E. coli readings from the fourth water sampling session of the summer by Souhegan Watershed Association volunteers saw normal to high e-coli readings in the Souhegan River because of the hot weather and thunderstorms two days prior to the sampling.

The Souhegan River through Milford continued a same pattern seen so far this season, with high bacteria levels from the Souhegan Valley Boys & Girls Club through Amherst Country Club. The association plans to see if anything has changed in town that might be contributing to the high numbers.

The Merrimack River, as is virtually always the case, had safe levels of the bacteria.

Dissolved oxygen, a good measure of river health, is also tested, and all readings were within normal ranges.

You could mention in the article how one major reason we share these results is to inform the swimmers of the popular swimming holes on the river how healthy the water quality is. An example is for years Boston Post Road site always had high e-coli readings and field research was performed by students at the Nashua Community College but the cause was never determined and it always remained a mystery.

Volunteers have been doing these tests for 15 years, but changing circumstances sometimes change the testing. For example, one site just west of the freeway in Merrimack will no longer be tested because the removal of the Merrimack Village Dam has increased water flow at the location to the point that it is no longer a good place to determine how much bacteria exists in the water.

For a updated online map showing test results over the past two years, as well as similar tests on the Nashua River, go to the Web site www.nashuatelegraph.com/specialreportsrivertestresults/.