Alaska has more than 800,000 miles of rivers and streams, an estimated 100,000 glaciers, and permafrost throughout the Arctic and Subarctic. River quantity and quality measurements are essential for wise and safe development and use of Alaska rivers. The Alaska Science Center monitors streamflow at 111 stations across Alaska. Water temperature data is collected at 64 of those sites and 10 locations are monitored continuously for water quality.

Water quality is of particular interest on the Salmon, Unuk, Stikine, Taku, and Alsek Rivers, which originate in Canada and flow into Southeast Alaska. All five rivers support traditional, recreational, and commercial salmon fisheries. Active and proposed largescale mining activity in the Canadian parts of these watersheds poses a potential threat to the fisheries and traditional lifestyles in Alaska. The Alaska Science Center is assessing the geology and mineralization potential of these watersheds and collecting new data to characterize the water, sediment, and biological quality of the rivers. We are actively engaged with Tribes and government agencies to ensure that assessments meet their needs and to share information and resources for more comprehensive assessments.

Our methods include updated geologic mapping and sample reanalysis, biological sampling, and discrete water quality sampling. Streamflow and water-quality data collected hourly at monitoring sites will be paired with periodically collected water quality samples that are analyzed for concentrations of metals, nutrients, and major ions. In combination, these datasets will allow analysts to quantify loads of important water-quality constituents at daily, monthly, and annual time-steps. These data will serve as the basis for identifying potential changes in water-quality conditions resulting from future upstream mining activities.