Los Angeles -L.A.- Aqueduct

What is the LA Aqueduct System

• Water is diverted from the Owens River near the Sierra Nevada mountains. The system is a gravity machine, requiring careful grading to keep water flowing without pumps.
• The California Water Wars The project was built amid shady dealings, souring relationships with Owens Valley residents, leading to acts of sabotage like bombing the aqueduct and seizing the Alabama Gates.
• Environmental Impact The diversion dried up Owens Lake, turning it into a massive source of dangerous dust pollution that LA is still trying to mitigate at a cost of over a billion dollars.
• Engineering Marvels The system utilizes inverted siphons to cross deep canyons (like Jawbone Canyon) and features the massive Elizabeth Tunnel to cut through mountain ranges.
• Power and Disasters The aqueduct generates hydroelectric power but also saw tragedy, notably the St. Francis Dam failure in 1928, which killed over 400 people.
• Modern Operations The terminal LA Reservoir uses 96 million shade balls to protect treated drinking water from sunlight and contamination.

How is the aqueduct water flow powered?

The entire Los Angeles Aqueduct system is a gravity machine  . It does not use pumps to push the water; instead, engineers carefully graded the system to leverage elevation changes over the 300-mile journey.Key details about the flow include:

Start elevation: The diversion from the Owens River is roughly 2,500 ft (750 m) higher in elevation than the terminal point in Los Angeles  .
Pressure sections: While mostly a free-flowing canal or conduit, the system uses inverted siphons to cross deep canyons, where the water becomes pressurized by the force of gravity .

What are the iconic shade balls for?

The 96 million black plastic shade balls floating on the LA Reservoir serve as a protective covering for the city’s treated drinking water . They were implemented to fulfill drinking water regulations by providing three key functions:

Preventing Water Chemistry Problems: By blocking sunlight, the balls stop reactions that can create harmful carcinogens in the water .
Contamination Control: They act as a physical barrier, keeping wildlife, dust, and other contaminants out of the water supply .
Reducing Evaporation: The balls help conserve water by decreasing the amount of water lost to the hot desert sun  .

Why did LA build a second aqueduct line?

According to the video, Los Angeles built a second aqueduct line in 1970 to increase the total flow of water into the city  . While the original open-top canal section was large enough to meet demands, the underground conduit sections were not, necessitating the construction of a second, parallel system to meet growing water needs .

What did the Alabama Gates actually do?

According to the video, the Alabama Gates served as a major flashpoint and focal point of resistance during the California Water Wars. Located along the aqueduct canal, these gates controlled the flow of water; by opening them, residents of the Owens Valley could divert the water back into the Owens River instead of allowing it to flow south to Los Angeles .The video details how rancher resistance flared when they seized these gates, symbolizing their attempt to regain control over their local water resources in the face of acquisitions by the city of Los Angeles .

How was Jawbone Canyon siphon pipe transported?

The steel pipe sections for the Jawbone Canyon siphon had to be specifically manufactured on the East Coast because that is where the major steel facilities were located . Due to their massive size, they were transported by ship all the way around Cape Horn to reach California, as the Panama Canal was still under construction at the time .

Why was the High Reservoir originally built?

The High Reservoir was originally built to serve as a buffer for the Los Angeles Aqueduct  . Due to the system’s vulnerability to vandalism, earthquakes, and other disruptions upstream, this reservoir allowed the city to maintain a steady water supply even if the aqueduct was temporarily shut down for repairs or due to sabotage .Additionally, the reservoir allowed the water to slow down, exposing it to the hot desert sun as a natural form of UV disinfection .