Description
Monitoring water quality is vital for managing drinking water treatment and public health and ecosystem advisories. In particular, monitoring harmful algal blooms and water transparency are crucial for assessing health and productivity of freshwater and saltwater fisheries. Conventional in situ measurements of water quality parameters are expensive and have limited spatial and temporal coverage. Remote sensing provides a cost-effective way to assess water quality in thousands of lakes and on coastal waters.
NASA has developed the Satellite-based Tool for Rapid Evaluation of Aquatic Environments (STREAM) — an 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 data from the Landsat 8/9 Operational Land Imager (OLI) and the 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 led by NASA's Applied Remote Sensing Training Program (ARSET) introduces the STREAM web tool to visualize maps of water quality parameters over lakes and coastal areas and how to use STREAM application programming interface (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 satellite images.