The Imperial Dam and All-American Canal Headworks

We started out from Yuma, Arizona, for Imperial Dam. Yuma is another agricultural area that is growing vegetables for the U.S. during the winter months. This is a field of lettuce.

These farmworkers outside of Yuma are harvesting cauliflower.
Dates are grown here outside of Yuma, as well as in the Coachella Valley.
The saltiness of the Colorado River water was evident in many places.
Imperial Dam, built in 1928, was authorized by the same legislative package that built Hoover Dam. The main function of the dam is to divert water into the All-American Canal, the Coachella Canal, the Gila Gravity Canal and the Yuma Project.
About a fifth of the flow of the Colorado River flows through here.
This aerial shot (from the BOR) shows how this is done. The basins on the left side are the desilting basins, and the All-American Canal is on the far left, leaving the bains. The California Sluiceway is off to the right of the desilting basins. The diversion works for Arizona's Yuma Project & the Gila Gravity Canal are on the right hand side of the picture.
Imperial Dam is a diversion dam, so there isn't a reservoir that builds up behind it. Because of the silt load of the river, dredging is needed every 7 years or so.
Here the water enters the headworks for the All-American Canal. These trashracks can collect a lot of trash due to the popularity of the river.
Here the water enters the headworks for the All-American Canal. These trashracks can collect a lot of trash due to the popularity of the river.
This Gantry Rake is used to clean the trashracks.
The rake loads the trash into carts where it is taken to a dumpster.
The water flows through the gate and then into desilting basins.
The water enters the desilting basin through a V-shaped structure in the center of the basin (in picture, off to the left) designed to distribute the water evenly. (Sorry, the shot of this is not so good.)
In the desilting basin, the water slows down and the sediments and silt sink to the bottom. Scrapers rotating on the bottom gather the sediments and push it to the sluiceway.
The clean water then flows over the weir and into the All-American Canal. The water spends 18 minutes in the desilting basins.
The sediments are flushed from the desilting basins into the California Sluiceway. This is technically what is left of the Colorado River once it leaves Imperial Dam.
Some water is released into the sluiceway to help move the sludge along.
This overflow weir, located between the California & Nevada sides, is here in case the water level gets too high. This occurs very rarely, as water is tightly controlled here.
Operations are monitored around the clock. Although the SCADA system is used, some of the original equipment is still in use as well.
This was pretty cool. It isn't used anymore, though.
The elevation, flow, and other details in all the canals controlled by Imperial Dam is carefully monitored. Records are kept, both by hand and in the computer.
These gates, located on the All-American Canal as the water is leaving the dam area, are used to maintain the elevation in the canal.
The water in the California Sluiceway flows south, and will eventually end up in Mexico.
The water from the sluiceway flows through Laguna Dam. Laguna Dam was originally built to serve the Yuma Project in the early 1900s, but the construction of the Imperial Dam made it obsolete.
The All-American Canal heads from Imperial Dam across the Algodones Dunes and into the Imperial Valley.
There is a nice park at Imperial Dam that is available for camping. What better place for us to camp at?, I say to the family. Funny, they don't seem to agree.....
We took some time to have our lunch by the river and enjoy the nice weather. Thanks to Marty, Vito & Doug for showing me around!

UPDATE: This post has been expanded into this presentation:

From Imperial Dam to the Salton Sea: The story of Imperial Valley's water

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