Design and methods of the Pacific Northwest Stream Quality Assessment (PNSQA), 2015

Open-File Report 2017-1103
National Water-Quality Assessment Project
By: , and 

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Abstract

In 2015, the U.S. Geological Survey (USGS) National Water-Quality Assessment (NAWQA) project conducted the Pacific Northwest Stream Quality Assessment (PNSQA) to investigate stream quality across the western part of the Pacific Northwest. The goal of the PNSQA was to assess the health of streams in the region by characterizing multiple water-quality factors that are stressors to in-stream aquatic life and by evaluating the relation between these stressors and the condition of biological communities. The effects of urbanization and agriculture on stream quality for the Puget Lowland and Willamette Valley Level III Ecoregions were the focus of this regional study. Findings will help inform the public and policymakers about human and environmental factors that are the most critical in affecting stream quality and, thus, provide insights into possible strategies to protect or improve the health of streams in the region.

Land-use data were used in the study to identify and select sites within the region that ranged in levels of urban and agricultural development. A total of 88 sites were selected across the region—69 were on streams that explicitly spanned a range of urban land use in their watersheds, 8 were on streams in agricultural watersheds, and 11 were reference sites with little or no development in their watersheds. Depending on the type of land use, sites were sampled for contaminants, nutrients, and sediment for either a 4- or 10-week period during April, May, and June 2015. This water-quality “index period” was immediately followed with an ecological survey of all sites that included stream habitat, benthic algae, benthic macroinvertebrates, and fish. Additionally, streambed sediment was collected during the ecological survey for analysis of sediment chemistry and toxicity testing.

This report provides a detailed description of the specific study components and methods of the PNSQA, including (1) surveys of stream habitat and aquatic biota, (2) discrete water sampling, (3) deployment of passive polar organic chemical integrative samplers for pesticides and pharmaceuticals, and (4) sampling of streambed sediment. At selected study sites, toxicity testing of streambed sediment, continuous water-quality monitoring, and daily pesticide sampling also were conducted and are described.

Suggested Citation

Sheibley, R.W., Morace, J.L., Journey, C.A., Van Metre, P.C., Bell, A.H., Nakagaki, Naomi, Button, D.T., and Qi, S.L., 2017, Design and methods of the Pacific Northwest Stream Quality Assessment (PNSQA), 2015: U.S. Geological Survey Open-File Report 2017-1103, 46 p., https://doi.org/10.3133/ofr20171103.

ISSN: 2331-1258 (online)

Study Area

Table of Contents

  • Abstract
  • Introduction
  • Study Design
  • Data Collection and Processing
  • Laboratory Analyses
  • Quality Assurance and Quality Control
  • Data Management Procedures
  • Summary
  • References Cited
  • Appendixes A–B

Additional publication details

Publication type Report
Publication Subtype USGS Numbered Series
Title Design and methods of the Pacific Northwest Stream Quality Assessment (PNSQA), 2015
Series title Open-File Report
Series number 2017-1103
DOI 10.3133/ofr20171103
Year Published 2017
Language English
Publisher U.S. Geological Survey
Publisher location Reston, VA
Contributing office(s) Washington Water Science Center
Description Report: viii, 46 p.; Table; 2 Appendixes
Country United States
State Oregon, Washington
Online Only (Y/N) Y