Rain Elevates E. coli Levels in Souhegan, Merrimack Rivers

New information released by the Souhegan Watershed Association shows unacceptable levels of E. coli in both the Souhegan and Merrimack Rivers.

According to the report, 21 spots along the Souhegan and 11 along the Merrimack were tested by volunteers.

According to officials, anything higher than 88 is “are unsatisfactory for public swimming areas in NH.” Swimming holes with levels between 88 and 126 are “satisfactory for most people,” while levels 126 or higher, “should be avoided,” according to the association.

The levels showed a wide range of results.

“Almost all the sites tested along the Souhegan had levels above 126, but the levels were not as high as expected after the heavy rains,” noted George May, the water monitoring coordinator. “And if the weather cooperates and doesn’t rain for a few days, the levels should return to more acceptable levels.”

Unacceptable levels were found in New Ipswich, Greenville, Wilton, Milford, Amherst, and Merrimack; Water Loom Pond in New Ipswich and Indian Ledges in Merrimack were found to be OK.

Along the Merrimack, levels came in “all over the place,” with unacceptable levels at every test site between the pond above the Amoskeag Bridge in Manchester and to the Tyngsborough Bridge in Massachusetts.

Levels in Nashua at the Greeley Park boat ramp tested at 613. At the Taylors Falls Bridge, the levels soared to 1,046. Levels were back down to 44 in Tyngsborough.

Unacceptable levels were also found in Merrimack and Hudson. A test in Litchfield was below normal.

The flow rate on the Merrimack, May noted, was four times higher than normal, which is why the numbers showed disparity.

There was, however, some good news in the testing.

Dissolved oxygen level counts on both rivers increased and the higher levels are better for the plants, fish, and animals that live in and around the river, May stated.

Another test will be performed on Aug. 12. The results will be available the next day, on the association’s website.