| Summary: | The Jack River, located along the Nelson River system in north-central Manitoba, Canada, is the drinking water source for the Norway House Cree Nation (NHCN). The Jack River lies downstream of the 2-Mile Channel which was built by Manitoba Hydro to increase the outflow capacity of Lake Winnipeg. The erosion of the 2-Mile Channel and the subsequent sedimentation downstream has been an on-going environmental concern for NHCN. This study characterizes the source water quality in NHCN with respect to sediments and turbidity, and uses a sediment fingerprinting technique to investigate the sources of sediment at the Jack River drinking water intake. The historic data show that turbidity has been gradually increasing over time (p<0.05) and is weakly positively correlated with the previous-day mean wind (p<0.05) and the previous 10-day accumulated precipitation (p<0.05). The gradual increase of turbidity over time indicates that environmental factors in the Lake Winnipeg Basin including precipitation, land use changes, and multi-decadal climate oscillations are the major influencing factors. To determine the origins of sediments at the Jack River intake, sediment fingerprinting was used and identified four discriminable source areas using three sediment colour properties. Modelling results using MixSIAR showed that 79.3 % (SD 31.2 %) of sediment was reflective of upstream sources while 9.3 % (SD 18.8 %) was reflective of the 2-Mile Channel erosion. These results show that NHCN drinking water was not significantly impacted by the 2-Mile Channel erosion throughout the summer of 2014 and the spring of 2015. October 2017
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