ST. PAUL, Minn. – The U.S. Army Corps of Engineers, St. Paul District, emptied all of the water out of Lock and Dam 7 recently to complete maintenance.
Lock and Dam 7, Located near La Crescent, Minn., and La Crosse, Wis., will remain empty until March 12, allowing the Corps to perform major maintenance on it, while the navigation season is on hold for the winter. This rehabilitative work happens every 15 to 20 years on each of the 13 St. Paul District Mississippi River locks and dams. Lock and Dam 7 was last dewatered in 1995.
Lock and Dam 7, which is closed to the public during the rehabilitation, will be open to reporters for a tour of the dewatering, Wednesday, Jan. 11 at 10:30 a.m. Subject matter experts will be available for your questions. Reporters will need to wear steel-toed safety shoes or work boots. Hard hats, reflective vests and safety glasses will be made available for the tour.
Scheduled maintenance on the lock chamber during the dewatering includes concrete, miter gate and bubbler system inspections. The gates will be sandblasted and painted and the bubbler system is being replaced with a stainless steel system.
The lock is 110 feet wide by 600 feet long. Normal project upper pool elevation is 639 feet. Normal project lower pool elevation is 631 feet. Normal lift is 8 feet. It takes approximately 10.9 million gallons of water, or the equivalent of 16.5 Olympic swimming pools, to completely fill the lock chamber to normal upper pool levels. The lock needs approximately 3.9 million gallons of water to maintain the lower pool levels. It takes a minimum of seven minutes to raise the water from the lower pool level to the upper pool level.
The St. Paul District operates and maintains 13 locks and dams beginning at Upper St. Anthony Falls and ending at Lock and Dam 10. Each dam represents a critical step in the “stairway of water” that makes navigation possible between Minneapolis and St. Louis.
The U.S. Army Corps of Engineers, St. Paul District, serves the American public in the areas of environmental enhancement, navigation, flood damage reduction, water and wetlands regulation, recreation sites and disaster response. It contributes around $175 million to the five-state district economy. The 700 employees work at more than 40 sites in five upper-Midwest states. For more information, see www.mvp.usace.army.mil.
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NOTE TO EDITORS/REPORTERS: If you would like to attend the tour of the dewatered lock and dam, please contact Vanessa Hamer at 651-290-5201 or Shannon Bauer at 651-290-5108/612-840-9453.
Release no. 12-002