North Dakota Real-time Water Quality

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

Model Form #1

log₁₀(TP) = - 2.253 + 0.468 log₁₀(TURB) + 0.217 log₁₀(Q) + 0.00881 cos(2π D / 365) - 0.137 sin(2π D / 365)

where:

TP is computed total phosphorus, in milligrams per liter as phosphorus
TURB is turbidity, YSI model 6136, in formazin nephelometric units
Q is computed discharge, stage-discharge rating curve, in cubic feet per second
D is day of year, in the range of integers 1 through 365

Model Calibration

Basic Data

Number of measurements:	84
Mean squared error:	0.013924
Multiple R²:	0.739
Bias correction (smearing) factor:	1.57426

Explanatory Variables

Variable	Value	Standard error
Intercept	-2.253	0.118
log₁₀(TURB)	0.468	0.0376
log₁₀(Q)	0.217	0.0489
cos(2π D / 365)	0.00881	0.035
sin(2π D / 365)	-0.137	0.0214

Correlation Matrix

A correlation matrix is not available for this model. Therefore, the prediction interval was calculated by assuming that there is no correlation between the explanatory variables.

Reference

Galloway, J., 2014, Continuous Water-Quality Monitoring and Regression Analysis to Estimate Constituent Concentrations and Loads in the Red River of the North at Fargo and Grand Forks, North Dakota, 2003–12: U.S. Geological Survey Scientific Investigations Report 2014–5064, 37 p.