Portland District provides recreational visitors with needed information to understand the potential risks associated with exposure to cyanobacteria (often called blue-green algae, though they are technically bacteria, not algae). It is important for visitors to make responsible decisions for themselves about the level of risk they are willing to take while recreating in the Portland District's reservoirs and lakes. 

 Cyanobacteria occur 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.  Observe water conditions before you swim, boat, water ski or recreate in or on the water. Use your best judgment to keep your family and animals safe. 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. 

Visitors need to take personal ownership of their health and safety. Due to different monitoring and testing protocols and the rapid changes to water conditions do not 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.  In addition to the FAQs below, the Oregon Health Authority is another excellent source of information on this topic.  Remember - If in doubt, stay out!