Lake Conditions

Why is this action being taken now?
Over the last two decades, golden algae blooms have become a growing issue across the western United States. Canyon Lake experienced its first bloom this past spring, which resulted in significant fish mortality. Golden algae prefer cooler water, so as lake temperatures rose over the summer, the algae went dormant and live cell densities decreased. As air and water temperatures declined in recent weeks, golden algae levels are rising again. Using data collected in Canyon Lake, environmental and water quality experts recommended an early, preemptive treatment to help reduce the algae before conditions worsen.

Are there even any fish remaining in the lake after the spring bloom?
Yes. An acoustic underwater survey conducted last week confirms that Canyon Lake continues to support an improving fish population, with more than 2,300 medium-sized fish detected in the East Bay alone.

Isn’t copper harmful to fish? Can it further impact the lake environment negatively?
When used at the recommended dosage, copper is safe to apply to lakes and has been widely used throughout the United States to reduce algae biomass. Chelated copper algaecides are less toxic to fish and other aquatic life compared with traditional copper sulfate. The chelated form binds copper ions, limiting the amount of free copper in the water column. Using lower concentrations, especially at cooler water temperatures, provides the best environmental protection.

Is this treatment harmful to other wildlife that use the lake?
At the recommended application dosage, studies show minimal to no impacts to waterfowl, pets, or people.

How long will the lake be closed to body contact, water sports, and boating?
The algaecide application will occur in two doses separated by about two weeks. Out of an abundance of caution, the lake will be closed to all activity except Marine Patrol and the application boats for up to 72 hours during and following each application.

Is the current golden algae bloom due to the recent alum treatment?
It is unlikely. Alum is used to remove nitrogen and phosphorus that enter the lake after rainfall. Blue-green algae thrive in nutrient-rich conditions. Golden algae, however, produce cysts that settle at the bottom of the lake and bloom when environmental conditions such as lower water temperatures are favorable.

Will the treatment prevent future golden algae blooms?
Possibly. Chelated copper is effective in immediately reducing golden algae and the severity of other algal blooms. Without this treatment, and the seasonal shift toward cooler temperatures that favor golden algae growth, conditions could allow the bloom to persist through the winter and into late spring. The algaecide works by disrupting the metabolic processes of algae, preventing it from multiplying and taking over the water. There is no guarantee it will prevent future blooms when the right environmental conditions occur.

Who is paying for this treatment?
The cost of the lake treatment will be shared between the Canyon Lake POA and EVMWD, with additional technical expertise provided by the Metropolitan Water District and third-party consultants.

When will the lake be restocked?
Restocking will be considered once the results of the algaecide application are measured and golden algae cells and toxins are no longer present.

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.