DEQ Works with Partners to Address Harmful Cyanobacterial Blooms

HCBs at Alcova Reservoir

By Kimberly Mazza

CHEYENNE, Wyo – Since 2017, the Department of Environmental Quality (DEQ) has worked with cooperators to improve our understanding of harmful cyanobacterial blooms in Wyoming waterbodies for the wellbeing of the public.

Harmful cyanobacterial blooms, also known as HCBs, blooms, or blue-green algae are dense accumulations of cyanobacteria that may lead to serious health effects in people and animals (pets, wildlife, and livestock) through contact, ingestion, or inhalation of cyanotoxins or other cyanobacteria-related irritants. 

Cyanobacteria occur naturally in surface waters. However, many factors, including excess nutrients, sunlight, and warm water temperatures can contribute to the proliferation of cyanobacteria and the

formation of HCBs. 

David Waterstreet is DEQ’s Watershed Protection Section Manager and  oversees the HCB program which is part of the DEQ’s Water Quality Division (WQD). 

According to Waterstreet there is a growing national focus on this issue.  “Wyoming is part of a small number of states that are leading the way to identify recreation areas with HCBs and the associated risks to recreators and animals.”

Though the DEQ has learned a great deal about HCBs in Wyoming surface waters over the past few years, Waterstreet says there is still more work to do to better delineate where and when blooms occur and to delineate which blooms have increased toxicity risks. 

“Through annual monitoring we are obtaining trends at certain site locations. There are also a number of studies taking place to uncover toxicity triggers and markers,” said Waterstreet.  “Moreover, the DEQ has implemented the Wyoming‘s Nutrient Strategy.  This program continues to address nutrient pollution which is a major contributor to HCBs.”


Researchers inspect Rainbow Lake

With this information, the DEQ can collaborate with the Wyoming Department of Health (WDH) to advise the public.  The WDH informs the public through recreational use advisories when cyanobacterial cell densities or cyanotoxin concentrations pose a risk to people engaging in swimming or similar water contact activities in areas where HCBs occur. When an advisory is issued for a waterbody, WDH coordinates placement of signage at the waterbody. WDH also responds and tracks reports and inquiries regarding HCB-related illnesses. 

Along with the WDH, Waterstreet noted that there are many other local, statewide, and national agency partners. 

“The Wyoming State Parks, the Wyoming Game and Fish, the United States Forest Service, and other cooperators assist with surveillance for HCBs and play a big part in education and outreach as well as notifying the public via placement of signage. Additionally, the Wyoming Livestock Board, Conservation Districts, the United States Bureau of Reclamation, the National Park Service, and local entities such as counties and municipalities are all involved to respond to HCBs and inform the public of potential health risks,” he said.

Another important participant is the University of Wyoming. DEQ has partnered with the University to better understand HCBs in Wyoming’s waters. In a recently completed Water Research Program project, researchers evaluated the efficacy of satellite imagery at predicting cyanobacterial blooms in lakes and reservoirs and used satellite imagery to evaluate bloom conditions in lake and reservoirs over the last 40 years. DEQ and researchers hope to begin a second Water Research Program project in the near future that will help to improve understanding of cyanotoxin production and evaluate monitoring methods for cyanotoxins.

The United States Environmental Protection Agency (EPA), who directly oversees public water supplies (PWS) in Wyoming under the Safe Drinking Water Act, coordinates voluntary cyanotoxin monitoring of PWS source water at susceptible water supplies during the HCB season. The EPA and WDH are responsible for coordinating response activities should one of Wyoming’s public water supplies become impacted by an HCB. 


HCBs found at Ocean Lake

Kelsee Hurshman is the HCB Program Coordinator for DEQ’s HCB monitoring activities. In Wyoming, most HCBs occur during the warmer summer and fall months. “We monitor waterbodies throughout the state from July through October,” she said.  

According to Jennifer Zygmunt, DEQ’s WQD Administrator, it is largely due to Kelsee’s dedication and initiative that the DEQ has been able to investigate and monitor as many HCBs as it has in waters across Wyoming. 

“Monitoring waterbodies with HCBs in order to understand potential health risks requires extensive travel and  many miles. The number of sites that Kelsee monitors each year is impressive, and coordinating the HCB program is no small task,” noted Zygmunt. 

During the 2022 blooms season, the DEQ, along with its partners, conducted sampling at a total of 56 waterbodies in the state. Twenty-four of those waterbodies were monitored routinely on a biweekly to monthly basis to identify blooms and elevated health risks due to cyanotoxins.

 “Publicly accessible lakes and reservoirs used frequently for swimming, waterskiing, waterplay by children, and similar activities are the primary focus of our monitoring because these water bodies are where humans are most likely to ingest water with HCBs,” said Hurshman. 

The DEQ also responds to reports from the public and cooperators as well as potential detections of HCBs found in  satellite imagery from the Cyanobacteria Assessment Network (CyAN), a joint project of the EPA, the United States Geological Survey, the National Aeronautics and Space Administration, and the National Oceanic and Atmospheric Administration. Last season reports from partners and the public and satellite imagery led the DEQ to investigate and collect samples from 32 additional waterbodies.

The Laboratory

The DEQ Water Quality Division laboratory running tests

The DEQ Water Quality Division laboratory plays a critical role in Wyoming’s HCB program. The DEQ has invested in necessary analytical and microscope technology making Wyoming one of only a handful of states that has built the capacity to identify and analyze HCB toxins.  

Though the laboratory provides analysis for other DEQ programs, the HCB Program accounted for 20 to 25 percent of the lab’s time in 2022. 

Steve Vien is the Supervisor for the laboratory and oversees a three-member team. According to Vien, “In 2022, about 600 cyanotoxin samples were analyzed by the lab.”   

An additional 182 cyanobacteria samples were sent to a contracted lab to determine the type and quantity of cyanobacteria present. 

Public Safety

Collaboration plays a critical role in public safety.

To inform and educate the public, the DEQ hosts a website ( where the public can not only access information about HCBs and Wyoming’s program, but also report an HCB or HCB illness. The site also includes a map showing waterbodies with recreational use advisories.

“This advisory web map is a very helpful tool,” noted Hurshman. “We strongly encourage the public to utilize it during the season when planning recreational trips that involve activities in the water.”

When the temperatures drop and the state moves into the cold months, HCBs die off, and recreational use advisories are lifted by the WDH. However, the work continues. 

According to Hurshman, the DEQ spends the winter and spring season managing data and records, refining processes, developing new resources, and planning for the upcoming season.

“HCBs and their formation are very complex,” she said. “As we continue to work with our partners to inform the public of potential health risks, DEQ is also committed to finding ways to prevent and minimize the development of HCBs in surface waters.”

Previous Notice to Avoid and Report Possible Harmful Cyanobacterial Blooms in Wyoming Waters