The Californian Aqueduct

Ever since I have been driving thru the Californian desert I have been fascinated by the huge canal system that cuts like a knife thru the desert landscape. It looks so clean and so new, but……………………………

From 1905 through 1913, Mulholland directed the building of the aqueduct. The 233 mile (375 km) Los Angeles Aqueduct, completed in November 1913, required more than 2,000 workers and the digging of 164 tunnels. The project has been compared in complexity by Mulholland's granddaughter to building the Panama Canal. Water from the Owens River reached a reservoir in the San Fernando Valley on November 5. At a ceremony that day, Mulholland spoke his famous words about this engineering feat: "There it is. Take it."

After the aqueduct was completed in 1913, the San Fernando investors demanded so much water from the Owens Valley that it started to transform from "The Switzerland of California" into a desert. Inflows to Owens Lake were almost completely diverted, which caused the lake to dry up by 1924. Farmers and ranchers tried to band together to sell water rights to Los Angeles as a group, but again through what historians called "underhanded moves", Los Angeles managed to buy the water rights at a substantially reduced price.

So much water was taken from the valley that the farmers and ranchers rebelled. In 1924, a group of armed ranchers seized the Alabama Gates and dynamited part of the system. This armed rebellion was for naught, and by 1928, Los Angeles owned 90 percent of the water in Owens Valley. Agriculture in the valley was effectively dead.

So there you have it, nearly a hundred years old and still going strong although improvements have been made over the years as cities expanded and the need for even more water became even more critical. For all you budding engineers out there, here's a more technical description…..

The California Aqueduct is a 444 mile (715 km)-long aqueduct in the United States that carries water from Northern California to Southern California. A typical section has a concrete-lined channel 40 feet (12 m) wide at the base and an average water depth of about 30 feet (9 m). The widest section of the aqueduct is 110 feet (33.5 m) and the deepest is 32.8 feet (10 m). The size of the channel varies according to how much capacity that section of the aqueduct was projected to need. The channel and pumping capacities at the start of the aqueduct are 10,300 and 10,670 cubic feet per second (292 and 302 m³/s), respectively. The largest channel capacity is 13,100 ft³/s (371 m³/s) and the largest pumping plant capacity (Dos Amigos) is 15,450 ft³/s (437 m³/s).

The aqueduct begins at the San Joaquin-Sacramento River Delta at the Banks Pumping Plant which pumps from the Clifton Court Forebay. Water is pumped by the Banks Pumping Plant to the Bethany Reservoir. The reservoir serves as a Forebay for the South Bay Aqueduct via the South Bay Pumping Plant. From the Bethany Reservoir the aqueduct flows by gravity approximately 60 miles (97 km) to the O'Neil Forebay at the San Luis Reservoir. From the O'Neil Forebay it flows approximately 15 miles (24 km) to the Dos Amigos Pumping Plant. After the Dos Amigos the aqueduct flows about 95 miles (153 km) to where the Coastal Branch splits from the "main line". The split is approximately 10 miles (16 km) south-southeast of Kettleman City. After the coastal branch, the line continues by gravity another 66 miles (106 km) to the Buena Vista Pumping Plant. From the Buena Vista it flows approximately 27 miles (43 km) to the Teerink Pumping Plant. After Teerlink it flows about 2.5 miles (4 km) to the Chrisman Pumping Plant. Chrisman is the last pumping plant before Edmonston Pumping Plant, which is 13 miles (21 km) from Chrisman. South of the plant the coastal branch splits off in a South Westerly direction to serve the central coast. At Edmonston Pumping Plant it is pumped 1,926 feet (600 m) over the Tehachapi Mountains.

Once it has crossed the Tehachapi's the aqueduct divides into two branches; the West and the East Branch. The East Branch feeds Lake Perris and the San Gorgonio Pass area, while the West Branch heads towards Pyramid Lake and Castaic Lake in the Angeles National Forest to supply the western Los Angeles basin.

Water flows through the aqueduct in a series of abrupt rises and gradual falls. The water flows down a long segment, built at a slight grade, and arrives at a pumping station powered by Path 66 or Path 15. The pumping station raises the water, where it again gradually flows downhill to the next station. However, where there are substantial drops, the water's potential energy is recaptured by hydroelectric plants. The initial pumping station fed by the Sacramento River Delta raises the water 240 feet (73 m), while a series of pumps culminating at the Edmonston Pumping Plant raises the water 1,926 feet (600 m) to cross the Tehachapi Mountains. The Edmonston Pumping station requires so much power that several power lines off of Path 15 and Path 26 are needed to ensure proper operation of the pumps.

The Department of Water Resources (DWR) operates and maintains the California Aqueduct, including two pumped-storage hydroelectric plants, Castaic and Gianelli. Gianelli is located at the base of San Luis Dam, which forms San Luis Reservoir, the largest off stream reservoir in the United States. The Castaic Dam and Castaic Power Plant are located on the northern end of Castaic Lake.