best estimates for long-term sediment-load 

values for rivers in the study.
117

Table 1. U.S. Geological Survey streamflow-gaging stations in the State of Washington used for hydrologic and 

geomorphic analysis in this study. [km2

, square kilometer]

Station 

number Station name Drainage area (km2) Available record

12082500 Nisqually River near National 344 6/1/1942 to present

12083000 Mineral Creek near Mineral 195 6/1/1942 to present

12093500 Puyallup River near Orting 445 10/1/1931 to present

12094000 Carbon River near Fairfax 204 12/1/1910 to 6/30/1912; 

4/1/1929 to 5/31/1978; 

10/1/1991 to present

12094300 Carbon River near Orting 250 11/17/1970 to 2/24/1986

12097850 White River below Clearwater River near 

Buckley

971 6/1/1974 to 10/13/1976; 

3/18/1982 to 2/7/1996; 

10/1/2008 to present

12098500 White River near Buckley 1,040 10/1/1928 to 9/30/1933;

10/1/1938 to 9/30/2003

12099200 White River above Boise Creek at Buckley 1,060 7/18/2003 to present

12100490 White River at R Street near Auburn 1,230 5/29/2009 to present

12100496 White River near Auburn 1,230 8/20/1987 to 9/30/2009

12101500 Puyallup River at Puyallup 2,460 5/1/1914 to present

14226500 Cowlitz River at Packwood 743 7/1/1911 to 9/30/1919; 

10/1/1929 to present
118

Table 2. Twenty largest peak-flow events at the U.S. Geological Survey streamflow-gaging station Nisqually River 

near National (12082500) between 1989 and 2009 and the resulting change in stage, for median flow, at the gage 

after to peak-flow event. [PDT, Pacific Daylight Time; m3

, square meter; s, second; m, meter]

Peak-flow date Peak-flow time 

(PDT)

Maximum 

discharge (m3/s)

Daily average 

discharge (m3/s)

Change in stage 

(m)

12/4/1989 16:30 249 165 -0.43

1/9/1990 15:45 411 279 -0.43

11/24/1990 21:30 311 223 -0.03

12/20/1994 11:30 192 166 -0.01

2/1/1995 0:45 194 138 0.01

11/8/1995 17:15 212 135 -0.09

11/29/1995 19:30 467 354 -0.09

2/8/1996 14:00 600 445 -0.28

1/1/1997 3:45 232 183 -0.13

3/19/1997 11:45 272 227 0.08

11/26/1998 4:30 167 131 0.03

11/25/1999 18:15 248 164 0.17

1/8/2002 0:30 244 167 -0.15

1/31/2003 9:30 306 244 -0.13

1/18/2005 9:00 230 157 0.15

12/24/2005 4:30 174 166 0.20

1/10/2006 9:00 199 174 0.20

11/6/2006 17:20 617 425 0.68

3/25/2007 1:30 189 132 -0.07

1/8/2009 4:45 374 242 -0.34
119

Table 3. Sample of 81 meteorological, hydrologic, and atmospheric parameters collected and correlated to the 

change in stage for the 20 largest peak-flow events measured at the Nisqually River gage. 

[bold indicated coefficient of determination greater than 0.20]

Variable Source Correlation 

coefficient

Coefficient of 

determination (R2)

Available data (out 

of 20 peak events)

Minimum temperature (day before peak) SNOTEL1 0.16 0.03 20

Minimum temperature (day of peak) SNOTEL1 0.24 0.06 20

Minimum temperature (day after peak) SNOTEL1 0.75 0.56 20

Maximum temperature (day before peak) SNOTEL1 -0.12 0.02 20

Maximum temperature (day of peak) SNOTEL1 0.32 0.11 20

Maximum temperature (day after peak) SNOTEL1 0.50 0.25 20

Average temperature (day before peak) SNOTEL1 0.04 0.00 20

Average temperature (day of peak) SNOTEL1 0.26 0.07 20

Average temperature (day after peak) SNOTEL1 0.60 0.36 20

Snow-water equivalent (day before peak) SNOTEL1 -0.12 0.01 20

Cumulative precipitation (day before 

peak) SNOTEL1 -0.26 0.07 20

Antecedent moisture conditions (total 

rainfall 15 days before peak) Paradise2 0.06 0.00 17

Total Precipitation (3 day) Longmire3 -0.23 0.05 20

Total Precipitation (1 day) Longmire3 0.05 0.00 20

Peak rainfall intensity (in 48 hours before 

peak) Longmire3 0.04 0.00 15

Freezing elevation (12 hours before peak) Sounding4 0.34 0.11 19

Freezing elevation (24 hours before peak) Sounding4 0.20 0.04 19

Pressure at surface elevation (12 hours 

before peak) Sounding4 0.31 0.09 19

Dew point at 3,000 meters (12 hrs before 

peak) Sounding4 -0.10 0.01 19

Wind direction at 3,000 meters Sounding4 0.42 0.18 18

Wind speed at 3,000 meters Sounding4 0.39 0.15 18

Showalter index Sounding4 -0.21 0.04 18

Lifted index Sounding4 0.20 0.04 18

SWEAT index Sounding4 0.54 0.29 16

Precipitable water for entire sounding Sounding4 0.36 0.13 18

1 Natural Resources Conservation Service (2011)

2 National Climatic Data Center weather station at Paradise, Washington

3 National Climatic Data Center weather station at Longmire, Washington

4 National Oceanic and Atmospheric Administration atmospheric sounding data from Quillayute, Washington
120

Table 4. Published sediment-load estimates for rivers in the Mount Rainier National Park, Washington, watershed 

and for the Pacific Northwest.

[km2, square kilometer; yr, year]

River Total annual sediment load1

(tonnes/yr)

Drainage area 

(km2)

Yield 

((tonnes/km2)/yr)

White River basin

Huckleberry Creek2 119,234 98 1,200

West Fork White River2 332,401 171 1,900

Greenwater River3,4 120,000 197 610

Greenwater River2 60,232 197 310

White River melt from Emmons Glacier5,6 208,000 18 12,000

White River upstream of Greenwater2 561,683 290 1,900

White River above Mud Mountain Dam7,8 450,000 970 460

White River near Auburn9 1,300,000 1,184 1,100

Puyallup River basin

Puyallup River at Puyallup10 526,000 2,564 210

Puyallup River at Puyallup11 1,250,000 2,564 490

Puyallup River at Puyallup12 890,000 2,564 347

Nisqually River basin

Tahoma Creek13 500,000 38 14,000

Nisqually River near National14 300,000 16 344 870

Mineral Creek near Mineral14 14,000 16 195 70

Nisqually River at Alder Lake14 902,000 16 623 1,400

Nisqually River at La Grande14 42,000 16 756 55

Mashel River near La Grande14 15,000 16 209 69

Ohop Creek near Eatonville14 2,200 16 89 24

Nisqually River above Powell Creek, near 

McKenna14 91,000 16 1,116 81

Tanwax Creek near McKenna14 480 16 69 7

Muck Creek at mouth, near Roy14 1,500 16 238 6

Nisqually River near Nisqually14 95,000 16 1,844 52

British Columbia, Canada

Fraser River15 20,000,000 230,000 87

Homathko River15 4,300,000 5,700 750

Klinaklini River15 5,000,000 6,500 770

Skeena River15 11,000,000 55,000 200

Squamish River15 1,800,000 3,300 550

Washington

Deschutes River near La Grande14 20,00016 143 150

Chehalis River15 120,000 3,300 36

Columbia River15 9,700,000 670,000 14

Hoh River15 720,000 650 1,100

Oregon
121

River Total annual sediment load1

(tonnes/yr)

Drainage area 

(km2)

Yield 

((tonnes/km2)/yr)

Nehalem River15 220,000 2,200 100

Alsea River15 160,000 860 190

Tillamook River15 80,000 610 130

Coos River15 190,000 1,600 120

Coquille River15 290,000 2,700 110

Sixes River15 390,000 300 1,300

Rogue River15 2,300,000 14,000 160

Siuslaw River15 94,000 1,500 63

Umpqua River15 1,400,000 12,000 120

Siletz River15 60,000 520 120

Smith River15 300,000 1,600 190

1

Assumes bulk density of 1.65 tonnes/m3

2

Ketcheson and others (2003)

3

Laurie (2002)

4

Abbe and others (2007)

5

Fahnestock (1963)

6

Mills (1976)

7

Dunne (1986)

8

Nelson (1978)

9

Herrera Environmental Consultants (2010)

10Downing (1983)

11Wise and others (2007)

12Czuba and others (2011)

13Walder and Driedger (1994)

14Nelson (1974)

15Milliman and Farnsworth (2011)

16Bedload not included
122

Table 5. Summary of active-channel width measured in 1965, 1994, and 2009 and the change in width between 

dates, for rivers draining Mount Rainier, Washington. [km, kilometer; m, meter]

Tributary or river segment Draining 

glacier1

Total length 

in 2009 

(km)

Mean active-channel 

width (m)

Difference in mean 

active-channel 

width (m)

1965 1994 2009

from 

1965 to 

1994

from 

1994 to 

2009

Carbon River

Carbon River upstream of 

national park boundary Carbon 13.4 156 163 208 6 45

Carbon River from national park 

boundary to canyon Carbon 12.2 123 122 160 -0.8 38

White River

West Fork White River upstream 

of national park boundary Winthrop 9.7 64 70 105 6 35

West Fork White River 

downstream of park boundary Winthrop 17.4 95 104 126 9 22

Inter Fork White River Inter 4.9 22 16 32 -6 16

Fryingpan Creek Fryingpan 5.6 25 29 31 5 2

Wright Creek Sarvant 1.9 22 5 8 -17 3

White River upstream of national 

park boundary Emmons 21.4 106 101 137 -5 36

White River downstream of park

boundary to West Fork White 

River Multiple 18.2 67 60 85 -8 25

White River downstream of West 

Fork White River to Mud 

Mountain Dam Multiple 24.0 76 68 94 -8 27

Cowlitz River

Ohanapecosh River Ohanapecosh 27.2 - 21 23 - 2

Williwakas Creek None 4.1 17 25 26 8 0.5
123

Tributary or river segment Draining 

glacier1

Total length 

in 2009 

(km)

Mean active-channel 

width (m)

Difference in mean 

active-channel 

width (m)

1965 1994 2009

from 

1965 to 

1994

from 

1994 to 

2009

Stevens Creek Stevens 9.0 33 29 36 -4 7

Muddy Fork Cowlitz River

IngrahamCowlitz 19.7 49 37 50 -12 13

Cowlitz River from Ohanapecosh 

to Riffe Lake Multiple 62.3 - - 158 - -

Nisqually River

Van Trump Creek Van Trump 3.9 - 19 27 - 8

Kautz Creek Kautz 10.5 116 63 102 -53 38

Tahoma Creek

Tahoma and 

South 

Tahoma 10.7 61 115 143 54 28

Nisqually River upstream of 

national park boundary

NisquallyWilson 17.7 106 92 127 -14 35

Nisqually River downstream of 

park boundary to Alder Lake Multiple 25.4 195 190 231 -5 40

Puyallup River

North Mowich River

North 

Mowich 5.0 20 11 21 -9 10

Mowich River

South 

Mowich 17.5 77 77 104 0.4 27

South Fork Puyallup River Tahoma 12.0 36 34 45 -2 11

Puyallup River upstream of South 

Fork Puyallup River Puyallup 8.1 25 19 47 -6 28

Puyallup River downstream of 

South Fork Puyallup River to 

Mowich River Multiple 8.0 44 40 64 -4 24

Puyallup River downstream of 

Mowich River to canyon Multiple 11.4 46 56 77 10 20

1

Dominant glacier(s) within tributary watershed; 'multiple' indicates two or more large glaciers contribute.
124

Table 6. Estimated sediment load contribution to river main stems due to increases in active-channel width, for

rivers draining Mount Rainier, Washington, 1965–2009.

[km, kilometer; m3, square meter; yr, year; m, meter; CRKM, Carbon River kilometer; NRKM, Nisqually River kilometer; 

PRKM, Puyallup River kilometer; WRKM, White River kilometer]

River Reach analyzed

Length of 

river 

analyzed 

(km)

Annual volume of 

sediment mobilized 

from flood plain, in 

m3/yr

Annual mass of 

sediment mobilized 

from flood plain, in 

tonnes/yr 

Annual volume of 

sediment 

mobilized from 

flood plain per unit 

length, in m3/yr/m

Carbon CRKM 13.7–23.9 10.2 13,000–27,000 20,000–48,000 1.3–2.6

Nisqually NRKM 17.8–40.2 22.3 45,000–170,000 67,000–300,000 2.0–7.5

Puyallup PRKM 5.4–20.8 14.5 10,000–78,000 14,000–140,000 0.7–5.4

White WRKM 21.2–55.7 34.4 15,000–100,000 23,000–180,000 0.4–2.9
125

Table 7. Summary of sediment-production potential for Cascade Range subcatchments outside Mount Rainier 

National Park, Washington. [MORA, Mount Rainier National Park; km2

, square kilometer; yr, year]

Subcatchment

Total sediment 

production 

(tonnes/yr)

Uncertainty in 

total sediment 

production 

estimate 

(tonnes/yr)

Yield 

((tonnes/km2)/yr)

Upper Nisqually River Basin (total area outside MORA = 605 km2)

Big Creek 12,000 ± 8,000 120 

Kautz Creek - - -

Little Nisqually River 8,500 ± 5,900 130

Mineral Creek 13,000 ± 8,400 68

Nisqually River in MORA - - -

Nisqually River, MORA to Alder Lake 16,000 ± 11,000 70

Tahoma Creek - - -

Total 50,000 ± 33,000 84

Puyallup River Basin (total area outside MORA = 352 km2)

Deer Creek 7,900 ± 5,600 270

Mowich River 9,000 ± 6,400 250

North Puyallup River 3,000 ± 2,200 820

Middle Puyallup River 16,000 ± 10,000 61

South Puyallup River 6,400 ± 4,600 380

Total 42,000 ± 29,000 120

Carbon River Basin (total area outside MORA = 484 km2)

Upper Carbon River - - -

Lower Carbon River 14,000 ± 9,600 110

Chenuis Creek 2,000 ± 1,400 160

Evans Creek 3,900 ± 2,800 200

Lily Creek 1,700 ± 1,200 150

South Prairie Creek 15,000 ± 9,300 63

Voight Creek 5,300 ± 3,400 63

Total 42,000 ± 28,000 86

White River Basin (total area outside MORA = 943 km2)

Boise Creek 3,200 ± 1,800 77

Canyon Creek 2,200 ± 1,300 130

Clearwater River 18,000 ± 11,000 180

Greenwater River 29,000 ± 21,000 150

Huckleberry Creek 9,900 ± 7,200 240 

West Fork White River 17,000 ± 12,000 180
126

Subcatchment

Total sediment 

production 

(tonnes/yr)

Uncertainty in 

total sediment 

production 

estimate 

(tonnes/yr)

Yield 

((tonnes/km2)/yr)

Upper White River 22,000 ± 16,000 210

Middle White River 32,000 ± 18,000 93

Total 130,000 ± 89,000 142

Calibration Basins

Deschutes River near La Grande 11,000 ± 6,900 80

Issaquah Creek 15,000 ± 7,900 100

Mashel River 16,000 ± 9,000 71
127

Table 8. Sediment load calculations and measurements completed as part of this study, for rivers draining Mount 

Rainier, Washington. [km2

, square kilometer; yr, year]

Location Total annual sediment 

discharge (tonnes/yr)

Drainage 

area (km2)

Yield 

((tonnes/km2)/yr)

Period of sediment-load 

estimates

Nisqually River 

into Adler Lake 1,200,000±180,000 590 2,000±300 1945–2011

Nisqually River 

into Adler Lake,

1956–1985

860,000±370,000 590 1,500±630 1956–1985

Little Nisqually 

River in Alder 

Lake

7,800±2,600 67 120±39 1945–2011

Nisqually River 

downstream of 

Alder Dam

120,000±18,000 590 200±25 1945–2011

Puyallup River at 

Puyallup 860,000±300,0001.2 2,450 350±120 1978–1994

Puyallup River at 

Puyallup 1,000,000±400,0003 2,450 400±160 late 20th century–2011

White River at R 

Street near Auburn 420,000 1,230 340 April 2010–March 2012

White River at R 

Street near Auburn 590,000 1,230 480 water year 2011

White River at R 

Street near Auburn 500,000±200,0003 1,230 400±160 late 20th century–2011

1

Bedload not included

2

Uncertainty based on temporal variability between years

3

Represents best guess of long-term load based on available data
128

Table 9. Scaling factors and U.S. Geological Survey streamflow-gaging stations used in developing long-term 

streamflow records for model simulations for the Nisqually, Carbon, Puyallup, and White Rivers, Washington. [USGS Streamflow-gaging stations: 12082500, Nisqually River near National; 12094000, Carbon River near Fairfax; 

12093500, Puyallup River near Orting; 12101500, Puyallup River at Puyallup; 12098500, White River near Buckley; 

12099200, White River above Boise Creek at Buckley; m3

, square meter; s, second]

Reach, in 

kilometers, for 

model nodes 

every 0.4 

kilometers

Water years

Gaging station for which flow data were 

obtained

Scaling factor (SF) for 

applying gaging-station 

data to the river reach

2-year 

recurrenceinterval flow, 

m3/s

Nisqually River

14.2 - 27.8 1946–2011 12082500 0.70 125

28.2 - 37.0 1946–2011 12082500 1.00 179

37.4 - 41.0 1946–2011 12082500 1.60 286

Carbon River

8.2 - 21.0 1930–2011 12094000 0.90 98

21.4 - 41.0 1930–2011 12094000 1.00 109

41.4 - 43.8 1930–2011 12094000 1.50 164

44.2 - 50.2 1930–2011 12094000 1.65 180

Puyallup River

16.2 - 53.8 1932–2011 12093500 1.00 191

54.2 - 65.4 1932–2011 12093500 (x SF1) + 12094000 (x SF2) 1.00 (SF1), 1.65 (SF2) 343

65.8 - 82.2 1932–2011 12101500 1.00 667

White River

13.4 - 33.0 1939–2011 12094000 1.00 109

33.4 - 39.0 1939–2011 12094000 1.40 153

39.4 - 44.6 1939–2011 12094000 2.05 224

45.0 - 61.4 1939–2011 12094000 2.90 317

61.8 - 70.6 1939–2011 12094000 3.30 361

71.0 - 116.6 1939–2003 12098500 1.00 352

71.0 - 116.6 2004–2011 12099200 1.00 -
129

Table 10. Comparison of simulated sediment load into Alder Lake by the Nisqually River to measured sediment 

volumes of the delta of the Nisqually River in Alder Lake, Washington, from Czuba and others (2012).

[m3, cubic meter; yr, year]

Time Period

Measured volume (and estimated 

uncertainty) of the Nisqually River delta in 

Alder Lake (m3)1

Simulated volume 

transported into 

Alder Lake (m3)

1946– 1956 9,000,000±2,000,000 7,000,000

1946– 1985 22,000,000±5,000,000 27,000,000

1946– 2011 42,000,000±4,000,000 45,000,000

Mean annual rate between water years

1946 and 2011 (m3/yr) 630,000±60,000 690,000

1 Data from Czuba and others, 2012; does not include reservoir deposition downstream of the delta
130

Table 11. Simulated bed-material sediment loads for the Nisqually River at State Route 7, Carbon River at State 

Route 162/Pioneer Way, Puyallup River at Calistoga Street, and White River at R Street, Washington. Streamflow 

at the White River at R Street is controlled by Mud Mountain Dam.

[m3, cubic meter; yr, year; s, second; CRKM, Carbon River kilometer; NRKM, Nisqually River kilometer; PRKM, Puyallup 

River kilometer; WRKM, White River kilometer]

Location

2-year 

recurrenceinterval 

flow (m3/s)

Water 

years

Simulated annual sediment load (m3/yr)

Percent 

gravel in 

load

Portion of 

total 

sediment 

load

Mean Standard 

deviation Maximum Minimum

Mean; 

(Minimum -

Maximum)

Nisqually 

River at 

State 

Route 7

(NRKM 

41.0)

276 1946–

2011

Gravel 60,000 29,000 200,000 17,000 8;

Sand 630,000 170,000 1,300,000 320,000 (5–14)

Sand and 

gravel 690,000 200,000 1,500,000 340,000

Carbon 

River at 

State 

Route 

162 / 

Pioneer 

Way 

(CRKM 

41.0)

106 1930–

2011

Gravel 2,800 3,200 21,000 200 16;

Sand 12,000 8,000 56,000 2,600 (6–33)

Sand and 

gravel 15,000 11,000 77,000 2,800

Puyallup 

River at 

Calistoga 

Bridge 

(PRKM 

48.6)

184 1932–

2011

Gravel 7,100 5,600 40,000 1,200 8;

Sand 76,000 31,000 220,000 26,000 (4–16)

Sand and 

gravel 83,000 36,000 260,000 28,000

White 

River at 

R Street 

(WRKM 

104.6)

340 1939–

2011

Gravel 86,000 33,000 170,000 30,000 16;

Sand 450,000 120,000 730,000 210,000 (11–19)

Sand and 

gravel 530,000 160,000 900,000 250,000
131

Appendix A. Auxillary Tables

Table A1. Light Detection and Ranging (LiDAR) data source for river profiles, Washington.

[Source of Lidar data and year is listed in table footnote. DEM, Digital Elevation Model; NASA, National Aeronautics and 

Space Administration; NED, National Elevation Dataset; PSLC, Puget Sound LiDAR Consortium, accessed September 4, 

2012, at http://pugetsoundlidar.ess.washington.edu/ ; USGS, United States Geological Survey]

River LiDAR data source, in footnotes

Carbon River 3, 5, 9

Chenuis Creek 3, 10

Evans Creek 5

Lily Creek 5, 9

South Prairie Creek 5, 9

Voight Creek 5, 9

Wilkeson Creek 5, 9

Cowlitz River 5, 8

Butter Creek 8, 10

Clear Fork Cowlitz River 8, 10

Johnson Creek 8, 10

Lake Creek 8, 10

Ohanapecosh River 3, 8

Silver Creek 8, 10

Skate Creek 8, 10

Nisqually River 7

Big Creek 7

Catt Creek 6, 7, 10

Kautz Creek 3

Mineral Creek 6, 7, 10

North Fork Mineral Creek 6, 7

Tahoma Creek 3

Puyallup River 3, 5, 9

Deer Creek 5

Mowich River 3, 5

South Puyallup River 3, 5

White River 1, 3, 4, 9

Boise Creek 1

Canyon Creek 10

Clearwater River 10

Greenwater River 4, 10

Huckleberry Creek 3, 4, 10

West Fork White River 3, 4, 10

1 King County; 2003

2 King County; Lower White River; 2009

3 Mount Rainier National Park; 2009
132

4 Mount Rainier National Park; Upper White River; 2007

5 NASA/USGS; West Mt. Rainier 2002/2003

6 PSLC; Lewis County; 2003

7 PSLC; Lewis County; 2009 

8 PSLC; Lewis County (6-foot geodatabase); 2009 

9 PSLC; Puget Sound Lowlands; Pierce County; 2004

10 USGS; NED 1/3 Arc Second (10 meter) DEM
133

Table A2. Suspended-sediment concentration measurements at USGS streamflow-gaging station White River at R 

Street near Auburn (12100490) for water years 2010–2011.

[m3, cubic meter; s, second; FNU, formazine nephelometric unit; mg, milligram; L, liter; mm, millimeter; d, day]

Date / Time Streamflow 

(m3/s)

Turbidity 

(FNU)

Suspended-sediment concentration 

(mg/L) Percent by 

weight finer 

than 0.0625 mm

Suspendedsediment load 

(tonnes/d)

Fines Sand Total

6/2/10 11:45 88 15 41 217 258 16.0 1,970

6/3/10 11:15 132 160 466 694 1,160 40.2 13,200

8/25/10 13:45 22 37 37 5 42 87.5 79

12/13/10 14:30 137 285 456 612 1,070 42.7 12,700

1/18/11 15:45 202 412 543 645 1,190 45.7 20,800

1/20/11 15:15 185 240 341 567 908 37.6 14,500
134

Table A3. Bedload measurements at USGS streamflow-gaging station White River at R Street near Auburn (12100490) for water years 2010–2011.

[m3, cubic meter; s, second; mm, millimeter; d, day]

Date / Time Streamflow 

(m3/s)

Bedload 

(tonnes/d)

Percent by weight finer than indicated size (mm)

0.0625 0.125 0.25 0.5 1 2 4 8 16 32 64 128

6/2/10 14:02 86 149 0.0 0.2 1.5 18.4 72.0 79.6 81.0 82.6 84.4 86.6 90.8 100.0

6/3/10 12:39 124 706 0.1 0.2 1.6 12.8 40.2 45.5 47.0 48.5 50.8 58.9 83.1 100.0

12/13/10 11:52 137 2,286 0.0 0.1 0.4 3.3 11.3 18.1 25.5 30.2 36.8 50.8 75.7 100.0

1/18/11 13:08 202 3,659 0.0 0.0 0.1 0.9 3.4 5.3 7.8 14.1 26.5 48.2 79.5 100.0

1/20/11 12:21 185 1,165 0.0 0.1 0.2 2.4 8.9 13.1 16.8 21.6 28.3 40.6 75.9 100.0
Publishing support provided by the U.S. Geological Survey

Publishing Network, Tacoma Publishing Service Center

For more information concerning the research in this report, contact the

 Director, Washington Water Science Center

U.S. Geological Survey

934 Broadway, Suite 300

Tacoma, Washington 98402

http://wa.water.usgs.gov
Czuba and others—Geomorphiic Analysis of the River Response to Sedimentation Downstream of Mount Rainier, Washington—Open-File Report 2012-1242