Scientific Investigations Report 2006-5188
U.S. GEOLOGICAL SURVEY
Scientific Investigations Report 2006-5188
Table 6. Regression coefficients and coefficients of determination (R2) for load models used to estimate dissolved and total cadmium, lead, and zinc loads at four streamflow-gaging stations in the Spokane River basin, Idaho.
[Gaging station locations are shown in figures 1 and 2. Long-term records are for the periods: Enaville (1992-2004), Pinehurst, Harrison (1991-2004), and Post Falls (1991-2003). Regression equation is ln(L) = a + b(ln Q) + c(ln Q2) + d[sin(2•T)] + e[cos(2•T)] + fT + gT2, where L is constituent load; Q is streamflow; T is time in decimal years from beginning of calibration period; a, b, c, d, e, f, and g are regression coefficients. Symbols: –, explanatory variable not used in regression; <, less than]
| Gaging station No. | Gaging station name | Regression coefficient | R2 (percent) | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| a | b | c | d | e | f | p-value of f |
g | p-value of g |
|||
| Dissolved cadmium (DCd) | |||||||||||
| 5 | Pinehurst | 2.1468 | .6013 | -0.0736 | 0.0798 | 0.2101 | -0.0474 | <0.001 | -0.0029 | 0.04 | 93.4 |
| 6 | Enaville | -1.8831 | .9942 | .0274 | -.0116 | .2051 | -.2843 | <.001 | .0293 | .001 | 96.1 |
| 7 | Harrison | 1.9382 | .8366 | -.1057 | .0908 | .1527 | -.0810 | <.001 | – | – | 96.1 |
| 9 | Post Falls | 1.1276 | .9752 | – | .0184 | .2246 | -.1639 | <.001 | – | – | 92.8 |
| Total cadmium (TCd) | |||||||||||
| 5 | Pinehurst | 2.1242 | 0.7909 | – | -0.2745 | -0.0834 | -0.0465 | <0.001 | – | – | 78.7 |
| 6 | Enaville | -1.8090 | 1.2197 | .1347 | -.0131 | -.0983 | -.2970 | <.001 | 0.0253 | <0.001 | 96.7 |
| 7 | Harrison | 2.0933 | 1.0082 | – | -.3460 | -.2173 | -.0635 | <.001 | – | – | 84.9 |
| 9 | Post Falls | 1.1790 | .9300 | – | -.3064 | -.2743 | -.1188 | <.001 | – | – | 91.8 |
| Dissolved lead (DPb) | |||||||||||
| 5 | Pinehurst | 1.6491 | 0.8307 | – | 0.0812 | -0.3614 | -0.0361 | 0.076 | – | – | 75.1 |
| 6 | Enaville | -1.3706 | 1.1582 | 0.0967 | .0073 | .1954 | -.1412 | .003 | 0.0376 | <0.001 | 87.8 |
| 7 | Harrison | 3.1052 | 1.2741 | – | – | – | – | – | – | – | 86.5 |
| 9 | Post Falls | .5203 | .8471 | -.0112 | .3731 | .5585 | -.1728 | <.001 | .0447 | <.001 | 73.8 |
| Total lead (TPb) | |||||||||||
| 5 | Pinehurst | 3.4695 | 1.7819 | 0.4036 | -0.2484 | -0.3025 | -0.0621 | <0.001 | -0.0099 | 0.073 | 90.0 |
| 6 | Enaville | .1051 | 1.6317 | .3643 | – | – | -.1820 | <.001 | – | – | 87.6 |
| 7 | Harrison | 4.5146 | 1.5535 | .2601 | -.1865 | -.2269 | -.0511 | <.001 | – | – | 89.6 |
| 9 | Post Falls | 2.5816 | .9318 | .0323 | -.5161 | .1712 | -.1419 | <.001 | .0203 | <.001 | 82.6 |
| Dissolved zinc (DZn) | |||||||||||
| 5 | Pinehurst | 7.1708 | 0.5584 | -0.0380 | 0.0513 | 0.1592 | -0.0564 | <0.001 | -0.0041 | 0.004 | 92.8 |
| 6 | Enaville | 2.8899 | 1.2202 | -.0541 | .0984 | .1196 | -.0713 | <.001 | .0176 | <.001 | 93.2 |
| 7 | Harrison | 7.0855 | .7306 | -.0690 | .2148 | .078 | -.0915 | <.001 | – | – | 97.1 |
| 9 | Post Falls | 6.3186 | .9838 | – | -.2365 | .347 | -.0509 | <.001 | – | – | 98.9 |
| Total zinc (TZn) | |||||||||||
| 5 | Pinehurst | 7.0444 | 0.6686 | 0.0533 | -0.2184 | 0.0185 | -0.0500 | <0.001 | – | – | 82.9 |
| 6 | Enaville | 3.1654 | 1.2801 | .0890 | – | – | -.1199 | <.001 | – | – | 88.0 |
| 7 | Harrison | 7.0945 | .9485 | – | -.2767 | -.2635 | -.0300 | .004 | – | – | 82.2 |
| 9 | Post Falls | 6.3402 | .9369 | – | -.0723 | -.4163 | -.0388 | <.001 | – | – | 93.5 |
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