The climate is cool in the summer with mild winters. Annual precipitation ranges from 40 inches in and about the Sound to more than 120 inches in the mountains. Return to top of page. An outlet for American Lake was provided to eliminate flooding along the perimeter of the lake. An energy dissipator, an inlet weir, and an open channel conduit direct high water through Sequallitchew Lake and Creek to Puget Sound.
Pierce County is responsible for maintenance.
Return to top of page. Underway Mud Mountain Dam is on the White River, about six miles southeast of Enumclaw on the boundary of King and Pierce Counties. Completed in 1948, the project provides flood control for the White and Lower Puyallup River valleys and Tacoma's industrial area. The structure is an earth and rockfill dam standing 432 feet above bedrock. The reservoir has a storage capacity of 106,000 acre-feet of water and is capable of controlling floods 50 percent greater than the maximum flow of record.