Topline:
In an effort to curb harmful algal blooms that have long been a problem for Lake Elsinore and Canyon Lake, the Santa Ana Water Board recently adopted more stringent pollution limits, including for nitrogen and phosphorus. The two nutrients are often found in yard and agricultural runoff and fuel algal blooms.
A long time coming: Experts have been working since 2004 to understand how to best keep the two Riverside County lakes healthy. Strategies include: keeping oxygen levels up using aeration; adding aluminum sulfate, which binds with excess nutrients; and adding recycled water to keep lake levels up.
Ongoing research: For the next several decades, experts will continue to evaluate the effectiveness of different treatments by comparing lake quality to reference sites that haven’t been affected by development.
Why it matters: Lake Elsinore and Canyon Lake are large freshwater lakes often used for fishing, swimming and boating. Algal blooms can kill fish and make the lakes too dangerous to recreate in at times.
Go deeper: Read the extremely detailed analysis that led to the water board’s decision.