Estimation of Bed-Material Transport in the lower Chetco 

River, Oregon, Water Years 2009–2010

By J. Rose Wallick and Jim E. O’Connor

Prepared in cooperation with the U.S. Army Corps of Engineers and the Oregon Department 

of State Lands

Open-File Report 2011–1123

U.S. Department of the Interior

U.S. Geological Survey
Cover: The Chetco River near its confluence with the North Fork Chetco River, looking upstream. Gravel bars line 

the stream on both banks. (Photograph by J. Rose Wallick, U.S. Geological Survey, April 9, 2008.) 
Prepared in cooperation with the U.S. Army Corps of Engineers and the Oregon Department 

of State Lands

Estimation of Bed-Material Transport in the lower Chetco 

River, Oregon, Water Years 2009–2010

By J. Rose Wallick and Jim E. O’Connor 

Open-File Report 2011–1123

U.S. Department of the Interior

U.S. Geological Survey
ii

U.S. Department of the Interior

KEN SALAZAR, Secretary

U.S. Geological Survey

Marcia K. McNutt, Director

U.S. Geological Survey, Reston, Virginia 2011

For product and ordering information:

World Wide Web: http://www.usgs.gov/pubprod

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its natural and living resources, natural hazards, and the environment:

World Wide Web: http://www.usgs.gov

Telephone: 1-888-ASK-USGS

Suggested citation:

Wallick, J.R., and O’Connor, J.E., 2011, Estimation of bed-material transport in the lower Chetco River, Oregon, 

water years 2009–2010: U.S. Geological Survey Open-File Report 2011–1123, 12 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

Significant Findings.....................................................................................................................................................1

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

Purpose and Scope.................................................................................................................................................2

Background.............................................................................................................................................................4

Locations and Units.................................................................................................................................................5

Chetco River Study Area ............................................................................................................................................6

Approach and Key Findings........................................................................................................................................6

Estimation of Bed-Material Transport Rates Using Established Transport Equations.............................................6

Calculation of Bed-Material Flux .............................................................................................................................6

Results of Calculated Bed-Material Flux .................................................................................................................7

References Cited ...................................................................................................................................................... 12

Figures

Figure 1. Map showing drainage basin and study area, Chetco River, Oregon. .........................................................3

Figure 2. Orthophotograph showing an example of an alternating bar sequence near flood-plain kilometer (FPkm) 

11, Chetco River Oregon. ...........................................................................................................................................4

Figure 3. Graphs showing discharge and calculated bed-material transport capacity for water years 2009–2010 at 

the USGS streamflow gaging station at flood plain-kilometer 15.3 (144000000), Chetco River, Oregon.....................8

Figure 4. Graphs showing peak discharge, annual transport capacity, and mean annual discharge for water years 

1970–2010 at the USGS streamflow gaging station at flood plain kilometer 15.3 (14400000), 

Chetco River Oregon ...................................................................................................................................................9

Tables

Table 1. Summary of calculated transport capacity, peak flow, and mean annual flow in the Chetco River, Oregon 

for water years 1970–2010 ........................................................................................................................................10
iv

Conversion Factors

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 (km

) 

2

) 0.3861 square mile (mi2)

Volume

cubic meter (m3) 0.0008107 acre-foot (acre-ft) 

cubic meter (m3) 35.31 cubic foot (ft3

cubic meter (m

)

3

) 1.308 cubic yard (yd3

liter (L)

) 

0.03531 cubic foot (ft3)

Flow rate

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

cubic meter per year (m

/s)

3

/yr) 1.308 cubic yard per year (yd3

meter per second (m/s)

/yr)

3.281 foot per second (ft/s) 

meter per year (m/yr) 3.281 foot per year (ft/yr)

millimeter per year (mm/yr) 0.0397 inch per year (in/yr)

kilogram per meter per second 

[(kg/m)/s]

4.486 pound avoirdupois per foot per 

second [(lb/ft)/s]

Mass

kilogram (kg) 2.205 pound avoirdupois (lb)

metric ton (also megagram) 1.102 ton (U.S.)

Datums

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 the distance above the vertical datum.
v

Abbreviations and Acronyms

BAGS Bedload Assessment in Gravel-bedded Streams

FPkm flood-plain kilometer

BLM Bureau of Land Management 

GIS geographic information system 

GPS global positioning system 

ka kiloannum, a unit of time equal to 1,000 years

HEC-RAS Hydrologic Engineering Center’s River Analysis System

LIDAR Light Detection and Ranging 

NAIP National Agriculture Imagery Program

MLLW mean lower low water

Rkm river kilometer

RMSE root mean square error 

RTK real-time kinematic

USFS U.S. Forest Service 

USGS U.S. Geological Survey 

UTM Universal Transverse Mercator

WY water year
vi

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1

Estimation of Bed-Material Transport in the lower Chetco 

River, Oregon, Water Years 2009–2010

By J. Rose Wallick and Jim E. O’Connor

Significant Findings

This assessment of bed-material transport 

uses methods developed in a previous study 

(Wallick and others, 2010) to estimate bedmaterial flux at the USGS Chetco River 

streamflow gaging station located at flood-plain 

kilometer 15 (14400000). On the basis of 

regressions between daily mean flow and 

transport capacity, daily bed-material flux was 

calculated for the period October 1, 2008 to 

March 30, 2011. The daily flux estimates were 

then aggregated by water year (WY) for WY 

2009 and WY 2010 and the period April 1–

March 31 during 2008–09, 2009–10 and 2010–

11. The main findings were: 

• Estimated bed-material flux for WY 2009 

(October 1, 2008 to September 30, 2009) 

was 87,300 metric tons as calculated by the 

Parker (1990a, b) equation (hereinafter “the 

Parker equation”) and 116,900 metric tons

as calculated by the Wilcock and Crowe 

(2003) equation (hereinafter “the Wilcock–

Crowe equation”). 

• Estimated bed-material flux for water year 

2010 (October 1, 2008 to September 30, 

2009) was 56,800 metric tons as calculated 

by the Parker equation and 96,700 metric 

tons as calculated by the Wilcock–Crowe

equation. 

• Estimated bed-material flux for April 1, 

2008, to March 31, 2009, was 84,700 metric 

tons as calculated by the Parker equation 

and 111,700 metric tons as calculated by the 

Wilcock–Crowe equation. Flux values from 

April 1 to September 30, 2008, are from 

Wallick and others (2010). 

• Estimated bed-material flux for April 1, 

2009, to March 31, 2010, was 45,500 metric 

tons as calculated by the Parker equation 

and 79,100 metric tons as calculated by the 

Wilcock–Crowe equation. 

• Estimated bed-material flux for April 1, 

2010, to March 31, 2011, was 67,100 metric 

tons as calculated by the Parker equation 

and 134,300 metric tons as calculated by the 

Wilcock–Crowe equation. These 

calculations used provisional flow data for 

December 29, 2010, to March 31, 2011, and 

may be subject to revision.

• Water years 2009 and 2010 both had less 

bed-material transport than the average 

annual transport values of 105,300 and 

152,300 metric tons for the period 1970–

2010 as calculated by the Parker and 

Wilcock–Crowe equations, respectively.
2

Introduction

The Chetco River is a steep, gravel-bed 

river in southwestern Oregon that drains 914 

km2

fig. 1

 of the rugged Klamath Mountains before 

entering the Pacific Ocean 5 km north of the 

California–Oregon State line ( ). 

Downstream of the confluence of the South 

Fork Chetco River at river kilometer (Rkm) 29, 

the Chetco River is flanked by varying widths 

and areas of gravel bars and flood plains. 

Downstream of Rkm 18, the channel is fully 

alluvial and characterized by expansive gravel 

bars whose positions are constrained by valley 

geometry (fig. 2 [p. 4]). Several of these

voluminous gravel bars have been mined as a 

source of aggregate for the last several decades. 

Ongoing permitting actions have given rise to 

questions of possible effects from such mining 

on physical channel conditions (for example, 

Kondolf, 1994, 1997), prompting the U.S. Army 

Corps of Engineers, in conjunction with 

regulatory agencies and stakeholder groups, to 

request that the U.S. Geological Survey (USGS) 

complete a measurement and analysis program 

to evaluate transport rates of bed material and to 

assess changes in channels and flood plains for 

the lower 18 km of the Chetco River. In 2010, 

the USGS completed a comprehensive study of 

channel change and bed-material transport in the 

lower Chetco River for WY 1970–2008 

(Wallick and others, 2010). This study uses

identical methods to calculate bed-material flux 

for WY 2009 and 2010. 

Purpose and Scope

This report presents daily bed-material 

transport as calculated at the location of the 

USGS Chetco River streamflow gaging station 

for October 1, 2008, to March 30, 2011. The 

daily flux estimates were calculated using 

equations of bedload flux described in Wallick 

and others (2010) and aggregated by water year 

beginning October 1 and extending through 

September 30 for WY 2009 and 2010. The daily 

flux estimates also were summed to determine 

annual totals for April 1–March 31 for 2008–09, 

2009–10, and 2010–11. Together with the longterm estimates of bed-material recruitment 

provided in Wallick and others (2010), the 

transport values in this report enable estimation 

of bedload flux for the 40-year period 1970–

2010 and enhance overall understanding of 

annual variation in bed-material flux in the 

lower Chetco River.

Refer to Wallick and others (2010) for a

description of the study area (including basin 

geology, hydrology, landuse, and historical 

disturbances to the channel, such as instream 

gravel mining) and data types and methods used 

to analyze channel change and bed-material 

transport in this study. 
3

Figure 1. Map showing drainage basin and study area, Chetco River, Oregon. The reaches analyzed were

defined by valley geomorphology and tributary junctions. Morris Rock and Tide Rock are informal names for 

prominent local landmarks. Topography based on U.S. Geological Survey 10-m digital elevation data and Light 

Detection and Ranging (LIDAR) topography acquired in 2008. 
4

Figure 2. Orthophotograph showing an example of 

an alternating bar sequence near flood-plain 

kilometer (FPkm) 11, Chetco River Oregon. The 

photograph, from 2005, depicts large, channelflanking gravel bars and the low-flow channel. Flow is 

to the south. 

Background

In Oregon, rivers potentially subject to 

inchannel gravel extraction undergo a two-phase 

process of review and assessment by multiple 

regulatory agencies, such as the U.S. Army 

Corps of Engineers. The first phase is a 

preliminary assessment of “vertical stability” 

primarily based on available information. If the 

Phase I analysis shows no clear evidence of 

adverse channel or flood plain conditions, a 

Phase II analysis may be initiated to provide 

more information relevant to permitting 

decisions. For the Chetco River, a Phase I 

analysis was completed in May 2007 (Janine 

Castro, U.S. Fish and Wildlife Service, written 

commun., 2007). This assessment of maps and 

surveys concluded that although the lowermost 

2 km of the river “appears to have deepened 

slightly over the past 20 years,” there was no 

evidence of systematic channel incision for the 

balance of the lower 18 km of the Chetco River. 

These findings prompted the U.S. Army Corps 

of Engineers to request that the USGS complete 

a more extensive, Phase II, analysis for the 

Chetco River. The Phase II analysis, completed 

by Wallick and others (2010), consisted of data 

acquisition and analysis aimed at (1) 

determining spatial and temporal rates of bedmaterial transport and 

(2) assessing planform and vertical changes to 

the river channel. Specific tasks in the Phase II 

analysis included:

1. Detailed analysis of historical channel 

change from 1939 through 2008 

2. Direct measurements of bedload flux in 

the winter of 2008–09 

3. Estimation of annual bed-material 

transport for 1970–2008 using equations 

of bedload flux 

4. Estimation of bed-material transport for 

1995–2008 from changes in channel 

morphology 

5. Comparison of Chetco River bedmaterial flux rates with those in nearby 

basins. 

Among the findings from these multiple, 

independent analyses, Wallick and others (2010) 

determined that bed-material flux in the lower 

18 km of the Chetco River was transport 

limited—that is, the transport capacity (the 

amount of sediment the channel could, 

theoretically, transport given its geomorphic and 

hydrologic characteristics) was approximately 

balanced by sediment supply. Average annual 

bed-material flux for the period 1970–2008 was 
5

approximately 84,000–210,000 metric tons. 

Most of this sediment was routed through the 

historically stable upper study reaches and 

deposited in the more dynamic lower gradient 

reaches. Analyses of channel change found a 

large reduction in bar area from 1939 to 2005 in 

the lower 18 km of the channel and up to 2 m of 

incision for large parts of the study area, which 

were attributed to a combination of (1) bedsediment removal and (2) transient effects as the 

river adjusted to large volumes of sediment 

delivered by the flood of December 1964. 

On the basis of these findings, the U.S. 

Army Corps of Engineers and other regulatory 

agencies are working to adaptively manage

instream gravel extraction in the Chetco River. 

Under currently proposed guidelines, the USGS 

will provide annual estimates of gravel 

recruitment, which regulatory agencies will use 

to determine the level of permissible gravel 

extraction. An ongoing monitoring and analysis 

program also entails additional measurements of 

bed-material transport to improve the existing 

transport capacity relations and ultimately 

establish a sediment-discharge rating curve for 

the Chetco River. Although two bedload 

transport measurements were obtained in the 

winter of 2010–2011, the findings from these 

measurements will be summarized in a 

subsequent report and are not reported herein. 

Future monitoring efforts will likely also 

incorporate future channel mapping from 

LIDAR and bathymetric surveys to assess longterm changes to channel morphology. 

Location References

Locations along the channel alignment in 

summer 2008 are referenced to river kilometers 

(Rkm) measured from the mouth of the Chetco 

River (fig. 1) along the channel centerline 

mapped from Light Detection and Ranging 

(LIDAR) topography acquired in 2008. 

Ambiguity because of channel shifting was 

avoided by referencing locations and analyses 

for the lowermost 18 km to a flood-plain 

kilometer (FPkm) centerline, measured from the 

river mouth along the centerline of the Holocene 

flood plain. In 2008, approximately 18 km of 

channel was within the 16-km length of flood 

plain comprising the study reach. Prominent 

landmarks and locations include the U.S. 

Highway 101 bridge at FPkm 0.9 (Rkm 1.4), 

Tide Rock at FPkm 4.2 (Rkm 4.9), North Fork 

Chetco River confluence at FPkm 7.6 (Rkm 

8.3), and the USGS streamflow-gaging station 

(at Second Bridge) at FPkm 15.3 (Rkm 16.7). 

Bed-material transport was calculated using 

sediment transport capacity relations of Parker 

(1990a,b) and Wilcock and Crowe (2003), which 

both provide transport capacity in terms of mass 

(in kilograms). This report presents bed-material 

transport in terms of mass (in metric tons, 

equivalent to 1,000 kg). In the previous Chetco 

River bed-material transport study (Wallick and 

others, 2010), bedload flux was presented in 

terms of volume (in cubic meters) by converting 

from mass to volume using equation (1), which 

is approximately equivalent to applying a bulk 

density of 2.1 metric tons/m3

v = m /(1-n) ρ (1)

: 

where m is mass in kilograms, v is volume in 

m3

, n is in situ porosity of bed-material 

sediment, and ρ is particle density. In Wallick 

and others (2010), an in situ porosity of 0.21 

was applied based on a range of porosity data 

collected by Milhouse (2001) as presented in 

Bunte and Abt (2001). A standard particle 

density of 2,650 kg/m3 was applied.
6

Chetco River Study Area

Refer to Wallick and others (2010) for 

description of Chetco River Basin and study 

area. 

Approach and Key Findings

For this study, we followed the approach 

developed by Wallick and others (2010) to 

calculate daily bed-material flux using 

established sediment-transport relations at the 

Chetco River USGS streamflow gaging station

at FPkm 15.3 (14400000). A complete 

description of the equations and their 

application to the Chetco River are provided in 

Wallick and others (2010) and summarized 

here.

Estimation of Bed-Material Transport Rates 

Using Established Transport Equations

Application of bed-material transport 

formulas is a common means of estimating 

sediment fluxes in streams (Collins and Dunne, 

1989; Gomez, 1991; Hicks and Gomez, 2003). 

The basic premise of this approach is that for a 

site where hydraulic geometry and bed-material 

characteristics are known, transport capacity can 

be estimated as a function of discharge.

Sediment-transport capacity is defined as the 

“maximum load a river can carry” (Gilbert and 

Murphy, 1914, pg. 35). For gravel-rich, 

transport-limited streams such as the Chetco 

River, transport capacity can be used to 

approximate bedload flux, so long as a valid

transport relation is applied and an accurate 

description of channel hydraulics and bed 

material are used as inputs to the formula.

On the basis of multiple, independent 

analyses, Wallick and others (2010) determined 

that transport capacity estimates as computed 

using the Parker and Wilcock–Crowe equations 

provided a reasonable approximation of bedmaterial flux. Both of these equations have a 

similar theoretical framework and use grainsize 

data from the bar surface. The major distinction 

between the two approaches is in determination 

of the reference Shields shear stress ( *

rsg τ ); in 

the Parker equation, *

rsg τ is assumed to be the 

constant value 0.0386, but in the Wilcock–

Crowe equation, *

rsg τ varies with the sand 

content of the surface bed material.

Calculation of Bed-Material Flux 

In the previous Chetco River bed-material 

transport study, Wallick and others (2010) 

implemented the transport capacity relations

using the software package Bedload Assessment 

in Gravel-bedded Streams (BAGS), (Pitlick and 

others, 2009). Within BAGS, users specify a

transport equation, then provide cross section 

geometry, flow, and sediment parameters. The 

program then calculates the bed-material 

transport rate for a particular cross-section, at 

the specified flow. Repeating this process for 

multiple flows produces a relation between 

discharge (Q) and bed-material transport rate 

(Qs

The 

), producing a site-specific sediment–

discharge rating curve. For the Chetco River, 

the data underlying the calculated Q–Qs curves 

includes bed-material size data (collected at 

each of the analysis sites in 2008) and channel 

hydraulics, which were characterized with a 

validated HEC–RAS model constructed using 

2008 LiDAR topography and 2008 bathymetric 

survey data (see Wallick and others [2010] for 

complete model description). 

Q–Qs relations serve as a basis for 

calculating annual sediment transport fluxes. 

Typically, annual transport volumes are 

calculated using mean daily values (for 

example, Collins and Dunne [1989]), but 

because of the combination of the highly 

nonlinear transport rates and the rapid flow 

changes on the Chetco River during transport 

events, annual bed-material transport volumes 

determined from mean daily values are likely to 

underestimate true values. Therefore, Wallick 

and others (2010) based annual bed-material 

transport volumes on higher resolution unit-
7

discharge values (recorded every 30 minutes 

before 2006 and every 15 minutes after 2006). 

However, substantial gaps in the unit-discharge 

data precluded a full accounting of sediment 

flux, so regression formulas were developed 

between daily transport volumes calculated 

from the unit-flow measurements and mean 

daily flow for all days of predicted transport 

(Wallick and others, 2010). 

In the previous Chetco River study 

(Wallick and others, 2010), this process was 

repeated for multiple cross-sections throughout 

the study area, but in this study bed-material 

flux was calculated solely at the USGS 

streamflow gaging station at FPkm 15.3 

(14400000) using the regression formula 

developed for that site by Wallick and others 

(2010). The regression formula was applied to 

daily mean flow data from the period October 1, 

2009, to March 30, 2011. 

Although daily mean flow for the Chetco 

River gaging station is computed automatically 

on a daily basis, these data are considered 

provisional (subject to revision) until the data 

are formally reviewed and approved, which 

occurs on an ongoing basis. At the time this 

report was prepared, daily mean flow data were 

approved through December 28, 2010, so 

calculations for the period December 29, 2010, 

to March 31, 2011, used provisional data and 

may be subject to change once the final, 

approved flow record is available. 

Results of Calculated Bed-Material Flux

The calculated bed-material flux for WY 

2009 was 87,300 metric tons, as calculated by 

the Parker equation or 116,900 metric tons, as 

calculated by the Wilcock–Crowe equation (fig. 

3, table 1). Calculated bed-material flux in WY 

2010 was substantially lower: 56,800 metric 

tons or 96,700 metric tons as calculated by the 

Parker and Wilcock–Crowe equations, 

respectively (fig. 3, table 1). 

Annual flux estimates for the period 

beginning April 1 and extending through March 

31 were 84,700 metric tons in 2008–09, 45,500 

metric tons in 2009–10 and 67,100 metric tons 

in 2010–11, as calculated by the Parker 

equation. For the same periods, the Wilcock–

Crowe equation provides slightly higher annual 

flux values: 111,700 metric tons 2008–09, 

79,100 metric tons 2009–10, and 134,300 metric 

tons in 2010–2011. 

Temporal variation in bed-material 

transport reflects the timing and magnitude of 

peak flows, with most of the annual transport 

occurring during short periods of high 

discharge. For example, 61 percent of the WY 

2009 transport occurred over 2 days, December 

28–29, 2008, when peak flows exceeded the 5-

year recurrence-interval discharge of 1,425 m3

fig. 3

/s 

( , table 1). Although the mean annual flow 

for WY 2010 was greater than that for WY 

2009, peak flows in WY 2010 were slightly less 

than the 2-year recurrence interval discharge of 

1,060 m3

fig. 3

/s, resulting in much lower annual 

transport in WY 2010. The corresponding bedmaterial transport for the WY 2010 peak flow 

(occurring on January 1, 2010; ) was 

16,800 metric tons, equivalent to 30 percent of 

the total WY 2010 bed-material transport 

In terms of long-term trends in bed-material 

transport, the calculated flux values for WY 

2009–10 were less than the average annual bedmaterial transport for the period 1970–2010: 

105,300 or 152,300 metric tons for the Parker

and Wilcock–Crowe equations, respectively. 

Overall, between 1970 and 2010, bed-material 

flux exceeded 200,000 metric tons in 7 years, 

(as calculated with the Parker equation), 

including two particularly high transport years 

(WY 1982 and WY 1997), which both 

encompassed wet winters and large flood events 

(table 1, fig. 4). During several exceptionally 

dry years, including WY 2001 and WY 1977 

transport (as calculated with the Parker 

equation) was less than 3,000 metric tons. 
8

Figure 3. Graphs showing discharge and calculated bed-material transport capacity for water years 2009–2010 at 

the USGS streamflow gaging station at flood plain-kilometer 15.3 (144000000), Chetco River, Oregon: A. Daily 

mean discharge. B. Daily transport capacity and cumulative transport capacity, as calculated using the Parker 

(1990a,b) transport equation. 
9

Figure 4. Graphs showing peak discharge, annual transport capacity, and mean annual discharge for water years 

1970–2010 at the USGS streamflow gaging station at flood plain kilometer 15.3 (14400000), Chetco River 

Oregon: A. Peak discharge. B. Annual transport capacity, as calculated on the basis of the Parker (1990a,b) and 

Wilcock and Crowe (2003) transport equations. 
10

Table 1. Summary of calculated transport capacity, peak flow, and mean annual 

flow in the Chetco River, Oregon for water years 1970–2010—continued

[Transport capacity values for 1970–2008 from Wallick and others, (2010);

Abbreviations: m3

Water year

/sec, cubic meters per second]

Transport, using 

Parker equation

Transport, using 

Wilcock–Crowe 

equation

Peak 

discharge 

Mean annual 

discharge

(metric tons) (metric tons) (m3/sec) (m3

1970

/sec)

216,700 273,400 1,269 70.5

1971 215,100 271,200 1,863 82.4

1972 220,900 266,800 1,543 78.6

1973 26,600 49,200 399 42.9

1974 206,800 316,100 821 96.1

1975 83,900 134,500 1,102 62.3

1976 40,200 68,100 728 49.6

1977 2,900 5,900 430 15.6

1978 177,200 245,000 1,306 88.1

1979 40,600 70,000 1,045 44.8

1980 89,800 130,900 943 62.8

1981 77,600 99,500 1,524 49.6

1982 280,800 391,400 1,467 110.8

1983 198,400 290,400 1,311 93.6

1984 120,300 191,900 1,263 81.3

1985 62,700 99,000 742 50.8

1986 141,100 204,300 1,045 71.8

1987 53,000 90,600 753 53.1

1988 66,700 99,200 1,037 44.6

1989 60,800 102,900 1,127 58.5

1990 51,500 63,800 1,396 42.5

1991 26,800 40,400 663 35.9

1992 25,600 46,100 651 36.2
11

Table 1. Summary of calculated transport capacity, peak flow, and mean annual 

flow in the Chetco River, Oregon for water years 1970–2010—continued

[Transport capacity values for 1970–2008 from Wallick and others, (2010);

Abbreviations: m3

Water year

/sec, cubic meters per second]

Transport, using 

Parker equation

Transport, using 

Wilcock–Crowe 

equation

Peak 

discharge 

Mean annual 

discharge

(metric tons) (metric tons) (m3/sec) (m3

1993

/sec)

90,800 151,200 1,192 80.8

1994 15,100 22,500 566 31.6

1995 176,500 260,300 1,138 89.7

1996 131,900 226,400 952 88.7

1997 275,400 335,900 2,155 84.8

1998 108,400 190,200 734 82.6

1999 126,000 181,100 1,133 73.7

2000 83,000 119,500 1,238 59.5

2001 2,200 4,400 279 21.8

2002 59,900 107,100 816 61.6

2003 95,800 152,900 1,042 69.1

2004 76,100 113,900 1,289 57.3

2005 65,800 82,700 1,365 49.3

2006 218,500 288,600 1,651 90.2

2007 108,200 152,600 1,300 65.1

2008 52,600 90,300 949 58.2

2009 87,300 116,900 1,447 52.3

2010 56,800 96,700 1,025 70.2
12

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Geology, v. 13, no. 3, p. 213–224. 

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and Urban Planning, v. 28, no. 2–3, p. 225–243. 

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