Mud Mountain Dam and Recreation area is located just four miles east of Enumclaw and just 2.5 miles south off of Hwy 410. The dam and recreational are are run by the US Army Corps of Engineers. Visitors to the facility, can view the dam, picnic, hike, bike or ride their horses in a scenic woodland setting. The Mud Mountain Dam is a 432 foot tall flood control dam protecting the lower White and Puyallup River valleys from flooding by holding back water from heavy rains and melting snow in its reservoir.
Congress authorized construction of Mud Mountain Dam with the Flood Control Act of June 22, 1936. Work began on August 25, 1939, but was halted by World War II. Construction resumed in 1947, and the dam was completed in 1948. At that time, it was the highest rock and earth-filled dam in the world. Fishway facilities in Buckley were finished in 1949, and the Rim Trail and picnic areas were added in 1980.
The core of the dam is a compacted blend of sand, gravel and glacial till. Upstream and downstream sides of the dam are crushed rock covered by large quarry rocks. The massive weight of the rock holds the core firmly in place. Two tunnels channel the river around and under the dam. A 9-foot-wide tunnel passes normal flows. A 23-foot-wide tunnel is used during periods of high flows and during floods.
Together, these structures have saved an estimated $308 million in flood damages. The project currently helps protect the homes and businesses of about 400,000 people. The 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 park contains picnic tables, playground, "kiddie" pool a large open space and two excellent trails. Vista Trail begins within the park and is 0.3 miles. Starting at the upper viewing platform, it winds down the hill to a lower and closer observation deck. Here are the best views of the dam itself.
The second trail is the Rim Trail. Starting just outside the park entrance, this trail extends north 2 miles along the edge of the bluff. If you are adventurous you can extend this walk down a gravel road to the rivers edge, then walk walk another three miles along the river itself. Just remember, during heavy rainfall this are will likely by flooded at the dam and the Army Corps put this facility to its primary purpose.
This facility has hours that vary depending on the time of year. At the time that this cache was placed the hours were Monday through Friday 8am to 4pm. Please check the current park hours here. As a result the cache has been placed along the rim trail just outside the gated area at a small overlook. If the park is closed when you arrive, you will have to walk approximately 0.5 miles round trip. If the facility is open you will have a quick 200 foot walk.
2016 was the 100th anniversary of the National Park Service, and to celebrate, Visit Rainier and WSGA hosted the Visit Rainier Centennial GeoTour - 100 caches placed in and around Mount Rainier National Park. The geocaches highlighted the rich history, scenic wonders, quaint communities, and hidden gems of the Rainier region. Participants received geocoin and pathtag prizes for finding all the caches.
