The Metropolitan Water District's Sepulveda Canyon Facility
A Vital Water Plant Perched Between Cultural Pillars

MANY LOS ANGELES MOTORISTS ARE familiar with the Sepulveda Pass, a canyon on the 405 freeway, and the eight lane artery connecting LA's west side and the San Fernando Valley. The steep sides of the vegetated canyon are largely undeveloped, with the exception of two large cultural complexes on the west wall of the pass: the Skirball Center, a museum and Jewish Cultural Center, recently built near the top of the pass; and the new Getty Center complex, which looms on a sculpted plateau near the bottom. Yet few travelers may be aware that a third vital complex of structures is located in between these two prominent cultural heavyweights: The Sepulveda Canyon Water Control Facility.

At times, as much as 10% of the city's water enters the control facility, as it comes through the pass in a nine foot diameter pipe, called the Sepulveda Feeder. The purpose of the facility is to reduce the pressure that builds up in the pipe as the water cascades down the steep grade of the pass, as without a reduction, the pressure would burst the pipe.

1223 View of the power plant (right) and the pressure control facility (left). CLUI photo
The Sepulveda Canyon Facility consists of five structures, built in the early 1970's, when the feeder was built to augment the supply of State Water that was deliverable to the City. The pipe enters the site on the northeast side and splits into two, with one part leading into a small power plant, and the other part connecting to the Pressure Control Facility.

1224 Battery of valves at the pressure control facility. CLUI photo
Pressure Control Facility
The Pressure Control Facility is the key feature of the site. The facility reduces pressure that builds up in the pipe by "breaking the head" -slowing the water down through a battery of valves. The pipe runs through the middle of the building, splitting into a dozen or so cone valves which de-pressurize the water by forcing it into a conical spray within the pipe, much like the spray nozzle on a garden hose.

1227 View of Sepulveda Pass and the 405 Freeway, from the top of the electrical turbine. CLUI photo
The Power Station
An electrical generating plant was installed on the site to take advantage of the energy contained in the flowing water. The plant has the capacity to produce 8.6 megawatts, which is sold to the local power utility and put on the commercial grid. The rotor of the generator is turned by an "impulse turbine," a series of water jets which spray onto paddles mounted on the shaft at the base of the turbine. The ten-foot diameter rotor turns at a stately 120 revolutions per minute.

1226 View of the large water tank. CLUI photo
Water Tanks
There are two tanks at the site, one of which is the largest in the MWD system --the top of the tank covers nearly an acre, and is 230 feet in diameter, with a capacity of 13 million gallons. The smaller tank holds another 5 million gallons, and together they are used to balance the amount of water in the system, filling and draining in response to demand and inflow.

1225 The MWD residence. CLUI photo
The residence was built to accommodate a caretaker for the facility, and has been lived in by an MWD employee since the site opened. Few duties require working at the site, however, and the current tenant works at the Jensen Plant during most days. Rent on the two-story single family dwelling is less than $100 per month.

Like the rest of the water in Southern California, the water coming through the Sepulveda Feeder comes from a natural drainage system a long way off. It originates in the High Sierras of Northern California and the Sacramento River. As "State water," it travels a few hundred miles through the Central Valley, via the California Aqueduct, and rests for a while in the Castaic Reservoir, near Santa Clarita. From there it enters into the MWD system, flowing into the Jensen Filtration and Treatment plant, located at the north end of the San Fernando Valley (one of the largest water treatment plants in the world), across from the Cascades, which is where William Mulholland turned a valve opening of the Los Angeles Aqueduct for the first time in 1913, and said to the gathered citizens of Los Angeles as the water spilled into the valley, "...There it is. Take it."

There are three primary water supply systems that bring water to Los Angeles, and three primary water agencies that operate them:
1. The Metropolitan Water District (MWD) which operates the Sepulveda Canyon Facility, built and maintains the Colorado River Aqueduct. The MWD also operates five filtration plants, and over 700 miles of large-diameter water mains.
2. The California Department of Water Resources operates the California Aqueduct, which brings water to Los Angeles from Northern California through the Central Valley. The State also operates reservoirs on the edges of Los Angeles, such as Castaic Lake and Lake Perris, from which the MWD and other local suppliers draw water.
3. The Los Angeles Department of Water and Power (DWP) built the Los Angeles Aqueduct and, as the largest supplier of water to Los Angeles, maintains an extensive network of supply lines and filtration plants.