APPLICATION OF LONG-TERM BIOLOGICAL MONITORING DATA IN MANAGING WATER QUALITY OF MAINE'S STREAMS AND RIVERS

The Maine Department of Environmental Protection (MDEP) is responsible for managing the water quality of the State's stream and rivers. MDEP has accumulated 35 years of data on benthic macroinvertebrate communities from across the state. Macroinvertebrates are animals without backbones that can be seen without magnification, such as crayfish, snails, mayflies, stoneflies, and caddisflies. Over the years, MDEP has used the data to identify waterbodies that did not attain water quality goals, develop restoration plans, and document the recovery of waterbodies. MDEP has also used the data to adjust pollution discharge limits, flow requirements downstream of dams, and other permits. Long-term data have been used to propose upgrades in class for waterbodies that exceed water quality goals. The accumulation of hundreds of samples led to the development of a statistical model that predicts attainment of class AA/A, B, or C water quality goals based on macroinvertebrate community composition. More recently, MDEP has used the large data set to build statistical models to infer water quality parameters, such as total phosphorus, based on the composition of biological communities. The inference models will be useful for determining likely causes responsible for impairing streams and rivers and documenting incremental improvements in water quality.