Satellite Monitoring of Algal Blooms in Idaho Water Bodies

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Harmful algal blooms (HABs) are a growing concern in Idaho. Within the past five years, Idaho agencies have issued at least 57 HAB notices on 29 water bodies throughout the state. Toxins produced by HABs pose risks to human and animal health. Local economies may also be adversely affected when algal blooms discourage outdoor recreation.

Routinely monitoring the state's many water bodies is too expensive to be practical. As a result, state agencies and health districts are often forced to respond to citizen reports to send field crews out to collect water samples. Earth observation satellites can guide more proactive field monitoring by capturing multispectral images of entire water bodies with a frequency of greater than one capture per week. These images will help agencies to know when and where to collect water samples for testing. 

We are developing automated software tools to collect and process imagery from a suite of three satellites:

Early results comparing satellite imagery with field samples collected form Brownlee Reservoir show promise in pinpointing areas as small as about 100 feet square where alglal blooms may be developing. The frequency of image capture from the overlapping satellite flights means that we can identify areas of concern in near real time. 

In January 2020, we held a stakeholder meeting in Boise to share information and gather feedback which will guide the future of this project. The meeting included representatives form Idaho Power Company, the Bureau of Reclamation, the U.S. Army Corps of Engineers, the Idaho Department of Environmental Quality, the U.S. Environmental Protection Agency, the Idaho Department of Fish and Game, the Idaho Department of Health and Welfare, and the Central and Southwest Public Health Districts. We thank all of these agencies for their interest and input. 

Meeting to discuss remote sensing of algal blooms

Hydrologist Tyler King leads a meeting of stakeholders to discuss a USGS project to apply remote sensing techniaues to monitor Idaho water bodies for algal blooms

(Credit: Tim Merrick, Idaho Water Science Center. Public domain.)

Our next step will be to develop a screening tool that will provide alerts and necessary information to resource managers. We hope to have the initial tool ready by the summer of 2020.

Prototype of algal bloom screening tool

Screenshot showing a prototype of the screening tool that would help agencies determine where and when they should collect field samples for algal blooms.

(Public domain.)