Sampling results from the fourth round of Friends of the Mad River’s Mad River Watch water quality monitoring show one site with unfavorable E. coli levels as of Tuesday morning, July 25, and one other close to the threshold. This week, we switched sampling from our regular Monday schedule to Tuesday to try and capture data during a higher river flow than previously captured this summer. After many beautiful days of sun over the week and weekend, a day of steady but not heavy rain began early Monday morning. The river topped out at 439 cubic feet per second (cfs) at the US Geological Service flow gage in Moretown on Monday, July 24, around 8:45 pm.
The flow condition of the Mad River at the time of sampling Tuesday morning was High and Declining (HD), measuring approximately 268 cfs. The mean flow for this date in the last 89 years is 116 cfs.
One site showed unfavorable swimming conditions as of Tuesday morning. Ward Access in Moretown results showed 365 colonies of E. coli per 100 ML of water, well over the DOH/EPA accepted “swimmable” E. coli level of 235 colonies/100ML while another site was close. Moretown Village Swim Access showed 225 colonies/100ML. Elevated E. coli levels in Moretown are not surprising as there had been a full day of rain to carry pollutants off the land and into the streams, but because the rain had stopped before sampling, most runoff had left the headwater region. Remember that rains can cause E. coli levels to fluctuate, even on a daily basis, as water carrying pathogens moves down the watershed. When weather across the watershed varies from hill to hollow, swimming safety varies too! FMR’s E. coli sampling results are only a snapshot in time 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 for several days after a rain. 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 samplers: Charlie Baldwin, Richard Czaplinski, Susy Deane, Hazel Macmillan, Kinny Perot, Fran & Gary Plewak, and Eloise Reid. Thanks to Susanne and George Schaefer who drove water samples to the DEC’s lab in Burlington for phosphorus, nitrogen, and turbidity analysis and to Sally Boudreau for posting data at swimholes across the watershed. The Mad River Watch Program would not be possible without these dedicated volunteers! Our Lab Coordinator, Paula Baldwin, did the labwork.
The river connects our Mad River Valley community and its clean water is a measure of our success as stewards of the land. For more information about E. coli and the Mad River Watch program and to view our most recent complete data report please click here. Results are also available on Facebook (“Friends of the Mad River”) and on sign posts at swimholes across the Valley. Friends is a community-supported organization, and depends on the generous contributions of its members to continue the Mad River Watch and other important programs; learn how to become a member and donate securely here.