EVMWD owns two dams in its service area – the Canyon Lake Dam and the Lee Lake Dam – which it is responsible for operating, maintaining and repairing. The structures are inspected monthly by EVMWD staff and yearly by the Division of Safety of Dams (DSOD), an arm of the California Department of Water Resources, to ensure they are properly maintained and performing as intended.
Canyon Lake Dam
Canyon Lake Dam, also known as Railroad Canyon Dam, is a variable arch concrete structure built in 1928. In 1996, EVMWD spent about $9.1 million to upgrade and widen the dam to withstand a 1,000-year flood event. Canyon Lake Dam, like other dams across the state, has valves that allow water to be drained for maintenance and emergency purposes at its base. These valves do not function as a flood control measure. Rather, EVMWD uses these valves for flushing and maintenance. Regular exercising of these valves helps prevent major maintenance problems for the dam and are required to be opened when inspected by the State. The dam maintains the level of Canyon Lake Reservoir, an important drinking water source that is replenished primarily by rain. When the lake rises above the dam’s spillway at 1381.76 feet above sea level, water flows into the San Jacinto River.
Lee Lake Dam
The Lee Lake Dam was built decades ago of compacted soil and rock. Behind the dam is a man-made storage reservoir for non-drinking water. The small lake was used for agricultural irrigation and recreation, but during the statewide, five-year drought it dried up almost completely.
How do I know these dams are safe?
The structures are regularly monitored by third party engineers and EVMWD staff. They are also inspected by the Division of Safety of Dams, the state agency tasked with making sure such facilities are operating properly and would be able to withstand an earthquake or flood.
Do EVMWD’s dams meet requirements set by the Division of Safety of Dams?
Both facilities are properly maintained based on standards set when they were designed. Because of a recent change in the state’s evaluation criteria, the spillway at Lee Lake Dam is considered undersized. EVMWD is studying ways to update to the dam’s design.
Why does EVMWD keep the Lee Lake Dam if there’s no water behind it?
EVMWD evaluates its facilities monthly to monitor their condition and usefulness. The drying up of Lee Lake is a recent event, and the District is assessing options for the future of the dam and reservoir. As a resident of Canyon Lake, should I be worried about flooding? Sometimes, when rains are heavy, residents will see water flowing over the dam’s spillway. The dam is designed to handle significant flows over the spillway. A recent evaluation performed by Division of Safety of Dams determined that the dam can withstand a 1000-yr flood event.
As a dam owner and operator, what are EVMWD’s responsibilities?
EVMWD is expected to regularly inspect dams to identify and resolve potential problems and ensure all parts are in working order. A dam owner also has to work with the Division of Safety of Dams to guarantee safety and compliance.