Waterbodies that are assessed as impaired for Recreation Use or Aquatic Life Use in the 2014 Connecticut Integrated Water Quality Report:
- Crandall Pond in Tolland (in the Skungamaug River sub-watershed) is impaired for recreation use due to excess indicator fecal bacteria (E. coli).
- The main stem of the Willimantic River has one segment that is impaired for recreation use due to excess indicator fecal bacteria (E. coli) and one segment that is impaired for aquatic life use:
- For aquatic life: 1.65 miles from the confluence with Bonemill Brook in Tolland upstream to the Stafford POTW
- For recreation: 0.4 miles from Stafford POTW upstream to headwaters at confluence of Middle River and Furnace Brook, Stafford Springs.
- Tributaries that are impaired for Recreation due to excess indicator fecal bacteria (E. coli):
- Upper Hop River (3.22 miles) from confluence with Skungamaug River in Andover to Route 6 crossing in Bolton.
- Upper Skungamaug River (6.29 miles) from inlet to Summer Lake in Tolland upstream to headwaters.
- Lower Ten Mile River (8.62 miles) from confluence with Willimantic River in Columbia upstream to Stiles Pond in Lebanon
- Upper Cedar Swamp Brook (0.61 miles) in Mansfield from confluence with Nelson Brook upstream to Route 44 crossing
- Upper Eagleville Brook (1.67 miles) in Mansfield from confluence with Kings Brook to Stadium Road
- Lower Middle River (5.15 miles) from confluence with Furnace Brook in Stafford upstream to Orcutt Pond
- Furnace Brook from confluence with Middle River in Stafford upstream to Staffordville Pond
- Tributaries that are impaired for Aquatic Life:
- Ruby Lake outlet stream (0.12 miles) in Willington due to accidental spill of diesel fuel at truck stop on I-84
- Upper Eagleville Brook (1.67 miles) in Mansfield from confluence with Kings Brook to Stadium Road due to streambank modification and stormwater runoff from developed areas upstream.
Impaired waterbodies can be remediated through either a water pollution analysis known as Total Maximum Daily Load (TMDL) and/or a watershed plan to address the causes of the water quality problem(s). Eagleville Brook has an approved TMDL and a watershed plan with several implementation projects completed or in planning mode. The Town of Tolland has developed a watershed plan for Crandall Pond to address potential sources of bacteria and other pollutants. Check the attached appendices to the Connecticut Statewide Bacteria TMDL for these Willimantic River tributaries: Middle River, Furnace Brook, Skungmaug River, Cedar Swamp Brook and Ten Mile River that include bacteria analyses and management measures. The other listed impaired areas (except Ruby Lake Outlet) are priorities for implementing the statewide TMDL, which might be most effectively addressed in a watershed-wide approach.