Proposed Lakeside Sand Mine Owner Sues City of San Diego for Damages From Water Release at El Capitan Dam
91-year-old dam is too dangerous for city to keep reservoir filled, leading to massive water waste and now, damage claims downstream
By Karen PearlmanSept. 1, 2025 (Lakeside) – A lawsuit against the city of San Diego is highlighting safety and management concerns at the El Capitan Dam and Reservoir (photo, left, by Billy Ortiz).
The suit is also dredging up residents’ longstanding fight against sand mining in Lakeside’s picturesque El Monte Valley.
Even deeper, it shines a floodlight on failure to make the dam safe, which could not only protect public safety, but also prevent wasting billions of gallons of water that the city currently must release from this and other reservoirs to prevent disastrous dam breaks.
The old earthen dam is considered one of the most dangerous in the region because of concerns about water overflow, major flooding and catastrophic loss of life. It sits near the site of a proposed sand mining area in the El Monte Valley.
When the Biden administration passed an infrastructure bill that provided money to repair aging dams, Rep. Darrell Issa voted against the legislation and did not offer any proposal seeking money to fix the El Capitan Dam, located in his district.
East County Magaizine over the years has asked State Senator Brian Jones and San Diego County Supervisor Joel Anderson about this dam in their districts. While both voiced concerns, neither have taken action to pursue funding to repair the dam nor increase its capacity.
The lawsuit
In 2024, El Monte Nature Preserve, LLC – the ironically named group that has been planning to mine the area for aggregate – filed a $300 million lawsuit in San Diego County Superior Court against the city of San Diego.
Residents and community groups have been fighting against sand extraction in the valley for decades. Yet ironically, the city releasing excess water to prevent severe flooding may be what prevents the area from being mined for sand.
The city of San Diego has owned and operated the El Capitan Dam and Reservoir (see photo, below, right) since its construction. The dam was built by the city in the early 1930s and completed in 1934 to provide a reliable water source for the region.
El Monte Nature Preserve’s legal action alleges that in 2023, when the city of San Diego released six billion gallons of water from the dam, it damaged the company’s property in the El Monte Valley.
The lawsuit filed by Vincent J. Bartolotta Jr. and Karen R. Frostrom claims the water surge caused the underground water table to rise by about 40 feet. County regulations prohibit sand mining below the water table.
The suit claims that after the city of San Diego released the six billion gallons of water and raised the water table, it deprived El Monte Nature Preserve “of all economically viable use of its property rights… and interfered with distinct investment-backed expectations because the City has invaded Plaintiff’s property and caused loss of property rights.”
The city released the water in 2023 in anticipation of a potential spill due to Tropical Storm Hilary.
El Monte Nature Preserve seeks $300 million in damages. The city of San Diego denies all claims, stating in court documents that El Monte Nature Preserve is not entitled to any compensation.
The case is scheduled for a jury trial on Dec. 5.
In its response, the city claims that “carelessness and negligence on Plaintiffs’ own part proximately contributed to the happening of the incident(s) and to the losses and damages complained of, if any...”
How dangerous is the dam?
El Capitan is an aging dam made of rocks. It is 237 feet tall and 1,170 feet wide. It has not met state standards for safety for many years.
East County Magazine covered the issue two years ago here.
State researchers report that the dam is considered in poor condition and would pose a high risk of loss of life downstream if it were kept full and ruptured.
If the dam were to break with significant water, it would cause catastrophic loss of life not only in El Monte Valley, but could flood all the way down to Mission Valley where the new San Diego State University campus is now on the old Qualcomm Stadium site, as well as at Snapdragon Stadium, and beyond.
Maps showing the inundation a dam break could cause can be found here.
The maps show how many seconds or minutes it would take to reach critical points and how many feet depth of water there would be.
For example, in 33 seconds, El Capitan High School in Lakeside would be under 23 feet of water, and several other schools are in danger of being drowned before people could possibly evacuate out of Lakeside.
In 1 minute, 23 seconds, the Las Colinas detention facility in Santee would have water 22 feet deep. The scenario would be much the same at the Santee Trolley stop and Santee’s emergency responder sites.
Downstream, within minutes, Old Mission Dam would be under 60 feet of water. Further away, parts of Interstate 5 could get 18 feet of water depth, and even areas near the coast could get a few feet.
The report noted that near-term repairs in the spillway were “under construction” and were to be completed in 2024. A seismic stability analysis is currently underway to develop long-term improvements based on analysis results, according to the report.
Water management under scrutiny
This lawsuit has also brought broader questions about San Diego’s water management practices to the surface.
Critics argue that the city has spent billions on water reclamation projects while essential infrastructure like dams have been neglected.
The need to release water from reservoirs to maintain safety seems at odds with a region that often faces water scarcity, prompting some to question the city’s strategic planning for its water resources, especially with the growing impacts of climate change.
At a time when the Colorado River is drying up and climate change is contributing to drier conditions, some operators have reservoirs have invested heavily in increasing water storage.
For example, the San Diego County Water Authority oversaw the nation’s highest dam raise at the San Vicente Reservoir, also in Lakeside.
Completed in 2015, that project raised the dam height by 117 feet and provided an addition 152,000 acre feet of water storage capacity -- double the capacity before the project began in 2009. Read about that dam raise project here.
But the city of San Diego, by contrast, released billions of gallons of water from its reservoirs in just one year to prevent overflows, CBS 8 reported in 2024.
Precious water was wasted — literally washed out to sea.
El Monte Nature Preserve, based out of Solana Beach, owns five parcels at 13950 El Monte Road in Lakeside, of which the majority of the property is zoned S82 – extractive use.
The company’s suit also refers to the 2017 Oroville Dam spillway, after which 180,000 people were evacuated. That led to the state examining all the dams.“Rather than fix the dams to make them safe, the State then placed a limit on how much water each dam could hold,” the suit states.
It goes on to note that two of the regulated dams are in San Diego County – El Capitan (photo, left) as well as Lake Hodges Dam.
The Lake Hodges Dam and Reservoir is also owned and operated by the City of San Diego. That dam was built in 1918 and was purchased by the city in 1925.
The 2024 reservoir restrictions report by the state calls Lake Hodges’ condition assessment as “unsatisfactory,” and classifies its downstream hazard potential as “extremely high,” also due to seismic concerns.
The report said that the city has made near-term repairs on the dam’s upstream face, spillway and inside the tunnel. It also said that vegetation removal and leakage monitoring improvements started this year and that “10 percent design of the new dam is being developed.”
Could the sand mine still be built?
Meanwhile, the sand mining operation is still a possibility.
The county’s website shows plans for it here.
The proposed sand mining project shows 12 years of grading more than 12 million tons of “construction-grade aggregate” from a 500-hundred-acre stretch of the river valley, to a depth of around 40 feet.
El Monte Valley Preserve is hoping to extract more than 500 tons of sand per hour which will be trucked away about 150 times a day.
The environmental impact report from 2018 identified potentially significant environmental impacts to aesthetics (and land use), air quality, biological resources, cultural resources, mineral resources, paleontological resources, hazards (vectors), noise and traffic.
ECM has covered the issue extensively through the years:
https://www.eastcountymagazine.org/county-scoping-meeting-lakeside-aug-26-sand-mine-project
https://www.eastcountymagazine.org/lakeside-planners-hold-hearing-thursday-and-vote-sand-mine-eir
https://www.eastcountymagazine.org/zoning-history-sand-mining-site-explained