Information from the Wyoming Department of Environmental Quality:
A harmful cyanobacterial bloom (HCB) recreational use Bloom Advisory has been issued for Glendo Reservoir, West Granite Springs Reservoir, Sodergreen Lake, and Twin Buttes Reservoir. The Wyoming Department of Health (WDH) works cooperatively with the Wyoming Department of Environmental Quality to issue 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 cyanobacterial blooms occur. HCBs may also pose a health risk to animals. The WDH is working directly with resource management agencies to ensure signs are posted at the reservoir. Additional details regarding advisories and other HCB resources can be found at WyoHCBs.org.
Bloom advisories are issued when a HCB is present and cyanotoxins may be present. Toxin advisories are issued when cyanotoxins exceed recreational thresholds. Waterbodies under an advisory are not closed since HCBs may only be present in certain areas and conditions can change frequently. Advisories will remain in place until blooms have fully dissipated and cyanotoxin concentrations are below recreational use thresholds identified in Wyoming's HCB Action Plan.
If you encounter a potential HCB, the Wyoming Department of Health and the Wyoming Livestock Board recommend the following:
- Avoid contact with water in the vicinity of the bloom, especially in areas where cyanobacteria are dense and form scums.
- Do not ingest water from the bloom. Boiling, filtration and/or other treatments will not remove toxins.
- Rinse fish with clean water and eat only the fillet portion.
- Avoid water spray from the bloom.
- Do not allow pets or livestock to drink water near the bloom, eat bloom material, or lick fur after contact.
- If people, pets, or livestock come into contact with a bloom, rinse off with clean water as soon as possible and contact a doctor or veterinarian.
Questions about health effects and recreational use advisories can be directed to Courtney Tillman, Surveillance Epidemiologist, Wyoming Department of Health, at This email address is being protected from spambots. You need JavaScript enabled to view it. or (307) 777-5522. Questions regarding cyanobacteria sampling can be directed to Kelsee Hurshman, Natural Resource Analyst, Wyoming Department of Environmental Quality, at This email address is being protected from spambots. You need JavaScript enabled to view it. or (307) 777-2073.
Current HCB Recreational Use Advisories*
| Waterbody Name | Observation or Sampling Location(s) | Advisory Type | Date Issued |
| Beck Lake | East Ramp | Bloom | 08/03/2023 |
| Brooks Lake | South Ramp | Bloom | 08/03/2023 |
| Festo Lake | East Shore | Bloom | 07/13/2023 |
| Flaming Gorge Reservoir | Firehole Beach | Bloom | 07/19/2023 |
| Glendo Reservoir | Custer Cove, Cottonwood Campground | Bloom | 08/09/2023 |
| Goshen Hole Reservoir | Northwest Campground | Bloom | 07/29/2023 |
| West Granite Springs Reservoir | West Causeway | Bloom | 08/09/2023 |
| High Savery Reservoir | Dam | Bloom | 07/12/2023 |
| Lake Viva Naughton | East Shore | Bloom | 07/19/2023 |
| Leazenby Lake | South Access | Toxin | 08/03/2023 |
| Miller Lake | Northeast Shore | Bloom | 08/01/2023 |
| Pathfinder Reservoir | Diabase Marina, Bishops Point | Bloom | 08/01/2023 |
| Saratoga Lake | West-Central Shore | Bloom | 08/01/2023 |
| Seminoe Reservoir | Sunshine Beach, South Red Hills, North Red Hills | Bloom | 08/01/2023 |
| Sodergreen Lake | Southeast Access | Bloom | 08/09/2023 |
| Twin Buttes Lake | South-Central Ramp | Bloom | 08/09/2023 |
| Wheatland Reservoir Number 3 | Northwest Causeway | Toxin | 08/03/2023 |
| Woodruff Narrows Reservoir | North Ramp | Bloom | 08/04/2023 |
*There may be additional waterbodies with HCBs that WDH and WDEQ are not aware of. Please report potential blooms to WDEQ and HCB-related illnesses to WDH.