| Attribute | Symbol | Rating characteristics | ||||
|---|---|---|---|---|---|---|
| 0 worst | 1 | 2 | 3 | 4 (best) | ||
| Late summer stream flow | X1 | CPF 10% ADF | CPF = 10–15% ADF | CPF = 16–25% ADF | CPF = 26–55% ADF | CPF 55% ADF |
| Annual stream flow variation | X2 | Intermittent stream | Extreme fluctuation, but rarely dry, little base flow | Moderate fluctuation, base flow occupies up to 2/3 of channel | Small fluctuation, base flow stable, occupies most of channel | Little or no fluctuation |
| Maximum summer stream temperature | X3 | 6 or 26.4 | 6–8 or 24.2–26.3 | 8.1–10.3 or 21.5–24.1 | 10.4–12.5 or 18.7–21.4 | 12.6–18.6 |
| Nitrate nitrogen mg/1 | X4 | 0.01 or 2.0 | 0.01–0.04 or 0.91–2.00 | 0.05–0.09 or 0.51–0.90 | 0.10–0.14 or 0.26.0.50 | 0.15–0.25 |
| Cover (%) | X7 | 10 | 10–25 | 25–40 | 41–55 | 55 |
| Eroding stream banks (%) | X8 | 75–100 | 50–74 | 25–49 | 10–24 | 0–9 |
| Substrate | X9 | SAV lacking | Little SAV | Occasional patches of SAV | Frequent patches of SAV | Well developed and abundant SAV |
| Water velocity m³/s | X10 | 8 or 122 | 8–15.4 or 106.6–122 | 15.5–30.3 or 91.4–106.5 | 30.4–45.5 or 76.1–91.3 | 45.6–76 |
| Stream width (m) | X11 | 0.6 or 46 | 0.6–2.0 or 23.46 | 20.1–3.5 or 15.1–22.9 | 3.6–5.3 or 6.7–15 | 5.4–6.6 |
CPF = Average daily flow during August and first half September
ADF = Average daily flow throughout year
SAV = Submerged aquatic vegetation including moss or algae growing on rocks
