Water samples taken by Friends of the Mad River (FMR) volunteers on Monday morning June 30th show favorable swimming conditions with only one of thirty-seven sites tested in violation of Vermont’s water quality standards. Site 31, located at Lover’s Lane Bridge was in violation of the Vermont standard (no more than 77 colonies of E.coli per 100mL water). Site 31 is the most downstream sampling site in the program; generally the most downstream sites in the watershed show higher levels of E.coli as they represent the accumulation of pollution throughout the watershed.
**Download E.coli data from 6/30/08**
The state water quality standard for recreational waters measures E. coli bacteria, an indicator of pollution from human or animal waste. High E.coli levels can pose a danger to swimmers since the presence of fecal borne pathogens is likely. At the time of sampling there were favorable swimming conditions shown throughout the watershed, exhibited by relatively low E.coli levels. E.coli levels tend to rise when rain washes pollutants into the river.
The volume of water flowing in the Mad River was high and declining at the time of sampling. After several brief passing disturbances and lingering storm systems moved through the area late last week and on Sunday, drier weather late Sunday and into Monday allowed water levels to begin to decline. At the time of sampling on June 30th, the water level at the US Geologic Survey station in Moretown was at approximately 175 cubic feet per second, which is well above the median value for this date (87 cubic feet per second).
Cyndee Button is the Lab Coordinator for Friends of the Mad River, and has processed hundreds of E.coli samples throughout her time with the group. “Cyndee and I were a bit surprised by the results this week. The water levels were high throughout the watershed, which usually results in higher E.coli levels, especially at certain sites. However, E.coli levels were generally very low.” explains FMR Coordinator Caitrin Noel. She adds “While it is difficult to say definitively why this happened, I think Cyndee has a strong theory—that the low numbers seen throughout the watershed could be a result of the continued “flushing” we have seen over the past week. The frequent small rain storms have already washed many of the accumulated pollutants into the river to be carried away, and the additional rainfall has not added as much E.coli as it normally would. Declining water levels also mean lower E.coli levels”
For more information about E. coli and the Mad River Watch program, or to report a river-related illness call 496-9127. Thanks to this week’s Mad River Watch volunteers; samplers this week included: Michael Ware, Elizabeth Walker, Monserrat Carbonell, Mary Gow, Cathy & Barry Glick, and Fran & Gary Plewak. Thanks to Kinny Perot for posting the results at various sites and to Cyndee Button for her work in the lab.