Water Quality in the

Willamette Basin

Oregon, 1991–95

U.S. Department of the Interior

U.S. Geological Survey Circular 1161

science for a changing world
A COORDINATED EFFORT

NAWQA Program contact:

Chief, NAWQA Program

U.S. Geological Survey

Water Resources Division

12201 Sunrise Valley Drive, M.S. 4

Reston, VA 20192

FOR ADDITIONAL INFORMATION ON THE

NATIONAL WATER-QUALITY ASSESSMENT (NAWQA) PROGRAM:

Coordination among agencies and organizations is an integral part of the NAWQA Program. We acknowledge 

lowing agencies and organizations, who contributed to the success of the Willamette Basin NAWQA by serving as mem

our liaison committee.

• Bureau of Land Management

• Bureau of Reclamation

• City of Eugene

• City of Portland

• City of Salem

• Columbia River Inter-Tribal Fish Commission

• Metro Regional Government

• National Resources Conservation Service

• Oregon Department of Agriculture

• Oregon Department of Environmental Quality

• Oregon Department of Fish and Wildlife

• Oregon Department of Forestry

• Oregon Department of Human Resources, He

Division

• Oregon Department of Land Conservation and 

opment

• Oregon State University

• Oregon Water Resources Department

• Portland State University

• Tualatin Valley Water District

• Unified Sewerage Agency

• U.S. Army Corps of Engineers

• U.S. Environmental Protection Agency

• U.S. Fish and Wildlife Service

All photography by Dennis Wentz, except page 12 by Ian Waite and page 14 by Steve Hinkle.

Front cover photograph: Little Abiqua Creek near Scotts Mills drains the Cascade Foothills of Marion County. The b

within a mostly protected and forested reserve, and serves as a reference area for water chemistry and ecological stud

Back cover photographs: Left, Kurt Carpenter (left) and Ian Waite (right) use a backpack electroshocker to assess the f

munity of Muddy Creek near Peoria; right, Kathy Kuivila (left, California District) and Martell Kiefer (right) collec

sample from the Pudding River near Woodburn.

Willamette Basin Study Unit contact:

District Chief

U.S. Geological Survey

Water Resources Division

10615 S.E. Cherry Blossom Drive

Portland, OR 97216

Information on the NAWQA Program is also available on the Internet via the World Wide Web. Yo

connect to the NAWQA Home Page using the Universal Resources Locator (URL):

http://water.usgs.gov/lookup/get?nawqa

The Willamette Basin Study Unit’s Home Page is at URL:

http://oregon.usgs.gov/projs_dir/pn366/nawqa.html

An electronic version of this report is available at URL:

http://water.usgs.gov/lookup/get?circ1161
U.S. GEOLOGICAL SURVEY CIRCULAR

Water Quality in the Willamette Basin, Orego

1991–95

1161

By Dennis A. Wentz, Bernadine A. Bonn, Kurt D. Carpe

Stephen R. Hinkle, Mary L. Janet, Frank A. Rinella, Ma

Uhrich, Ian R. Waite, Antonius Laenen, and Kenneth E. Be

CONTENTS

National Water-Quality Assessment Program................

Summary of major issues and findings ...........................

Environmental setting and hydrologic conditions.........

Major issues and findings ..................................................

Fish communities, habitat, and water chemistry........

Suspended sediment.......................................................

Ground water/surface water interactions...................

Nutrients...........................................................................

Pesticides and volatile organic compounds ................

Dioxins and furans ..........................................................

Organochlorine pesticides, PCBs, and

trace elements...............................................................

Water quality conditions in a national context ...............

Study design and data collection......................................

Summary of compound detections

and concentrations ..........................................................

References ............................................................................

Acknowledgments...................................... inside back c
Library of Congress Cataloging in Publications Data

The use of firm, trade, and brand names in this report is for identification purposes only and

does not constitute endorsement by the U.S. Government

Free on application to the

U.S. Geological Survey

Information Services

Box 25286 Federal Center

Denver, CO 80225

U.S. DEPARTMENT OF THE INTERIOR

BRUCE BABBITT, Secretary

U.S. GEOLOGICAL SURVEY

Thomas J. Casadevall, Acting Director

Water quality in the Willamette Basin, Oregon, 1991–95 / by Dennis A. Wentz ... [et al.].

p. cm.—(U.S. Geological Survey circular ; 1161)

Includes bibliographical references.

ISBN 0–607–89231–5 (pbk.)

1. Water quality—Oregon—Willamette River Watershed.

I. Wentz, Dennis A. II. Series.

TD224.O7W28 1998 98–16276

363.739’42’097953—dc21 CIP

1998
U.S. Geological Survey Circular 1161 

NATIONAL WATER-QUALITY ASSESSMENT PROGRAM

Began in 1991

Began in 1994

Began in 1997

Not scheduled yet

EXPLANATION

K

ment, conservation, and regulation. In 1991, the U.S. Congress appropriated funds for

the U.S. Geological Survey (USGS) to begin the National Water-Quality Assessment

(NAWQA) Program to help meet the continuing need for sound, scientific information on the areal extent of the water quality problems, how these problems are changing with time, and an understanding of the effects of human actions and natural factors on water quality conditions.

The NAWQA Program is assessing the water quality conditions of more than 50 of

the Nation's largest river basins and aquifers, known as Study Units. Collectively,

these Study Units cover about one-half of the United States and include sources of

drinking water used by about 70 percent of the U.S. population. Comprehensive

assessments of about one-third of the Study Units are ongoing at a given time. Each

Study Unit is scheduled to be revisited every decade to evaluate changes in water

quality conditions. NAWQA assessments rely heavily on existing information collected by the USGS and many other agencies as well as the use of nationally consistent study designs and methods of sampling and analysis. Such consistency simultaneously provides information about the status and trends in water quality conditions

in a particular stream or aquifer and, more importantly, provides the basis to make

comparisons among watersheds and improve our understanding of the factors that

affect water quality conditions regionally and nationally.

This report is intended to summarize major findings that emerged between 1991

and 1995 from the water quality assessment of the Willamette Basin Study Unit and

to relate these findings to water quality issues of regional and national concern. The

information is primarily intended for those who are involved in water resource management. Indeed, this report addresses many of the concerns raised by regulators,

water utility managers, industry representatives, and other scientists, engineers, public

officials, and members of stakeholder groups who provided advice and input to the

USGS during this NAWQA Study Unit investigation. Yet, the information contained

here may also interest those who simply wish to know more about the quality of water

in the rivers and aquifers in the area where they live.

Robert M. Hirsch, Chief Hydrologist

nowledge of the quality of the Nation's streams and aquifers is important

because of the implications to human and aquatic health and because of the

significant costs associated with decisions involving land and water manage-

“The U.S. Geolog

Survey’s Willame

Basin NAWQA P

gram is a high qu

scientifically cred

water quality ass

ment. The progra

took a comprehe

approach which

included ground w

surface water, lan

use, conventiona

lutants, toxic pollu

habitat, physical 

tions, and biologi

components. The 

mation obtained

through this prog

complements our 

monitoring efforts 

provide a much m

accurate and com

plete understand

water quality con

tions within the W

lamette watershe

Such an understa

is essential to the 

and effective man

ment of these tre

sured water reso

and their protecti

present and futur

generations.”

— Greg Pettit,

Manager, Wat

Quality Monito

Oregon Depa

of Environmen

Quality
2 Water Quality in the Willamette Basin, Oregon, 1991–95

SUMMARY OF MAJOR ISSUES AND FINDINGS

IN THE WILLAMETTE BASIN

Relative abundances of fish species correlated best with instream and riparian

habitat quality (p. 8–9). Habitat and fish communities in agricultural and urban

streams were degraded compared with those in other NAWQA Study Units (p. 21).

• Pollution sensitive native fish, such as cutthroat trout and torrent sculpin, were found predominantly in forested streams with large riffle areas, high quality riparian habitat, and low

water temperatures. No external anomalies were found on fish from these streams.

• Pollution tolerant introduced fish, such as carp and bullheads, were collected primarily from streams with few ri

poor quality riparian habitat, and high water temperatures. External anomalies were most abundant on fish from 

streams.

• Relative abundances of fish generally were not highly correlated with water chemistry; however, pollution toleran

fish, including minnows and reticulate sculpin, were found mostly in agricultural and urban streams with the hig

nutrient and pesticide concentrations. External anomalies were moderately high on fish from these streams.

Erosion has increased downstream from dams (p. 10).

• Suspended sediment transport has remained unchanged downstream from 10 dams since their construction, but 

particle size of the transported sediment has decreased. These facts indicate that erosion has increased downstrea

the dams to compensate for the sediment trapped by the reservoirs.

• Erosion of stream channels and/or recently developed land could account for much of the sediment presently tran

downstream from the dams.

Ground water/surface water interactions are significant in large, gravel-bed rivers

(p. 11).

• Dye injection studies and streamflow measurements demonstrate the widespread occurrence of significant ground water/surface water interactions in large, gravel-bed rivers.

• Interchange of water between streams and adjacent aquifers can result in changes to associated nutrient and pesticide concentrations.

Nutrients in streams and ground water are degrading water quality (p. 12–13).

• In 45 percent of streams sampled, total phosphorus concentrations exceeded 0.1 mg/L

(milligram per liter), which is the maximum value cited by the U.S. Environmental Protection Agency (USEPA) as a goal for prevention of nuisance plant growth.

• Sixty-eight percent of streams where total phosphorus concentrations exceeded 0.1 mg/L

drained predominantly agricultural land.

• Guidelines do not exist for evaluating the effects of nitrate concentrations on algal growth, but nitrate concentrat

only 2 of 51 of streams exceeded the 10 mg/L maximum contaminant level (MCL) established by the USEPA fo

ing water. Neither stream was used as a source for drinking water.

• In streams of the Pudding Basin, nitrate and soluble reactive phosphorus concentrations during spring runoff incr

the percent of drainage area in agriculture increased.

• Nitrate concentrations in ground water exceeded the USEPA MCL in 6 of 70 shallow domestic wells drawing wa

the alluvial aquifer of the Willamette Valley.

• Nitrate concentrations were higher downgradient from irrigated agricultural areas than from nonirrigated agricu

areas.

• Nitrate concentrations in ground water are likely to increase in the future because water sampled as part of the p

study entered the ground water system when nitrogen fertilizer application rates were lower than in subsequent y

Water quality issues were identified at the start of the National Water-Quality Assessment of the Willamette Basin (W

McKenzie, 1991). The findings summarized below represent our contribution to an increased understanding of these i
U.S. Geological Survey Circular 1161 

Pesticides in streams are degrading water quality (p. 14–15).

• Fifty pesticides were detected in streams, and 10 pesticides exceeded criteria established by

the USEPA for the protection of freshwater aquatic life from chronic toxicity.

• Atrazine exceeded the drinking water MCL of 3 μg/L (micrograms per liter) in one sample,

and simazine exceeded the MCL of 4 μg/L in a different sample from the same stream; however, the stream was not used as a source of drinking water.

• Atrazine, simazine, metolachlor, deethylatrazine, diuron, and diazinon were detected in more than one-half of str

samples. Their concentrations varied seasonally in response to runoff and application rates.

• Forty-nine pesticides were detected in streams draining predominantly agricultural land, whereas 25 pesticides w

detected in streams draining mostly urban areas. The highest pesticide concentrations generally occurred in strea

draining predominantly agricultural land.

• In streams of the Pudding Basin, concentrations of atrazine, simazine, and metolachlor during spring runoff incre

the percent of drainage area in agriculture increased.

Ground water quality generally has not been degraded by pesticides or volatile organic compounds

(VOCs) (p. 15). Radon and dissolved solids concentrations and pesticide detection rates were low w

compared with other NAWQA Study Units (p. 22–23).

• Dinoseb (an herbicide) exceeded the MCL of 7 μg/L in ground water from one shallow domestic well, and tetrac

hene (a VOC) exceeded the MCL of 5 μg/L in a second well. These were the only organic compounds detected a

centrations greater than USEPA drinking water MCLs in domestic wells.

• Pesticides were detected in water from about one-third of the shallow alluvial wells sampled, but concentrations t

were low. A greater variety of pesticides was found at higher concentrations in agricultural areas than in urban ar

• VOCs were detected in water from about 20 percent of the shallow alluvial wells sampled. VOCs were found mo

quently in urban areas than in agricultural areas.

Dioxins and furans were detected in all bed sediment and fish tissue samples, including those from

forested reference basins (p. 16–17).

• Concentrations of total dioxins and furans in bed sediment from streams and lakes exceeded the USEPA guidelin

risks to fish at 2 of 22 sites; both sites were downstream from industrial areas. Concentrations in fish tissue did not 

the threshold for risks to predator fish at any of the 8 sites where fish were collected.

• Dioxin and furan concentrations in bed sediment from forested and agricultural basins are similar to those found 

areas of the United States where atmospheric deposition is the presumed source.

Although they have been banned since the late 1980s or earlier, organochlorine pesticides and PCB

still present in bed sediment and aquatic biota from streams and lakes (p. 18).

• Concentrations in bed sediment exceeded USEPA guidelines for protection of aquatic life at 10 of 47 sites. Chlo

and its component compounds, and DDT and its degradation products accounted for most guideline exceedances

• Concentrations in fish at 17 sites did not exceed National Academy of Sciences and National Academy of Engin

criteria for protection of fish-eating wildlife.

• The most commonly detected organochlorine compound both in bed sediment and aquatic biota was p,p’-DDE, 

dation product of DDT.

Concentrations of trace elements in bed sediment from streams and lakes exceeded Environment C

draft guidelines for protection of aquatic life at 26 of 52 sites (p. 18–19); however, concentrations ge

were low when compared with other NAWQA Study Units (p. 21).

• Chromium and nickel, which are relatively abundant in Willamette Basin rocks, commonly exceeded guidelines.

• The highest concentrations of cadmium, lead, silver, and zinc in bed sediment were in urban streams.

• The highest mercury concentrations in bed sediment were downstream from an abandoned mercury mine. High m

concentrations in fish have prompted the Oregon Health Division to issue advisories warning of health risks from 

sumption of fish taken from some streams and reservoirs.
4 Water Quality in the Willamette Basin, Oregon, 1991–95

ENVIRONMENTAL SETTING AND HYDROLOGIC CONDITIONS

OF THE WILLAMETTE BASIN

USEPA does not require to be filtered. The Willamette and Sandy

Rivers are tributary to the Columbia River, which flows west to the

Pacific Ocean along Oregon’s northern border.

Land Use

Land use in the

Willamette Basin has

been described based on

1970s high altitude

aerial photography

(U.S. Geological Survey, 1990) updated with

1990 census data (Hitt,

1994). Forested land (70

percent of the basin)

dominates the foothills

and mountains of the

Coast and Cascade

Ranges. Agricultural

land is mostly cropland, comprises 22 percent of the basin, and is

located predominantly

in the Willamette Valley. About one-third of

the agricultural land is

irrigated (Oregon Water

Resources Department,

1979; 1980; 1981), and most of this is adjacent to the main stem

Willamette River in the southern basin or scattered throughout the

northern valley. Urban land (6 percent of the basin) is located primarily in the valley along the main stem Willamette River. Other

land uses and water account for less than 2 percent of the basin

area.

In contrast to the 1970s land use data described above,

Landsat data collected during 1992–93 and analyzed as part of the

present study provide considerably greater detail with rega

crop types and native valley vegetation and (2) forest types 

nonforest upland.

During 1992, the Willamette Basin accounted for 5

cent of Oregon’s total gross farm sales and 58 percent of O

crop sales (Oregon Agricultural Statistics Service, 1993). T

sales came from nine counties that comprise most of the b

Pristine headwater streams, such

as Fir Creek in the Bull Run

watershed, contribute to Portland’s drinking water supply.

The Willamette River flows through Portland—Oregon’s largest 

politan area—before entering the Columbia River.

The Willamette Basin is drained by the Willamette 

Sandy Rivers and includes all or parts of 13 coun

(boundaries shown in yellow).

The Willamette Basin NAWQA Study Unit

comprises the Willamette and Sandy River

Basins in northwestern Oregon. The 12,000-

square-mile basin is bordered on the west by the

Coast Range, where elevations exceed 4,000 feet,

and on the east by the Cascade Range, with several

peaks higher than 10,000 feet. The interlying Willamette Valley, with elevations near sea level, is

filled mostly with sediment of alluvial origin.

The Willamette River is the 13th largest

river in the conterminous United States in terms of

streamflow and produces more runoff per square

mile than any of the larger rivers (Kammerer, 1990).

The Sandy River Basin includes the Bull Run watershed, which has been Portland’s primary drinking

water supply for more than 100 years; it is one of the

few surface supplies in the United States that the

During 1992, the Willamette Basin

accounted for 51 percent of Oregon’s total

gross farm sales.

Coast

Range

OREGON

C

d

R

Willamette

Valley
U.S. Geological Survey Circular 1161 

area, and were due to production of grass seed, wheat, hay,

oats, corn, and many specialty crops.

About 2 million people, or 70 percent of Oregon’s

population, lived in the Willamette Basin in 1990 (Center

for Population Research and Census, 1992). Portland, with

1.2 million people, is the State’s largest metropolitan area.

Population growth in the basin from 1990 to 1991 was

about 3.5 percent and is expected to continue.

Top 10 crops (by acreage) grown in the Willamette

Basin during 1987 (Rinehold and Witt, 1989)

Rank Crop Acres

1 Grass seed 293,000

2 Wheat 173,000

3 Other hay 152,000

4 Oats 62,200

5 Clover and vetch seed 49,600

6 Sweet corn 35,500

7 Alfalfa hay 26,400

8 Filberts 25,000

9 Snap beans 21,400

10 Mint 17,000

FOREST

AGRICULTURAL

URBAN LAND

WATEROTHER

0

2,000

4,000

6,000

8,000

10,000

Irrigated

Nonirrigated

AREA, IN SQUARE MILES

TOTAL AREA = 12,000 SQUARE MILES

Land use data from the 1970s (left and above

cate that 22 percent of the basin was agricult

that the area of nonirrigated land was about tw

area of irrigated land. LAND

About 2 million people, or 70 percent

of Oregon’s population, lived in the

Willamette Basin in 1990.

Land use data from 1992–93 provide greater detail w

regard to crop and forest types than do the 1970s la

use data (top of page).

1970s Land Use
6 Water Quality in the Willamette Basin, Oregon, 1991–95

ENVIRONMENTAL SETTING AND HYDROLOGIC CONDITIONS

OF THE WILLAMETTE BASIN

Water Use

More than three-fourths of the water used in the Willamette

Basin during 1990 was surface water (Broad and Collins, 1996).

The largest single use was for irrigation of crops, such as berries,

hops, mint, nursery stock, sugar beets, and vegetables (including

beans, broccoli, cabbage, corn, garlic, onions, and squash). Public

supply (serving cities, towns, mobile home parks, apartment complexes) was the second largest use; it consisted mostly of withdrawals from Cascade streams, including the Bull Run in the

Sandy Basin and the Clackamas, Santiam, and McKenzie Rivers.

The small amount of ground water used for public supply (10 percent of the total) came predominantly from alluvial aquifers

located along Cascade streams or along the main stem Willamette

River. Most commercial water use was by fish hatcheries, and most

industrial use was by pulp-and-paper mills.

Climate and Hydrology

The Willamette Basin is characterized by cool, wet winters

and warm, dry summers. About 70–80 percent of the annual precipitation falls from October through March, but less than 5 percent falls in July and August. Most precipitation falls as snow

above about the 5,000-foot level of the Cascades; however, the

Coast Range and Willamette Valley receive relatively little snow.

Mean monthly air temperatures in the valley range from about

3–5o

C during January to 17–20oC during August.

Although annual precipitation averaged 62 inches in the

Willamette Basin during 1961–90, topography strongly influenced

its distribution. Yearly amounts ranged from 40–50 inches in the

valley to as much as 200 inches near the crests of the Coast and

Cascade Ranges.

Streamflow in the Willamette Basin reflects the sea

distribution of precipitation, with 60–85 percent of runoff 

ring from October through March, but less than 10 percent 

ring during July and August. Releases from 13 tributary re

are managed for water quality enhancement by maintainin

of 6,000 cubic feet per second (ft3/s) in the Willamette Riv

Salem during summer months (U.S. Army Corps of Engin

1989).

Mean annual discharge of the Willamette River ne

mouth at Portland was 32,400 ft3

/s during water years 1972

water year extends from October 1 of one year through Sep

30 of the following year and is designated by the calendar 

which it ends.) Typical monthly flows at Portland ranged f

about 8,000 ft3/s in August to about 70,000 ft3/s in Decem

Recorded extreme flows were 4,200 ft3

/s in July 1978 and 

ft3/s in January 1974, although the river reached an estimat

flow of 460,000 ft3/s during the flood of February 1996.

Mean annual precipitation during 1961–90 was as 

as 200 inches near the mountain crests, but the W

lamette Valley received only 40–50 inches.

0

200

400

600

800

1,000

1,200

0

10

20

30

40

50

60

70

80

90

100

TOTAL

PUBLIC SUPPLY

DOMESTIC 

SUPPLY

COMMERCIAL

INDUSTRIAL AND 

MINING

IRRIGATION AND 

LIVESTOCK

THERMOELECTRIC

GROUND WATER

SURFACE WATER

POPULATION SERVED,

IN THOUSANDS

(1,629)

(330)

(1,629)

PERCENT OF TOTAL

WATER WITHDRAWALS

ESTIMATED WATER WITHDRAWALS IN 1990

WATER WITHDRAWALS,

IN MILLIONS OF GALLONS PER DAY

More than three-fourths of the water used

in the Willamette Basin during 1990 was

surface water.

About 70–80 percent of the annual

precipitation falls from October throu

March, but less than 5 percent falls in J

and August.

Estimated water withdrawals in 1990 were mostly from

surface water. Irrigation was the largest single use.
U.S. Geological Survey Circular 1161 

1994 was the second lowest on record.

However, because streamflow at this site is

regulated by nine tributary reservoirs, it

may not strictly represent upstream hydrologic conditions.

An analysis of precipitation data

from five National Oceanic and Atmospheric Administration sites distributed

O ND J FMAMJ J AS

7,000

6,000

5,000

4,000

3,000

2,000

1,000

0

MONTHLY MEAN DISCHARGE,

in cubic feet per second

OND J FMAMJ J AS

20

15

10

5

0

MONTHLY PRECIPITATION, in inches

throughout the basin generally corroborated results from th

streamflow analysis. Total precipitation was about 5 percen

the water years 1961–90 average during water year 1993, 

was 32 percent below average during water year 1994. Ho

water year 1995 (18 percent above average) was slightly w

than indicated by the streamflow data.

Mont

ditions durin

years 1993–9

differed cons

ably from lon

average cond

For example, 

itation and st

flow were ab

average durin

1993 when s

were collecte

northern Wil

Basin stream

determine nu

and pesticide 

centrations during a stormflow event following fertiliz

pesticide applications. On the other hand, spring 1994 

tation and streamflow generally were below average (p

larly during May) when samples were collected to eva

pesticide and nutrient concentrations in southern Willa

Basin streams, where crop types differ somewhat from 

the northern Willamette Basin.

Streamflows were about average during July–O

of all 3 water years. During these periods, many stream

wadable, most streams had stable beds, and conditions 

ideal for collection of streambed sediment and aquatic 

and for measurement of aquatic habitat characteristics

0

5,000

10,000

15,000

20,000

25,000

ANNUAL MEAN DISCHARGE,

1890 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 

WATER YEAR

WATER YEARS 1993–95

MEAN ANNUAL DISCHARGE

Annual mean discharges for the Willamette River at Albany indicate that water years 

and 1995 were typical of long term average conditions, but that discharge for water y

1994 was the second lowest on record.

Monthly precipitation and monthly mean discharges show

that conditions during water years 1993–95 (dots) usually

were considerably above or below average (horizontal bars).

Water Years

(water years 1961–90)

Headworks

Sandy River near Marmot

(Bull Run)

in cubic feet per second

1993–95

Hydrologic

Conditions During

1993–95

Hydrologic conditions during the intensive

data collection phase (water

years 1993–95) of the Willamette Basin NAWQA

study were evaluated using

discharge data for the Willamette River at Albany,

about 20 miles south of

Salem. This site has the

longest continuous record in

the basin and drains about

40 percent of its area.

Annual mean discharges

during water years 1993 and

1995 were about average,

but discharge for water year

Annual mean discharges during water

years 1993 and 1995 were about average,

but discharge for water year 1994 was the

second lowest on record.

Median

Range

(water years

 1961–90)
8 Water Quality in the Willamette Basin, Oregon, 1991–95

MAJOR ISSUES AND FINDINGS IN THE WILLAMETTE BASIN

Fish Communities, Habitat, and Water Chemistry

Stream sites in the Willamette Basin

have been categorized on the basis

of relative abundance of fish species

(percentage of total fish collected at a given

site) by Waite and Carpenter (in press).

They distinguished four categories of sites:

• forested reference (n=3);

• small agricultural/urban (n=14);

• large agricultural (n=4); and

• highly impaired (n=3).

Although land use influences upstream

from the highly impaired sites were primarily agricultural, the pie chart shows that

fish communities at these sites were quite

different from those at other agricultural

sites.

A total of 29 fish species, including 10

non-native (introduced) species, were collected from the 24 sites during 1993–95.

The most abundant species, in decreasing

order of relative abundance, were reticulate

sculpin, redside shiner, torrent sculpin,

speckled dace, yellow bullhead, and cutthroat trout.

Site Characteristics

Forested reference sites were characterized by high abundances of trout (cutthroat,

rainbow) and sculpin (mottled, Paiute, torrent, reticulate); no external anomalies

were found on fish from these sites. Fish

communities from the other three categories consisted of few or no trout and generally low abundances of pollution sensitive

sculpin species (including mottled, Paiute,

torrent). As seen in the bar graph, forested

sites exhibited the largest riffle areas, most

extensive canopies with best riparian quality (greatest species and diversity of vegetation and largest riparian zone), lowest

maximum water temperatures, highest

minimum dissolved oxygen (DO) percent

saturation, lowest nutrient concentrations

(example, total nitrogen), and no detections

of pesticides (sum of atrazine, metolachlor

and simazine).

Small agricultural/urban sites were

characterized by high abundances of pollution tolerant fish species (including minnows and reticulate sculpin), low levels of

external anomalies, and low abundances of

introduced species, such as bullheads, carp,

and sunfish. These sites exhibited small riffle areas, moderately open canopies of

moderate riparian quality, relatively high

maximum water temperatures, lowest minimum DO percent saturation, and highest

nutrient and pesticide concentrations.

had poor quality instream habitat. 

sites exhibited relatively low conc

tions of nutrients and pesticides; h

the highest maximum water temp

and percent open canopies, poores

quality, smallest riffle areas, and l

mum DO percent saturation were 

these sites.

Controlling Factors

From a basinwide perspective, 

abundances of native fish species 

most correlated with the quality o

instream and riparian habitat (Wa

Carpenter, in press). Trout and sen

sculpin species were common at f

reference sites characterized by ab

riffles, closed canopies, and lowes

temperatures. Tolerant reticulate s

and minnows dominated fish com

at small agricultural/urban sites, w

fles were rare, canopies were rela

open, and water temperatures wer

than at forested reference sites.

Within the small agricultural a

sites, water chemistry became mo

tant than habitat in controlling fish 

nities. For example, nutrient and p

concentrations and DO percent sa

were critical for understanding fis

butions (Waite and Carpenter, in p

Also, at highly impaired sites, hig

Large agricultural sites were characterized by relatively high abundances of torrent and reticulate sculpin, minnows, and

introduced species, with moderate levels of

external anomalies. These sites exhibited

relatively small riffle areas, open canopies

of low riparian quality, high maximum

water temperatures, and intermediate nutrient and pesticide concentrations.

The highly impaired sites—Long Tom

River, Bear Creek (tributary to the Long

Tom River), and Little Muddy Creek

(located north of Eugene and east of the

Willamette River)—were characterized by

high abundances of introduced species and

tolerant reticulate sculpin, and high levels

of external anomalies. The Long Tom and

Little Muddy sites have been channelized;

discharge of the Long Tom River is regulated by an upstream dam; and Bear Creek

Forested

Reference Sites

Large

Agricultural Sites

Small Agricultural/

Highly

Impaired Sites

Urban Sites

Fish communities varied significantly among site categories.

RIFFLES RIPARIAN OPEN MINIMUM MAXIMUM

0

80

20

40

60

QUALITY CANOPY WATER

Site categories derived from fish relative abundances reflect average 

conditions and water chemistry at the sites.

Forested Reference Sites

Small Agricultural/Urban Sites

Large Agricultural Sites

 Highly Impaired Sites

HABITAT VARIABLES and DO, in percent

PESTI- TOTAL

CIDES NITROGEN

HABITAT VARIABLES TEMPERATURE

DO

SATURATION

NO DETECTIONS

WATER TEMPERATURE, in degrees Celsius

Introduced species

Minnows

Reticulate sculpin

Torrent Sculpin

Trout

Other

Relative abundance

native fish species w

most correlated with 

quality of instream a

riparian habitat.
U.S. Geological Survey Circular 1161 

0

30

10

20

FORESTED

SMALL AGRICULREFERENCE

LARGE

AGRICULTURAL

HIGHLY

IMPAIRED

NO ANOMALIES

External anomalies were nonexistent at forested reference sites,

greatest at highly impaired sites,

and intermediate at remaining sites. EXTERNAL ANOMALIES, in percent

temperatures and low DO percent saturation were correlated with high relative

abundance of introduced species and with

external anomalies, such as anchor worms

and lesions.

On the basis of other studies in Oregon

and throughout the United States, occurrences of introduced species and external

anomalies at rates greater than 2 percent

are considered an indication of impaired

conditions (Hughes and Gammon, 1987;

Karr, 1991). The large agricultural and the

highly impaired sites were characterized by

introduced and tolerant fish species with

relatively high percentages of external

anomalies (9 and 25, respectively).

Although small agricultural/urban sites

exhibited smaller percentages of introduced species and lower numbers of anomalies (2 percent each), these sites also

showed higher numbers of tolerant fish and

generally were dominated by one or two

species—another indication of impairment.

An Index of Biotic Integrity (IBI)

(Hughes and others, in press), which

expresses fish community structure numerically, has been developed for wadable

streams in the Willamette Valley and was

applied to the small agricultural/urban sites

in the current study. The results suggest

that all sites were at least moderately

impaired; the five sites with the highest

percentages of introduced species also

reflected the poorest community structure

(lowest IBI scores).

Assessment of fish communitie

revealed different patterns of imp

among sites and helped develop hy

to explain these differences. It als

ported the conclusion that identifi

all fish species, not just game fish

needed to allow a complete assess

ecological health and sound comp

among all sites. This is demonstra

the distributions of the four sculpi

commonly collected. Forested ref

and small agricultural/urban sites 

similar percentages of total sculpi

the small agricultural/urban sites 

dominated by tolerant reticulate s

whereas forested reference sites s

sensitive species that were either 

dant or absent from the other sites

Instream and riparian habitat differences are apparent when comparing a forested reference site, such as Gales Creek in the Coast Range (top left) with

an agricultural site, such as the Little Pudding River in the Willamette Valley

(bottom right).

 Additional Information

During spring and summer of 19

fish communities, habitat, and wate

istry were evaluated at 6 intensive a

ment and 18 synoptic assessment si

(p. 25). Site locations are shown on 

ecoregion map on page 24. Fish we

collected at the most downstream (n

most) Willamette River site on the m

Fish were collected within a min

reach length of 500 feet using backp

boat electrofishing procedures, and 

were identified to species (Meador 

others, 1993a).

Habitat measurements were mad

four to six transects aligned perpend

the stream channels. Thirty-eight in

variables (including discharge, velo

depth, substrate size, percent riffles)

stream channel and bank variables (

ing channel dimensions, bank heigh

stability, riparian quality, percent op

opy, tree size and density) were mea

(Meador and others, 1993b).

Twenty-four water chemistry va

including stream temperature, speci

ductance, and concentrations of dis

oxygen (DO), nutrients (nitrate, am

total nitrogen, soluble reactive phos

total phosphorus), and dissolved pe

(sum of atrazine, metolachlor, and si

were evaluated during high and low 

Identification of all fi

species, not just ga

fish, was needed to al

complete assessmen

ecological health

Cutthroat trout was the predominant species in Gales Creek.

Lynn Bjork

Reticulate sculpin dominated the

fish community in the Little

Pudding River.

TURAL/URBAN
10 Water Quality in the Willamette Basin, Oregon, 1991–95

MAJOR ISSUES AND FINDINGS IN THE WILLAMETTE BASIN

Suspended Sediment

0.001

100

0.01

0.1

1

10

SUSPENDED SEDIMENT LOAD,

0.01 0.1 1 10

STREAMFLOW, in cubic feet per secon

USGS data (1991-93)

USACE data (1949-51)

Best fit regression line

 in tons per day per square mile

 per square mile

Willamette River at Salem

post-reservoir periods.

This suggests that erosion

has increased downstream

from dams since their construction. Possible sources

of sediment downstream

from dams include channel

erosion and erosion of land

developed after dam construction.

The graph for the Willamette River at Salem is

typical of relationships

between suspended sediment load and streamflow

for the 14 USGS and/or

USACE sites shown on the

map (Laenen, 1995).

These relationships indicate that annual suspended sediment loads for

Willamette Valley tributaries are about twice those

for Coastal tributaries and

nearly four times those for

Cascade tributaries.

At the four sites labeled on the map,

data were sufficient to determine that relationships between suspended sediment load

and stream discharge downstream from

sizes of suspended sediment for p

voir samples were finer than for p

voir samples at some sites (Laene

For example, the pre-reservoir ave

65 percent clay and silt for the W

River at Salem, whereas the post-

average was 82 percent. For the S

River at Jefferson, the pre-reservo

age was 45 percent clay and silt, a

post-reservoir average was 68 per

smaller particle size measured sin

construction suggests that a new s

contributing the sediment now be

sured downstream from the dams

Decreased particle size may be 

tant because nutrients, such as pho

and toxic constituents, such as dio

furans, chlorinated pesticides, and 

elements, can be transported in as

with fine sediment.

USACE dams were

not different during

pre- and post-reservoir periods. This is

demonstrated by the

clustering of 1991–

93 data within the

area of the graph

outlined by the

1949–51 data. The

similarity of sediment transport during pre- and postreservoir periods

suggests that the

amount of sediment

trapped by the reservoirs has been balanced by increased

erosion of downstream sediment

sources.

Particle Size

Decreased particle size of suspended sediment

downstream from

dams since their

construction provides further evidence that sediment

sources have

changed. Particle

Construction of USACE dams since 1949 h

affected downstream relationships betwee

suspended sediment load and streamflow.

Eleven multipurpose and two reregulation reservoirs (1.88 million

acre-feet of usable storage) are

operated in the Willamette Basin by the

U.S. Army Corps of Engineers (USACE)

(Shearman, 1976). Measurements of suspended sediment in streams downstream

from dam sites indicate that sediment

sources have changed since completion of

10 reservoirs after 1949.

Sediment Transport

Reservoirs intercept sediment and may

be expected to change the downstream

relationship between suspended sediment

load and stream discharge. However, data

for Willamette Basin streams indicate that

the relationships are similar for pre- and

USACE reservoirs are located on major tributaries.

Suspended sediment and streamflow were measured on

the Willamette River and major tributaries.

Additional Information

Stream discharge, suspended 

ment concentrations, and percent

of clay and silt were determined f

seven streamflow gaging stations 

ing 1991–93 (Laenen, 1995). Sim

data from two additional gaging s

tions were collected as part of the

USGS National Stream Quality

Accounting Network. These data 

compared to published informatio

available for 11 stream sites (U.S

Army Corps of Engineers, 1954) 

evaluate possible changes in sedim

transport downstream from USAC

reservoirs completed since 1949.

Measurements of

suspended sediment in

Willamette Basin streams

suggest that erosion has

increased downstream

from dams since their

construction.
U.S. Geological Survey Circular 1161 

MAJOR ISSUES AND FINDINGS IN THE WILLAMETTE BASIN

Ground Water/Surface Water Interactions

Permeable, coarsegrained, alluvial

deposits occur within

the channel and flood plain

of the main stem Willamette

River and many of its tributaries, particularly those

draining the Cascade Range.

Within these permeable

deposits, stream and ground

water may exchange within

an area known as the

hyporheic (hy-po-ree-ic)

zone—a diffuse and somewhat ill-defined region that

forms the boundary between

the stream channel and the adjacent ground

water flow system. Water in the hyporheic

zone flows along the overall downvalley

direction of the stream channel, but fluctuates between the channel and the subsurface (Bencala, 1993).

Hyporheic exchange can affect both the

quantity and chemistry of water in streams

and adjacent aquifers. For example,

hyporheic exchange can cause a significant

underestimate of stream discharge if a considerable volume of water is flowing within

the channel deposits at the point of a

streamflow measurement. In addition,

because hyporheic exchange involves not

only water, but also associated chemicals

and nine major tributaries located 

out the basin showed that the low

tiam River had the highest potenti

extent (area) of hyporheic storage 

to river cross-sectional area. In th

Santiam River, which has a pool-a

gravel-bed channel, potential hyp

storage averaged about three time

Willamette Basin streams with sil

channels; the latter are not expect

exhibit much hyporheic exchange

simulation of the dye injection ex

in the Santiam River by assuming 

hyporheic exchange resulted in a 

cise fit of the curve to the data and 

ther evidence that hyporheic proc

important.

Streamflow Measureme

Detailed streamflow measurem

made during periods of one to sev

along reaches of the Santiam and 

lamette Rivers in 1992–95 showed 

ing streamflow gains and losses o

distances. In the main stem Willam

River during June 1993, gains and 

were as much as 15 percent of the 

charge and point to the likelihood 

icant hyporheic exchange. The rel

large flow changes occurred betw

miles 180 and 140, where the cha

gravelly and braided.

Measured and simulated dye concentrations in the

Santiam River in June 1995 provide evidence that

hyporheic storage may be important.

Willamette River streamflow gains and 

in June 1993 suggest hyporheic exch

1200 1500 1300 1400

TIME OF DAY

0

4

1

2

3

DYE CONCENTRATION,

in micrograms per liter

Simulation without

Observed data

Simulation with

hyporheic exchange

hyporheic exchange

-2,000

3,000

-1,000

0

1,000

2,000

GAIN OR LOSS, in cubic feet per second

200 150 100

WILLAMETTE RIVER MILE

EUGENE

McKenzie RiverSantiam River

dissolved in the water, constituents, such as nutrients and pesticides, may undergo important

biogeochemical transformations

within the hyporheic zone.

Two lines of evidence suggest

that hyporheic exchange is significant in large streams of the Willamette Basin (Laenen and

Bencala, 1997). First, injections

of rhodamine WT dye in nine

streams yielded graphs of dye

concentration versus time with

long recession times characteristic

of active hyporheic exchange.

Second, in the Willamette and

Santiam Rivers, detailed measurements of water discharge revealed

areas where streamflow losses and

gains could not be accounted for by tributary inflows or diversions. These data are

consistent with stream water entering and

leaving the channel through coarse-grained

riverbeds.

Dye Injections

An assessment of 1992–95 dye injection

studies in the main stem Willamette River

175 125 

Measurement

Error

Evidence suggests that

hyporheic exchange is

significant in large streams

of the Willamette Basin.

Dye mixes rapidly after injection in

the Santiam River in June 1995. Total

elapsed time for the three photographs (top left to bottom right) was

less than 5 minutes.

Additional Information

Simulations of dye injection ex

ments were made using the OTIS m

for transport of dissolved constitue

(Runkle and Broshears, 1991). An 

tic Doppler Current Profiler (Simps

Oltmann, 1993) was used to make 

ple discharge measurements along 

reaches during short time periods.
12 Water Quality in the Willamette Basin, Oregon, 1991–95

MAJOR ISSUES AND FINDINGS IN THE WILLAMETTE BASIN

Nutrients

During 1991, about 63,000 tons of

nitrogen and 20,000 tons of phosphorus fertilizer were applied in

the Willamette Basin (Rinella and Janet,

1998). These elements are essential nutrients for aquatic plants; however, in high

concentrations, they can cause excessive

square miles, in the Pudding and Molalla

Basins during April 26–29, 1993.

Nitrate concentrations varied seasonally during 1993–95, as shown for the

Pudding River at Aurora (drainage area,

490 square miles). The highest concentrations coincided with the

beginning of rainfall induced

runoff during late fall/early

winter. A similar relationship

was found for historic data in

streams of the Willamette

Basin (Bonn and others,

1995; 1996).

Phosphorus in

Streams

Ninety-five percent of

stream samples contained

detectable concentrations of

total (dissolved plus suspended) phosphorus, ranging from 0.01 to 1.3 mg/L.

Data for the

Pudding River

show that total

phosphorus and

SRP concentrations

varied seasonally.

The highest total

phosphorus concentrations generally coincided with

the beginning of

the fall/winter runoff period and

probably were

associated with the

transport of suspended sediment.

SRP concentrations

were high during

winter, but generally were higher 

summer when contributions from 

sources were greater relative to st

and, thus, dilution was less. Point 

contributed most of the SRP durin

mer low flow in 1994.

Nitrate in Ground Water

Nitrate concentrations in groun

exceeded the USEPA MCL of 10 m

of 70 shallow domestic wells (abo

cent) sampled in the Willamette B

Nitrate concentrations in str

the Pudding and Molalla Bas

increased with percent of dr

area in agriculture, April 26–

Maximum stream nitrate concentrations occurred w

flows increased during late fall/early winter.

M J J A S O N D J F M A M J J A S O N D J F M A M J J A S

1993 1994 1995

0

5

1

2

3

4

NITRATE, in milligrams per liter as nitrogen ( )

0 50

PERCENT OF DRAINAGE 

IN AGRICULTURE

0.01

100

0.02

0.05

0.1

0.2

0.5

1

2

5

10

20

50

NITRATE, in milligrams per liter

Minimum Reporting Level (M

Open symbol represents

Excessive algal growth in the Little Pudding River

results from high nutrient concentrations.

Pudding River at Aurora

growth (eutrophication) that chokes stream

channels. In drinking water, high nitrate

concentrations cause methemoglobinemia

or “blue baby” syndrome, which can be

fatal to infants.

Nitrate in Streams

Ninety-eight percent of stream samples

contained detectable nitrate concentrations:

values ranged from 0.054 to 22 mg/L as

nitrogen. The lowest nitrate concentrations

were in streams draining predominantly

forested basins (greater than 90 percent

forest, by area).

Although none of the streams sampled

were used as a source of drinking water, the

10 mg/L maximum contaminant level

(MCL) established for drinking water protection by the U.S. Environmental Protection Agency (USEPA, 1996) is a widely

accepted standard for comparing nitrate

concentrations. Nitrate concentrations

exceeded the MCL in Bear and Zollner

Creeks in the Pudding Basin northeast of

Salem. Both streams drained predominantly agricultural land (greater than 50

percent agricultural land, by area).

In general, nitrate concentrations in

streams increased as the percent of drainage area in agriculture increased. An example of this relationship is presented for 20

watersheds, ranging in size from 3.4 to 490

Soluble reactive phosphorus (SRP, essentially dissolved orthophosphate) was

detected in 89 percent of stream samples

and varied from 0.01 to 0.93 mg/L.

Forty-five percent of streams yielded

total phosphorus concentrations that

exceeded 0.1 mg/L, the maximum value

cited by the USEPA (1986) as a goal for

prevention of nuisance plant growth in

streams. Sixty-eight percent of streams

where total phosphorus concentrations

exceeded 0.1 mg/L drained largely agricultural land. In Pudding and Molalla Basin

streams during April 1993, SRP concentrations increased with the percent of drainage

area in agriculture, in a manner similar to

that for nitrate. The lowest total phosphorus and SRP concentrations were observed

in streams draining predominantly forested basins.

as nitrogen

 Nitrate concentrations in

streams increased as the

percent of drainage area in

agriculture increased.

Forty-five percent 

streams yielded tot

phosphorus

concentrations tha

exceeded a value cite

a goal for prevention 

nuisance plant grow

values less than the MR
U.S. Geological Survey Circular 1161 

1993 as part of the NAWQA Program. In

contrast, the MCL was exceeded for 21

percent of 123 shallow domestic wells

sampled by Oregon Department of Environmental Quality (ODEQ) during the

1980s (Bonn and others, 1995). Because

ODEQ focused on known or perceived

problems, a greater percentage of exceedances for their data is not unexpected.

As seen from the graph, nitrate concentrations generally were higher in ground

water with high dissolved oxygen (DO)

concentrations than in ground water with

low DO concentrations. Microbial reduction of nitrate, common in low DO ground

water, is one likely explanation for the near

absence of nitrate under low

DO conditions.

Nitrate concentrations

were greater where aquifer

permeability was high than

where aquifer permeability

was low. Ground water in

aquifers with low permeability tends to be older than in

aquifers with high permeability. Because nitrogen fertilizer application rates in the

Willamette Basin have

increased in recent decades,

older ground water would be

expected to contain lower

nitrate concentrations.

Nitrate concentrations

were greater downgradient

from irrigated agricultural

areas than from nonirrigated agricultural

areas. This pattern may

reflect the generally

greater application rate

of nitrogen on irrigated crops (compared

with nonirrigated

crops) and the flushing

effect of irrigation.

To a large degree,

nitrate concentrations

in ground water reflect

land use practices at

the time the water infiltrated into the soil, and

these practices may not

have been the same as

when the ground water

was sampled. For

example, low tritium

concentrations in water from 21 percent of

the wells sampled in 1993 indicate that this

water entered the ground before 1953 when

nitrogen application rates also were low.

Because nitrogen fertilizer application

rates in the Willamette Basin have increased

in recent decades, nitrate concentrations in

ground water pumped during 1993 probably

reflect application rates that were less than

1993 rates. Water pumped in the future may

contain higher nitrate concentrations than in

1993, as the increasing fertilizer application

rates of the past continue to influence ground

water quality downgradient from application

areas. Because of the time lag between infiltration of water into the ground and its arrival

at a downgradient well, effects of past and

present ground water management practices

may take years or decades to become apparent in ground water pumped from shallow

domestic wells.

Total phosphorus concentrations in streams were

highest in late fall/early winter when flows increased.

SRP concentrations were highest in late summer

when dilution by streamflow was minimal.

M J J A S O N D J F M A M J J A S O N D J F M A M J J A S

1993 1994 1995

0

0.4

0.1

0.2

0.3

PHOSPHORUS, in milligrams per liter

Total

SRP

Nitrate concentrations in ground

water were low where dissolved

oxygen concentrations were low.

Nitrogen fertilizer application rates in the Willam

Basin have increased since 1945. (Data from Ale

and Smith, 1990.)

Irrigation can accelerate tran

nitrate to shallow ground w

heavily fertilized areas.

Pudding River at Aurora

Phosphorus

0 10 5

DISSOLVED OXYGEN,

0

30

10

20

NITRATE, in milligrams per liter

0

120

20

40

60

80

100

NITROGEN APPLICATION RATE,

in millions of pounds per year

1945 1950 1955 1960 1965 1970 1975 198

YEAR

Water from 21 percent of wells

sampled in 1993 entered the ground

water system prior to 1953

as nitrogen

Additional Information

During 1993–95, more than 26

stream samples were collected for 

ysis of nutrients from 51 sites loc

throughout the Willamette Basin (

Site locations are shown on the la

map on page 24.

In 1993, 70 shallow domestic 

from throughout the Willamette V

were sampled for nutrients (p. 25)

wells selected for sampling were 

pleted in alluvium because more th

percent of ground water used in th

lamette Basin is pumped from allu

aquifers. Site locations are shown 

hydrogeology map on page 24.

Detailed analyses of the data a

sented by Rinella and Janet (1998

surface water and by Hinkle (199

ground water.

Nitrate concentrations in

ground water exceeded the

USEPA MCL of 10 mg/L in

6 of 70 shallow domestic

wells sampled in 1993.

in milligrams per liter
14 Water Quality in the Willamette Basin, Oregon, 1991–95

MAJOR ISSUES AND FINDINGS IN THE WILLAMETTE BASIN

Pesticides and Volatile Organic Compounds

About 4.5 million pounds of pesticides are used each year in the Willamette Basin to control weeds,

insects, and other pests in agricultural and

urban settings (Rinehold and Witt, 1992).

Many pesticides are relatively soluble in

water, whereas others attach strongly to

soil particles. Pesticides are transported

from the land surface to streams through a

combination of subsurface drainage, surface runoff, and soil erosion. Infiltration of

rain and irrigation water facilitate transport

of pesticides to ground water.

Volatile organic compounds (VOCs) are

synthetic organic compounds that include

two main categories: (1) non-halogenated,

fuel-related components, such as benzene,

toluene, ethylbenzene, and xylenes

(BTEX), and (2) chlorinated

solvents, such as chloroform,

trichloroethene (TCE), and tetrachloroethene (PCE). Because

of their uses, VOCs are typically

associated with urban environments. Examples of VOC

sources include leaky underground storage tanks and emissions from automobiles. In

drinking water, they may be carcinogenic or otherwise harmful

to human health.

Pesticides in Streams

Of 86 dissolved pesticides

(herbicides, insecticides, fungicides) and pesticide degradation products analyzed in

streams as part of this study, 50

were detected at concentrations

greater than or equal to about

0.001 μg/L (micrograms per

liter). Of the most frequently

detected pesticides, the majority were herbicides.

Atrazine, simazine, metolachlor, deethylatrazine, diuron,

and diazinon were the most

commonly detected pesticides

in stream water. All were found

in more than 50 percent of the samples analyzed. Other pesticides were detected in

less than 50 percent of all samples.

Maximum recorded pesticide concentrations in stream water were: diuron (14

μg/L), carbofuran (9.0 μg/L), simazine (5.8

μg/L), atrazine (4.5

μg/L), and metolachlor (3.3 μg/L).

Eight pesticides

were detected at 1–

2 μg/L.

Criteria for the

protection of freshwater aquatic life

from chronic toxicity (as summarized

by Gilliom and others, in press) were

exceeded for 10

pesticides, including atrazine (4 of 183

detections), azinphos-methyl (3 of 3 detections), carbaryl (17 of 46 detections), carbofuran (3 of 51 detections), chlorpyrifos

(4 of 65 detections), diazinon (66 of 105

detections), p,p’-DDE (6 of 8 detections),

diuron (24 of 83 detections), lindane (1 of

13 detections), and malathion (1 of 12

detections).

In one sample each, atrazine and

simazine exceeded their maximum contaminant levels (MCLs) of 3 and 4 μg

respectively, as established by the 

(U.S. Environmental Protection A

1996) for protection of drinking w

Although the stream where the ex

ances occurred (Zollner Creek, no

Salem) was not used as a drinking 

source, the MCLs are widely acce

teria for comparing concentration

All aquatic life criteria and MC

exceedances occurred at sites drai

mostly (greater than 50 percent, b

agricultural or urban land; the hig

ticide concentrations occurred in 

tural basins.

Atrazine concentrations in stre

those for nitrate, increased with p

drainage area in agricultural land, 

for 20 watersheds less than 490 sq

miles in the Pudding and Molalla 

during April 26–29, 1993. Simazi

metolachlor concentrations at the

behaved similarly to atrazine.

Forty-nine pesticides were dete

streams draining predominantly a

tural land. Forty-three of these pe

were found in Zollner Creek, whi

drainage basin that is 99 percent a

tural. In contrast, 25 pesticides we

detected in urban streams, and 23 

were found in Fanno Creek, a bas

Portland metropolitan area that is 

cent urbanized. Herbicides were d

twice the rate of insecticides in bo

Atrazine concentrations incr

with percent of drainage are

agriculture for Pudding and 

Basin streams, April 26–29, 

0 50

PERCENT OF DRAINAGE 

IN AGRICULTURE

0.0001

10

0.001

0.01

0.1

1

ATRAZINE, in micrograms per liter

Method Detection Limit (M

Open symbol represent

0 100 20 40 60 80

DETECTION FREQUENCY, in percent

Herbicide

Insecticide

40 20

Atrazine

Simazine

Metolachlor

Deethylatrazine*

Diuron

Diazinon

Napropamide

EPTC

DCPA

Chlorpyrifos

Carbofuran

Terbacil

Ethoprop

Prometon

Carbaryl

Fonofos

Tebuthiuron

Pronamide

Trifluralin

Metribuzin

2,4-D

Triclopyr

Lindane

Malathion

Alachlor

STREAMS GROUND

WATER

Dinoseb

Propachlor

Dieldrin

p,p’-DDE*

Bromacil

Propanil

Herbicides, such as atrazine, are applied primarily in

spring and early summer.

Most of the pesticides detected in streams and

ground water were herbicides.

Criteria for the protec

of freshwater aquatic 

from chronic toxicity 

exceeded for 10 pestic

in streams.

Pesticide

Degradation

Product

*

values less than the MD
U.S. Geological Survey Circular 1161 

cultural and urban streams. Only atrazine

and deethylatrazine were detected in

streams draining forested basins (greater

than 90 percent forest, by area), and these

compounds were present at extremely low

concentrations (0.002 to 0.004 μg/L).

Of the six most frequently detected pesticides, all but diazinon were found at highest concentrations in predominantly

agricultural streams. Diazinon concentrations were similar in agricultural and urban

streams. Three herbicides—prometon,

tebuthiuron, and dichlobenil—were

detected most frequently in urban streams.

Concentrations of the six most frequently detected pesticides varied seasonally. For example, the graph for Zollner

Creek shows that the highest atrazine concentrations generally coincided with spring

runoff following application; however, relatively high concentrations also were found

during late fall/early winter when increasing rainfall flushed land that had been dry

most of the summer.

Pesticides and Volatile

Organic Compounds in

Ground Water

One to 5 pesticides were detected in

water from each of 23 domestic wells

(about one-third of the wells sampled); 13

different pesticides were detected at these

sites. Concentrations ranged from less than

0.001 to 0.89 μg/L, with one exception:

dinoseb (an herbicide) was detected in

water from one well at 7.9 μg/L, which is

greater than the MCL of 7 μg/L. This was

the only measured exceedance of an MCL

for pesticides in ground water.

Ground water with

detected pesticides

generally came from

domestic wells penetrating smaller thicknesses of overlying

clay than did ground

water containing no

detected pesticides.

This is partly because

pesticides tend to be

retained by clay particles. In addition,

ground water flows

more slowly through

clay than it does

through coarser

grained materials,

and the increased

contact time with the

clay allows greater

pesticide degradation.

Pesticides were

present at lower concentrations and detection rates in water from urban monitoring

wells than from the mostly agricultural

domestic wells, possibly reflecting smaller

pesticide application rates in urban areas

compared to agricultural areas. Trace concentrations (less than 0.01 μg/L) of one or

two pesticides were detected in water from

three urban monitoring wells, but no

USEPA MCLs

were exceeded.

One to five

VOCs were

detected in water

from each of

seven domestic

wells. Six different VOCs were

detected, but only

tetrachloroethene (one

occurrence)

exceeded the 5

μg/L MCL.

VOCs were

detected in water

from a greater

percentage of

urban monitoring wells than from 

mostly agricultural domestic well

bly reflecting a larger number of p

nonpoint sources of VOCs associa

urban land use practices. From on

VOCs were detected in water from 

monitoring wells. Five different V

were detected; tetrachloroethene e

the MCL in one well.

AMJ J ASOND J FMAMJ J ASOND J FMAMJ J AS

1993 1994 1995

0

5

1

2

3

4

ATRAZINE, in micrograms per liter ( )

Atrazine concentrations were highest during spring following pesticide application, but relatively high concentrations also occurred during fall runoff.

VOCs in ground water were detected mostly in urba

DETECTION FREQUENCY,

Domes

Monito

Zollner Creek near Mt. Angel

Approximate

pesticide

application

period

Carbon

Chloroform

1,1-Dichloroethene

Tetrachloroethene

1,1,1-Trichloroethane

Trichloroethene

Trichlorofluoromethane

0

20

40

60

80

tetrachloride

Volatile

Organic

Compounds

(mostly

(urban)

in percent

Additional Information

During 1993–95, 195 samples w

collected from 43 stream sites in th

lamette Basin for analysis of dissol

ticides and pesticide degradation pr

(p. 25). At four sites, pesticides we

lyzed monthly and during extremes 

streamflow. Pesticides were analyz

additional sites during periods of on

or less to examine spatial distributi

ing high and low streamflow. Site lo

are shown on the land use map on p

During 1993–95, 69 of 70 shall

domestic wells and 10 shallow USG

monitoring wells were sampled for 

cides, whereas 65 of 70 shallow do

wells and the 10 USGS monitoring 

were sampled for VOCs. Site locat

shown on the hydrogeology map on 

24. Because more than 80 percent o

ground water used in the Willamett

is pumped from alluvial aquifers, o

wells completed in alluvium were s

pled. Most of the domestic wells w

agricultural settings. USGS monito

wells were in urban areas comprisi

marily residential land, with small a

of interspersed commercial propert

Laboratory procedures for VOC

pesticides are given by Rose and Sc

(1995), Werner and others (1996), 

Zaugg and others (1995). Detailed 

ses of the Willamette Basin data ar

sented by Rinella and Janet (1998) 

surface water and by Hinkle (1997) 

ground water.

Only one pesticide and

one VOC were detected in

ground water from

domestic wells at

concentrations greater

than the USEPA MCL for

drinking water.

0

400

100

200

300

STREAMFLOW, in cubic feet per second ( )

agricult
16 Water Quality in the Willamette Basin, Oregon, 1991–95

MAJOR ISSUES AND FINDINGS IN THE WILLAMETTE BASIN

Dioxins and Furans

Dioxins and furans are organic

chemicals that are of environmental interest because of their acute

toxicity to some animal species. Recently,

they have been implicated as potential

endocrine disrupters—chemicals that can

interfere with the normal function of hormones, and thereby affect reproductive

success. A review of health risks associated

with dioxins and furans has been published

in Environmental Science and Technology

(1995, v. 29, p. 24A–35A).

Structure, Toxicity, and

Sources

Dioxins and furans are not single chemicals, but rather families of related compounds that differ in the number and

position of their chlorine atoms. Each different compound is called a congener. Congeners that have the same number of

chlorine atoms form a congener class.

Toxicity varies among congeners. The

most toxic congener is 2,3,7,8-TCDD (tetrachlorodibenzo-p-dioxin), which has four

chlorine atoms located at the 2,3,7, and 8

positions. Toxicity decreases as chlorine

atoms are added or removed. For example,

OCDD (octachlorodibenzo-p-dioxin), the

congener with eight chlorine atoms, is considered a thousand times less toxic than

2,3,7,8-TCDD. However, regardless of the

number of chlorine atoms, the most toxic

congeners are those that have chlorine

atoms in at least the 2,3,7, and 8 positions.

Because toxicity varies among congeners,

concentrations of dioxins and furans can be

expressed as equivalent concentrations of

2,3,7,8-TCDD in order to provide an indication of potential total toxicity.

Toxicity of dioxins and furans also varies widely among animal species. The

USEPA has estimated that 2,3,7,8-TCDD

equivalent concentrations below 60 pg/g

(picograms per gram) in sediment are of

low risk to fish exposed to the sediment

(U.S. Environmental Protection Agency,

1993). Similarly, concentrations below 50

pg/g in fish tissue are estimated to be of

low risk to predator fish.

Dioxins and furans are not deliberately

manufactured. Rather, small quantities of

these compounds are inadvertently produced as by-products of a variety of industrial processes. Two important sources are

waste incineration, especially of plastics,

and effluent discharge from pulp and paper

mills that use chlorine bleaching. In addition, dioxins and furans are trace contaminants in many chlorinated chemicals, such

as some wood preservatives and pesticides.

Chlorination of sewage effluent also may

produce dioxins and furans.

Concentrations in Bed

Sediment

A survey of dioxin and furan occurrence

in the Willamette Basin during 1992–95

found a wide range of concentrations in

bed sediment, with the highest concentrations being about 1,000 times greater than

the lowest concentrations (Bonn, 1998; in

press). Samples from industrial areas generally contained the highest concentrations.

Concentrations of 2,3,7,8-TCDD equivalent were found at levels greater than the

USEPA threshold for risk to fish at two

sites (A-3 Channel in Eugene and Middle

Fourth Lake near Albany), both of which

are downstream from industrial areas.

Throughout the basin, total dioxin and

furan concentrations were 100–1,000 times

more than 2,3,7,8-TCDD equivalent concentrations because the most abundant congeners also were the least toxic. OCDD

was the dominant congener found in bed

sediment. It accounted for about 80 percent

of total concentrations. The sum of concentrations for the TCDD congener class was

usually about 100 times lower than the

OCDD concentration at the same site, and

2,3,7,8-TCDD was rarely detected.

Dioxins were detected in every bed sediment sample, including those from forested reference basins, such as Mack Creek

in the Cascade Range east of Eugene and

Fir Creek in the Bull Run Watershed east of

Portland. Concentrations below 100 pg/g

occurred in sediment from Mack Creek and

from Cottage Grove Reservoir, w

receives drainage from a large for

basin. Concentrations at other fore

were somewhat higher (100–300 p

were similar to those at agricultur

Atmospheric deposition contai

concentrations of dioxins and fura

wood burning and waste incinerat

is the most likely source of these 

pounds in bed sediment at foreste

agricultural sites. Low concentrat

Mack Creek and Cottage Grove R

probably result because these site

ther from atmospheric sources tha

sampling sites. In general, dioxin 

concentrations at forested and agr

sites in the Willamette Basin are s

or less than those at reference site

elsewhere in the United States wh

spheric deposition is the presume

In addition to atmospheric dep

some sites may be influenced by s

local sources. For example, a bed 

O

O 1

4

2

7 3

6

9

8

1

4

2

7 3

6

9

8

Dioxins

Furans

Dioxins and furans contain

from one to eight chlorine

atoms located in the positions

indicated by the numbers 1–4

and 6–9. There are 75 different

dioxin congeners and 135

different furan congeners. Dioxins

and furans containing four or more

chlorine atoms were analyzed in

this study.

Atmospheric depositi

the most likely sourc

dioxins and furans in 

sediment at forested 

agricultural sites

Newberg

Portland

Portland

Corvallis 1995

102

103

104

DIOXIN PLUS FURAN,

Dioxin and furan concentra

in bed sediment from the m

stem Willamette River incr

downstream from Newberg

through the Portland area.

Because the less toxic cong

predominated, 2,3,7,8-TCDD

equivalent concentrations we

100–1,000 times less than to

dioxin and furan concentratio

[Note different ordinate scales; s

collected in 1992 unless otherw

cated.]

(RM 137) (RM 55)

(RM 5)

(RM 13)

in picograms per gram

Downstream

O
U.S. Geological Survey Circular 1161 

0 25 MILES

Eugene

Salem

Portland

Willamette R

(Portland area)

Johnson C

at Milwaukie

Tualatin R

at West Linn

Fanno C

at Durham

Willamette R

at Newberg

Willamette R

at Corvallis

Mack C

near Blue R

Amazon C

near Eugene

RM 13

RM 5

RM 9

1993

1995

1993

1995

10-2

10-1

1

10

102

2,3,7,8-TCDD EQUIVALENT, in picograms per gram

10

102

103

104

105

DIOXIN PLUS FURAN, in picograms per gram

carpsculpinsculpinsculpin

largescale sucker

largescale suckerlargescale suckercutthroat troutbluegill

Dioxin and furan concentrations in fish tissue were much lower than in

bed sediment obtained from the same area. Fish tissue, however, generally contained greater proportions of the most toxic congeners (especially

2,3,7,8-TCDD) than sediment. Consequently, 2,3,7,8-TCDD equivalent concentrations usually were higher in fish than in bed sediment at a given site.

[Note different ordinate scales; samples collected in 1992 unless otherwise indicated.]

sample obtained beneath a wooden bridge

at one forested reference site showed

unusually high concentrations of furans.

Other samples obtained from the same general area, but upstream from the bridge, did

not. The high furan concentrations may

have been associated with wood preservatives used on the bridge.

In the main stem Willamette River,

dioxin and furan concentrations in bed sediment increased as the predominant adjacent land use changed from agricultural to

industrial. Sediment from RM (river mile)

55 near Newberg exhibited essentially

background concentrations. In contrast,

higher concentrations at RMs 13 and 5 may

reflect chemical use and production in the

Portland Harbor area. Interestingly, sediment from Corvallis (RM 137) contained

considerably higher 2,3,7,8-TCDD equivalent concentrations than that from Newberg, even though total concentrations were

not very different. This is because the Corvallis site exhibited a larger proportion of

2,3,7,8-TCDD than the other sites. The

Corvallis site is downstream from a pulp

and paper mill that has used elemental

chlorine bleaching—a process known to

produce trace amounts of 2,3,7,8-TCDD.

The measured decrease in concentration of

2,3,7,8-TCDD equivalent in bed sediment

at Corvallis between 1992 and 1995 may

be related to the mill’s reduction of elemental chlorine use in 1993.

Concentrations in Fish

Tissue

Dioxin and furan concentration

whole fish generally were about 1

less than in bed sediment from the 

area. However, when expressed as 

TCDD equivalent, concentrations 

exceeded those in sediment at mo

one-half the sites because fish con

larger proportion of the most toxi

pounds (2,3,7,8-chlorinated conge

TCDD) than did sediment.

No fish analyzed in this study c

2,3,7,8-TCDD equivalent concent

that exceeded the USEPA threshol

to predator fish. The highest 2,3,7

equivalent concentrations in fish t

occurred in carp (16 pg/g) from th

lamette River at RM 9 (an industr

tion of the Portland Harbor) and i

(10 pg/g) from lower Johnson Cre

area with considerable adjacent u

and light industry).

No fish analyzed in t

study contained 2,3,

TCDD equivalent

concentrations tha

exceeded the USEP

threshold for risk t

predator fish.

 Additional Information

Bed sediment samples ( ) were

obtained from 22 sites; composite sam

ples of 5–20 whole fish ( ) were

obtained from 8 sites (p. 25). Industrial, urban, agricultural and forested

reference areas were represented.

Three reaches of the main stem Willamette River were sampled both for

bed sediment and fish tissue.

All samples were analyzed for tetra

through octa-chlorinated congener

class totals of dioxins and furans. In

addition, concentrations of all congeners with chlorine atoms in at least the

2,3,7, and 8 positions were determined

Results are expressed as picograms pe

gram dry weight. Detailed analyses of

the data are presented by Bonn (1998

in press).

DIOXIN PLUS FURAN IN BED SEDIMENT

DIOXIN PLUS FURAN IN FISH

2,3,7,8-TCDD EQUIVALENT IN BED SEDIMENT

2,3,7,8-TCDD EQUIVALENT IN FISH
18 Water Quality in the Willamette Basin, Oregon, 1991–95

MAJOR ISSUES AND FINDINGS IN THE WILLAMETTE BASIN

Organochlorine Pesticides, PCBs, and Trace Elements

Organochlorine pesticides and polychlorinated biphenyls (PCBs) are

synthetic organic chemicals that

have been linked to reproductive problems

in aquatic invertebrates, fish, birds, and

mammals. PCBs were used in the manufacture of electrical equipment, such as capacitors and transformers. Use and

manufacture of PCBs and the pesticides

chlordane, DDT, dieldrin, and toxaphene

have been restricted or banned in the

United States since the late 1980s or earlier, but they are still present in aquatic systems because of their environmental

persistence. Similarly, many trace elements

have important anthropogenic sources and

are toxic at high concentrations; however,

they also can have natural geologic

sources, and some are essential for biological function. Organochlorine pesticides,

PCBs, and trace elements are more likely

to be associated with sediment or incorporated into tissue than to be dissolved in

water. Thus, bed sediment and aquatic

biota were used to evaluate general levels

of occurrence and spatial distributions of

these constituents.

Organochlorine Pesticides

and PCBs

Of 27 organochlorine compounds analyzed both in bed sediment and aquatic

biota during 1992–95, 19 were detected in

sediment, and 14 were detected in biota.

The most common compound in sediment

and biota was p,p’-DDE, a degradation

product of DDT, which was used extensively to control insects from about 1940

until its ban in 1972. Concentrations of

p,p’-DDE were detected at 45 percent of

sites where bed sediment was collected and

at 63 percent of sites where aquatic biota

were collected. Detections were about

equally divided among basins with predominantly agricultural,

urban (residential, commercial, industrial), and

mixed land uses. Detections were more common

in biota than in sediment.

The largest concentration of p,p’-DDE in bed

sediment (120 micrograms

per kilogram dry weight)

was found in upper

Johnson Creek east of Portland, where the basin is

mostly agricultural. This

value is higher than

reported for the agricultural

Central Columbia Plateau

Basin, Washington (Gruber and Munn, 1996), but it

is less than one-tenth the maximum concentration reported for the Yakima Basin,

Washington, where DDT contamination in

runoff from agricultural land has been documented (Rinella and others, 1992; 1993).

Total PCBs were detected at 11 percent

of sites where bed sediment was collected,

but detections were reported for 32 percent

of sites where aquatic biota were c

All sediment and biota with PCB 

tions were from streams draining 

with strong urban influences.

Recommended concentration g

lines for protection of aquatic life 

organochlorine pesticides and PC

sediment are summarized by Gilli

others (in press). Criteria for prote

fish-eating wildlife have been reco

mended by the National Academy 

ences and National Academy of

Engineering (NAS/NAE) (1973). 

dane and its component compoun

sites), and DDT and its degradatio

ucts (six sites) accounted for 94 p

exceedances of recommended gui

bed sediment. Ten of 47 sites exh

exceedances; two agricultural, on

and one urban/industrial basin acc

for 77 percent of the exceedances

nochlorine pesticide and PCB con

tions in fish tissue from 17 sites d

exceed the NAS/NAE criteria.

Trace Elements

Arsenic, cadmium, chromium, 

lead, mercury, nickel, silver, and z

particular interest in the Willamet

because they are potentially toxic 

aquatic organisms and are widesp

products of human activities (Rick

others, 1977). Of these, median ch

and nickel concentrations in bed s

showed no obvious differences fo

draining forested, agricultural, urb

mined areas.

Lead concentrations in bed sed

were significantly higher for strea

ing urban areas than for streams d

other land uses. Median lead conc

tions from urban areas were 50 μg

(micrograms per gram) dry weigh

highest value was 240 μg/g dry w

0

10

20

30

40

60

FREQUENCY OF DETECTION, in percent

p,p’-DDE p,p’-DDD p,p’-DDT cis- dieldrin trans- chlordane chlordanetrans- cis- Total

nonachlor nonachlor

0

50

100

150

200

250

LEAD CONCENTRATION,

in micrograms per gram dry weight

Forested Agricultural Urban Mixed 

LAND USE

Range

Median

The highest lead concentrations in bed sedi

were found in urban streams.

Most organochlorine compounds were detected more frequently in aquatic

biota than in bed sediment.

50

PCB

ORGANOCHLORINE COMPOUND

Bed Sediment

Aquatic Biota

Lead

The most common

organochlorine compound

was p,p’-DDE, a

degradation product of

DDT.
U.S. Geological Survey Circular 1161 

from Beaverton Creek—an urban stream in

the Portland area. Median values for all

other land uses were 14 μg/g dry weight or

less. Common lead sources in urban environments include batteries, dyes, and

paints. Much of the lead probably also was

contributed by leaded gasoline, which is no

longer sold but is persistent in the environment. Distributions of cadmium, silver, and

zinc in relation to land use were similar to

that for lead.

Although mercury concentrations in bed

sediment generally were higher in urban

areas than in forested or agricultural areas,

the highest values were downstream from

the abandoned Black Butte Mine, south of

Eugene. This area was mined for cinnabar

until about 1968 and was the second largest

producer of mercury in Oregon (Brooks,

1971). The relationship of arsenic to land

use was similar to that for mercury; copper

concentrations were elevated downstream

from the mined area but were not consistently high in urban areas.

Mercury concentrations in bed sediment

generally decreased downstream from the

Black Butte Mine. The affected area

includes Cottage Grove Reservoir (located

on the Coast Fork Willamette River),

where a mercury advisory warning of

health risks from consumption of fish has

been in effect since 1979 (Newell and others, 1996). Mercury concentrations as high

as 1.79 μg/g wet weight have been reported

for fillets from largemouth bass collected in

this reservoir (Allen-Gil and others, 1995;

Newell and others, 1996). In February

1997, the Oregon Health Division issued a

mercury advisory for consumption of

smallmouth bass, largemouth bass, and

northern squawfish from the entire main

stem Willamette River, including the Coast

Fork to Cottage Grove Reservoir; a separate advisory was issued for consumption

of all fish from Dorena Reservoir, which

also is located in the Coast Fork Basin.

Guidelines for protection of aquatic life

from trace element concentrations in bed

sediment have been recommended by Environment Canada (1995). The most commonly exceeded guidelines were for nickel

(12 sites) and chromium (15 sites), which

occur naturally at high concentrations in

basaltic rocks (Parker, 1967), such 

found in much of the Willamette B

The next most commonly exceede

lines were for arsenic (eight sites) 

cury (six sites); four of the mercu

exceedances were for samples col

downstream from the abandoned 

Butte Mine. Zinc and lead concen

exceeded guidelines at four and th

respectively, and no exceedances 

found for cadmium or copper. Exc

for at least one trace element occu

of 52 sites.

Although fewer samples of aqu

than bed sediment were collected 

ysis of trace elements, results in r

land use generally were similar. N

established guidelines were availa

evaluating risks of trace elements 

aquatic biota to fish-eating wildlif

0

.5

1.0

1.5

2.0

2.5

MERCURY CONCENTRATION,

in micrograms per gram dry weight

Garoutte

Creek

Dennis

Creek

Coast Fork

Willamette

River above

Cottage

Grove

Reservoir

Wi

Riv

C

Coast Fork

Willamette

River below

0

.5

1.0

1.5

2.0

2.5

MERCURY CONCENTRATION,

in micrograms per gram dry weight

Forested Agricultural Urban Mixed Mined

Additional Information

Twenty sites were sampled both for bed

sediment and aquatic biota, and 32 additional sites were sampled for bed sediment

only (p. 25). Site locations are shown on the

land use map on page 24. The sites reflect

important land uses in the basin, including

forested (12 sites), agricultural (10 sites),

urban (12 sites), mixed (14 sites), and mined

(4 sites). Samples were collected following

protocols given by Crawford and Luoma

(1993) and Shelton and

Capel (1994).

Bed sediment

samples to be analyzed for trace elements were wet

sieved through a

62-micrometer nylon

cloth; samples for

analysis of organochlorine pesticides and PCBs 

passed through a 2-millimeter st

steel sieve. Aquatic biota samples 

mostly composites of 6–10 sculpin 

body) or 35–5

Asiatic clams 

sue only). Liv

carp, largemou

and largescale 

were analyzed 

trace elements 

sites.

Analyses w

formed by US

oratories in De

Colorado, foll

procedures de

by Arbogast (

Foreman and o

(1995), Leiker 

others (1995), 

Hoffman (199

Downstream

LAND USE

Mercury concentrations in bed sediment were higher in urban areas than in forested or agricultural areas (left

cury concentrations were highest below the Black Butte Mine, and they generally decreased downstream (righ

Range

Median

Black Butte Mine

Mercury

Asiatic clams

(above) and

sculpin (left)

were the main

species analyzed.

Mercury concentrations in

bed sediment were highest

downstream from an

abandoned mercury mine.

reservoir reservoir
20 Water Quality in the Willamette Basin, Oregon, 1991–95

Nutrient concentrations in

water were similar to those

found nationally. Concentrations in two streams were in

the top 25 percent of data

from the 20 NAWQA Study

Units. One stream drained a

small agricultural basin, and

the other received sewage

treatment plant effluent. No

exceedances of the aquatic

life criterion for unionized

ammonia were found.

Pesticide concentrations in

water generally were representative of those found in

other NAWQA Study Units.

At one urban and two agricultural sites, exceedances of

aquatic life criteria occurred

for azinphos-methyl, carbofuran, chlorpyrifos, and/or

diazinon.

Seven major water quality characteristics were evaluated for stream sites i

NAWQA Study Unit. Summary scores for each characteristic were comput

sites that had adequate data. Scores for each site in the Willamette Basin w

compared with scores for all sites sampled in the 20 NAWQA Study Unit

1992–95. Results are summarized by percentiles; higher percentile values g

indicate poorer quality compared with other NAWQA sites. Water quality

conditions at each site also are compared to established criteria for protect

aquatic life. Applicable criteria are limited to nutrients and pesticides in w

semivolatile organic compounds in bed sediment, and organochlorine pestic

PCBs in bed sediment. (Methods used to compute rankings and evaluate aq

criteria are described by Gilliom and others, in press.)

Concentrations of or

nochlorine pesticide

PCBs in bed sedime

biological tissue wer

of those in other NA

Study Units; howeve

centrations were am

highest 25 percent at 

mostly agricultural s

Lindane in bed sedim

exceeded the aquatic 

standard at one of the

EXPLANATION

Ranking of stream quality relative 

NAWQA stream sites — Darker co

circles generally indicate poorer qua

Bold outline of circle indicates one 

more aquatic life criteria were excee

Greater than the 75th percentile

(among the highest 25 percent

of NAWQA stream sites)

Between the median and the 75th pe

Between the 25th percentile and the 

Less than the 25th percentile

(among the lowest 25 percent

of NAWQA stream sites)

No data

NUTRIENTS in water

PESTICIDES in water

Portland

Salem

Eugene

Sandy River

Willamette

River

ORGANOCHLORINE PES

and PCBs in bed sedimen

ological tissue

WATER QUALITY CONDITIONS IN A NATIONAL CONTEXT

Comparison of Stream Quality in the Willamette Basin

with Nationwide NAWQA Findings

Portland

Salem

Eugene

Sandy River

Willamette

River

Portland

Salem

Eugene

Sandy River

Willamette

River
U.S. Geological Survey Circular 1161 

Trace element concentrations in bed

sediment were lower than typically

found nationally, with concentrations at 7 of 10 sites falling in the

bottom 50 percent of data from the

20 NAWQA Study Units. The three

streams with concentrations in the

top 50 percent of NAWQA data

were the only streams draining

basins with large urban areas.

Stream habitat conditions for five

streams draining basins with agric

tural and/or urban influences were

among the worst found when com

pared with other NAWQA Study

Units. The most common factors 

tributing to these conditions were

poor riparian quality, high suscept

ity to bank erosion, and a high deg

of channel modification.

Fish community conditions in five

streams draining basins with agricultural and/or urban influences

ranked among the poorest 25 percent of streams sampled in other

NAWQA Study Units, as determined by percentages of external

anomalies and of species that are

pollution tolerant, omnivorous, and

non-native. At one agricultural site,

fish were 99 percent non-native and

61 percent exhibited anomalies.

Concentrations of semivolatile

organic compounds in bed sediment

were low compared with other

NAWQA Study Units; however,

one agricultural site and one urban

site ranked in the top 25 percent

nationally. No exceedances of

aquatic life criteria were found at

any of the sites shown.

CONCLUSIONS

Nutrient and pesticide concentrat

in Willamette Basin streams were 

cal of concentrations in streams f

other NAWQA Study Units, as we

concentrations of organochlorine 

cides and PCBs in streambed sed

ment and biological tissue.

Concentrations of trace elements 

semivolatile organic compounds in 

sediment generally were low relat

other NAWQA Study Units.

Stream habitat and fish communi

conditions in agricultural and urba

streams were among the most de

ed compared with other NAWQA S

Units. Degraded habitat and fish c

munity conditions generally occurr

the same sites.

TRACE ELEMENTS in bed sediment

SEMIVOLATILE ORGANIC COMPOUNDS

in bed sediment

FISH COMMUNITY DEGRADATION

Portland

Salem

Eugene

Sandy River

Willamette

River

STREAM 

DEGRAD

Portland

Salem

Eugene

Sandy River

Willamette

River

Portland

Salem

Eugene

Sandy River

Willamette

River

Portland

Salem

Eugene

Sandy River

Willamette

River
22 Water Quality in the Willamette Basin, Oregon, 1991–95

EXPLANATION

Drinking water aquifers

Alluvium (AL) (70 wells)

Shallow ground water areas

Irrigated Agriculture (IA) (16 we

Nonirrigated Agriculture (NA) (3

Urban (UR) (10 wells)

Five major water quality characteristics were evaluated for ground water studie

NAWQA Study Unit. Ground water resources were divided into two categorie

(1) drinking water aquifers, and (2) shallow ground water underlying agricultu

urban areas. Summary scores were computed for each characteristic for all aqui

shallow ground water areas that had adequate data. Scores for each aquifer and 

ground water area in the Willamette Basin were compared with scores for all a

and shallow ground water areas sampled in the 20 NAWQA Study Units durin

95. Results are summarized by percentiles; higher percentile values generally 

poorer quality compared with other NAWQA ground water studies. Water qua

conditions for each drinking water aquifer also are compared to established dr

water standards and criteria for protection of human health. (Methods used to c

rankings and evaluate standards and criteria are described by Gilliom and othe

press.)

Nitrate concentrations in ground

water were similar to those found in

other NAWQA Study Units .

Nitrate concentrations generally

were low in ground water from

domestic wells in the alluvial aquifer, although almost 10 percent of

samples exceeded the USEPA MCL

for nitrate in drinking water.

Radon concentrations in ground

water were low relative to national

conditions, with all areas falling in

the lowest 50 percent of data from

the 20 NAWQA Study Units.

Ranking of ground water quality rel

to all NAWQA ground water studies 

Darker colored circles generally indica

poorer quality. Bold outline of circle 

cates one or more drinking water stan

dards or criteria were exceeded.

Greater than the 75th percentile

(among the highest 25 percent

of NAWQA ground water studies)

Between the median and the 75th perc

Between the 25th percentile and the m

Less than the 25th percentile

(among the lowest 25 percent

of NAWQA ground water studies)

No data

(IA)

(NA)

Portland

Salem

Eugene

(UR)

(AL)

RADON

(IA)

(NA)

Portland

Salem

Eugene

(UR)

(AL)

NITRATE

WATER QUALITY CONDITIONS IN A NATIONAL CONTEXT

Comparison of Ground Water Quality in the Willamette Basin

with Nationwide NAWQA Findings
U.S. Geological Survey Circular 1161 

Pesticide detection rates in ground wate

cally were low compared with other NA

Study Units, especially for urban and no

gated agriculture areas. The MCL for di

was exceeded in water from one domest

in the alluvial aquifer.

Detections of volatile organic compounds in

ground water were typical of those found nationwide, but detection rates in urban wells in the

Portland area were within the top 25 percent of

NAWQA data. The USEPA drinking water MCL

for tetrachloroethylene was exceeded in water

from one domestic well in the alluvial aquifer.

CONCLUSIONS

Radon and dissolved solids concentrat

and pesticide detection rates in Willam

Basin ground water generally were low

when compared with other NAWQA S

Units.

Nitrate concentrations and detection r

for volatile organic compounds were f

typical of those found in other NAWQA

Study Units.

Although a few exceedances of USEP

drinking water standards were noted i

ground water from domestic wells in t

luvial aquifer, water quality generally w

good.

Dissolved solids concentrations in ground water

were low compared with other NAWQA Study

Units. This is consistent with the maritime climate and the paucity of easily dissolved minerals in the geologic source rock of the Willamette

Basin. The USEPA Secondary MCL for dissolved solids in drinking water was exceeded in

water from two domestic wells in the alluvial

aquifer.

DISSOLVED SOLIDS

VOLATILE ORGANIC

COMPOUNDS

PES

(IA)

(NA)

Portland

Salem

Eugene

(UR)

(AL)

(IA)

(NA)

Portland

Salem

Eugene

(UR)

(AL)

(IA)

(NA)

Portland

Salem

Eugene

(UR)

(AL)
24 Water Quality in the Willamette Basin, Oregon, 1991–95

STUDY DESIGN AND DATA COLLECTION

IN THE WILLAMETTE BASIN

To the extent possible, sampling sites represent homogeneous areas relative to ecoregions, hydrogeology,

and land use (Uhrich and Wentz, in press). Ecoregions

provided a first, or basinwide, level of stratification. Hydrogeology, the second level of stratification, was useful in subdividing the Willamette Valley into major aquifers. Land use

provided a third, or local, level of stratification that was

important because of the emphasis of this study on nutrients

and pesticides from nonpoint sources.

One of the hallmarks of the NAWQA design is the use of

multiple lines of evidence to describe water quality conditions

(Gilliom and others, 1995). Thus, the 1991–95 data collection

activities in the Willamette Basin provided information on

stream water chemistry, contaminants in bed sediment and

aquatic biota, stream ecological conditions, and chemistry of

ground water. The sampling sites associated with the various

study components are plotted on the maps, and the designs of

the individual study components are described in the table on

the following page.

Finally, it should be noted that data collected for this study

are based on multiple scales. For example, samples for analysis of water chemistry were collected from streams draining

basins with areas of 1.76 to 11,200 square miles. This range

of scales provided an opportunity to consider land use and

streamflow effects in relation to basin size.
U.S. Geological Survey Circular 1161 

SUMMARY OF DATA COLLECTION IN THE WILLAMETTE BASIN STUDY UNIT, 1991–95

Study component What data were collected and why Types of sites sampled Number

of sites

Sa

qu

Stream Chemistry

Basic sites—

general water

quality

Streamflow, nutrients, major chemical constituents, organic

carbon, suspended sediment, water temperature, specific

conductance, pH, and dissolved oxygen were determined

to describe concentrations and seasonal variations.

 Streams draining basins ranging in size

from 7.10 to 11,200 square miles and representing forested, agricultural, urban,

and mixed land uses were sampled.

7 Mont

Apri

Intensive sites—

pesticides

In addition to the above constituents, approximately 86 dissolved pesticides were analyzed to describe concentrations and seasonal variations.A subset of basic water chemistry sites

draining agricultural and urban land uses

was sampled.

4 Mont

Apri

Synoptic studies—

nutrients and

pesticides

Streamflow, nutrients and/or pesticides, organic carbon, suspended sediment, water temperature, specific conductance, pH, and dissolved oxygen were determined during

high and/or low flow conditions to describe concentrations and spatial distributions.

Streams draining basins ranging in size from

1.76 to 403 square miles and representing

forested, agricultural, urban, and mixed

land uses were sampled.

44 total

17 high flow

12 high flow

32 low flow

Once 

A

Ma

July

Contaminants in

bed sediment

 Total PCBs, 32 organochlorine pesticides, 63 semivolatile

organic compounds, and 44 trace elements were analyzed

to determine occurrence and spatial distribution.

Depositional zones of all basic and intensive

sites and most synoptic sites were sampled.

52 Onc

four 

mu

Contaminants in

aquatic biota

Total PCBs, 30 organochlorine pesticides, and 24 trace elements were analyzed to determine occurrence and spatial

distribution. Clam and mussel tissue and whole fish were

analyzed for organic contaminants. Clam tissue, whole

fish (sculpin), fish livers (several species), and caddisflies

were analyzed for trace elements.

 All basic and intensive sites and some synoptic sites were sampled.20 Onc

three 

mu

Stream Ecology

Intensive assessmentsFish, macroinvertebrates, algae, and aquatic and riparian

habitat were described to assess aquatic biological community structure.

 Stream reaches were colocated with basic

water chemistry sites. The basins represent forested, agricultural, and urban land

uses, and each of the primary ecoregions.

7 (1993)

5 (1994–95)

Once 

‘95; 

samp

four 

Synoptic studies Fish, macroinvertebrates, algae, and aquatic and riparian

habitat were described to assess spatial distribution of

aquatic biological community structure.

Stream reaches were colocated with a subset

of synoptic stream chemistry sites sampled during July–August 1994. The basins

represent forested, agricultural, urban,

and mixed land uses.

18 Onc

te

Ground Water Chemistry

Aquifer survey—

alluvial

Major chemical constituents, nutrients, 85 pesticides, 60 volatile organic compounds, radon, and arsenic were analyzed to describe the spatial distribution of shallow

ground water quality in alluvial aquifers used for domestic drinking water supply.

Existing domestic wells less than 83 feet

deep and screened within 67 feet of the

water table were chosen using a statistically random selection process.

70 O

Land use effects—

agricultural

Data from the alluvial aquifer survey were reinterpreted to

determine effects of irrigated and nonirrigated agricultural land use on the quality of recently recharged ground

water.

Only wells representing agricultural land use

were included; wells were categorized as

irrigated or nonirrigated.

16 irrigated

37 nonirrigated

O

Land use effects—

urban

 Major chemical constituents, nutrients, pesticides, volatile

organic compounds, and 17 trace elements were analyzed

to determine effects of urban land use on the quality of

recently recharged ground water in alluvial aquifers.

Monitoring wells were drilled to depths of

less than 147 feet in the Portland metropolitan area and were screened within 52

feet of the water table.

10 O

Special Studies

Suspended sedimentStreamflow, suspended sediment concentration, and sediment particle size were analyzed and compared to historical data collected during 1949–51 to determine changes

in sediment transport before and after dam construction.

Data were collected on the Willamette River

and major tributaries. (See map, p. 10.)

7 1

i

Ground water/surface water interactionsDye injection studies and streamflow gain/loss measurements were interpreted to quantify the extent of ground

water/surface water interactions.

Dye studies were conducted in nine streams,

including the Willamette River. Streamflow gain/loss measurements were made

on two of these streams.

41 reaches Onc

two 

sured 

Dioxins and furans Bed sediment and whole fish were analyzed for 15 congeners and 10 congener classes of tetra- through octachlorinated dioxins and furans to determine occurrence, spatial

distribution, and congener patterns.

Sites were a subset of those sampled for

organochlorine compounds and trace elements in bed sediment and tissue. (See

map, p. 17.)

22 sediment

8 tissue

Onc

three 

pled 
26 Water Quality in the Willamette Basin, 1991–95

SUMMARY OF COMPOUND DETECTIONS AND CONCENTRATIONS

Herbicide

(Trade or common

name)

Rate

of

detection b

Concentration, in μg/L

0.001 0.01 0.1 1 10 100 1,000

The following tables summarize data collected for NAWQA studies during 1992–95 by showing results for the Willamette Basin

Study Unit compared to the NAWQA national range for each compound detected. The data were collected at a wide variety of places

and times. In order to represent the wide concentration ranges observed among Study Units, logarithmic scales are used to emphasize

the general magnitude of concentrations (such as 10, 100, or 1,000), rather than the precise number. The complete data set used to construct these tables is available upon request. (The tables were designed and constructed by Sarah Ryker, Jonathon Scott, and Alan Haggland.)

Concentrations of herbicides, insecticides, volatile organic compounds, nutrients, and radon detected in ground and surface waters of

the Willamette Basin Study Unit. [mg/L, milligrams per liter; μg/L, micrograms per liter; pCi/L, picocuries per liter; %, percent; <, less than;

- -, not measured; trade names may vary]

EXPLANATION

Range of surface water detections in all 20 Study Units

Detection in the Willamette Basin Study Unit

Range of ground water detections in all 20 Study Units

Drinking water standard or guideline a

Freshwater chronic criterion for the protection of aquatic life a

Herbicide

(Trade or common

name)

Rate

of

detection b

Concentration, in μg/L

0.001 0.01 0.1 1 10 100 1,000

Metolachlor (Dual,

Pennant, Goal)

62%

3%

Metribuzin (Lexone,

Sencor)

19%

0%

Napropamide

(Devrinol)

26%

0%

Norflurazon (Evital,

Solicam)

2%

0%

Oryzalin (Surflan) 1%

0%

Pendimethalin

(Prowl)

4%

0%

Prometon (Pramitol,

prometone)

19%

0%

Pronamide (Kerb,

propyzamid)

9%

0%

Propachlor (Ramrod,

propachlore)

1%

<1%

Propanil (Stampede,

Prostar)

<1%

1%

Simazine (Princep) 77%

5%

Tebuthiuron (Spike) 15%

0%

Terbacilc (Sinbar) 24%

1%

Triallate (Far-Go) <1%

<1%

Triclopyr (Garlon,

Crossbow)

9%

0%

Trifluralin (Treflan) 4%

0%

Alachlor (Lasso) 5%

0%

Atrazine (AAtrex) 85%

16%

Deethylatrazinec

(Atrazine metabolite)

38%

15%

Bentazon (Basagran,

bentazone)

4%

0%

Bromacil (Bromax) 2%

1%

Bromoxynil (Buctril) 1%

0%

Butylate (Sutan +,

butilate)

<1%

0%

Cyanazine (Bladex) 1%

0%

2,4-D (Dacamine,

Weedar 64)

12%

0%

DCPA (Dacthal,

chlorthal-dimethyl)

10%

<1%

Dicamba (Banvel) 2%

0%

Dinoseb (DNBP,

dinosebe)

5%

1%

Diuron (Karmex) 53%

3%

EPTC (Eptam, Eradicane)

17%

0%

Linuron (Lorox,

Linex)

1%

0%

MCPA 4%

0%
U.S. Geological Survey Circular 1161 27

Azinphos-methylc

(Guthion)

3%

0%

Carbarylc (Sevin) 18%

0%

Carbofuranc

(Furadan)

29%

0%

Chlorpyrifos (Dursban, Lorsban)

21%

0%

p,p’-DDE (p,p’-DDT

metabolite)

<1%

<1%

Diazinon 35%

0%

Dieldrin 1%

1%

Ethoprop (Mocap,

ethoprophos)

15%

0%

Fonofos (Dyfonate) 12%

0%

gamma-HCH (Lindane, gamma-BHC)

4%

0%

Malathion (malathon,

Cythion)

5%

0%

Methiocarb (Grandslam)

1%

0%

Oxamyl (Vydate,

oxamil)

1%

0%

cis-Permethrinc

(Pounce)

1%

0%

Propargite (Omite,

Comite)

<1%

0%

Terbufos (Counter) 0%

<1%

Volatile organic

compound

(Trade or common

name)

Rate

of

detection b

Concentration, in μg/L

1,1,1-Trichloroethane

(Methylchloroform)

--

8%

1,1-Dichloroethene

(Vinylidene chloride)

--

1%

Tetrachloromethane

(Carbon tetrachloride)

--

1%

total Trihalomethanes --

12%

Trichloroethene

(TCE)

--

8%

Trichlorofluoromethane

(CFC 11, Freon 11)

--

1%

0.01 0.1 1 10 100 1,000

Tetrachloroethene

(Perchloroethene, PCE)

--

12%

Nutrient Rate

of

detection b

Concentration, in mg/L

Dissolved ammonia 93%

86%

Dissolved ammonia

plus organic nitrogen

as nitrogen

53%

13%

Dissolved phosphorus as phosphorus

91%

99%

Dissolved nitrite plus

nitrate

98%

71%

Other Rate

of

detection b

Concentration, in pCi/L

Radon 222 --

100%

0.01 0.1 1 10 100 1,000 10,000 100,000

1 10 100 1,000 10,000 100,000

Volatile organic

compound

(Trade or common

name)

Rate

of

detection b

Concentration, in μg/L

0.01 0.1 1 10 100 1,000 10,000 100,000

Insecticide

(Trade or common

name)

Rate

of

detection b

Concentration, in μg/L

0.001 0.01 0.1 1 10 100 1,000
28 Water Quality in the Willamette Basin, 1991–95

SUMMARY OF COMPOUND DETECTIONS AND CONCENTRATIONS

1,2-Dimethylnaphthalene

--

4%

1,6-Dimethylnaphthalene

--

19%

1-Methyl-9H-fluorene --

4%

1-Methylphenanthrene

--

15%

1-Methylpyrene --

15%

2,2-Biquinoline --

4%

2,3,6-Trimethylnaphthalene

--

4%

2,6-Dimethylnaphthalene

--

41%

2,6-Dinitrotoluene --

4%

2-Ethylnaphthalene --

4%

2-Methylanthracene --

7%

4,5-Methylenephenanthrene

--

22%

4-Chloro-3-methylphenol

--

4%

9H-Carbazole --

15%

9H-Fluorene --

15%

Acenaphthene --

7%

Acenaphthylene --

19%

Concentrations of semivolatile organic compounds, organochlorine compounds, and trace elements detected in fish and clam tissue and

bed sediment of the Willamette Basin Study Unit. [μg/g, micrograms per gram; μg/kg, micrograms per kilogram; %, percent; <, less than;

- -, not measured; trade names may vary]

EXPLANATION

Range of detections in fish and clam tissue in all 20 Study Units

Detection in bed sediment in the Willamette Basin Study Unit

Range of detections in bed sediment in all 20 Study Units

Guideline for the protection of aquatic life d

Detection in clam tissue in the Willamette Basin Study Unit

Detection in fish tissue in the Willamette Basin Study Unit

Semivolatile

organic compound

Rate

of

detection b

Concentration, in μg/kg dry weight

0.1 10 100 1,000 10,000 100,000 1

Semivolatile

organic compound

Rate

of

detection b

Concentration, in μg/kg dry weight

0.1 10 100 1,000 10,000 100,000 1

Acridine --

15%

Anthracene --

30%

Anthraquinone --

15%

Benz[ a ]anthracene --

33%

Benzo[ a ]pyrene --

37%

Benzo[ b ]fluoranthene

--

37%

Benzo[ ghi ]perylene --

30%

Benzo[ k ]fluoranthene

--

37%

Butylbenzylphthalate --

52%

Chrysene --

37%

Di- n -butylphthalate --

96%

Di- n -octylphthalate --

4%

Dibenz[ a,h ]

anthracene

--

15%

Dibenzothiophene --

11%

Diethylphthalate --

41%

Dimethylphthalate --

11%

Fluoranthene --

56%
U.S. Geological Survey Circular 1161 29

Indeno[1,2,3- cd ]

pyrene

--

33%

Naphthalene --

4%

Phenanthrene --

44%

Phenanthridine --

7%

Phenol --

67%

Pyrene --

52%

bis(2-Ethylhexyl)phthalate

--

93%

p-Cresol --

52%

Organochlorine

compound

(Trade name)

Rate

of

detection b

Concentration, in μg/kg wet weight (tissue)

Concentration, in μg/kg dry weight (sediment)

Aldrin 0%

3%

total-Chlordanee 45%

28%

p,p’-DDEf (p,p’-

DDT metabolite)

64%

52%

total-DDTf 64%

55%

Dieldrin 36%

31%

Endosulfan I (alphaendosulfan, Thiodan)

--

3%

gamma-HCH (Lindane, gamma-BHC)

5%

7%

Heptachlor epoxide

(heptachlor metabolite)

0%

3%

Hexachlorobenzene 5%

--

p,p’-Methoxychlor

(Marlate)

0%

3%

PCB, total 32%

7%

Pentachloroanisole 9%

0%

0.01 0.1 1 10 100 1,000 10,000 100,000

Arsenic 65%

100%

Cadmium 20%

100%

Chromium 90%

100%

Copper 100%

100%

Lead 25%

88%

Mercury 50%

82%

Nickel 90%

100%

Selenium 40%

100%

Zinc 100%

100%

Semivolatile

organic compound

Rate

of

detection b

Concentration, in μg/kg dry weight

0.1 10 100 1,000 10,000 100,000 1

Trace element Rate

of

detection b

Concentration, in μg/g dry weight

0.01 0.1 1 10 100 1,000 10,000
30 Water Quality in the Willamette Basin, 1991–95

SUMMARY OF COMPOUND DETECTIONS AND CONCENTRATIONS

Semivolatile organic compounds, organochlorine compounds, and trace elements not detected in fish and clam tissue and bed

sediment of the Willamette Basin Study Unit.

Semivolatile

organic

compounds

1,2,4-Trichlorobenzene

1,2-Dichlorobenzene (o-Dichlorobenzene, 1,2-DCB)

1,3-Dichlorobenzene (m-Dichlorobenzene)

1,4-Dichlorobenzene (p-Dichlorobenzene, 1,4-DCB)

2,4-Dinitrotoluene

2-Chloronaphthalene

2-Chlorophenol

3,5-Dimethylphenol

4-Bromophenyl-phenylether

4-Chlorophenyl-phenylether

Azobenzene

Benzo [c] cinnoline

C8-Alkylphenol

Isophorone

Isoquinoline

N-Nitrosodi-n-propylamine

N-Nitrosodiphenylamine

Nitrobenzene

Pentachloronitrobenzene

Quinoline

bis (2-Chloroethoxy)methane

Organochlorine

compounds

Chloroneb (chloronebe, Demosan,

Soil Fungicide 1823)

DCPA (Dacthal, chlorthaldimethyl)

Endrin (Endrine)

Heptachlor (Heptachlore, Velsicol

104)

Isodrin (Isodrine, Compound 711)

Mirex (Dechlorane)

Toxaphene (Camphechlor, Hercules 3956)

alpha-HCH (alpha-BHC, alphalindane, alpha-hexachlorocyclohexane, alpha-benzene hexachloride)

beta-HCH (beta-BHC, betahexachlorocyclohexane, alphabenzene hexachloride)

cis-Permethrin (Ambush, Astro,

Pounce, Pramex, Pertox, Ambushfog, Kafil, Perthrine, Picket, Picket

G, Dragnet, Talcord, Outflank,

Stockade, Eksmin, Coopex, Peregin, Stomoxin, Stomoxin P, Qamlin, Corsair, Tornade)

delta-HCH (delta-BHC, deltahexachlorocyclohexane, delta-benzene hexachloride)

o,p’-Methoxychlor

trans-Permethrin (Ambush, Astro,

Pounce, Pramex, Pertox, Ambushfog, Kafil, Perthrine, Picket, Picket

G, Dragnet, Talcord, Outflank,

Stockade, Eksmin, Coopex, Peregin, Stomoxin, Stomoxin P, Qamlin, Corsair, Tornade)

Trace elements

No non-detects

a

 Selected water quality standards and guidelines (Gilliom and others, in press).

b

 Rates of detection are based on the number of analyses and detections in the Study Unit, not on national data. Rates of detection for herbicides and insecticides were

computed by only counting detections equal to or greater than 0.01 μg/L in order to facilitate equal comparisons among compounds, which had widely varying

detection limits. For herbicides and insecticides, a detection rate of “<1%” means that all detections are less than 0.01 μg/L, or the detection rate rounds to less

than one percent. For other compound groups, all detections were counted and minimum detection limits for most compounds were similar to the lower end of the

national ranges shown. Method detection limits for all compounds in these tables are summarized in (Gilliom and others, in press). c

 Detections of these compounds are reliable, but concentrations are determined with greater uncertainty than for the other compounds and are reported as estimated

values (Zaugg and others, 1995). d

 Selected sediment quality guidelines (Gilliom and others, in press).

e

Total-chlordane includes chlordane, cis-chlordane, trans-chlordane, cis-nonachlor, trans-nonachlor, and oxychlordane. f

 Total-DDT includes o,p’-DDT, p,p’-DDT, o,p’-DDE, p,p’-DDE, o,p’-DDD, and p,p’-DDD; p,p’-DDE also is presented separately.

Herbicides, insecticides, volatile organic compounds, and nutrients not detected in ground and surface waters of the Willamette Basin

Study Unit.

Herbicides

2,4,5-T

2,4,5-TP (Silvex, Fenoprop)

2,4-DB (Butyrac, Butoxone, Embutox Plus, Embutone)

2,6-Diethylaniline (Metabolite of

Alachlor)

Acetochlor (Harness Plus, Surpass)

Acifluorfen (Blazer, Tackle 2S)

Benfluralin (Balan, Benefin,

Bonalan, Benefex)

Chloramben (Amiben, AmilonWP, Vegiben)

Clopyralid (Stinger, Lontrel,

Reclaim, Transline)

Dacthal mono-acid (Dacthal

metabolite)

Dichlorprop (2,4-DP, Seritox 50,

Kildip, Lentemul)

Ethalfluralin (Sonalan, Curbit)

Fenuron (Fenulon, Fenidim)

Fluometuron (Flo-Met, Cotoran,

Cottonex, Meturon)

MCPB (Thistrol)

Molinate (Ordram)

Neburon (Neburea, Neburyl,

Noruben)

Pebulate (Tillam, PEBC)

Picloram (Grazon, Tordon)

Propham (Tuberite)

Thiobencarb (Bolero, Saturn,

Benthiocarb, Abolish)

Insecticides

3-Hydroxycarbofuran (Carbofuran

metabolite)

Aldicarb (Temik, Ambush,

Pounce)

Aldicarb sulfone (Standak, aldoxycarb, aldicarb metabolite)

Aldicarb sulfoxide (Aldicarb

metabolite)

Disulfoton (Disyston, Di-Syston,

Frumin AL, Solvirex, Ethylthiodemeton)

Methomyl (Lanox, Lannate, Acinate)

Methyl parathion (Penncap-M,

Folidol-M, Metacide, Bladan M)

Parathion (Roethyl-P, Alkron,

Panthion, Phoskil)

Phorate (Thimet, Granutox,

Geomet, Rampart)

Propoxur (Baygon, Blattanex,

Unden, Proprotox)

alpha-HCH (alpha-BHC, alphalindane, alpha-hexachlorocyclohexane, alpha-benzene hexachloride)

Volatile organic

compounds

1,1,1,2-Tetrachloroethane

(1,1,1,2-TeCA)

1,1,2,2-Tetrachloroethane

1,1,2-Trichloro-1,2,2-trifluoroethane (Freon 113, CFC 113)

1,1,2-Trichloroethane (Vinyl

trichloride)

1,1-Dichloroethane (Ethylidene

dichloride)

1,1-Dichloropropene

1,2,3-Trichlorobenzene (1,2,3-

TCB)

1,2,3-Trichloropropane (Allyl

trichloride)

1,2,4-Trichlorobenzene

1,2,4-Trimethylbenzene

(Pseudocumene)

1,2-Dibromo-3-chloropropane

(DBCP, Nemagon)

1,2-Dibromoethane (EDB, Ethylene dibromide)

1,2-Dichlorobenzene (o-Dichlorobenzene, 1,2-DCB)

1,2-Dichloroethane (Ethylene

dichloride)

1,2-Dichloropropane (Propylene

dichloride)

1,3,5-Trimethylbenzene (Mesitylene)

1,3-Dichlorobenzene (m-Dichlorobenzene)

1,3-Dichloropropane (Trimethylene dichloride)

1,4-Dichlorobenzene (p-Dichlorobenzene, 1,4-DCB)

1-Chloro-2-methylbenzene (oChlorotoluene)

1-Chloro-4-methylbenzene (pChlorotoluene)

2,2-Dichloropropane

Benzene

Bromobenzene (Phenyl bromide)

Bromochloromethane (Methylene

chlorobromide)

Bromomethane (Methyl bromide)

Chlorobenzene (Monochlorobenzene)

Chloroethane (Ethyl chloride)

Chloroethene (Vinyl chloride)

Chloromethane (Methyl chloride)

Dibromomethane (Methylene

dibromide)

Dichlorodifluoromethane (CFC 12,

Freon 12)

Dichloromethane (Methylene chloride)

Dimethylbenzenes (Xylenes (total))

Ethenylbenzene (Styrene)

Ethylbenzene (Phenylethane)

Hexachlorobutadiene

Isopropylbenzene (Cumene)

Methyl tert-butyl ether (MTBE)

Methylbenzene (Toluene)

Naphthalene

cis-1,2-Dichloroethene ((Z)-1,2-

Dichloroethene)

cis-1,3-Dichloropropene ((Z)-1,3-

Dichloropropene)

n-Butylbenzene (1-Phenylbutane)

n-Propylbenzene (Isocumene)

p-Isopropyltoluene (p-Cymene)

sec-Butylbenzene

tert-Butylbenzene

trans-1,2-Dichloroethene ((E)-1,2-

Dichlorothene)

trans-1,3-Dichloropropene ((E)-

1,3-Dichloropropene)

Nutrients

No non-detects

OREGON
U.S. Geological Survey Circular 1161 

REFERENCES

This report was based on the publications listed below.

Publications shown in bold resulted

from the Willamette Basin NAWQA.

Alexander, R.B., and Smith, R.A., 1990,

County-level estimates of nitrogen

and phosphorus fertilizer use in the

United States, 1945 to 1985: U.S.

Geological Survey Open-File Report

90–130, 12 p.

Allen-Gil, S.M., Gilroy, D.J., and Curtis,

L.R., 1995, An ecoregion approach to

mercury bioaccumulation by fish in

reservoirs: Archives of Environmental Contamination and Toxicology,

v. 28, p. 61–68.

Arbogast, B.F., ed., 1990, Quality assurance manual for the Branch of

Geochemistry: U.S. Geological Survey Open-File Report 90–668, 184 p.

Bencala, K.E., 1993, A perspective on

stream-catchment connections: Journal of the North American Benthological Society, v. 12, no. 1, p. 44–47.

Bonn, B.A., 1998, Occurrence and congener concentration patterns of

chlorinated dibenzo-p-dioxins and

dibenzo furans in the Willamette

Basin, Oregon, 1992–95: Environmental Science and Technology,

v. 32, no. 6, p. 729–735.

Bonn, B.A., in press, Dioxins and furans

in bed sediment and fish tissue of

the Willamette Basin, Oregon,

1992–95: U.S. Geological Survey

Water-Resources Investigations

Report 97–4082–D.

Bonn, B.A., Hinkle, S.R., Wentz, D.A.,

and Uhrich, M.A., 1995, Analysis of

nutrient and ancillary water-quality data for surface and ground

water of the Willamette Basin, Oregon, 1980–90: U.S. Geological

Survey Water-Resources Investigations Report 95–4036, 88 p.

Bonn, B.A., Wentz, D.A., and Hinkle,

S.R., 1996, Willamette Basin, Oregon—Nitrogen in streams and

ground water, 1980–90: U.S. Geological Survey Open-File Report

96–227, 4 p.

Broad, T.M., and Collins, C.A., 1996, Estimated water use and general hydrologic conditions for Oregon, 1985

and 1990: U.S. Geological Survey

Water-Resources Investigations

Report 96–4080, 166 p.

Brooks, H.C., 1971, Quicksilver deposits

in Oregon: Portland, Oregon Department of Geology and Mineral Industries, Miscellaneous Paper 15, 1 pl.

Center for Population Research and Census, 1992, Population estimates for

Oregon, 1980–91: Portland State

University, 22 p.

Clarke, S.E., White, Denis, and Schaedel,

A.L., 1991, Oregon, USA, ecological

regions and subregions for water

quality management: Environmental

Management, v. 15, no. 6, p. 847–

856.

Crawford, J.K. and Luoma, S.N., 1993,

Guidelines for studies of contaminants in biological tissues for the

National Water-Quality Assessment

Program: U.S. Geological Survey

Open-File Report 92–494, 69 p.

Environment Canada, September 1995,

Draft interim sediment quality guidelines: Ottawa, Ontario, Environment

Canada, 8 p. plus app.

Foreman, W.T., Connor, B.F., Furlong,

E.T., Vaught, D.G., and Merten,

L.M., 1995, Methods of analysis by

the U.S. Geological Survey National

Water Quality Laboratory—Determination of organochlorine pesticides

and polychlorinated biphenyls in bottom sediment by dual capillarycolumn gas chromatography with

electron-capture detection: U.S. Geological Survey Open-File Report

95–140, 78 p.

Gannett, M.W., and Caldwell, R.R., in

press, Geologic framework of the

Willamette Lowland Aquifer System, Oregon and Washington: U.S.

Geological Survey Professio

1424–B.

Gilliom, R.J., Alley, W.M., and G

M.E., 1995, Design of the N

Water-Quality Assessment P

gram—Occurrence and distr

of water-quality conditions: 

Geological Survey Circular 

33 p.

Gilliom, R.J., Mueller, D.K., and 

L.H., in press, Methods for c

ing water-quality conditions 

National Water-Quality Ass

Study Units: U.S. Geologica

Open-File Report 97–589.

Gruber, S.J., and Munn, M.D., 19

nochlorine pesticides and PC

aquatic ecosystems of the C

Columbia Plateau: U.S. Geo

Survey Fact Sheet 170–96, 4 

Hinkle, S.R., 1997, Quality of sh

ground water in alluvial aq

the Willamette Basin, Oreg

1993–95: U.S. Geological S

Water-Resources Investiga

Report 97–4082–B, 48 p.

Hitt, K.J., 1994, Refining 1970’s l

data with 1990 population d

indicate new residential deve

U.S. Geological Survey Wat

Resources Investigations Re

94–4250, 15 p.

Hoffman, G.L., 1996, Methods of 

by the U.S. Geological Surv

National Water Quality Lab

tory—Preparation procedure 

aquatic biological material d

mined for trace metals: U.S.

Grass seed is the primary crop grown in the Willamette Basin.
32 Water Quality in the Willamette Basin, Oregon, 1991–95

REFERENCES

Geological Survey Open-File Report

96–362, 42 p.

Hughes, R.M., and Gammon, J.R., 1987,

Longitudinal changes in fish assemblages and water quality in the Willamette River, Oregon: Transactions

of the American Fisheries Society,

v. 116, p. 196–209.

Hughes, R.M., Reynolds, Lou, Kaufmann,

P.R., Herlihy, A.T., and Kincaid,

Tom, in press, Development and

application of an index of fish assemblage integrity for wadable Willamette Valley, Oregon, streams:

Canadian Journal of Fisheries and

Aquatic Sciences.

Kammerer, J.C. 1990, Largest rivers in the

United States: U.S. Geological Survey Open-File Report 87–242, 2 p.

Karr, J.R., 1991, Biological integrity—A

long-neglected aspect of water

resource management: Ecological

Applications, v. 1, no. 1, p. 66–84.

Laenen, Antonius, 1995, Willamette

River water quality study—

Sediment transport in the main

stem and major tributaries: Corvallis, Oregon Water Resources

Institute, The Cutting Edge of

Water Research, v. 1, no. 1, 4 p.

Laenen, Antonius, and Bencala, K.E.,

1997, Transient storage assessments of dye-tracer injections in

the Willamette River Basin, Oregon [Abstract]: American Society

of Limnology and Oceanography

Annual Meeting, February 10–14,

Santa Fe, New Mexico.

Leiker, T.J., Madsen, J.E., Deacon, J.R.,

and Foreman, W.T., 1995, Methods of

analysis by the U.S. Geological Survey National Water Quality Laboratory—Determination of chlorinated

pesticides in aquatic tissue by capillary-column gas chromatography

with electron-capture detection: U.S.

Geological Survey Open-File Report

94–710, 42 p.

Meador, M.R., Cuffney, T.F., and Gurtz,

M.E., 1993a, Methods for sampling

fish communities as part of the

National Water-Quality Assessment

Program: U.S. Geological Survey

Open-File Report 93–104, 40 p.

Meador, M.R., Hupp, C.R., Cuffney, T.F.,

and Gurtz, M.E., 1993b, Methods for

sampling stream habitat as part of the

National Water-Quality Assessment

Program: U.S. Geological Survey

Open-File Report 93–408, 48 p.

National Academy of Sciences and

National Academy of Engineering,

1973, Water quality criteria, 1972:

U.S. Environmental Protection

Agency Report R3–73–033, 594 p.

Newell, Avis, Drake, Douglas, and Stifel,

B.L., 1996, Mercury in Oregon

Lakes: Portland, Oregon Department

of Environmental Quality [variously

paged].

Oregon Agricultural Statistics Service,

1993, 1992–93 Oregon agriculture &

fisheries statistics: Oregon Agricultural Statistics Service, Portland,

82 p.

Oregon Water Resources Department,

1979, Upper Willamette drainage

basin land use, 1978: Salem, Oregon

Water Resources Department map.

———1980, Lower Willamette & 

drainage basins land use, 19

Salem, Oregon Water Resou

Department map.

———1981, Middle Willamette d

basin land use, 1980: Salem

Water Resources Departmen

Parker, R.L., 1967, Chapter D. Co

tion of the Earth’s crust, in F

Michael, ed., Data of geoche

U.S. Geological Survey Pro

Paper 440–D, 19 p.

Rickert, D.A., Kennedy, V.C., Mc

S.W., and Hines, W.G., 1977

optic survey of trace metals i

sediments of the Willamette 

Oregon: U.S. Geological Su

cular 715–F, 27 p.

Rinehold, J.W., and Witt, J.M., 19

County pesticide use estima

1987—National Pesticide Im

Assessment Program, Suppl

Special Report 843: Corvall

gon State University Extens

vice [variously paged].

———1992, Oregon pesticide us

mates for 1987: Corvallis, O

State University Extension S

Extension Miscellaneous 85

nally published as Special R

843], 75 p.

Rinella, F.A., and Janet, M.L., 1

sonal and spatial variabilit

nutrients and pesticides in 

of the Willamette Basin, O

1993–95: U.S. Geological S

Water-Resources Investiga

Report 97–4082–C, 59 p.

Rinella, J.F., Hamilton, P.A., and 

zie, S.W., 1993, Persistence 

DDT pesticide in the Yakim

Basin, Washington: U.S. Ge

Survey Circular 1090, 24 p.

Rinella, J.F., McKenzie, S.W., Cr

J.K., Foreman, W.T., Gates, 

Fuhrer, G.J., and Janet, M.L

Surface-water-quality assess

the Yakima River Basin, Wa

Pesticide and other trace-org

compound data for water, se

soil, and aquatic biota, 1987

Geological Survey Open-Fil

92–644, 154 p.

Rose, D.L., and Schroeder, M.P., 

Methods of analysis by the U

logical Survey National Wat

ity Laboratory—Determinat

volatile organic compounds 

by purge and trap capillary g

Tulips, which are grown for bulbs, are one of many specialty crops contributing to the diverse agricultural nature of the Willamette Basin.
U.S. Geological Survey Circular 1161 

matography/mass spectrometry: U.S. Geological Survey Open-File Report 94–

708, 26 p.

Runkle, R.L., and Broshears, R.E., 1991,

One-dimensional transport with

inflow and storage (OTIS)—A solute

transport model for small streams:

Boulder, University of Colorado,

Center for Advanced Decision Support for Water and Environmental

Systems, 85 p.

Shearman, J.O., 1976, Reservoir-system

model for the Willamette River

Basin, Oregon: U.S. Geological Survey Circular 715–H, 22 p.

Shelton, L.R., and Capel, P.D., 1994,

Guidelines for collecting and processing samples of stream bed sediment for analysis of trace elements

and organic contaminants for the

National Water-Quality Assessment

Program: U.S. Geological Survey Open-File

Report 94–458, 20 p.

Simpson, M.R., and Oltmann, R.N., 1993, Discharge measuring

system using an acoustic doppler profiler

with applications to

large rivers and estuaries: U.S. Geological

Survey Water-Supply

Paper 2395, 32 p.

Uhrich, M.A., and Wentz,

D.A., in press, Waterquality study design

for the Willamette

Basin, Oregon, using

a Geographic Information System:

Gdansk, Poland, Proceedings of the

Poland-USA Jointly

Sponsored International River Quality

Symposium, June

13–17, 1994.

U.S. Army Corps of Engineers, 1954, Report on

sedimentation, Willamette River Basin,

Oregon, December

1948–July 1951: Portland District, U.S.

Army Corps of Engineers report, 160 p.

———1989, Willamette River Basin Reservoir system operation: Portland

District, U.S. Army Corps of Engineers report, 43 p. plus app.

U.S. Environmental Protection Agency,

1986, Quality criteria for water 1986:

U.S. Environmental Protection

Agency report EPA–440/5–86/001

[variously paged].

U.S. Environmental Protection Agency,

1993, Interim report on data and

methods for assessment of 2,3,7,8-

tetrachlorodibenzo-p-dioxin risks to

aquatic life and associated wildlife:

U.S. Environmental Protection

Agency report EPA/600/R-93/055,

[variously paged].

U.S. Environmental Protection Agency,

1996, Drinking water regulations and

health advisories: U.S. Environmental Protection Agency report 

822/B–96/002, 11 p.

U.S. Geological Survey, 1990, La

and land cover digital data f

1:250,000- and 1:100,000-sc

maps: U.S. Geodata Users G

33 p.

Waite, I.R., and Carpenter, K.D

press, Assessment of habit

quality, and fish communit

streams of the Willamette 

Oregon—A multivariate a

approach: Canadian Journ

Fisheries and Aquatic Scie

Walker, G.W., and MacLeod, N.S

Geologic map of Oregon: U

logical Survey, scale 1:500,0

Wentz, D.A., and McKenzie, S.W

National Water-Quality As

ment Program—The Willa

Basin, Oregon: U.S. Geolo

Survey Open-F

Report 91–167, 

Werner, S.L., Burkhar

and DeRusseau, 

1996, Methods o

sis by the U.S. G

Survey National 

Quality Laborato

Determination o

cides in water by

Carbopak-B soli

extraction and h

performance liqu

matography: U.S

logical Survey O

Report 96–216, 

Zaugg, S.D., Sandstro

Smith, S.G., and 

berg, K.M., 1995

ods of analysis b

U.S. Geological 

National Water

Quality Laborato

Determination o

cides in water by

C-18 solid-phase 

tion and capillar

column gas chro

phy/mass spectr

with selected-ion 

toring: U.S. Geo

Survey Open-Fil

95–181, 49 p.

Old growth can still be found in Forest Park, which is

located within Portland’s city limits.
34 Water Quality in the Willamette Basin, Oregon, 1991–95.

REFERENCES

The following publications, not specifically cited in the text of this report, also describe results of water quality 

gations conducted as part of the Willamette Basin NAWQA.

Altman, Bob, Henson, C.M., and Waite, I.R., 1997, A review of aquatic biological information for the Willamette Basin, Oregon, t

1995: U.S. Geological Survey Water-Resources Investigations Report 97–4023, 174 p.

Hinkle, S.R., 1997, Regional distribution of nitrite plus nitrate in shallow groundwater from alluvial deposits of the Willamette Ba

gon, in Laenen, Antonius, and Dunnette, D.A., eds., River quality—Dynamics and restoration: New York, CRC Press, Inc.,

p. 141–149.

Uhrich, M.A., and Wentz, D.A., in press, Environmental setting of the Willamette Basin, Oregon, and hydrologic conditions durin

1993–95: U.S. Geological Survey Water-Resources Investigations Report 97–4082–A.

Wentz, D.A., Waite, I.R., and Rinella, F.A., in press, Comparison of streambed sediment and aquatic biota as media for characteriz

elements and organochlorine compounds in the Willamette Basin, Oregon: Environmental Monitoring and Assessment.

Results of studies conducted in collaboration with and/or partially supported by the Willamette Basin NAWQA 

described in the publications listed below.

Anderson, C.W., Rinella, F.A., and Rounds, S.A., 1996, Occurrence of selected trace elements and organic compounds and their re

land use in the Willamette River Basin, Oregon, 1992–94: U.S. Geological Survey Water-Resources Investigations Report 96

68 p.

Anderson, C.W., Wood, T.M., and Morace, J.L., 1997, Distribution of dissolved pesticides and other water quality constituents in s

streams, and their relation to land use, in the Willamette River Basin, Oregon: U.S. Geological Survey Water-Resources Inves

Report 97–4268, 87 p.

Caldwell, J.M., and Doyle, M.C., 1995, Sediment oxygen demand in the lower Willamette River, Oregon, 1994: U.S. Geological S

Water-Resources Investigations Report 95–4196, 14 p.

Harrison, H.E., Anderson, C.W., Rinella, F.A., Gasser, T.M., and Pogue, T.R., Jr., 1995 [revised and reprinted 1997], Analytical da

Phases I and II of the Willamette River Basin Water Quality Study, Oregon, 1992–94: U.S. Geological Survey Open-File Rep

95–373, 171 p.

Laenen, Antonius, and Risley, J.C., 1997, Precipitation-runoff and streamflow-routing modeling as a foundation for water-quality si

in the Willamette River Basin, Oregon, in Laenen, Antonius, and Dunnette, D.A., eds., River quality—Dynamics and restorati

Press, Inc., p. 117–130.

———1997, Precipitation-runoff and streamflow-routing models for the Willamette River Basin, Oregon: U.S. Geological Survey 

Resources Investigations Report 95–4284, 197 p.

Lee, K.K., 1995, Stream velocity and dispersion characteristics determined by dye-tracer studies on selected stream reaches in the 

lamette River Basin, Oregon: U.S. Geological Survey Water-Resources Investigations Report 95–4078, 39 p.

Pogue, T.R., Jr., and Anderson, C.W., 1995, Processes controlling dissolved oxygen and pH in the upper Willamette River Basin, O

1994: U.S. Geological Survey Water-Resources Investigations Report 95–4205, 71 p.

Opal Creek drains one of the few protected old growth forest reserves remaining in the Willamette Basin.
ACKNOWLEDGMENTS

We thank the following individuals, agencies, and organizations for contributing to the success of this study.

• Lynn Bjork and Carl Bond granted permission to use the fish illustrations on page 9.

• Betty Brickson provided patience, encouragement, and occasional reviews of the report.

• Gail Cordy and Dave Mueller (USGS), Greg Pettit (Oregon Department of Environmental Quality), and Mike Wolf (Oregon Dep

of Agriculture) provided technical reviews of the report.

• Chris Daley (Oregon Climate Service) contributed Willamette Basin precipitation data.

• Alan Donner (U.S. Army Corps of Engineers) estimated peak Willamette River flow for February 1996.

• Steve Ellis (TetraTech, Inc.) and Chuck Henny (USGS, BRD) furnished fish from the Willamette River for tissue analysis.

• Stan Fox (Natural Resources Conservation Service) provided information on Willamette Basin snowfall.

• Susan Hathaway-Marxer and Dave Gray (City of Portland, Parks and Recreation) granted access to city parks to drill wells.

• Chip Hill and Doug Markle (Oregon State University) identified and vouchered fish specimens.

• Kathy Kuivila (USGS, California District) contributed field support and analyses of selected pesticides during April 1993.

• Mount Angel Abbey (Norman Hettwer) provided access to Little Abiqua Creek.

• National Biological Service (now USGS, Biological Resources Division) contributed funds for dioxin and furan analyses.

• Oregon Department of Environmental Quality (ODEQ) contributed data from Phases I and II of the Willamette River Basin Water 

Study.

• Greg Pettit (ODEQ) analyzed ground water for selected pesticides during 1993.

• Paul Seevers (USGS, EROS Data Center) provided land use based on 1992–93 Landsat data.

• Unified Sewerage Agency contributed data from the Tualatin River Basin Water Quality Study.

• Dave Wills (U.S. Fish and Wildlife Service) provided and operated boat electroshocking equipment.

• Shamsul Alam, Dorie Brownell, Doug Cushman, Ben Davis, Mike DeVolder, Tom Edwards, Phil Gallaway, Ned Gates, Howard

Harrison, Tim Jannsen, Martell Kiefer, Julie Laenen, Karl Lee, Dan McClelland, Jennifer Morace, Rick Mulder, Richard No

Greg Olsen, Ted Pogue, Dan Polette, Ines Ruiz-Huston, Roy Wellman, and Winston Woo (USGS, Oregon District), Kathryn C

and Kathy Kuivila (USGS, California District), and Jeff Litteral (National Water Quality Laboratory) assisted with collection 

compilation of data.
Wentz and others • Water Quality in the Willamette Basin

 USGS Circular 1161 • 1998

National Water-Quality Assessment (NAWQA) Program

Willamette Basin

NAWQA

Portland

Salem

Eugene

Willamette River

Sandy River