Canyon Lake Algal Blooms

Canyon Lake Algal Bloom Frequently Asked Questions

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 fresh-water ecosystems.

Who is responsible for lake warnings or closures based on the risk of cyanobacteria or toxins?

  • The Canyon Lake Property Owner’s Association (CLPOA) and Elsinore Valley Municipal Water District (EVMWD) are partnering on development of an Harmful Algae Bloom (HAB) monitoring and sampling program. Harmful algal blooms are overgrowths of algae in water. Some produce dangerous toxins in fresh or marine water but even nontoxic blooms hurt the environment and local economies.
  • The CLPOA 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 bad for the lake?

  • 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 are Blue-Green Algae (BGA)?

  • 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 inmoderate 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 a resident do when they 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.

Will the alum treatments being applied to Canyon Lake help reduce algae blooms?

  • 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.

Is there anything I can do to 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.

Do algae affect our 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.

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