Southeast Alaska I&M Network water quality monitoring program: 2020 annual update

Goodwin, Deborah; Amundson, Courtney; Ziomek, Thomas

Water quality is an indicator of aquatic and terrestrial ecosystem health and one of the priority Vital Signs for the National Park Service’s Southeast Alaska Network (SEAN), which includes Glacier Bay National Park and Preserve, Klondike Gold Rush National Historical Park, and Sitka National Historical Park. Data collected under this program inform several management-relevant topics: • Monitoring the frequency and magnitude of low dissolved oxygen events (hypoxia) in the Indian River in Sitka • Measuring the natural quality of wilderness lands in Glacier Bay • Describing effects of a changing climate on the physical and chemical properties of park waters • Assessing whether state and federal water quality standards are met This 11th annual update provides a concise data summary for park staff, managers, superintendents, and other interested parties. All water quality data products and past reports, as well as the associated peer-reviewed protocol, are publicly available through the SEAN website (https://www.nps.gov/im/sean/index.htm) and the NPS Data Store (https://irma.nps.gov/DataStore/Reference/Profile/2182282). In 2020, hourly water temperature, specific conductance, dissolved oxygen, and pH data were collected in the Salmon River (Glacier Bay) from April 29 through November 4, and in the Indian River (Sitka) from May 24 through November 25. The same parameters plus turbidity were collected in the Taiya River (Klondike Gold Rush) from May 31 through November 4. No observations signaled a change to the fundamental water quality patterns of the three rivers. Daily mean temperature for the Salmon River ranged from 1.5 to 11.5°C (peaking on August 3), while the Indian River ranged from 4.0 to 9.3°C (peaking on October 2). Daily mean temperature for the glacially influenced Taiya River ranged from -0.1 to 7.0°C (peaking on September 9). Taiya River hourly turbidity measurements ranged from 4.1 to 345.2 NTU with few high flow events. Patterns in the ranges and distributions of specific conductance, dissolved oxygen, and pH were generally similar to those previously observed for all three rivers. The critically low dissolved oxygen levels in the Indian River observed during summer 2013 have not been recorded in subsequent years.

Southeast Alaska I&M Network water quality monitoring program: 2020 annual update

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