“Ever wonder how San Diego gets a good portion of its drinking water?”
Welcome to El Capitan Dam. This impressive structure creates El Capitan Reservoir. It is a vital part of San Diego’s water supply. El Capitan Dam is not just a concrete and earth structure. It has a fascinating history.
In the early 1900s San Diego faced severe drought. The city needed a reliable water source. Engineer Hiram N. Savage was commissioned to design a dam. He proposed a site at Mission Gorge. But San Diego favored a site further upstream. That site was El Capitan.
El Capitan offered a narrower and deeper reservoir. This meant less water loss from evaporation. However the El Capitan site presented challenges. It required a more expensive embankment dam. A longer aqueduct was needed to transport water to the city. Savage refused to consider the El Capitan site. He was fired in 1923.
The native Kumeyaay people lived in the Capitan Grande Reservation. Part of their land would be flooded. They opposed the project. In 1919 Congress passed the El Capitan Act. This transferred the Indians’ water rights and lands to San Diego. The city resettled them and paid them $361420.
Local water districts also fought against the project. They feared the dam would reduce their water supply. Litigation dragged on for years.
Construction finally began in December 1931. The hydraulic fill method was used. The embankment was completed in 1934. The final cost was $5.8 million. El Capitan Pipeline was completed in the same year. It connects the reservoir to the city.
El Capitan Dam is an embankment dam with a clay core. It stands 237 feet high. It is 1170 feet long. The spillway is on the north side. It allows water to overflow when levels are too high.
El Capitan Reservoir can hold 112800 acre-feet of water. It is the biggest of San Diego’s local surface water reservoirs. The reservoir is about 8 miles long when full.
Interestingly the reservoir rarely fills completely. This is because its capacity is large. It holds a lot relative to the average runoff. The water level is kept low as a precaution. This helps prevent failure during an earthquake.
You can enjoy limited recreation here. Canoes, kayaks, and rowboats are allowed. Fishing is permitted. Water contact is not allowed. This protects the water quality. There is no camping at El Capitan.
El Capitan Dam provides drinking water and flood control. It is a testament to engineering. It reflects the challenges of water management. It also shows the impact on native populations. Next time you turn on the tap in San Diego remember El Capitan Dam.