Lower Monumental Dam Lock - Washington
Posted by: 
Volcanoguy
N 46° 33.660 W 118° 32.212
11T E 382205 N 5157528
The navigation lock at Lower Monumental Dam on the Snake River near Kahlotus, Washington.
Waymark Code: WM89Z2
Location: Washington, United States
Date Posted: 02/24/2010
Views: 5
The Lower Monumental Dam is located on the Snake River at river mile 41.6 near the mouth of Devils Canyon. The dam is at the upper end of Lake Sacajawea, which is the reservoir formed by the Ice Harbor Dam, nearly 32 miles downstream. Behind the dam is Lake Herbert G. West, which extends upstream for just over 28 miles to Little Goose Dam. The Lower Monumental Dam is a concrete gravity-type dam with short earthfill abutments. The dam is 3,791 feet long and 100 feet high. The dam includes a spillway, powerhouse, navigation lock, and two fish ladders. Construction of the dam began in June 1961 and became operational in 1969.
There are four dams and locks on the Snake River which allow 140 miles of slack water navigation from the Columbia River to Lewiston, Idaho. The Lower Monumental Dam Lock is the second in the system. The lock lifts/drops river traffic 100 feet. The lock is a single-lift type with demensions of 86 feet by 666 feet.
A good view of the dam and lock is available from parking area below the dam at N 46° 33.624' W 118° 32.853'.
Waterway Name: Snake River
Connected Points:
Lock links Lake Sacajewea with Lake Herbert G. West.
Type: Lock
Date Opened: 01/01/1969
Elevation Difference (meters): 30.00
Site Status: Operational
Web Site: [Web Link]
Date Closed (if applicable): Not listed
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