U.S. Department of the Interior

U.S. Geological Survey

Fact Sheet 2015–3020

March 2015

CANADA

OREGON

WASHINGTON

PACIFIC

OCEAN

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0 50 100 KILOMETERS

125° 120°

48°

46°

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EXPLANATION

Base-map image is the intellectual property of Esri and isused herein under license. Copyright © 2014 

Esri and its licensors. All rights reserved. Base modified from Esri digital data, 1:70,000 (Esri, 2009)

Land cover from National Land Cover Database, 2006, Web Mercator Projection, 

World Geodetic System of 1984 (WGS 84)

Land cover 

Urban

Forest/Undeveloped

Pasture/Hay

Cultivated crops

Site type 

Agriculture

Reference

Urban

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National Water-Quality Assessment Program

The Pacific Northwest Stream Quality Assessment

In 2015, the U.S. Geological Survey (USGS) National WaterQuality Assessment (NAWQA) program is assessing stream quality 

in the Pacific Northwest. The goals of the Pacific Northwest Stream 

Quality Assessment (Pacific Northwest study) are to assess the quality of streams in the region by characterizing multiple water-quality 

factors that are stressors to aquatic life and to evaluate the relation 

between these stressors and biological communities. The effects of 

urbanization and agriculture on stream quality for the Puget Lowlands and Willamette Valley are the focus of this regional study (fig. 

1). Findings will provide the public and policymakers with information regarding which human and environmental factors are the most 

critical in affecting stream quality and, thus, provide insights about 

possible approaches to protect or improve the health of streams in 

the region.

The Pacific Northwest study will be the third regional study by the 

NAWQA program, and it will be of similar design and scope as 

the first two—the Midwest in 2013 and the Southeast in 2014 (Van 

Metre and others, 2012, 2014).

Objectives

1. Determine the status of stream quality—contaminants, nutrients, sediments, toxicity of the bed sediments, streamflow, 

habitat, and biological communities—across the region. 

2. Evaluate the relative influence of contaminants, nutrients, 

sediment, toxicity, streamflow, and habitat on biological communities in the streams sampled.

3. Evaluate relations between measured stressors and biological 

communities and the natural and anthropogenic characteristics of the watersheds. 

4. Develop statistical models and management tools to predict 

concentrations of stressors, and, if possible, ecological conditions in wadeable streams across the region.

Approach

Eighty-eight sites are scheduled for sampling during April, May, and 

June 2015 in the region, with weekly sampling for 4 or 10 weeks 

at each site, depending on the land use in the watershed. Samples 

will be analyzed for contaminants, nutrients, and sediment (fig. 1). 

This water-quality “index” period will culminate with an ecological 

survey of habitat, algae, benthic invertebrates, and fish at all sites. 

Sediment will be collected during the ecological survey for analysis 

of sediment chemistry and toxicity. Rapid urban growth, particularly 

in the greater Seattle and Portland metropolitan areas, is causing 

water-quality concerns in the region. The study design therefore 

includes sampling 80 sites that reflect a wide range of urbanization, 

from dense urban watersheds to undeveloped reference watersheds. 

Eight sites representing the major types of agriculture in the region 

also will be sampled. The resulting data should span ranges of many 

specific stressors (for example, contaminants), allowing us to better 

understand the effects of those stressors on stream ecology.

Study Components

Assessing Ecological Condition—Algae, benthic macroinvertebrate, and fish communities will be sampled and physical habitat 

assessed once at all 88 sites in late June 2015. Samples will be 

collected along multiple transects within the stream reach following 

USGS NAWQA protocols (Moulton and others, 2002).

Figure 1. The Pacific Northwest Stream Quality Assessment study 

area. Study area boundary is based on the Willamette Valley and 

Puget Lowlands level 3 ecological regions (ecoregions) of the United 

States.
Water Sampling—By using depth- and width-integrating methods, 

water samples will be collected weekly at 70 urban and agricultural 

sites for 10 weeks and at reference and rural sites for 4 weeks preceding the ecological sampling to characterize the water chemistry 

during spring runoff, a period of potential concern for chemical 

runoff. Water samples will be analyzed for nutrients, suspended 

sediment, major ions, and about 230 dissolved pesticides and pesticide degradates. Some samples also will be analyzed for mercury, 

pharmaceuticals, and wastewater-indicator compounds.

Integrated Sampling—Passive polar organic chemical integrative 

(POCIS) samplers will be deployed in streams at about 75 sites for 

about 7 weeks to collect dissolved chemicals from stream water. 

These time-integrating samplers will be used to characterize longerterm chronic contaminant exposure to organisms. The POCIS 

samples will be analyzed for water-soluble pesticides and degradates, pharmaceuticals, and wastewater-indicator compounds. 

Sediment Sampling—Streambed sediment will be sampled coincident with the ecological sampling at all 88 sites. Surficial bed 

sediment (about 1 inch of sediment on the stream bottom) will be 

collected from depositional areas and analyzed for trace elements, 

polycyclic aromatic hydrocarbons (PAHs), halogenated organic 

compounds (compounds containing chlorine or bromine atoms, such 

as DDT), pharmaceuticals, wastewater-indicator compounds, and 

hormones. Sediments tend to accumulate different contaminants 

than those found in the water and can be an important contaminant 

source to organisms. 

Time-integrating suspended-sediment samplers will be deployed 

at about 13 sites to characterize sources of sediments entering the 

streams. These sediment samples will be analyzed for radionuclides 

and trace elements.

Toxicity Testing—Surficial bed-sediment samples from a subset of 

urban sites will be tested using standard whole-sediment toxicity 

tests conducted with amphipod crustaceans (Hyalella azteca 28-day 

exposures), midge larvae (Chironomus dilutus 10-day exposures), 

and freshwater mussels (Lampsilis siliquoidea 28-day exposures) to 

measure potential effects of contaminants on survival and growth. 

Amphipods, mussels, and fish are sensitive to many contaminants, 

notably some current-use insecticides and PAHs. This is of particular interest because a number of species of salmonids are threatened 

or endangered in Pacific Coast streams.

Continuous Monitoring—Stream-water level and temperature 

are being monitored continuously at all 88 sites across the region, 

and continuous water-quality monitors will be deployed at 6 sites. 

Continuous monitoring for parameters such as dissolved oxygen 

and nitrate concentration, in conjunction with periodic sampling of 

nutrients and periphyton biomass, can provide useful information on 

the effects of nutrients in streams.

Daily Pesticide Sampling—Small-volume automated pesticide samplers will be deployed at 7 streams to assess temporal variations in 

concentrations of about 230 pesticides and pesticide degradates. The 

samplers will collect daily and weekly composite samples that will 

be analyzed by the U.S. Environmental Protection Agency (EPA), 

Office of Pesticide Programs. Results will provide valuable information for determining short-term acute exposure of aquatic organisms 

to pesticides and for optimizing temporal sampling strategies.

Assessing Fish Health—A fish-health assessment approach, or 

“Juvenile Salmonid Scorecard,” is being developed and tested at 

about 15 of the Pacific Northwest study sites in collaboration with 

researchers at the University of Washington. Key metrics include 

average growth rate, lipid content, and total calories, as well as the 

activity of 2 dozen gene transcripts from quantitative polymerase 

chain reaction 

(qPCR) measurements, which can 

indicate genetic 

responses in the fish 

to specific stressors 

(Moran and others, 

2007). The Scorecard is designed 

to allow a tiered 

approach (a range of 

cost and complexity) and to be used 

by State and local 

agencies as a standard 

tool for evaluating 

salmonid health.

References

Esri, 2009, World terrain base map service, accessed February 25, 

2015, at http://www.arcgis.com/home/item.html?id=c61ad8ab0

17d49e1a82f580ee1298931.

Moran, P.W., Aluru, Neelakanteswar, Black, R.W., and Vijayan, 

M.M., 2007, Tissue contaminants and associated transcriptional 

response in trout liver from high elevation lakes in Washington: 

Environmental Science & Technology, v. 41, 

no. 18, p. 6591–6597.

Moulton, S.R., II, Kennen, J.G., Goldstein, R.M., and Hambrook, 

J.A., 2002, Revised protocols for sampling algal, invertebrate, 

and fish communities as part of the National Water-Quality 

Assessment Program: U.S. Geological Survey Open-File Report 

02–150, 75 p., available online at 

http://pubs.usgs.gov/of/2002/ofr-02-150/.

Van Metre, P.C., Frey, J.W., and Tarquinio, Ellen, 2012, The Midwest Stream Quality Assessment: U.S. Geological Survey Fact 

Sheet 2012–3124, 2 p., available online at 

http://pubs.usgs.gov/fs/2012/3124/. 

Van Metre, P.C., and Journey, C.A., 2014, The Southeast Stream 

Quality Assessment: U.S. Geological Survey Fact Sheet 

2014–3023, 2 p., available online at http://pubs.usgs.gov/

fs/2014/3023/.

For Additional Information

Visit the NAWQA Web site to access reports, data, and maps: 

http://water.usgs.gov/nawqa

For information on the NAWQA Regional Stream Quality 

Assessments, visit: http://water.usgs.gov/nawqa/studies/msqa/

Or contact: 

Peter Van Metre (512) 927-3506 pcvanmet@usgs.gov

Jennifer Morace (503) 251-3229 jlmorace@usgs.gov

Rich Sheibley (253) 552-1611 sheibley@usgs.gov

ISSN 2327-6916 (print) 

ISSN 2327-6832 (online) 

http://dx.doi.org/10.3133/fs20153020

Pacific Northwest Stream Quality Assessment

Oregon Department of Fish and Wildlife salmon 

spawning sign at Tickle Creek near Boring, 

Oregon, 2004. Photograph by Andy Arnsberg, 

Portland Bureau of Environmental Services.