Three-Year Study of Thermal Discharge Effects on the Local Benthic Infauna Community in the Vicinity of a Steam-Electric Power Plant on the Connecticut River in Massachusetts

The three-year benthic invertebrate study was conducted in the vicinity of the thermal outfall of the West Springfield Generating Station located on the Connecticut River in western Massachusetts.  The study was conducted to compare the differences of the local benthic infauna communities located outside of and within the influence of the thermal plume discharged by the plant.  Local benthic infauna communities were characterized using a shallow water bottom dredge and Hester –Dendy artificial substrate plate samplers from 2005 to 2007.  Analysis of the data indicated that the benthic community is somewhat elastic.  Complexity with respect to community composition was a consequence of the effects of abiotic processes including substrate type and water quality.  As observed in the Connecticut River waters adjacent to the station during the study period, a range of benthic infauna communities were present across years; ranging from those dominated by oligochaetes, tubificid oligochaetes, and chironomid midge larvae, to those dominated by EPT taxa including sensitive species such as Ephemerella sp. and Ameletus sp. (Ephemeroptera) and Lepidostoma sp. (Trichoptera).  In most instances, the differences in community composition between the control and plume sites were attributed to variation in habitat type and not control versus plume effects.