Scientific Investigations Report 2006–5101–D
U.S. GEOLOGICAL SURVEY
Scientific Investigations Report 2006–5101–D
Effects of Urbanization on Stream Ecosystems in the Willamette River Basin and Surrounding Area, Oregon and Washington
National Water-Quality Assessment Program
By Ian R. Waite, Steven Sobieszczyk, Kurt D. Carpenter, Andrew J. Arnsberg, Henry M. Johnson, Curt A. Hughes, Michael J. Sarantou, and Frank A. Rinella
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Figures
Figure 1. Map showing location of the Willamette River basin and surrounding area, Oregon and Washington.
Figure 2. Map showing Level III ecoregions of the Willamette River basin and surrounding area, Oregon and Washington.
Figure 3. Map showing National land cover data, Willamette River basin and surrounding area, Oregon and Washington, 2001.
Figure 4. Map showing candidate and final watersheds selected for the urban gradient study, Willamette River basin and surrounding area, Oregon and Washington.
Figure 5. Graph showing relation between urban intensity index (UII) and number of falling hydrologic events greater than or equal to 9 times the median, Willamette River basin and surrounding area, Oregon and Washington.
Figure 6. Graph showing percentage of riffle habitat in relation to summer dissolved oxygen concentrations, Willamette River basin and surrounding area, Oregon and Washington.
Figure 7. Boxplots showing pesticide concentrations and detection frequency for all stream samples, Willamette River basin and surrounding area, Oregon and Washington.
Figure 8. Graph showing urban intensity index (UII) and percentage of agricultural land for all 28 sites, Willamette River basin and surrounding area, Oregon and Washington.
Figure 9. Graph showing total pesticide concentration in relation to urban intensity index (UII) for all 28 sites, Willamette River basin and surrounding area, Oregon and Washington.
Figure 10. Graph showing total insecticide concentration in relation to urban intensity index (UII) for all 28 sites, Willamette River basin and surrounding area, Oregon and Washington.
Figure 11. Graphs showing relations between Pesticide Toxicity Index (PTI) and urban intensity index (UII) and road density (ROADDEN), Willamette River basin and surrounding area, Oregon and Washington.
Figure 12. Graphs showing relation between the urban intensity index (UII) and semipermeable membrane device results for the toxic equivalent index (TEQ) and pyrene index.
Figure 13. Graphs showing relations between average total nitrogen concentrations and urban intensity index (UII) and percentage of urban plus agricultural land, Willamette River basin and surrounding area, Oregon and Washington.
Figure 14. Graphs showing relation between the urban intensity index (UII) and chlorophyll-a and ash-free dry mass, Willamette River basin and surrounding area, Oregon and Washington.
Figure 15. Graphs showing relations between ash-free dry mass and nutrient index and concentrations of dissolved organic carbon, and dissolved organic carbon and concentrations of dissolved oxygen, Willamette River basin and surrounding area, Oregon and Washington.
Figure 16. Graphs showing relations between urban intensity index (UII) and percentage of algal taxa requiring high levels of dissolved oxygen, and relative density of eutrophic algae, Willamette River basin and surrounding area, Oregon and Washington.
Figure 17. Graph showing relation between urban intensity index (UII) and number of benthic macroinvertebrate taxa (richness) in the Ephemeroptera, Plecoptera, and Trichoptera orders (EPT), Willamette River basin and surrounding area, Oregon and Washington.
Figure 18. Graphs showing benthic macroinvertebrate nonmetric dimensional scaling ordination axis 1 scores in relation to urban intensity index (UII), summer dissolved oxygen concentrations, percentage of flat and low elevation land in watershed and and toxic equivalents from semipermeable membrane devices, Willamette River basin and surrounding area, Oregon and Washington.
Figure 19. Graph showing relation between urban intensity index (UII) and percent dominance by single fish species at all 28 sites (highest relative abundance), Willamette River basin and surrounding area, Oregon and Washington.
Figure 20. Graphs showing relation between fish assemblages (nonmetric dimensional scaling first axis ordination scores) and urban intensity index (UII), toxic equivalents (TEQ) from semipermeable membrane devices, summer dissolved oxygen (DO) concentrations and the number of falling hydrologic events (PeriodF5), Willamette River basin and surrounding area, Oregon and Washington.
Figure 21. Graph showing relation between midday summer dissolved oxygen (DO) concentrations and percentage of salmonids, Willamette River basin and surrounding area, Oregon and Washington.
Tables
Table 1. Land cover and other watershed characteristics for 28 streams sampled during the urbanization gradient study, Willamette River basin and surrounding area, Oregon and Washington.
Table 2. Correlations of urban indicator metrics and environmental setting metrics, Willamette River basin and surrounding area, Oregon and Washington.
Table 3. Spearman’s rank correlations between urban indicator and water-chemistry metrics and select environmental variables, Willamette River basin and surrounding area, Oregon and Washington.
Table 4. Number of pesticide detections at each site by pesticide type for spring and summer 2004, Willamette River basin and surrounding area, Oregon and Washington.
Table 5. Summary statistics of pesticide concentrations collected during spring and summer 2004, Willamette River basin and surrounding area, Oregon and Washington.
Table 6. Spearman’s rank correlation coefficients (rho values) between urban indicator and water-chemistry variables, Willamette River basin and surrounding area, Oregon and Washington.
Table 7. Most common algal taxa from the five major Divisions identified in Richest Targeted Habitat samples, Willamette River basin and surrounding area, Oregon and Washington.
Table 8. Dominant algal taxon (by cell density) at each site, dominant diatom taxon, and diatom water-quality indicator classification, Willamette River basin and surrounding area, Oregon and Washington.
Table 9. Spearman’s rank correlation coefficients (rho values) between diatom algal metrics and the urban intensity index and select environmental variables, Willamette River basin and surrounding area, Oregon and Washington.
Table 10. Number of benthic macroinvertebrate taxa and maximum abundance per insect order or noninsect group, Willamette River basin and surrounding area, Oregon and Washington.
Table 11. Commonly observed benthic macroinvertebrate taxa and tolerance values, Willamette River basin and surrounding area, Oregon and Washington.
Table 12. Single dominant benthic macroinvertebrate taxon at each site, taxon name, U.S. Environmental Protection Agency tolerance value, Ephemeroptera, Plecoptera, and Trichoptera richness, and richness percentage per site, Willamette River basin and surrounding area, Oregon and Washington.
Table 13. Comparison of average benthic invertebrate abundance and richness metrics for high- and low-urban streams, Willamette River basin and surrounding area, Oregon and Washington.
Table 14. Correlation between selected benthic macroinvertebrate metrics and environmental variables, Willamette River basin and surrounding area, Oregon and Washington.
Table 15. Fish species richness, total abundance, percentages of dominance (single species), salmonids, and nonnative fish for 28 sites, Willamette River basin and surrounding area, Oregon and Washington.
Table 16. Correlations of fish metrics and nonmetric dimensional scaling axis 1 ordination scores with environmental variables, Willamette River basin and surrounding area, Oregon and Washington.
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Send questions or comments about this report to the author, I.R. Waite, (503) 251 3463.
For more information about USGS activities in Oregon, visit the USGS Oregon Water Science Center home page.
U.S. Department of the Interior | U.S. Geological Survey