Lock and Dam No. 7

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Lock and Dam No. 7[1]
Mississippi River Lock and Dam number 7.jpg
Mississippi River Lock and Dam No. 7
Lock and Dam No. 7 is located in Minnesota
Lock and Dam No. 7
Location of the Lock and Dam No. 7 on the border of Minnesota and Wisconsin
Country United States
Location Winona County, Minnesota
La Crosse County, Wisconsin
near La Crescent, Minnesota
Coordinates 43°52′01″N 91°18′26″W / 43.86694°N 91.30722°W / 43.86694; -91.30722Coordinates: 43°52′01″N 91°18′26″W / 43.86694°N 91.30722°W / 43.86694; -91.30722
Purpose Navigation
Status In use
Construction began 1933
Opening date April 1937
Operator(s) United States Army Corps of Engineers
Dam and spillways
Impounds Upper Mississippi River
Height (foundation) 41 ft (12 m)
Length 10,860 ft (3,310 m)
Spillways 2
Spillway type 5 Roller Gates
11 Tainter Gates
Spillway capacity 273,000 acre·ft (0.337 km3)
Reservoir
Creates Lake Onalaska
Pool No. 7
Total capacity 5,000 acre·ft (0.0062 km3)
Catchment area 62,340 sq mi (161,500 km2)
Surface area 13,440 acres (54.4 km2)
Normal elevation 636 ft (194 m)[2]
Power station
Hydraulic head 25
NIDID# MN00587

Lock and Dam No. 7 is a lock and dam located on the Upper Mississippi River at river mile 702.5 near the cities of La Crescent, Minnesota and Onalaska, Wisconsin. It forms pool 7 and Lake Onalaska. The facility was constructed in the mid-1930's and placed in operation on April, 1937. It underwent major rehabilitation from 1989 through 2002.

The lock and dam system consists of a concrete structure 940 feet (286.5 m) long with five roller gates and 11 tainter gates, a segment of earth embankment 8,100 feet (2,468.9 m) long from the dam to French Island separated by a concrete spillway 1,000 feet (304.8 m) long, and another embankment 2,400 feet (731.5 m) long from French Island to Onalaska which has a concrete spillway 670 feet (204.2 m) long. The lock is 110 feet (33.5 m) wide by 600 feet (182.9 m) long.[3]


http://www.mvr.usace.army.mil/Portals/48/docs/CC/FactSheets/MISS/UMR%20Locks%20&%20Dams%20-%202016%20(MVD).pdf

See also[edit]

Notes[edit]

  1. ^ "The National Inventory of Dams (NID)". nid.usace.army.mil. United States Army Corps of Engineers. Retrieved 26 Mar 2017. 
  2. ^ Lake Onalaska on Topozone.com
  3. ^ "Lock and Dam 7". United States Army Corps of Engineers. Retrieved 2012-08-19. 

External links[edit]

Public Works Administration construction project 
PWA construction of Lock and Dam No. 7 
Lock and Dam No. 7 
Lock and Dam No. 7 
Locks and dams of the Upper Mississippi River
Upstream:
Lock and Dam No. 6
Downstream:
Lock and Dam No. 8