Cowanesque River at Lawrence, PA (COWN 2.2)

Group 1

• Water Quality: Total aluminum and total manganese failed to meet water quality standards.
• Macroinvertebrate IBI Score: Moderately Impaired
• Habitat Assessment: Supporting
• Discussion: Although aluminum and manganese concentrations exceeded acceptable limits, WQI values decreased in 2009, indicating a possible improvement in water quality. Physical habitat was rated supporting. The extremely altered stream channel lacks unaltered riparian areas and contains primarily closely cropped vegetation. The macroinvertebrate IBI score at COWN 2.2 was the worst among all interstate river sites, receiving a moderately impaired rating for the fifth straight year.
• Other Notes: This sampling site is located directly downstream of the Cowanesque Reservoir. In 2007 and 2008, COWN 2.2 possessed the worst bioassessment score and the worst macroinvertebrate metric scores of all Pennsylvania-New York Interstate streams. Concerns with habitat at COWN 2.2 include epifaunal substrate, channel alteration, and frequency of riffles.