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Nashua;53.0;http://forecast.weather.gov/images/wtf/small/nsct.png;2014-10-25 22:44:18
Sunday, August 31, 2014

Souhegan and Merrimack rivers test well on bacteria except for a few locations

The Merrimack and Souhegan rivers showed a predictable pattern when tested Tuesday morning by the Souhegan Watershed Association’s long-standing volunteer monitoring program.

The good news is that the Merrimack River showed acceptable E. coli levels all the way from Manchester to Tyngsborough, Mass. This has been the pattern for several years as the river has been cleaned up. ...

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The Merrimack and Souhegan rivers showed a predictable pattern when tested Tuesday morning by the Souhegan Watershed Association’s long-standing volunteer monitoring program.

The good news is that the Merrimack River showed acceptable E. coli levels all the way from Manchester to Tyngsborough, Mass. This has been the pattern for several years as the river has been cleaned up.

Occasionally, after heavy rainstorms that overwhelm the cities’ sewage treatment plants, E. coli rises to an unhealthy level, but the Merrimack normally would test better than many public beaches.

The Souhegan River is much smaller, and its E. coli levels are much higher than the Merrimack.

The river begins in Ashburnham, Mass., and crosses the border north into New Ipswich, Greenville and Wilton.

Here, the E. coli level is in the range of 100 colonies per 100 milliliters of water.

The river passes into Milford and Amherst, where it slows down and meanders back and forth through sandy soils.

Here, the E. coli level is in the 200 range.

When the river passes into Merrimack, the soil and gradient change, and the E. coli level drops to an acceptable level.

This is exactly how the Souhegan River tested this week.

There are several swimming holes on the Souhegan, and these, too, tend to follow a pattern.

The Horseshoe in Wilton, and Indian Ledges, Turkey Hill Bridge and Watson Park in Merrimack usually test OK – as they did last week.

The Boston Post Road
Canoeport in Amherst usually tests high, and it did again this week. The level here was 307.

Levels of E. coli higher than 88 are not acceptable for public swimming beaches in New Hampshire.

Levels between 88 and 126 may be suitable for swimming, but some people may
experience gastrointestinal problems, rashes, or swimmer’s ear and eye.

Levels higher than 400 are dangerous and should be avoided.

The program collects from 21 sites along the Souhegan River and 11 on the Merrimack River every two weeks during the summer.

Labs at the wastewater treatment plants in Nashua, Milford, Merrimack and Manchester perform the tests.

All of of the results can be found at nashua
telegraph.com/special
reports/rivertestresults
.

The next test will be done Sept. 9.

Volunteers to help with the monitoring are always welcome, and can email swawatertesting@gmail.com for more information.