| dc.description.abstract | Several mine-influenced lakes have become meromictic in Northwestern Ontario,
a state in which complete turnover of the water column does not occur. Whether or not a
lake experiences complete turnover has a significant impact on dissolved oxygen,
nutrient cycling, available fish habitat and the production of potentially toxic compounds.
Lower Unnamed Lake is the stormwater receiving body for Barrick Gold’s Hemlo Gold
mine. The mine-influenced water discharged into Lower Unnamed Lake is laden with a
high concentration of total dissolved solids. Rather than freely mixing with the lake water,
the mine influenced water sank to the bottom of the lake as a result of the density
difference between the discharge and the lake water in the receiving body. It was of
concern that stratification, induced by the density gradient, caused by the concentration
of total dissolved solids had stabilized the lake and prevented turnover, causing Lower
Unnamed Lake to become meromictic. This study used CE-QUAL W2 to create a
hydrodynamic and water quality model of Lower Unnamed Lake, in order to evaluate
mixing trends. Full turnover was predicted in the fall and two additional mixing events
were produced by the model. The mixing events are evident in field observations of the
lake outflow total dissolved solids, temperature and in-lake profiles of temperature, total
dissolved solids and dissolved oxygen. [...] | en_US |
