Lock and Dam No. 4

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Lock and Dam No. 4
Mississippi River Lock and Dam No. 4
Location of Lock and Dam No. 4 in Wisconsin
Location	Alma, Buffalo County, Wisconsin / Greenfield Township, Wabasha County, Minnesota, United States.
Coordinates	44°19′32″N 91°55′13″W / 44.32556°N 91.92028°W / 44.32556; -91.92028
Construction began	1932; 92 years ago (1932)
Opening date	May 1935; 89 years ago (1935)
Operator(s)	U.S. Army Corps of Engineers, St. Paul District
Dam and spillways
Impounds	Upper Mississippi River
Length	1,367 feet (416.7 m) (movable portion)
Reservoir
Creates	Pool 4
Total capacity	878,000 acre⋅ft (1.083 km3)
Catchment area	57,100 sq mi (148,000 km2)

Lock and Dam No. 4 is a lock and dam located near Alma, Wisconsin and Kellogg, Minnesota on the Upper Mississippi River around river mile 752.8. The lock and dam are owned and operated by the St. Paul District of the United States Army Corps of Engineers-Mississippi Valley Division.

The lock and dam was constructed and placed in operation in May 1935. There were ten major injuries and three deaths recorded during construction of the facility. Its last major rehabilitation was from 1988 to 1994.

• Lake Pepin, located above Lock and Dam No. 4
• Upper Mississippi River National Wildlife and Fish Refuge

Wikimedia Commons has media related to Mississippi River Lock and Dam number 4.

• U.S. Army Corps of Engineers, St. Paul District: Lock and Dam 4
• U.S. Army Corps of Engineers, St. Paul District: Lock and Dam 4 brochure
• Historic American Engineering Record (HAER) No. WI-47, "Upper Mississippi River 9-Foot Channel, Lock & Dam No. 4, Alma, Buffalo County, WI", 118 photos, 12 data pages, 7 photo caption pages