Fort Peck Dam is not the only massive structure holding back the rushing waters of the Missouri River, though it was the first to be constructed by the US Army Corps of Engineers. The Corps now manages six dams and reservoir projects along the course of the Missouri River, the longest river in North America.
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After Fort Peck Dam was completed in 1940, the Corps of Engineers built five additional dams on the mainstem Missouri River over the next 19 years. As you float downstream from Fort Peck, you would find Garrison Dam in North Dakota, Oahe, Big Bend, and Fort Randall in South Dakota, and Gavins Point on the South Dakota/Nebraska state line before hitting the Mississippi River at St Louis.

Once free-flowing with meandering channels, sand bars, and expansive tree-covered riparian areas, the river was allowed to carve its own banks, which were ever-changing. Seasonal flooding was a common occurrence impacting homes, farm ground and river navigation. The dams limit flooding most years, but there are always exceptions. Since 1940, there have been seven years when the volume of water run-off from the upper plains and entire eastern front of the Rocky Mountains was more water than could be held in Fort Peck Reservoir. At these times, water is sent through the Spillway, directly to the Missouri River, bypassing the hydropower and dam structure. Because the Spillway is in a drainage three miles east of the Dam, this flow keeps the dam structure safe. The historic precipitation seen in 2011 required 50,000 cubic feet per second of water going down the Spillway in addition to the maximum 15,000 cubic feet going through the hydropower plant.

There are several smaller dams upstream of Fort Peck at Great Falls and Helena. The four dredges which pumped muddy slurry to build Fort Peck Dam were operated by electricity generated at Rainbow Falls near Great Falls, MT, thus requiring the building of 288 miles of transmission lines.

The Corps of Engineers manages water flows at Fort Peck in combination with the other Corps dams on the Missouri. For example, water may be held back in Fort Peck Lake due to precipitation occurring downstream and the need to store water in corresponding reservoirs. Or certain demands for water in the river below Fort Peck Dam require flows even though Fort Peck Lake levels are low. Each action results in positive or negative impacts to a user group or fish and wildlife locally, up or down the river.

Progress is often coupled with controversy, and, while there is plenty of that as it relates to the Missouri River and its dams, they have also brought substantial economic, environmental, and social benefits like water storage for hydroelectric power generation, irrigation access, and recreational opportunities.