It's hard to miss the impressive dams in the U.S. There are hundreds, especially in the mountainous stretches of Arizona, California, Washington, and Montana. Whether embankment, concrete, or even sometimes steel, these dams are all helping the US to manage its water for potable water, power, irrigation, flood defence and recreation. We couldn't let these go unvisited, so here's a little taste of a few we've been to. Time for some Dam Top Trumps Trivia:
The prima donna:
1. Hoover Dam, Colorado River, Arizona/Nevada
This is the big one, the one we've all heard about, the iconic dam that likes to take centre stage...
Built: 1931-1935 as part of the New Deal era. Design: Concrete Arch Dam
Special Features: Art Deco-detailed dam was easily the most expensive engineering project in the country at the time.
Height: 726 feet (tallest at the time)
Records: Now the second-tallest dam overall and the tallest concrete dam, in the U.S.
Concrete: 3,250,000 cubic yards
Length of Dam: 1,244 ft
Reservoir: holds back the Colorado River in Lake Mead, the largest man made reservoir in the country.
Location: straddles the border between Arizona and Nevada near Boulder City, Nevada, a town originally created for the project's workers.
The picture below shows the intake towers upstream of the dam, and the top photo the dam and reservoir, note the watermark around the rock showing how low the water level is.
The spillway channels on either side were used to re-route the Colorado during construction, and have only been used twice in recent history. In 1941 as a system test, and during floods of 1983. They are vast. Shown below, the diameter is 50ft. Each spillway can handle the flow of Niagara Falls!
And here's just a little photo of our mascot Bonneville living life on the edge.
The hero: 2. Grand Coulee Dam, Columbia River, Washington
We hadn't heard about this one until we came to the U.S., maybe you have, but if not, here's an unsung hero who does a lot of work (and has the best visitor centre!) Built: 1933 - 1941 as part of the New Deal era. Third powerplant added 1967 - 1974 which involved the bold move of blowing up part of the existing dam to make room for the powerplant. You can see where the rock was cut to make room for the powerplant in the centre of the photo below. This powerplant alone creates enough electricity that it could power Portland and Seattle on its own if needed.
Design: Concrete Gravity Dam Special Features: spans the Columbia River for nearly a full mile. Height: 550 feet Records: Creates the most hydroelectric power of any dam in the U.S. with a generating capacity of 6,809 megawatts (roughly 21 billion kilowatt hours of electricity annually). (The hoover dam has a total capacity of 2,078 megawatts).
Concrete: 11, 975,521 cubic yards
Length of Dam: 5,223 ft Reservoir: holds back the Columbia River in the Franklin D. Roosevelt reservoir reaching nearly all the way back to Canada.
Location: near Spokane, right beside Grand Coulee town, originally created for the project's workers.
Not only used for power provision to the grid, the dam has a pump-generating plant that pumps water 280 ft up to Banks Lake, the equalizing reservoir for feeding irrigation to 670,000 acres of farmland in the Columbia Basin Project. The plant uses reversible pumps so that during peak periods of power demand water can be run back through them from Lake Banks.
You can just see the pipes at the top of this photo.
Can you tell that I found this dam the most interesting and impressive!? The main thing now is to try to enable fish passage... Hopefully I'll get in a blog about that before the end of the trip.
For more information on this dam visit their website and watch the construction video at:
usbr.gov/pn/grandcoulee/history/construction/
The best friend: 3. Glen Canyon Dam, Colorado River, Arizona
None of the large dams would be half as effective if it weren't for dams like this one which are crucial for water management. And it's not exactly small itself. (Sorry for the jaunty photo angle, it was the only way I could get it in!) And no, that's not a football pitch at the bottom.
Built: 1956 -1966, it was thought of before the Hoover Dam but built afterwards
Design: Concrete Arch-Gravity Dam Height: 710 feet Records: During the dam's construction, the Glen Canyon Bridge, a steel arch bridge spanning the river's canyon, became the highest arch bridge in the world at the time of its 1959 completion. Concrete: 5,370,000 cubic yards Length of Dam: 1,560 ft Reservoir: holds back the Colorado River in Lake Powell, the second-largest man-made reservoir in the U.S. Location: Page, Arizona, a town originally created for the project's workers (you'll see the theme emerging with this point!)
Glen Canyon helps manage water distribution in the river's basin and, along with hydroelectricity generation, can help hold onto runoff for lean water years while ensuring fewer droughts for those downstream. It's been fascinating to learn about the catchment areas and water management plans in the U.S. I had no idea that the lower 48 states relied so heavily on 3 major catchments, those of the Mississippi, Colorado, and Columbia Rivers. With this comes a lot of interstate water management negotiations. It took years for the 7 States that rely on the Colorado to agree before the Hoover Dam could be built, and in total it took 51 years for these states to finally agree what is now referred to as 'the law of the river'. It's a constant balancing game of storing, releasing, and using water, and requires a lot of inter-state teamwork. It made me wonder, how many people here are aware of where their water actually comes from? And for that matter, on a much smaller scale, I wonder how many people in the UK know where their water source originates. As you may be able to tell, I could talk about these dams for a good while longer, and I have a lot more information, so if you'd like to know anymore please contact me.