Water Quality of Terminal Lakes Across the Great Basin of the Western United States, 2023 – 2026

The Great Basin of the Western United States hosts dozens of terminal lake systems that provide critical, abundant, and diverse ecosystems that support migratory bird species, local wildlife, and nearby communities. Water quality varies across terminal lakes in the region depending on basin geology, anthropogenic water use, climate, hydrology, and water quantity. Seasonal and long-term changes in terminal lake hydrology cause fluctuations in water quality, which can shift distributions of habitat types and alter productivity of aquatic environments in ways that affect the suitability of habitat for birds. To better understand spatial and temporal variations in water quality across Great Basin terminal lake systems, water quality samples and in-situ measurements were collected and analyzed from 14 sub-basins across multiple years and seasons. In-situ water quality measurements were collected using water quality sondes from more than 500 sites to measure barometric pressure, specific conductance, pH, water temperature, dissolved oxygen concentration, water depth, and turbidity. At a subset of these sites, water samples were collected and analyzed for specific conductance, density, total dissolved solids as residue on evaporation, sodium, potassium, calcium, magnesium, chloride, bromide, sulfate, alkalinity, tritium (3H), isotopes of hydrogen and oxygen (δ2H, δ18O), radon-222, and strontium (87Sr/86Sr) isotopes. Goals of water quality monitoring were to provide information about current conditions, elucidate terminal lake hydrological processes, identify water quality factors that influence habitat quality, and inform resource management. This data release will be updated as additional data are collected.