The Enterococcus Project: February 2, 2004
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Figure 1. The chart shows the average enterococcus concentration (in MPN/100ml, most probable number of enterococcus in 100 ml of water – the “most probable number” since test results are based on statistical determination) during the small Feb. 2 rainstorm; the averages include samples taken during the storm and for 2 days afterward. The error bars represent the “standard error of the mean,” a large error bar indicates that sample concentrations varied widely. The dashed line at the bottom of the figure shows the acceptable water quality standard for beaches – less than 104 enterococcus per 100 ml. Only Rattlesnake Creek met this standard throughout the storm. The results indicate increasing pollution as Mission Creek flows downstream to the beach: at Montecito Street the highest count was 26,130 (at 4:30 PM during the height of the rainfall). This is more than 250-times over the pollution limit. Interestingly, the beach sampling site nearest Mission Creek (beach 2) had lower concentrations than the site further away (beach 1).