TABLE 4.
Comparison of Regional SPARROW Model Instream-Loss Coefficient Estimates
| Predictor Variable Type | Predictor Variable Description | Coefficient Units | Statistical Measures | MRB1 | MRB2 | MRB3 | MRB4 | MRB5 | MRB7 |
|---|---|---|---|---|---|---|---|---|---|
| Total nitrogen instream attenuation rate estimates | Time of travel in each stream reach where mean discharge <1.13 m3/s (days) | (days)−1 | Estimate | 0.424 | |||||
| Standard error | 0.100 | ||||||||
| Significance level | <0.001 | ||||||||
| Time of travel in each stream reach where mean discharge <1.42 m3/s (days) | (days)−1 | Estimate | 0.365 | ||||||
| Standard error | 0.082 | ||||||||
| Significance level | <0.001 | ||||||||
| Time of travel in each stream reach where mean discharge <2.83 m3/s (days) | (days)−1 | Estimate | 0.224 | ||||||
| Standard error | 0.144 | ||||||||
| Significance level | 0.060 | ||||||||
| Time of travel in each stream reach where mean discharge <3.11 m3/s (days) | (days)−1 | Estimate | 0.150 | ||||||
| Standard error | 0.057 | ||||||||
| Significance level | 0.004 | ||||||||
| Time of travel in each stream reach where mean discharge >1.13 and <1.98 m3/s (days) | (days)−1 | Estimate | 0.233 | ||||||
| Standard error | 0.096 | ||||||||
| Significance level | 0.016 | ||||||||
| Time of travel in each stream reach where mean discharge >1.42 and <28 m3/s (days) | (days)−1 | Estimate | 0.079 | ||||||
| Standard error | 0.021 | ||||||||
| Significance level | <0.001 | ||||||||
| Time of travel in each stream reach where mean discharge <28 m3/s (days) | (days)−1 | Estimate | 0.140 | ||||||
| Standard error | 0.050 | ||||||||
| Significance level | <0.001 | ||||||||
| Time of travel in each stream reach where mean discharge >28 m3/s (days) | (days)−1 | Estimate | 0.014 | ||||||
| Standard error | 0.020 | ||||||||
| Significance level | 0.260 | ||||||||
| Total phosphorus instream attenuation rate estimates | Time of travel in each stream reach where mean discharge <1.42 m3/s (days) | (days)−1 | Estimate | 0.198 | 0.254 | ||||
| Standard error | 0.072 | 0.067 | |||||||
| Significance level | 0.006 | <0.001 | |||||||
| Time of travel in each stream reach where mean discharge >1.42 and <2.27 m3/s (days) | (days)−1 | Estimate | 0.298 | ||||||
| Standard error | 0.100 | ||||||||
| Significance level | 0.003 | ||||||||
| Time of travel in each stream reach where mean discharge <13.4 m3/s (days) | (days)−1 | Estimate | 0.093 | ||||||
| Standard error | 0.052 | ||||||||
| Significance level | 0.038 | ||||||||
| Time of travel in each stream reach per meter of stream depth (days/m) | (days/m)−1 | Estimate | 0.048 | ||||||
| Standard error | 0.028 | ||||||||
| Significance level | 0.085 |
Notes: Values represent the coefficient estimates for the models, their standard error, and their significance levels. MRB, major river basin.