Fifth alum treatment scheduled to begin Monday


Canyon Lake is about to receive its fifth and final alum treatment in the initial program of treatments planned over the past two-and-a-half years. Despite recent rain runoff and the prediction of rain next week, Mark Norton, administrator of the Lake Elsinore & San Jacinto Watersheds Authority (LESJWA), says the the treatment is still scheduled to begin September 21.

If water officials determine conditions aren’t optimum for spraying the liquid alum in the Main Lake and East Bay, the treatment could be delayed. Residents can follow the schedule and see where the Aquatechnex boats disperse the alum each day at It is expected the City and POA websites will have a link to this site during the application process. As the Aquatechnix boat completes each cove, the applicator will update the blog.

Norton explained at the last POA Board meeting that the application is mapped via GPS so no parts of the waterways are overlooked. He says if it appears the Aquatchnix boat hasn’t gone all the way into the farthest reaches of a cove, it’s because the cloud of liquid alum is able to spread into the cove.

Following the fifth alum treatment, a preliminary report will be compiled to suggest next steps in improving conditions in Canyon Lake. The Total Maximum Daily Load (TMDL) Task Force says that, while algae cannot be entirely eliminated, the alum applications have been proven effective and possible future alum treatments will likely be suggested.”

Mark Norton summarizes how the alum treatments work by saying, “Historically, Canyon Lake has been known to suffer from algae blooms. Because of nitrogen and phosphorus that enters the lake through water runoff, the lake suffers from an excess amount of nutrients. These nutrients encourage algae growth. When the alum is added to the lake, it immediately binds to the phosphorus, which reduces the opportunity for algae growth.”

In order to comply with water quality regulations enforced by the State through the local Santa Ana Regional Water Quality Control Board, the TMDL Task Force has been using a state-funded grant to continue alum water treatments in Canyon Lake.

The 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 Canyon Lake residents.

Funding for the alum applications has been provided by a state grant and by the 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 Property Owners Association.

See a Q&A at the end of the article at

LESJWA is a joint powers authority entrusted with state and local funds to improve water quality and wildlife habitats in Lake Elsinore, Canyon Lake and the surrounding San Jacinto watershed. For more information about LESJWA, visit


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Donna Ritchie