TABLE 11.
Summary of SPARROW-Estimated Total Phosphorus Enrichment and 303(d) Listings in HUC8 Watersheds in the United States Pacific Northwest (2002 conditions)
| TP Enrichment Estimated by SPARROW | ||||||
|---|---|---|---|---|---|---|
| Percentage of Stream Reach Length Placed on State 303(d) Lists Because of Impairment Related to Nutrient Enrichment | None | Very Low | Low | High | Very High | Total |
| None | 4 | 12 | 16 | 21 | 19 | 72 |
| <50% | 3 | 17 | 28 | 46 | 44 | 138 |
| >50% | 0 | 0 | 0 | 3 | 5 | 8 |
Notes: SPARROW, SPAtially Referenced Regressions On Watershed attributes; TP, total phosphorus. Values indicate the number of watersheds.