Portland District wants to provide recreational visitors with all the information needed to understand the potential risks associated with exposure to cyanobacteria (often called blue-green algae, though they are technically bacteria, not algae). We want visitors to make responsible decisions for themselves about how much risk they are willing to take while recreating in the Portland District's reservoirs and lakes. 

 Cyanobacteria occurs naturally in most water bodies--including USACE-managed reservoirs--but can develop into a bloom when warm, calm water and excess nutrients occur. Some blooms have the potential to produce toxins harmful to people and animals. Increased exposure leads to greater risk of side effects from these toxins. Because of this, the best advice is: When in doubt, stay out!

Children and pets are at highest risk. Use your best judgment to keep your family and animals safe. Observe water conditions before you swim, boat, water ski or recreate in or on the water. Don’t get into water that is foamy, scummy, thick (like paint), or has a pea-green, blue-green or brownish-red color. Many lakes in Oregon and Washington, including Portland District reservoirs, are not regularly tested for presence of cyanobacteria toxins. 

Because of different monitoring and testing protocols, lake and reservoir visitors should not rely on public health advisories to determine whether or not the water is safe. Visitors need to take personal ownership of their health and safety, and never rely on the presence or absence of a public health advisory to determine if the water at any given lake or reservoir is safe. We encourage visitors to learn how to identify cyanobacteria blooms and how to protect themselves from the potential risks. If in doubt, stay out!