Mad River Watch volunteers collected water samples throughout the watershed on Monday morning July 26th. Results show there were favorable swimming conditions at some locations, while at others E.coli levels were above the state water quality standard. 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. Eight of thirty-six sites tested were found to be in violation of the standard at the time of sampling. Sites in violation of water quality standards were located in Warren, Waitsfield and Moretown and included: Warren Village, Couples Club, Waitsfield Covered Bridge, Meadow Road bridge, Moretown Village Swim Access, and Ward’s swimhole.
Heavy rains brought the river up to approximately 3,000 cubic feet per second (cfs) on Wednesday July 21st, and some scattered rain also fell on Sunday. At the time of sampling on Monday morning, the volume of water flowing in the Mad River (as measured at the USGS gage in Moretown) had declined to approximately 170 cfs. This level is higher than the median flow for this date (according to 80+ years of data; about 60 cfs), thus the flow in the river was high and declining at the time of sampling. Swimmers are more likely to encounter safer conditions in declining and low flows since pollutants are not being actively washed into the river by rain; rain that turns the Mad River brown also brings E.coli levels up and increases the risk to swimmers of contracting a water borne disease.
Since the heavy rain fell on July 21st, the Mad River has appeared especially cloudy; the river did not return to it’s usual clear appearance even after the high water subsided as typically happens. Upon investigation, it was discovered that several natural clay deposits along Stetson and Lincoln Brooks in Warren were heavily eroded during the storm. This problem may have been exacerbated due to several plugged and failed culverts along Stetson Hollow road. The river may continue to appear cloudy until the erosion of natural clay deposits subsides.
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. Many thanks to lab coordinator Cyndee Button and to this week’s Mad River Watch volunteers: Elizabeth Walker, Michael Ware, Kate Sudhoff, Fran & Gary Plewak, Patti Greene-Swift and Susy Deane.