Merwin Dam

Merwin Dam (also known as Ariel Dam^[3]) is a concrete arch gravity-type hydroelectric dam on the Lewis River, in the U.S. state of Washington. It is located on the border between Cowlitz County and Clark County. Its reservoir is called Lake Merwin.

Merwin Dam
Location	Clark / Cowlitz counties, Washington, USA
Coordinates	45°57′24″N 122°33′18″W
Construction began	1929
Opening date	1931[1]
Operator(s)	Pacificorp[1]
Dam and spillways
Impounds	Lewis River
Height	313 feet (95 m)
Length	1,250 feet (381 m)[1]
Reservoir
Creates	Lake Merwin
Total capacity	422,000 acre-feet (0.521 km3)[1]
Catchment area	731 square miles (1,890 km2)[1]
Surface area	3,921 acres (15.9 km2)[1]
Power Station
Commission date	1931/1949/1958
Turbines	3 x 45 MW Francis-type, 1 x 1 MW[2]
Installed capacity	136 MW
Annual generation	511,534 MWh

On November 24, 1971, the dam was fully lit allegedly giving the skyjacker D. B. Cooper an identifiable landmark when he jumped from a Boeing 727 passenger liner. Cooper had ransomed 200,000 dollars from Federal Authorities after holding hostage the 727 and its passengers in Seattle.^[4]