Bioassessment of STREAMS in the NEW RIVER watershed of eastern Tennessee impacted by surface MINING of coal—a multidecade EVALUATION

Surface mining of coal has been practiced in the New River watershed of East Tennessee since the 1940’s, and its effects on streams was previously studied from 1976-1984.  We collected water quality and macroinvertebrate samples in 2008 to reassess previously studied streams.  Macroinivertebrates were collected with kick nets in accordance with contemporary state of Tennessee bioassessment protocols, and, concurrently, with surber samplers in accordance with the methods used in the 1976-1984 studies.  Habitat assessment and abiotic factors including water temperature, dissolved oxygen, pH, total dissolved solids, and alkalinity were also measured.  Habitat assessment scores of the streams ranged from “not impaired” to”moderately impaired” and there was wide variation in the physical and chemical conditions of the streams.  However, bioassessment classified all streams as “slightly impaired”. The “slightly impaired” classification of reference streams and the failure to discriminate greater levels of impairment among streams differing in extent and time since mining disturbance may reflect the effects of collecting macroinvertebrates in the midst of a severe two-year drought.  Individual surber samples showed the streams varied from “not impaired” ‘to slightly impaired”.  The average taxa richness and multimetric scores of individual surber samples was slightly lower than kick net samples.