The effects of ramping and flow rates at Steephill Falls hydroelectric dam on the macroinvertebrate community, the Magpie River, Wawa, Ontario

Benthic and drift studies were conducted in the spring of 2001, summer of 2001, and spring of 2002 to determine the effects of ramping and flow rates at the Brascan Corp. Steephill Falls hydroelectric dam on the macroinvertebrate community in the Magpie River. Macroinvertebrate abundance and diversity did not significantly differ from low to high ramping or flow rates. A canonical correspondence analysis showed seasonal differences, not flow and ramping rates, as the major explanatory variable for variability in macroinvertebrate community in the Magpie River.; Macroinvertebrate abundance and diversity were significantly lower at sites closest to the dam probably due to the low macroinvertebrate abundance and diversity in a plunge pool immediately downstream of the dam. Benthic non-drifting invertebrates were an insignificant proportion of the drift in the Magpie River. Summer on Magpie River had higher abundance and diversity than Batchawana River from the implementation of base flow conditions, thus avoiding summer drought conditions. The study provides us with a greater understanding of ramping rates and their effects on aquatic biota and allows us to establish better protocols for ramping rate assessment and reviews of hydroelectric plants' lease agreements.