Scientific Investigations Report 2006–5101–D
U.S. GEOLOGICAL SURVEY
Scientific Investigations Report 2006–5101–D
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.
[See appendix A for variable definitions. Correlation coefficients were considered strong when absolute value ≥ (bolded and shaded) and moderate when 0.66 > rho ≥ 0.5 (bolded). Abbreviations: ROADDEN, road density; TEQ, toxic equivalents; SPMD, semipermeable membrane device. Symbols: ≥, greater than or equal to; >, greater than]
| Stream and reach-scale variables | Urban indicators | |||||
|---|---|---|---|---|---|---|
| Urban intensity index (UII) |
Impervious area (percent) |
POPDEN00 | Urban + agriculture (percent) |
ROADDEN | ||
| Hydrologic variation metrics | ||||||
| Number of falling events > 5×median (PeriodF5) | 0.69 | 0.64 | 0.68 | 0.52 | 0.70 | |
| Number of falling events > 9×median (PeriodF9) | .69 | .65 | .67 | .51 | .71 | |
| Number of rising events > 5×median (PeriodR5) | .65 | .62 | .65 | .48 | .68 | |
| Richards-Baker Flashiness Index (Rb-flash) | .56 | .49 | .55 | .41 | .53 | |
| Water temperature metrics | ||||||
| Minimum temperature (95th percentile) | 0.56 | 0.51 | 0.56 | 0.44 | 0.53 | |
| Habitat metrics | ||||||
| Mean embeddedness (riffle and runs) | 0.59 | 0.58 | 0.57 | 0.57 | 0.49 | |
| Mean width/depth ration (riffle and runs) | -.51 | -.51 | -.52 | -.47 | -.49 | |
| Percent riffle habitat | -.63 | -.61 | -.63 | -.57 | -.55 | |
| Percent large substrate | -.30 | -.23 | -.30 | -.24 | -.27 | |
| Mean habitat heterogeneity | .30 | .21 | .29 | .20 | .28 | |
| Stream and reach-scale variables | Water-chemistry variables | |||||||
|---|---|---|---|---|---|---|---|---|
| Summer-time dissolved oxygen |
Dissolved organic carbon |
Total insecticides |
Total pesticides |
TEQ (SPMD) |
Average specific conductance |
Sulfate concentration |
Total nitrogen concentration |
|
| Hydrologic variation metrics | ||||||||
| Number of falling events > 5×median (PeriodF5) | -0.45 | 0.71 | 0.71 | 0.50 | 0.70 | 0.42 | 0.56 | 0.40 |
| Number of falling events > 9×median (PeriodF9) | -.40 | .62 | .68 | .48 | .67 | .49 | .66 | .43 |
| Number of rising events > 5×median (PeriodR5) | -.37 | .60 | .65 | .45 | .68 | .34 | .52 | .40 |
| Richards-Baker Flashiness Index (Rb-flash) | -.40 | .70 | .62 | .46 | .63 | .39 | .53 | .30 |
| Water temperature metrics | ||||||||
| Minimum temperature (95th percentile) | -0.53 | 0.67 | 0.57 | 0.42 | 0.45 | 0.28 | 0.32 | 0.22 |
| Habitat metrics | ||||||||
| Mean embeddedness (riffle and runs) | -0.66 | 0.46 | 0.36 | 0.39 | 0.41 | 0.69 | 0.55 | 0.52 |
| Mean width/depth ration (riffle and runs) | .50 | -.34 | -.26 | -.10 | -.24 | -.59 | -.50 | -.35 |
| Percent riffle habitat | .84 | -.60 | -.39 | -.33 | -.49 | -.61 | -.57 | -.46 |
| Percent large substrate | .48 | -.21 | -.12 | -.06 | -.00 | -.36 | -.14 | -.05 |
| Mean habitat heterogeneity | -.61 | .38 | .29 | .25 | .18 | .31 | .14 | -.05 |
U.S. Department of the Interior | U.S. Geological Survey
URL: https://pubs.usgs.gov/sir/2006/5101-D
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