Water Quality Testing Results
Heavy metal testing, macroinvertibrate testing, and DNA testing has also been done on occasion in the past
This monitoring program is conducted by trained volunteers who believe in cleaner rivers. Financial support for the program comes from your memberships and donations. If you would like to help continue this monitoring effort, please consider joining or donating to the SWA.
E-Coli Bacteria Counts
Dissolved Oxygen Measurements
Dissolved oxygen is "breathed" by fish and insects that live in the water. Besides occuring naturally (H2O), turbulence over rocks and rainstorms increases DO levels. Interestingly, rainstorms that can increase E.coli levels, which is bad for humans, increases DO levels, which is good for fish. Dissolved Oxygen requirements for different species vary greatly, even if only fish are considered. One of the more sensitive family groups is trout. The lower limit for them is about 5 mg/L (or 5 ppm). We never expect to see levels this low in either the Souhegan or Merrimack. The simplified conclusion is that adequate oxygen levels indicate a healthy, balanced river habitat.