Intermittent storms can cause E. coli levels to fluctuate
By: Corrie (friendv3) 2014.07.29

Sampling results from the fourth round of Friends of the Mad River’s 2014 Mad River Watch (MRW) volunteer water quality program show only one site with unfavorable swimming conditions Monday morning. Lover's Lane Bridge in Moretown tested "unsuitable for swimming" (according to EPA's E. coli threshold of 235 colonies per 100 ml of water). Several other sites tested close to this level, including Ward Swimhole.

The flow condition of the Mad River at the time of sampling Monday morning was low and declining (LD), measuring approximately 110 cubic feet per second (cfs) at the USGS flow gage in Moretown, down from 181 cfs Sunday evening. The median flow for this date is ~60 cfs.

Intermittent heavy rains can cause E. coli levels to fluctuate, even on a daily basis, as water carrying pathogens moves down the watershed. Of the 36 sites tested by Friends of the Mad River’s Mad River Watch program, the Lover’s Lane site is the lowest in the watershed. Just after sampling Monday morning, water levels began to increase as another storm passed through the Mad River Valley. E. coli sampling results are intended to give you a sense of the conditions that lead to high pathogen levels in the water so you can be informed. You are your best protector - use common sense and don't swim after a rain!

E. coli is a type of coliform bacteria and is used as an indicator of pollution from human or animal waste and the potential presence of disease causing organisms. It is estimated that at the level of 235 colonies E.coli per 100 mL water, approximately 8 out of every 1,000 swimmers are likely to contract a water borne illness related to fecal contamination.

Many thanks to this week’s Mad River Watch volunteers: Dave Gould, Mike Ware, Fran & Gary Plewak, Susy Deane, and Chase Fortier. Also, a big thanks to Cyndee Button, our volunteer Lab Coordinator, to Sally Boudreau for posting MRW data at swimholes, and to Kinny Perot who drove water samples to the Burlington lab for phosphorus and turbidity analysis. This is a true team effort!  

To view our most recent complete data report, click here.

For more information about E. coli and the Mad River Watch program, click here.

A map of the 36 sites sampled and most recent results is here.

Results are also available on Facebook (“Friends of the Mad River”) and on sign posts at swimholes across the Valley.

Friends is a membership organization, and depends on the generous contributions of members to continue the Mad River Watch and other programs; learn how to become a member and donate securely online at our website.