Alexis Robinson

High Arctic watersheds fluxes of water, sediment, and nutrients are traditionally dominated by snowmelt. Projected climate changes are anticipated to impact winter snowpack and melt season conditions, which in turn will affect water quality and quantity. The water within these watersheds is both a key source of freshwater for northern communities, and an important resource for local ecosystems. Understanding the current watershed dynamics and potential future trajectories is crucial to protecting source water. The goal of this study was to model current and predicted streamflow of an ungauged High Arctic watershed, using remotely sensed data as inputs for the Cold Regions Hydrological Model. Three study areas around Pond Inlet (Mittimatalik), NU were selected to model streamflow: the Salmon River watershed, Pond Inlet’s current reservoir watershed and the proposed reservoir watershed. Remote sensing data were used to derive both the meteorological data and topographic indices required for the model. Using current climatic conditions the Cold Regions Hydrologic Model predicted an initial streamflow peak during May and June for the current reservoir watershed and the Salmon River watershed. Additionally, all study areas experienced a significant streamflow peak in August 2014. The projected climate scenarios used were the Representative Concentration (RCP) 2.6, 4.5 and 8.5 scenarios developed by the International Panel on Climate Change. The model predicted that streamflow for RCP 2.6 would increase between 6-9%; for RCP 4.5 the increase would be between 10-12%; and RCP 8.5 would have an increase between 18-22%. RCP 2.6 had a peak streamflow between the years 2027 to 2037 for each of the study areas. After 2037 streamflow began to decrease illustrating the mitigating actions proposed in RCP 2.6; whereas, RCP 8.5 predicted an increasing streamflow until 2100 for each of the study areas. This scenario has no mitigation strategies occurring until after 2100. The results of this research provide a framework for Pond Inlet (Mittimatalik), Nunavut to predict changes in source water supply for multiple potential drinking water reservoirs. The results of this study will ultimately inform the development of strategic source water protection and management plans for Pond Inlet (Mittimatalik), NU and other small High Arctic communities.

Keywords: High Arctic watershed, remote sensing, hydrological modeling, climate change, Cold Regions Hydrological Model