Water officials announce alum treatment will be postponed until lake conditions improve


No one one wants a repeat of last February’s alum treatment aftermath when portions of the East Bay briefly were blanketed with a foamy scum because of the interaction between the alum and an unexpected algae bloom. This year, water officials did some preliminary testing, as Mark Norton, administrator for the Lake Elsinore & San Jacinto Watersheds Authority (LESJWA), explains in the following report.

Norton reported Wednesday that alum pre-application monitoring indicates that lake conditions this week are very similar to those in February 2014. To prevent a repeat of the “patching” that occurred in Canyon Lake last year, officials will reschedule the March 2015 treatments to wait for more ideal lake conditions. The new schedule will see treatments begin later in the month or in April, if conditions permit.

During last year’s first alum applications, unseasonably hot weather created temporary – but harmless – patches of green residue on some areas of the lake’s surface. To avoid future issues, LESJWA, in conjunction with other lake experts, developed sampling procedures to determine the best timing for alum applications.

“We continue to see great results from the alum applications and are confident that we can continue that success,” Norton says. “Although the clumping last February dissipated in a day or two, and we saw positive results, we definitely want to avoid a similar issue in the future.”

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.

The final alum treatment is scheduled for September 2015. The project is being funded by a state grant and by the Lake Elsinore and Canyon Lake Total Maximum Daily Load (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. LESJWA is a joint powers authority entrusted with $15 million in 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, please visit www.mywatersheds.com.


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Donna Ritchie