Table 1.
Overall impact of rainfall on E. coli concentrations in beach water. Mean E. coli concentration in beach water during a rainfall event was compared with the seasonal mean E. coli concentration at the same beach by analysis of variance. All beaches, except Nicolet Bay Beach, had a total of ten rain events with 7 samples collected per 24-hour sampling event. Nicolet Bay Beach had four rain sampling events. Bolded P-values indicated significantly higher E. coli concentrations during rain events (P < .05).
| Beach name | Mean E. coli during rain event | Seasonal E. coli mean | Significant difference |
|---|---|---|---|
| (MPN/100 mL) | (MPN/100 mL) | (P value) | |
| Baileys Harbor | 225.4 | 53.4 | .000 |
| Egg Harbor | 41.0 | 61.4 | .849 |
| Ellison Bay | 447.7 | 43.3 | .000 |
| Nicolet | 19.4 | 26.4 | .041 |
| Murphy Park | 191.0 | 115.9 | .000 |
| Sister Bay | 778.3 | 276.0 | .000 |
| Sunset Park | 187.5 | 102.1 | .011 |
| Whitefish Dunes | 39.8 | 48.3 | .110 |