Lake to receive 8th alum treatment


Canyon Lake will receive its 8th alum treatment Feb. 12 through Feb. 16. Lake Elsinore & San Jacinto Watersheds Authority (LESJWA) will be applying doses of alum to the lake in the main body, east bay and the area north of the causeway.

Aquatechnex biologists will be treating Canyon Lake with aluminum sulfate to sequester and remove phosphorus as part of the Total Maximum Daily Load (TMDL) Task Force. The plan is to mobilize equipment to Canyon Lake on Feb 11 and begin the alum treatment on Feb. 12.

Treatments will be applied to the main body of the lake on Feb. 12 from 7 a.m. to 4 p.m., Feb. 13 from 7 a.m. to 5 p.m. and Feb. 14 from 7 a.m. to 3 p.m. The east bay will be treated on Feb. 15 from 7 a.m. to 2 p.m. The area north of the causeway will be treated on Feb. 15 and Feb. 16, time pending.

The lake will remain open during the entire treatment process. Recreational users will experience little disruption during treatment application and implementation.

Alum, a naturally occurring mineral that is safe for humans and marine life, binds with phosphorus and sinks to the bottom of the lake, becoming part of the lake sediment. Because phosphorus is a critical element needed for algae to bloom, alum generally helps reduce algae production.

According to Lake Elsinore and San Jacinto Watershed Authority (LESJWA), there have been no reported incidents of fish kills or other evidence of aquatic toxicity as a result of these lake restoration activities.

When applied in lakes, alum rapidly binds with phosphorus to form a non-toxic mineral particle called aluminum phosphate. This reaction is usually complete within a few hours and the resulting particles slowly settle to the bottom after just a day or two.

Initially, the aluminum phosphate particles form a thin layer only 1 to 2 mm thick. Eventually, the particles are incorporated back into the soil.

Water officials note that in 2004, 700,000 gallons of liquid alum was applied to 1,550 acres of Big Bear Lake without any adverse effect to fish, aquatic organisms, birds or other wildlife. Afterward, Big Bear observed a 90 percent improvement in water clarity in the month following the alum application.

According to LESJWA spokesperson Mark Norton, alum has a proven track record of success and is safe to both humans and marine life. Drinking water quality will not be affected by any of the treatment options.

The (TMDL) Task Force evaluated several options during the CEQA process and determined that alum application provides the best option as a step to effectively treat the entire lake in a timely manner with minimal impact to residents.

The project is being funded by a state grant and by the Lake Elsinore and Canyon lake TMDL Task Force, which consists of cities, the County of Riverside, agriculture and dairy coalitions and other organizations in the San Jacinto River watershed.

Implementation of the alum project is being coordinated by the City of Canyon Lake, the Elsinore Valley Municipal Water District, LESJWA, the TMDL Task Force and the Canyon Lake POA.

Alum Schedule (Subject to Change):

  • Thursday, Feb. 8 – Pre-alum dosing monitoring
  • Sunday, Feb. 11- Mobilize equipment/ boat inspection
  • Monday, Feb. 12 – Applied to main body, 7:00 a.m. to 4:00 p.m.
  • Tuesday, Feb. 13 – Applied to main body, 7:00 a.m. to 5:00 p.m.
  • Wednesday, Feb. 14 – Applied to Holiday Harbor, 7:00 a.m. – 3 p.m.
  • Thursday, Feb. 15 – Applied to east bay, 7:00 a.m. to 2:00 p.m.
  • Thursday, Feb. 15/16 – Applied to area north of the causeway, time pending (late afternoon).

Questions and Answers

Here are questions and answers supplied by LESJWA.

Q:Why is water treatment being conducted in Canyon Lake?

A: Storm water runoff carries with it high levels of nutrients including nitrogen and phosphorus that hurt water quality and threaten marine life. In order to comply with water quality regulations enforced by the State through the local Santa Ana Regional Water Quality Control Board, the TMDL (Lake Elsinore and Canyon Lake Nutrient Total Maximum Daily Load) Task Force is going to be using a state-funded grant to begin alum water treatment in Canyon Lake.

Q: What is being used to treat the water in Canyon Lake?

A: The TMDL Task Force evaluated several options during the CEQA process and determined that alum application provided the best option as a first step to effectively treat the entire lake in a timely manner with minimal impact to Canyon Lake residents.

Q: What is alum?

A: Alum (aluminum sulfate) is one of the most common minerals found on earth and has been used since Roman times for water purification. Alum is a common ingredient in cosmetics, antiperspirants, toothpaste, bath salts and antacids. It is sold as a spice in most grocery stores.

Q: How does alum reduce phosphorous?

A: Once alum has been added to the lake, it binds immediately with the phosphorous and effectively removes the opportunity for algae to grow. With less algae in the water, light can penetrate deeper into the lake allowing plants to grow at the bottom while improving the overall health and water quality of the lake.

Q: Is alum safe for humans? Marine life?

A: Alum is a safe and effective method that has been used in many lakes across the country to mitigate excess phosphorus in lakes and reservoirs, according to the North American Lake Management Society. The alum application will be well within safe levels as determined by the U.S. Environmental Protection Agency, the California Office of Environmental Health Hazard Assessment and the Center for Disease Control and will not impact humans or marine life.

Q: Will alum affect the drinking water quality of Canyon Lake?

A: No. Aluminum concentrations in the lake itself will meet the Public Health Goal for aluminum in finished drinking water within 24 hours following the alum application.

Q: How will the alum be applied?

A: The alum will be injected directly into the lake off of boats in specific areas.

Q: Will my use and access of the lake be impacted by the water treatment?

A: Recreational users will experience minimal disruption during treatment application and implementation.

Q: Will boats be allowed on the lake during the application?

A: Yes, but certain areas of the lake will be blocked off during the application process which should last only a few hours. Boats will have full lake access immediately after the application process is completed.

Q: Will beaches be closed during the application? Will it be safe to swim?

A: Some areas might be briefly closed off during the alum application, but access will be open immediately once the application process is completed. Swimmers will be able to safely enjoy the lake immediately after the application process is complete.

Q: Will fishermen be allowed to fish during the application? Are the fish safe to eat?

A: Yes, but certain areas of the lake will be blocked off during the application process which should last only a few hours. Fishermen will have full lake access immediately after the application process is completed. There is no negative affect on aquatic life as a result of the alum application.

Q: Will there be any visual impacts with the water treatment?

A: No. In fact, Canyon Lake’s water clarity should improve immediately once the alum is applied.

Q: Can the material at the bottom of the lake become active again?

A: No, once the alum binds with the lake sediment it becomes inert and very stable.

Q: Is there a threat to Lake Elsinore when Canyon Lake overflows during high water levels?

A: No. By the time Canyon Lake water would reach Lake Elsinore, it would not contain alum since it would have been bound to the lake sediment of Canyon Lake. Even under severe storm water runoff events, if Canyon Lake sediment were to be carried downstream in an overflow event, the alum applied in Canyon Lake would remain inert and would have no effect on the downstream lake water quality or habitat.

Q: Will boating be allowed?

A: Yes. We are going to allow boating, but under a yellow status (5 mph) and no skiing or wake boarding because of the lower speed.

Q: Can we go in the water immediately after the treatment?

A: You certainly can. It’s the same as bath salts. To give an idea, it’s about the equivalent of one aspirin to 25 gallons of water. It’s no more toxic than holding a penny.

Q: Will fish have a response?

A: None whatsoever. If you see a dead fish in the water afterward, it died of natural causes.

Q: Why not remove the silt instead?

A: Costs, and there are too many to mention. Not to mention where to put all that silt.

For more information about LESJWA, visit For updates on Canyon Lake alum treatments, visit


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Donna Ritchie