NEWS NOTES ON SUSTAINABLE WATER RESOURCES  Mapping Algal Blooms ; Satellite Imagery Used to Measure Algal Bloom Frequency—Steps Toward Understanding Exposure Risk  Our Nation's lakes and reservoirs provide drinking water, habitat for wildlife, and recreational opportunities. Harmful algal blooms (HABs) can result in the loss of recreational opportunities and income, loss of aquatic habitat and important fisheries, and present health risks associated with exposure to the toxins these blooms can produce. One of the most common forms of HABs in inland lakes and reservoirs, cyanobacteria harmful algal blooms (CyanoHABs), can produce toxins that pose a range of health risks to humans, pets, livestock, and wildlife.  Although toxins cannot be directly measured from space, the pigments associated with algal blooms can be measured using remotely sensed data from satellites. Previous research indicates strategies to link toxin concentrations with pigments sensed remotely. There are questions as to the efficacy of the currently (2017) available remotely sensed data to identify algal blooms in small waterbodies used for recreation and drinking water, and the ability to use the data to understand trends in CyanoHABs over time.  Scientists developed an approach to assess the frequency of CyanoHABs over time at two test regions. This research was part of the Cyanobacteria Assessment Network (CyAN), which is a multiagency project among the National Aeronautics and Space Administration (NASA), National Oceanic and Atmospheric Administration (NOAA), U.S. Geological Survey (USGS), and the U.S. Environmental Protection Agency (EPA) to develop an early warning indicator system using historical and current satellite data to detect algal blooms in U.S. freshwater systems.  This study provides consistent and transferrable methods to characterize CyanoHAB frequency using remotely sensed data. The utility and limitations of the currently available satellite data for understanding CyanoHAB frequency is highlighted, including the importance of satellite resolution and sensing capability for measuring CyanoHABs on small inland lakes. This information can help identify and prioritize the resolution, observation frequency, and sensing capabilities needed for future imagers that are better equipped for algal bloom detection.  This study will also be linked on the 2017 Reports Page 02 of the Sustainable Water Resources Site at "> ; Tim SmithSustainable Water Resources CoordinatorGovernment Web Site, Water Resources Site, "> ;