A Short History of Grand Coulee Dam and Lake Roosevelt

An engineering wonder in Eastern Washington!

Mar 17, 2024

This is part two of a series of articles about the proposed EPA Superfund site on the upper Columbia River. Before we proceed in reviewing the EPA’s proposed listing, it’s important to undertake a very quick review of the history of Grand Coulee Dam and Lake Roosevelt. In our next article, we’ll explore the EPA’s proposal but if we don’t understand the massive size of Lake Roosevelt, it’s hard to understand the scope of the proposed listing.

Grand Coulee Dam

The information is this section is from the Lake Roosevelt Forum, and is used with permission. Be sure to visit this great website for additional information.

Grand Coulee Dam is one of the largest concrete structures ever built! It contains about twelve million cubic yards of concrete, which is enough to build a standard 16 foot wide highway from Seattle to New York City to Houston to San Diego and then back to Seattle.

The dam is just shy of a mile at 5,228 feet long and is 550 feet high. The dam construction was started in 1933. In 1941, Grand Coulee Dam was essentially complete. The Left Power Plant began to operate and power generation was used to support the energy intensive needs of World War II.

When construction of the dam was completed in 1942, the waters behind the dam rose by 380 feet to an elevation of 1,290 feet above sea level. The reservoir (called Franklin D. Roosevelt or Lake Roosevelt for short) extends 150 miles north, and provides over 630 miles of shoreline. The Columbia River from the Canadian border to the dam was no longer free flowing.

As authorized by Congress in 1935, Lake Roosevelt and Grand Coulee Dam were designed to primarily support irrigation, flood control and power generation needs. Over time, Lake Roosevelt’s operations also sought to meet the recreation needs of up to 1.5 million people annually, and the water needs of downstream fisheries.

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The Columbia Basin Project

From 1942 to 1952, construction continued at Grand Coulee, with the development of additional power plants as well as the pumping plant and pipes needed to pump water from the Lake Roosevelt uphill to Banks Lake, a massive, 30 mile long reservoir, which serves as the initial storage reservoir for the Columbia Basin Project, which irrigates over 671, 000 acres in Eastern Washington. The total amount of the Columbia flow that is diverted into the CBP at Grand Coulee varies a little from year to year, and is currently about 3.0 million acre-feet. This is about 3.8 percent of the Columbia's average flow as measured at the Grand Coulee dam.

Lake Operations

Lake operations refers to the ability of the Bureau of Reclamation, in concert with the U.S. Army Corps of Engineers (the Corps), the National Oceanic and Atmospheric Administration (NOAA) Fisheries, the Bonneville Power Administration (BPA) and other agencies, to raise and lower lake levels to meet irrigation, flood control, power generation, fishery, recreational and other needs.

From an operations perspective, the lake can fluctuate between minimum and maximum lake elevations. At its maximum, the lake’s elevation can rise to 1,290 feet above sea level and can hold over 9,000,000 acre-feet of water. That’s enough water to cover the states of Washington and Oregon with more than one inch of water.

The minimum lake level for normal operations is 1,208 feet above sea level. So if you can imagine raising and lowering water within an eight story building that’s one half to one mile wide and over one hundred miles long, that’s the “box” within which Lake Roosevelt’s operations are managed.

Part of the importance of Lake Roosevelt is also its ability to refill. The run-off from rivers and tributaries into the lake allows it to refill about seven times in an average water year. By comparison, one of the other large reservoirs in the region, Hungry Horse, could not refill in the same year if it were emptied.

Considering the fact that Lake Roosevelt holds 9 million acre-feet of water, and that natural run-off allows it to refill seven times in an average year, we can start to understand the massive size of the Columbia River watershed and Lake Roosevelt.

The Colville Tribes and the Spokane Tribe were the most negatively impacted by this project, with the destruction of the salmon fisheries above the Dam, as well as important heritage sites, villages, and sacred places. Only recently have the Colville tribal members begun reintroducing salmon above the dam at Kettle Falls, and the local communities all have high hopes that these efforts will be successful.

Coming Next

Now we have a better understanding of the size of the Columbia River and the Grand Coulee Dam, and the benefits the dam provides of irrigation, reliable green power generation, flood control, recreation and fishery management.

In future articles, we will examine the sources of pollution in the upper Columbia River, the types of pollution, and the history of the cleanup and testing that began in 2006 and continues to this day. After that, we will review the arguments for and against the proposed listing, and provide more information on how to comment on this proposal.

The 60-day comment period began on March 7, so we still have time to educate ourselves on the proposal and the science supporting it. Comments will be more effective if they specifically point to problems in the process and the science, rather than merely supporting or opposing the proposal.

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