Walla Walla District, U.S. Army Corps of Engineers

Corps seeks public input for McNary Master Plan Revision

The U.S. Army Corps of Engineers Walla Walla District has prepared a draft McNary Master Plan with an accompanying draft Finding of No Significant Impact (FONSI) and Environmental Assessment (EA) to revise the outdated 1982 McNary Master Plan. The Walla Walla District will be accepting public comments from July 10 through Aug. 10.

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Dworshak Dam changed many times during its design. The original plans in 1948 described that it would be 370 feet tall. Later plans increased the height to 570 feet, then 630 feet. When Dworshak Dam was constructed, its final height was 717 feet tall.

Larger than life: A history of Dworshak Dam

In May 1948, floodwaters on the Columbia River overtopped the cofferdam where construction was underway on McNary Lock and Dam. This flood, one of the largest on record, was one of many documented in the region since the mid-1880s. The propensity for flooding in the Northwest sparked much discussion about regional flood control.

Waiting in the wings: A history of Little Goose Lock and Dam

By 1962, Ice Harbor Lock and Dam had been built and construction of the second lower Snake River dam, Lower Monumental, was being passed to the US Army Corps of Engineers Seattle District. The third dam in the queue was right on the heels of Lower Monumental, but construction could not begin until the details of its downstream neighbor were determined.

'We’ll cross that bridge…': A history of Lower Monumental Lock and Dam

The construction of Lower Monumental Lock and Dam allowed for the development of an isolated region. Today, Lower Monumental allows convenient river crossing, as well as shoreline recreational opportunities. Boating is one of the primary activities enjoyed by visitors to the Lower Monumental Project. USACE parks along Lake West include six boat ramps, as well as multiple sites for picnicking and hiking. More than 6,900 acres of the project lands are open to public hunting.

photo of ice harbor spillway and photo of ice harbor powerhouse

From water to watts: A history of Ice Harbor Lock and Dam

Ice Harbor Lock and Dam boasts some of the most cutting-edge hydropower technology in the world. Two advanced technology turbines currently sit in the powerhouse, with a third one on the way. These new turbines were designed to improve fish passage and generate electricity more efficiently.

A step towards navigable waters: A history of McNary Lock and Dam

Today, McNary is an essential part of the river highway that was envisioned before the formation of the Walla Walla District. It sits as the midpoint, the last lock on the Columbia before the mouth of the Snake River. With its 14 generator units, McNary is also an incredible source of hydropower, capable of producing 980-megawatts or enough electricity to power about 686,000 homes.

Lucky Peak Dam became the first dam to be designed and constructed by the new Walla Walla District. Since its construction, Lucky Peak is estimated to have prevented over a billion dollars of flood damage.

Guarding the Treasure Valley: A history of Lucky Peak Dam

Every year, snowmelt from the surrounding mountains flows into creeks and streams that join the Boise River. When flows reach 7,000 cubic feet per second or higher, the river is considered at flood stage.

The Mill Creek Project is over 80 years old, older than the Walla Walla District, which will be celebrating its 75th Anniversary on Nov. 1, 2023. Since construction was completed in 1942, at least $300 million in potential flood damages have been prevented by the Mill Creek Project’s combined storage and channel operations.

Through fair or foul weather: A history of the Mill Creek Project

In 1931, a torrent of brown water roared down Mill Creek, with water levels rising at a rate of one foot per hour. The water escaped the confines of the riverbanks and rushed through the City of Walla Walla, destroying homes, roads and bridges. Born in the wake of this disastrous event, the Mill Creek Project now stands to protect the city from floods like this.

Welcome to the Walla Walla District!

The Walla Walla District constructs, operates, maintains, and secures multipurpose infrastructure to energize the economy, reduce flood risk, and serve as stewards of water resources for the Snake River Basin and the Nation.

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