Riffe Lake

Riffe Lake is a 23.5 mi (38 km) long reservoir on the Cowlitz River in the U.S. state of Washington. It was created in 1968 (1968) with the construction of Mossyrock Dam by Tacoma City Light (now Tacoma Power).[2] Originally named Mossyrock Lake, then later as Davisson Lake after a utilities commissioner in Tacoma, the lake was renamed in 1976 after the community of Riffe, which was inundated by the lake.[4][5] The residents of Kosmos and Nesika were also relocated as the lake's water level would submerge all of Nesika and much of Kosmos.[5]

Riffe Lake
Riffe Lake Show map of Washington (state) Riffe Lake Show map of the United States
Location	Lewis County, Washington, United States
Coordinates	46°32′4″N 122°25′43″W[1]
Type	reservoir
Primary inflows	Cowlitz River
Primary outflows	Cowlitz River
Catchment area	1,400 sq mi (3,630 km2)[2]
Basin countries	United States
Max. length	23.5 mi (37.8 km)[2]
Surface area	11,830 acres (47.9 km2)[3]
Max. depth	360 feet (110 m)
Shore length1	52 mi (83.7 km)[2]
Surface elevation	778.5 ft (237 m)[2]
References	[1][2][3]
1 Shore length is not a well-defined measure.

The lake contains species of fish including rainbow and brown trout, landlocked coho, bass both large mouth and small mouth, bluegill, crappie, and perch.[4]

In 2017, Tacoma Power lowered the maximum water level of the lake by 30 feet (9.1 m) due to concerns that the Mossyrock Dam could fail during a major seismic event and cause catastrophic flooding.[6]