Scientific Investigations Report 2006–5101–D
U.S. GEOLOGICAL SURVEY
Scientific Investigations Report 2006–5101–D
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.
[Average dissolved organic carbon (DOC), sulfate (SO4), total nitrogen (TN), total phosphorus (TP) concentration values were used for the correlations. Correlation coefficients were considered strong when absolute value ≥ 0.66 (bolded and shaded) and moderate when 0.66 > rho ≥ 0.50 (bolded). Abbreviations: PTI, Pesticide Toxicity Index; TEQ, toxic equivalents index; DO, dissolved oxygen; ROADDEN, road density. Symbol: ≥, greater than or equal to]
| Urban indicators | Sum of spring + summer | Water-chemistry variables | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Insecticide | Pesticide | PTI | TEQ | Pyrene index | Summer DO | DOC | SO4 | TN | TP | Nutrient index | ||
| Urban intensity index (UII) | 0.69 | 0.68 | 0.63 | 0.81 | 0.67 | -0.60 | 0.72 | 0.73 | 0.79 | 0.71 | 0.85 | |
| Percent impervious surface | .65 | .65 | .61 | .80 | .64 | -.56 | .65 | .72 | .83 | .71 | .86 | |
| POPDEN00 | .70 | .68 | .62 | .81 | .66 | -.61 | .70 | .71 | .81 | .73 | .85 | |
| Percent urban + agriculture | .63 | .72 | .60 | .73 | .58 | -.53 | .60 | .62 | .86 | .65 | .84 | |
| ROADDEN | .73 | .67 | .69 | .75 | .56 | -.54 | .69 | .69 | .75 | .65 | .79 | |
U.S. Department of the Interior | U.S. Geological Survey
URL: https://pubs.usgs.gov/sir/2006/5101-D
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