Kansas Real-Time Water Quality

Kansas Real-Time Water Quality

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USGS station:	Go to NWISWeb
Constituent:
Time period:
Model Form:

Model Form #3

log₁₀(TNR) = - 0.275 + 0.327 log₁₀(TURB) - 0.0994 log₁₀(Chls) + 0.0758 sin(2π D / 365) + 0.0306 cos(2π D / 365)

where:

TNR is computed total nitrogen, in milligrams per liter as nitrogen
TURB is turbidity, YSI EXO, in formazin nephelometric units
Chls is chlorophylls, in relative fluorescence units
D is day of year, in the range of integers 1 through 365

Model Calibration

Basic Data

Number of measurements:	94
Mean squared error:	0.007396
Multiple R²:	0.845
Bias correction (smearing) factor:	1.02

Explanatory Variables

Variable	Value	Standard error
Intercept	-0.275	0.0468
log₁₀(TURB)	0.327	0.0217
log₁₀(Chls)	-0.0994	0.022
sin(2π D / 365)	0.0758	0.0124
cos(2π D / 365)	0.0306	0.0153

Correlation Matrix

	Intercept	log₁₀(TURB)	log₁₀(Chls)	sin(2π D / 365)	cos(2π D / 365)
Intercept	1	-0.958	-0.695	-0.0811	-0.453
log₁₀(TURB)	-0.958	1	0.542	0.0576	0.497
log₁₀(Chls)	-0.695	0.542	1	0.068	0.349
sin(2π D / 365)	-0.0811	0.0576	0.068	1	0.0385
cos(2π D / 365)	-0.453	0.497	0.349	0.0385	1

Reference

Williams, T.J., 2021, Linear Regression Model Documentation and Updates for Computing Water-Quality Constituent Concentrations or Densities using Continuous Real-Time Water-Quality Data for the Kansas River, Kansas, July 2012 through September 2019: U.S. Geological Survey Open-File Report 2021-1018, 18 p.