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Lake Management Plan
Nanobubble Pilot Project
At the heart of this plan is the use of nanobubble technology, an innovative method of infusing oxygen into the lake's water at a microscopic level. The lake’s first nanobubble barge was installed in January 2024 and began full operation on February 6, 2024. This cutting-edge barge can treat up to 7.2 million gallons of water each day by compressing air to create nearly pure oxygen, which is then injected as nanobubbles into the water column.
Nanobubbles are approximately 2,500 times smaller than a grain of salt, allowing them to remain suspended in the water for extended periods. This results in a significant increase in dissolved oxygen levels, especially near the lakebed, which helps reduce internal phosphorus loading—a key driver of algae growth. Nanobubbles also directly impact algae by oxidizing the cell membrane, thereby preventing blooms from forming.
To measure the effectiveness of this pilot program, five monitoring buoys were installed around the barge to collect real-time data on dissolved oxygen, temperature, and other water quality indicators.
Results and Expansion
In June 2024, City staff presented the first side-by-side comparison of pre- and post-installation sediment mapping. The results showed positive changes in sediment hardness and composition. Harder, darker sediments indicate improved bottom conditions, which support aquatic life and reduce foul odors, while lighter, soft sediments are associated with poor water quality. These early results confirm that nanobubble technology is helping shift the lake’s health in the right direction.
Dissolved oxygen levels have also significantly improved in areas surrounding the nanobubble barge. Initial readings showed Oxidative Reduction Potential (ORP) levels below 100 millivolts (mV). Since then, those levels have surpassed 300 mV, demonstrating a major improvement in the lake's chemical balance.
Encouraged by these results, the City Council approved the purchase of two additional nanobubble barges on June 25, 2024. The new barges were installed at Launch Pointe on October 14, 2024, and at Elm Grove Beach on October 17, 2024. These upgraded units double the pumping and oxygen generation capacity of the original barge, significantly expanding the reach and impact of this treatment method. Although they do not yet include ozone capabilities, they are built to accommodate future upgrades.
2025 Lakewide Oxygen Levels
As part of our ongoing monitoring of Lake Elsinore and our continued efforts to evaluate the effectiveness of the nanobubble barges, the City has partnered with GEI Consultants, a firm specializing in aquatic and environmental science. GEI is conducting detailed assessments of dissolved oxygen levels throughout the lake to help us better understand overall water quality and ecosystem health.
The images below illustrate dissolved oxygen concentrations measured at 24 different monitoring locations, taken approximately 0.5 meters from the lake bottom. Oxygen levels near the bottom of the lake are a critical indicator of lake health, as they influence biological activity, nutrient cycling, and habitat conditions. Readings above 5.0 mg/L are considered ecologically favorable, indicating a healthy aquatic environment capable of supporting fish and other aquatic life.
Phosphorus Mitigation Project
In conjunction with the nanobubble system, the City is also launching a phosphorus mitigation project to further improve water quality. Specially designed boom socks filled with phosphorus-absorbing pellets will be deployed in targeted areas—starting on the south side of Elm Grove Beach near the recycled water entry point. These socks will help remove excess phosphorus from the lake, further disrupting the nutrient cycle that drives algae growth. This dual approach—nanobubbles and phosphorus capture—offers a powerful combination to tackle both immediate symptoms and underlying causes.
Cyanobacteria Monitoring and Satellite Tracking
To further protect public health and ensure the success of these water quality efforts, the City has partnered with national agencies to track cyanobacteria levels through the Cyanobacteria Assessment Network (CyAN). This initiative, led by the U.S. EPA in collaboration with NASA, NOAA, and the USGS, uses satellite imagery to detect harmful algal blooms in freshwater systems.
Landsat satellite data helps detect changes in water color and clarity, providing early warnings of bloom activity. The City has incorporated this data into its monitoring efforts and maintains a five-year graph tracking cyanobacteria levels in Lake Elsinore. This graph will be updated regularly throughout the year to inform residents of lake conditions.