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VERNAL — On Aug. 12, 2019, TriCounty Health Department (TCHD) posted danger signs at Matt Warner Reservoir, warning the public not to fish, swim or recreate in the water due to the harmful algal blooms (HABs). 


Utah Division of Wildlife Resources (DWR) Director Mike Fowlks issued an emergency amendment to the 2019 Utah Fishing Guidebook due to Matt Warner Reservoir being temporarily closed to fishing, as a result of the HAB. After consulting with officials from the TCHD, DWR made the decision to close the waterbody to fishing from Aug. 13 to Sept. 30. That means that it will be illegal for anyone to fish at the reservoir during that time and anyone found fishing there could be cited.


The Utah Department of Environmental Quality (DEQ) took water samples at Matt Warner. A recent sample showed 109 million cells per milliliter of cyanobacteria — over 11 times higher than the Environmental Protection Agency’s threshold for closure. 


“Harmful algal blooms happen frequently at Matt Warner Reservoir. Throughout the season, the bacteria grow,  bloom and die. As the cells die, toxins are released that are harmful to human and animal health,” Eric Larsen, Environmental Health Scientist said. “There is nothing we can do to mitigate or prevent the toxins. The best thing we can do is stay out of the water until the bacteria and toxins dissipate on their own.”


“The risk to humans and animals is too great. All contact with the water and any fish in the water should be avoided until the algal bloom subsides and toxicity levels decrease,” Fowlks said. “Typically, it is still safe to fish during algal blooms, but these levels caused safety concerns for any kind of contact with the water.” 


Hunting and camping in the Diamond Mountain Wildlife Management Area will still be allowed. However, campers and hunters with dogs should avoid the area unless they can ensure that their pets will not get in the water. 


While the fishing is closed at Matt Warner Reservoir, there are some other great options in the area for fishing and other recreation. Anglers can experience great fishing at nearby Red Fleet State Park, Steinaker State Park, East Park Reservoir, Old Fort Ponds or Flaming Gorge Reservoir. 


For more information, visit the Utah Department of Environmental Quality website.