the winston lake mine operated from 1988-1999 within the whitesand river watershed located near schreiber, on. operations resulted in releases of elevated cations and anions from tailings pond discharges above cleaver lake. the lake entered a period of meromictic stagnation but has since been reported to be experiencing seasonal turnover as a product of natural remediation. the overall goal of environmental studies in the watershed is to determine the likelihood of a successful reintroduction of brook trout. suitable habitat within cleaver lake and the outflow into the whitesand river is required for this to occur. this thesis involved the whitesand river. water quality data provided by first quantum minerals was used to assess the potential effect of heavy metals, total dissolved solids (tds), dissolved oxygen (do), ph, temperature and water hardness on survivability of brook trout. comparison of pre-operational data and recent water quality records indicated the return of examined water quality and benthic invertebrate populations to conditions statistically similar to the historical habitat. rising seasonal temperatures were identified as an area of concern having potential to impact future health of cold-water fish communities in the river.