Time really does fly when you’re having fun! It has been nearly four months since I joined the Corps of Engineers and I’ve already visited three of the six major “projects” that are operated by the Seattle District. A “project” in Corps parlance is a large autonomous facility run by the Operations Division within the larger District. The six projects within Seattle District are the Ballard Locks, Howard A. Hanson Dam, Mud Mountain Dam, Chief Joseph Dam, Libby Dam and Albeni Falls Dam.
Two weeks ago I visited Chief Joseph Dam in Bridgeport, WA. This huge concrete dam on the Columbia River produces some 2600 megawatts of power, making it the second largest hydroelectric power producer in the United States. The dam is located about 50 miles upstream of the even larger Grand Coulee Dam. Besides operating the powerhouse, the Seattle District is responsible for all bridges and hydraulic steel structures within the dam. HSS include intake gates, bulkheads, stoplogs and spillway gates. I’m slowly learning dam jargon and terminology.
A bit closer to home is the Mud Mountain Dam, an earthen dam on the White River just outside of Enumclaw, WA. This dam is used solely for flood control. When it was completed, it was the largest earthen dam in the world. Access to the downstream outlet is via a dramatic switchback road down the downstream face of the dam itself. Mud Mountain also includes a weir and fish ladder assembly. Fish climb an Archimedes screw system, placing them in a tank for transport upstream.
But perhaps the most important project for Seattle District currently is the Howard Hanson Dam. This is also an earthen dam located on the Green River near Enumclaw. The dam creates a 221 square mile watershed and freshwater storage for the Western Washington area. Completed in 1962, the dam has prevented an estimated $23 billion in flood damage.
The Corps of Engineers just awarded a contract to construct a new fish passage facility at the Howard Hanson Dam valued at $657 million. This project will construct a new intake tower and fish transport system to help convey fish downstream of the dam. There are many parts to this complex project in addition to the tower and intake structure itself. New retaining walls, a new outlet tunnel and stilling basin along with a new access bridge will be constructed.
A consultant firm is onboard to help design the intake tower structure, with the other features being designed in house by USACE. Awarding the construction contract now will allow input from the contactor on the design with an option to build the facility. This will ensure the new facility is operational by 2030.
This has already been an interesting and rewarding project to be part of. I look forward to seeing this one come to fruition.
USACE awards Howard A. Hanson Dam fish passage contract
