Purpose
Locks and Dams 2 through 10 have used the same miter gates since their construction in the 1930s. Over time, the gates have been damaged and distressed, which has led to serviceability and safety issues. This project will replace the gates and the anchorages system, increasing navigational longevity and operational readiness while decreasing repair costs and downtime due to maintenance or failure.
Location
Upper Mississippi Locks and Dams 2 through 10.
Description
To allow watercraft to pass through stretches of river of various depths, Congress authorized a series of locks and dams along the Mississippi River. Miter gates and the anchorage systems upon which they rest are an integral part of those locks.
Miter gates are comprised of two leaves that provide a closure at one end of a lock at a “miter” or angle. Each lock has a set upstream and downstream. In addition to other systems, these gates allow water levels within the lock to go up and down.
Status
Two U.S. Army Corps of Engineers’ districts — St. Paul and Rock Island — have been collaborating to design and install new miter gates for the Locks and Dams in the Upper Mississippi. To comply with modern design codes and best practices, the new miter gates are significantly heavier than the originals. Thus, the Corps is also upgrading miter gate anchorages.
In fall 2018, the Corps awarded a fabrication contract for gates at Locks and Dams 5A, 8 and 10. Fabrication began in fiscal year 2019. During June and July 2022, Corps crews installed new gates at Locks and Dams 5A and 8. The new Lock and Dam 10 miter gates are complete with fabrication and will be installed in August 2024. New miter gates for Locks and Dams 6, 7 and 9 are in fabrication. The Locks and Dams 6 and 7 gates are scheduled for installation in summer of 2025. The Lock and Dams 9 gates are scheduled to be installed in summer of 2026.
St. Paul engineers have completed designing new miter gates for Locks and Dams 3, 4 and 5. The Locks and Dams 3 and 4 miter gate fabrication contract is currently out for bid and on track for a fiscal year 2024 award. The Corps will advertise the Lock and Dam 5 miter gate fabrication contract in the future according to the operations division’s budget priorities.
Authority
Congress authorized the Upper Mississippi River 9-Foot Channel Navigation Project as part of the Rivers and Harbors Act approved July 3, 1930.
Funding
Miter gate replacement design and construction at the locks and dams are 100% federally funded.
FY 2024:
Gate Fabrication Award for LDs 3 & 4 $12,000,000
Installation of LD 10 Gates $1,000,000
FY 2025:
Installation of LD 6 and 7 Gates $2,000,000
Gate Fabrication Award for LD 5 $10,000,000