Data Series 412
U.S. GEOLOGICAL SURVEY
Data Series 412
Table 1. Regression equations for the 7Q2 low-flow statistic for unregulated streams in regions 1–8 in Idaho.
[7Q2 regression equation: A, drainage area, in square miles; P, mean annual precipitation, in inches; E, mean elevation, in feet. Abbreviation: 7Q2, 7-day, 2-year low flow]
| Region | 7Q2 regression equation | Standard error of prediction | |
|---|---|---|---|
| log10 | Percent | ||
| 1 | 7Q2 = 0.300A0.879 | 0.271 | +86.7 to -46.4 |
| 12 | 7Q2 = 0.000153A1.04P1.92 | .253 | +78.9 to -44.1 |
| 3 | 7Q2 = 0.0214A0.971 | .277 | +236 to -70.2 |
| 14 | 7Q2 = 0.0000215A1.04P2.41 | .341 | +119 to -54.4 |
| 5 | 7Q2 = 0.334A0.963 | .249 | +77.3 to -43.6 |
| 16 | 7Q2 = 0.000133A1.05P2.10 | .243 | +75.0 to -42.9 |
| 7 | 7Q2 = 0.0000115A0.837(E/1000)4.658 | .577 | +277 to -73.5 |
| 8 | 7Q2 = 0.00181A0.981P1.515 | .331 | +116 to -53.4 |
1 Denotes original Hortness (2006) equation.
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