What are algae
Algae are photosynthetic organisms (plants) found naturally in marine and freshwater environments. They produce their own food through photosynthesis and are vital for the well-being of marine and freshwater ecosystems.

Who manages algae concerns in Canyon Lake?
The Lake Elsinore and San Jacinto Watershed Authority (LESJWA) was formed to improve water quality in Lake Elsinore and Canyon Lake. This organization is made up of stakeholders from around the watershed who are implementing programs such as the alum treatments to Canyon Lake. Many of these programs are grant funded and are a result of numerous lake studies.

Who is responsible for lake warning or closures based on the risk of Cyanobacteria or toxins?
The Canyon Lake POA and EVMWD have partnered on the development and implementation of an HAB monitoring and sampling program. The Canyon Lake POA will post signs based on varying risk levels, and for closing/reopening the lake in response to known conditions.

When do algae bloom?
Conditions for algae blooms are ideal when there is an oversupply of nutrients in a lake, such as phosphorus and nitrogen from lawn fertilizers, high temperatures, low oxygen levels in the water, little water movement, and low water levels. Algae blooms result when phytoplankton, organisms living on water surfaces, reproduce rapidly and cause dense buildups. In a balanced ecosystem, phytoplankton are the food base for many other organisms. However, with an oversupply of nutrients, they experience excessively high growth rates that result in algal blooms.

Are algae harmful?
In a balanced ecosystem, most algae are necessary to keep a body of water healthy and productive. However, excessive algae growth reduces water clarity, releases a strong odor, and suffocates aquatic life forms by depleting oxygen levels and blocking sunlight.

What is blue-green algae?
While BGA looks very similar to normal algae, it is actually not an algae at all, but a cyanobacteria naturally found in fresh and salt water systems. Cyanobacteria have existed in water bodies for centuries and our understanding of them and detection of toxins has improved in recent decades. Similar to algae, cyanobacteria use photosynthesis, as well as nitrogen and phosphorus for food. Not all BGA blooms are harmful, as only a few very specific strains produce toxins that can result in moderate to severe health complications in humans and animals. Toxicity of the algae bloom cannot be detected by simple observation and requires a collection of water samples and lab analyses.

What should I do if I see an algae bloom?
Refrain from going into water that is foamy, scummy, pea-green, blue-green, brownish red, or looks like floating paint.

When In Doubt, Stay Out!
Do not allow children or pets to play in or drink the water until the algae bloom subsides and drops to the lake bottom. If pets swim in water tinted with an algae bloom, rinse them off immediately. Water with mats of algae should not be used for cooking, even if it is filtered or boiled.

Do alum treatments help?
Yes. The alum treatments are designed to reduce the phosphorus levels in Canyon Lake. Common sources of phosphorus include fertilizers, pet waste, natural mineral erosion, and existing lake sediment. Phosphorus is often the limiting nutrient for algae, therefore removal of it will likely reduce algae growth.

Why hasn't the alum applications prevented algal blooms in the coves?
In some situations, where lake waters are particularly stagnant and shallow as evident around lake coves, algae growth may still occur despite repeated alum treatment. Usually, the algae mats in the coves will dissipate over time and drop away within 2 to 3 weeks.

How can I help reduce algae?
Yes, together we can all help reduce nutrient inputs to the lake by picking up after our animals, reducing runoff from our irrigation, reducing fertilizer use, and avoid littering in our streets. All of these practices reduce the amount of pollutants that end up in Canyon Lake, which can lead to algae growth.

Does algae affect drinking water?
Canyon Lake is a drinking water reservoir that EVMWD seasonally utilizes to offset costly imported water. After proper treatment, algae does not have any negative health impacts, but can add an earthy taste to drinking water.

Who tests the lake for algae?
In recent years, algae testing has been conducted at Canyon Lake by the Southern California Coastal Water Research Project (SCCWRP) and LESJWA. These tests are not required by State or Federal law and are used for research purposes to help improve water quality.