Lock and Dam No. 7[1] | |
Location Map: | Minnesota |
Location Map Size: | 300px |
Location Map Caption: | Location of the Lock and Dam No. 7 on the border of Minnesota and Wisconsin |
Coordinates: | 43.8669°N -91.3072°W |
Country: | United States |
Location: | Winona County, Minnesota La Crosse County, Wisconsin near La Crescent, Minnesota |
Purpose: | Navigation |
Status: | In use |
Opening: | April |
Operator: | U.S. Army Corps of Engineers, St. Paul District |
Dam Crosses: | Upper Mississippi River |
Dam Height Foundation: | NaN41 |
Dam Length: | NaN10860 |
Spillway Count: | 2 |
Spillway Type: | 5 Roller Gates 11 Tainter Gates |
Spillway Capacity: | NaN273000 |
Res Name: | Lake Onalaska Pool No. 7 |
Res Capacity Total: | NaN5000 |
Res Catchment: | NaN62340 |
Res Surface: | NaN13440 |
Res Elevation: | NaN636[2] |
Plant Hydraulic Head: | 25 |
Extra: | 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-1930s and placed in operation on April, 1937. It underwent major rehabilitation from 1989 through 2002. 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 system consists of a concrete structure 940feet long with five roller gates and 11 tainter gates, a segment of earth embankment 8100feet long from the dam to French Island separated by a concrete spillway 1000feet long, and another embankment 2400feet long from French Island to Onalaska which has a concrete spillway 670feet long. The lock is 110feet wide by 600feet long.[3] The lock and dam is one of the most visited because of its proximity to Interstate 90, and is clearly visible to travelers crossing the I-90 Mississippi River Bridge.