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go to table of results from 7.12.10
The third round of water samples
taken by Friends of the Mad River volunteers on Monday morning July 12th show
generally favorable swimming conditions with eight of thirty-six sites (22%)
tested in violation of Vermont’s water quality standards. The eight sites that
were in violation of water quality standards were: Couple Club, Meadow Road
bridge, North Road in Moretown, Moretown Village swim access, Ward Clapboard
Mill, Welder Brook, Ward swimhole and Lover’s Lane Bridge. The state water quality standard for
recreational waters measures E. coli bacteria, an indicator of pollution from human or animal
waste and the potential presence of disease causing organisms.
E.coli levels throughout the watershed
were much higher on the June 28th sampling date due to a rain event
that washed pollution into the stream.
While a rainstorm two days before sampling on July 12th did
bring the river level up significantly, both the river flow and E.coli level had declined by sampling
time. Increasingly favorable
swimming conditions developed as water levels in the river declined: after peaking at approximately 1,000
cubic feet per second (cfs) on Saturday morning, the volume of water flowing in
the Mad River fell to approximately 160 cfs at the time of sampling on Monday
morning. This is higher than the
median flow for this date (~70 cfs).
Swimmers are more likely to
encounter safe swimming conditions in declining flow since pollutants are not
actively being washed into the river by rain; Mad River Watch historical data
shows that typically when river flow declines, E.coli levels begin to decline as
well. Conversely, rising water
levels mean rising E.coli levels, so be aware that when a rainstorm that turns the
Mad River’s waters brown with sediment there is also likely a rising risk to
swimmers.
For more information about E.
coli and the Mad
River Watch program, or to report a river-related illness call Friends of the
Mad Rive at 496-9127. Thanks to
this week’s Mad River Watch volunteers: Elizabeth Walker, Michael Ware, Kate
Sudhoff, Fran & Gary Plewak, Patti Greene Swift and Susy Deane.
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