Great Basin Water Resources: Creating a Remote Sensing User-Interface to Support Water Resource and Wetland Management for Inland Lakes

Saline terminal lakes across the Great Basin are rapidly shrinking due to increasing water demand,
groundwater extraction, and climate change, threatening wetland ecosystems, biodiversity, regional
economies, and public health. The Oregon Department of Water Resources and the Utah Department of
Natural Resources, Division of Water Resources currently rely on field measurements and conventional GIS
analyses to track changing lake and wetland conditions. Integrating satellite-based Earth observations into
routine decision-making is limited by time constraints and the need for domain-specific expertise. To address this, we developed a user-friendly QGIS plugin that automates long-term monitoring of terminal lakes and surrounding wetlands using Google Earth Engine. The workflow utilizes Landsat 5, 7, 8, and 9 imagery (1985–2026) to generate composites, calculate the Normalized Difference Water Index, Normalized
Difference Vegetation Index, Normalized Difference Moisture Index, and Land Surface Temperature,
classifying land cover into open water, wetlands, and land. Classification thresholds were optimized against
OPERA Dynamic Surface Water Extent, JRC Global Surface Water, Google Dynamic World, and the
National Wetlands Inventory. Validation showed strong performance, with Intersection-over-Union values
reaching 0.844 and 0.870 for open water at Lake Abert and the Great Salt Lake, respectively. These
thresholds serve as reliable defaults but can be adjusted by the user through the plugin. The finalized plugin
lets users visualize historical trends, generate land cover maps, and quantify changes in lake and wetland
extent. By streamlining Earth observation analysis, the tool supports partner ecosystem management and
long-term monitoring while lowering the technical barriers associated with satellite data processing.