Corps revising master plan at Howard Hanson Dam, seeks public input

Changes also coming to Mud Mountain Dam

U.S. Army Corps of Engineers officials are revising the Howard A. Hanson and Mud Mountain Dams Master Plans, and seeking public input.

Corps officials will also be available at three public events to answer questions and provide information about the dams, master plans and the master planning process.

As steward of lands and waters at the dams it manages for the nation, Corps officials use the master plan as a strategic land use management document, according to a Corps news release. It guides comprehensive management and development of all project recreational, natural and cultural resources throughout the dam’s life.

The original master plans were developed about 20 years ago and do not reflect current conditions at the dams. Changes in Corps regulations and community needs necessitate a revision, or update, to the plan. The revisions will classify the government lands around the dam based on environmental and socioeconomic considerations, public input and an evaluation of past, present and forecasted trends.

The public can begin providing input April 11 by sending comments to To find out more information visit the Corps’ Seattle District booth at the Washington State Spring Fair from 10 a.m. to 6 p.m., April 11-14.

The two other public event opportunities are:

• April 22, Enumclaw City Hall (1339 Griffin Ave.)

5 to 6:30 p.m., in the Enumclaw City Council chamber

7 to 8:30 p.m. outside the chamber – Operations Project Manager Kevin Heape will give a presentation to the Enumclaw City Council on the Master Plan revision

• May 11, Mud Mountain Dam (30525 SE Mud Mountain Rd, Enumclaw)

9 a.m. to 3 p.m., at the dam’s recreation site during the Corps’ Dam Safety Day and Daffodil Valley Volkssport’s “Just another dam walk.”

“We are looking for public input applicable to environmental stewardship of the lands and outdoor recreation,” said the dams Operations Project Manager Kevin Heape. “Flood risk management, fish passage, water supply, facility design and daily operations are included in other plans.”

Deadline for public input during the scoping period is May 15. The next public input opportunity is during public review of the draft master plans and environmental assessments anticipated in spring 2020.

Howard A Hanson Dam is an earthen dam on the Green River, 21 miles east of Auburn. The dam was authorized by the Flood Control Act of 1950 and completed in 1962. It is a multipurpose project that includes flood risk reduction, fish conservation, water supply and ecosystem restoration. Flood risk reduction is focused on the highly developed Green River Valley. It has prevented an estimated $21.5 billion in flood damage. The dam and its reservoir is closed to the public as it lies entirely within the City of Tacoma municipal watershed.

Mud Mountain Dam is an earthen dam, with a concrete cutoff wall in the core, on the White River, 5 miles southeast of Enumclaw. The dam was authorized by the Flood Control Acts of 1936 and 1944 and completed in 1948. It is flood risk reduction dam protecting the lower White and Puyallup River valleys.

Mud Mountain Dam regulates flooding by holding back water from heavy rains and melting snow in the reservoir, then releasing it slowly back into the river. The reservoir is usually empty, except for the normal flow of the White River. Completely filled, the reservoir would stretch 5.5 miles and cover 1,200 acres. The Corps also made channel improvements and built levees on the lower Puyallup River. Together, these structures have saved an estimated $308 million in flood damages and currently helps protect the homes and businesses of about 400,000 people.