A water quality assessment of Lake Manitoba, a large shallow lake in central Canada

Abstract

Water quality of Lake Manitoba is poorly understood in comparison to other large lakes and a study was undertaken to characterize the spatial and temporal variation in water quality. To characterize the lake wide water quality conditions, samples were collected from 15 stations over a 2 year period. Geospatial mapping and principal components analysis revealed that the south basin of the lake was more turbid, nutrient rich, and more dilute in comparison to the north basin. Water samples collected daily during the operation of the Assiniboine River Diversion in 2005 and 2006 indicated that the Assiniboine River Diversion was the single largest source of phosphorus and sediment and was the second largest source of nitrogen to the lake. A non-parametric trend analysis of a 17 year historical water quality dataset from a station in the south basin indicated that Lake Manitoba has become more dilute and nutrient rich over time.