An investigation of roof runoff during rain events at the Royal Military Collegeof Canada and potential discharge to Lake Ontario
David G. Kelly , Ron D. Weir , Steven D. White
DOI:
Received September 27, 2010,Revised January 24, 2011, Accepted , Available online
Volume 23,2011,Pages 1072-1078
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The Royal Military College of Canada, located on the north eastern shore of Lake Ontario, possesses an abundance of copper roofs
and lacks surface water treatment prior to discharge into Lake Ontario. Rainwater, roof runoff and soil samples were collected and
analyzed for copper and other parameters. Copper was consistently detected in runoff samples with average concentrations of 3200 2100 g/L. Multivariable linear regression analysis for a dependant copper runoff concentration yielded an adjusted R2 value of 0.611,
based on an independent variable model using minimum temperature, maximum temperature, total precipitation, and wind speed. Lake
water samples taken in the vicinity of storm water outfalls draining areas with copper roofs ranged from 2.0 to 40 g/L copper. Such
data exceed the 2.0 g/L Canadian Water Quality Guidelines for the Protection of Aquatic Life as outlined by the Canadian Council of
Ministers of the Environment (CCME). Analysis of raw, filtered and digested forms suggested that the majority of copper present in
runoff and lake water samples was in a dissolved form. The majority of soils taken in this study displayed copper concentrations below
the 63 g/g CCME residential/parkland land use limits. These findings suggested that ion exchange processes between runoff water and
soil do not occur to a sufficient extent to elevate copper levels in soil. It may therefore be concluded that the eventual fate of copper,
which is not discharged via storm water outfalls, is lost to the water table and Lake Ontario through the sub-soil.
