Scientific Investigations Report 2007–5164
U.S. GEOLOGICAL SURVEY
Scientific Investigations Report 2007–5164
Table 3. Regression equations and correlation coefficients for relations between turbidity and suspended-sediment concentrations, McKenzie River basin, Oregon.
[Equations are in the form y=bxa*cf, where y is suspended-sediment concentration (SSC), in milligram per liter, x is the reported, instantaneous turbidity, in formazin nephelometric units (FNU), a and b are regression coefficients, and cf is a bias correction factor. Turbidities listed as >1,360 FNU were higher than the upper limit of the instrument—loads may be computed with the value 1,360 FNU and are considered underestimates of the actual load. Maximum turbidity sampled is the highest recorded turbidity value with a corresponding SSC sample, whereas Maximum Turbidity Recorded is the highest turbidity value recorded at the site during the study period, showing the degree to which regressions of SSC from turbidity were extended beyond the nominal bounds of the regression. The range of SSC values shown are those that were sampled and used in the regressions. SSC values below the indicated ranges were not used. Model standard prediction error (MSPE), calculated as +MSPE= [10^(+MSE)-1]*100, and -MSPE= [1-10^(-MSE)]*100. Abbreviations: mg/L, milligram per liter; FNU, Formazin Nephelometric Units; >, greater than; ±, plus or minus]
| Station name | Equation [y=b(x)a] |
Correction factor (cf ) |
Number of samples |
Correlation coefficient r2 |
Mean square error (MSE) |
Model standard prediction error (±) | Range of turbidity sampled (FNU) |
Maximum turbidity recorded (FNU) |
Range of SSC (mg/L) |
|---|---|---|---|---|---|---|---|---|---|
| McKenzie River above South Fork, near Rainbow (MRBO) | 1.456*Turb(1.263) | 1.048 | 7 | 0.97 | 0.022 | 5.2 / 4.9 | 1.6–52 | 80 | 4–266 |
| South Fork McKenzie River above Cougar Lake, near Rainbow (SFCO) | 2.233*Turb(1.012) | 1.123 | 9 | .92 | .070 | 17.5 / 14.9 | 1.1–119 | 323 | 4–17 |
| South Fork McKenzie River near Rainbow (CGRO) | 1.079*Turb(0.916) | 1.013 | 25 | .98 | .005 | 1.16 / 1.14 | 5.2–334 | >1,360 | 4–351 |
| Blue River at Blue River (BLUE) | 1.027*Turb(0.946) | 1.107 | 9 | .81 | .045 | 10.9 / 9.8 | 2.5–45 | 103 | 1–30 |
| McKenzie River near Vida (VIDA) | 1.520*Turb(0.875) | 1.069 | 11 | .91 | .027 | 6.4 / 6.0 | 19–83 | 143 | 2–72 |
U.S. Department of the Interior | U.S. Geological Survey
URL: https://pubs.usgs.gov/sir/2007/5164
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