NASA has developed a Satellite-based Tool for Rapid Evaluation of Aquatic Environments (STREAM)—a new, interactive web tool that enables high-resolution (20–30 meter) monitoring of water quality in inland lakes and coastal waters across the U.S. and selected other countries. STREAM provides both past (since 2018) and near real-time maps of chlorophyll-a concentration, Secchi disk depth, and total suspended solids based on Landsat 8/9 Operational Land Imager (OLI) & Sentinel 2 Multispectral Instrument (MSI). Additionally, an open-source machine learning model based on a Mixture Density Network (MDN) is available to estimate water quality parameters for any inland or coastal water body worldwide (minimum size: 100m x 100m).

This two-part training introduces the STREAM web tool to visualize maps of water quality parameters over lakes and coastal areas and how to use STREAM API to discover and download satellite images and water quality data for a selected water body. The training demonstrates how to assess changes in water quality in a given lake using QGIS. The training also demonstrates the application of a MDN model to estimate water quality parameters from Landsat OLI & Sentinel-2 MSI images.