The hydrological characteristics of a stream within an integrated framework of lake–stream connectivity in the Lac de Gras Watershed, Northwest Territories, Canada

Lake–stream networks dominate much of northern Canada. This study explores the hydrological characteristics of an outlet stream from a headwater lake in the Northwest Territories of Canada. Flow hydrographs indicated that stream flow was maximal in most of the cross sections during the first week of July, and subsequently declined to zero by the first week of August 2009 and last week of August 2010. Water balance analysis indicated that the lake can be recharged by runoff from the catchment, but summer evaporation, combined with groundwater loss, caused draw down of lake level below the outflow threshold. Summer rainfall in this semi-arid environment was insufficient to overcome storage deficits to re-establish flow connectivity between lakes. The suitability of the stream sections were assessed for small and large young-of-the-year Arctic grayling based on stream geometry, stream flow characteristics, stream water temperature, and stream water quality.