Tacoma Power Parks are available to you and your family for camping, boating, fishing, water skiing, nature watching and day use. Parks are located in western Washington on the shores of lakes formed by our hydroelectric dams such as Mossyrock Dam, which generate clean, renewable electricity. Tacoma Power’s Mossyrock Park is a family-friendly getaway with access to Riffe Lake (formed by Mossyrock Dam) in Lewis County, Washington. The new boat launch was built in 2018 due to changes to Riffe Lake levels. A new swim area with an access trail and ADA-accessible parking were also added. It is located near the boat launch.