Letter to the editor: E. coli results put into context

It has come to my attention that I might need to correct a misperception that stemmed from my statements last week (and reported in this paper) about E. coli in our rivers.

On Aug. 8, River Watch volunteers collected water samples that were subsequently tested for E. coli. The samples were taken at several sites, including Bartlett’s Falls in Bristol and the Middlebury River Gorge in East Middlebury. Similar samples were also taken at some tributaries to the upper New Haven River, one of which has no roads or development in its watershed.

When the E. coli results came in the next day, we saw an extraordinary spike in E. coli at all sites tested. This was practically unprecedented. The Bartlett’s Falls site and the Middlebury Gorge sites almost never exceed the state standard for E. coli and the upper New Haven River sites have similarly shown very low levels of E. coli almost every time we sample.

I looked into what may have caused this anomaly and saw that, judging by the U.S. Geological Service flow gage on the New Haven River and local rain data, it appeared that our monitoring teams had sampled during the two or so hours when rain runoff was entering our rivers after several days of no or little rain. We have noticed before that, in late summer if there is a dry period followed by rain, that E. coli levels rise. What was extraordinary about this sampling event was that our timing appeared to catch that first pulse of overland runoff around the period when it was rushing through the streams.

That is why I tried to re-assure Addy Indy readers (in an article that Marin Howell wrote last week) that, for the most part, Bartlett’s Falls and the gorge in East Middlebury have for decades have shown low (and therefore compliant with the water quality standard) levels of E. coli.

A reader mentioned to me, however, that the message received by some people was that I was saying that water quality in our rivers is fine and that there is nothing to be concerned about. This is not true. 

Addison County River Watch Collaborative volunteers monitor seven rivers (Leicester, Lemon Fair, Little Otter, Barnes Brook, Middlebury, New Haven, Dead Creek) and they ALL have problems. Indeed, some of the OTHER recreation sites that we do or have monitored for E. coli often exceed the state water quality standards. That IS a problem, and we have brought that to the attention of state officials.

E. coli is only one of the several pollutants that we measure. Phosphorus tends to be the one of most concern because it is mandated by the EPA and the state to reduce its loading into Lake Champlain. Most of our rivers do not meet the water quality standard for phosphorus, and we are working hard with landowners to reduce the flow of that pollutant into our waters. Barnes Brook in Middlebury has very high levels of salt (measured as chloride), and this is also of great concern.

Although our local rivers have some fine fishing and wonderful swimming holes, there are indeed problems that we as a community need to pull together to solve. Recent flood events underline the need to manage stormwater runoff and to plant trees in riparian areas and engineer ways for rivers to have access to their floodplains (where possible), which in turn enables high-flow events to become less damaging.

Matthew Witten

Director, Addison County River Watch Collaborative

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