Merrimack watershed bacteria results: August 20, 2019

Dear River and Watershed Friends,

Upper Merrimack Monitoring Program volunteers continue the bacteria sampling season with 100% sampling at 100% of the eleven sites on the Merrimack River from Franklin to Bow and on the Pemigewasset, Winnipesaukee, and Contoocook Rivers. 

The results shown below are the probable number of E. coli bacteria colonies for every 100 millilitres of water. Warm blooded animals (including humans) all have E. coli in their guts. State designated swim beaches are not allowed to exceed 88 colonies and Class B waters (all of our sites are Class B waters) should be below 406 colonies. Here are the details.

Site number and description
1 Pemigewasset63
2 Winnipesaukee62
3 Merrimack above FWWT Plant10
4 Merrimack below FWWT Plant30
5 Merrimack Jamie Welch Park41
6 Merrimack Route 4 Bypass52
7 Contoocook at Rivco30
8 Merrimack Sewalls Falls20
9 Merrimack Manchester St10
10 Merrimack Blue Seal20
11 Merrimack Garvins Falls20

All sample results are as of Tuesday morning, August 20, 2019. Results may change from day-to-day, depending on upstream conditions and rainstorms.

This week, we have very good results. All sites meet the Class B designation for the Merrimack River. They all fall well within the more stringent designated swim beach standards, as well. The watershed had another rinse over the weekend and then a quick dry in the early part of the week. These low bacteria counts are expected after those weather events. The upper Merrimack watershed is relatively clean and healthy. We often say, “When it rains, it’s poor.” You may wish to wait a day or so after it rains before recreating in a surface water. 

You’ll hear from us again after the last sampling day of the season on September 3. 

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Michele L Tremblay                          Stephen C Landry
Program Manager                             Sampling Supervisor