Purpose
Locks and Dams (LD) 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
In order to allow watercraft to pass through stretches of river of various depths, Congress authorized a series of locks and dams along the Mississippi River. An integral part of those locks are miter gates.
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 collaboratively working on the design of new miter gates for 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 Locks and Dam 10 miter gates are still being fabricated with installation planned for fiscal year 2024. New gates for Locks and Dams 6, 7, and 9 will be next in the installation queue.
St. Paul district engineers are currently designing new miter gates for Locks and Dams 3, 4 and 5. These will be ready for fabrication contract award in 2023.
The district’s miter gate project delivery team is designing anchorage upgrades for Locks and Dams 3 and 4 with installation planned for the 2022-2023 river winter closure period.
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 2022:
Award of Gates at LDs 6, 7 & 9 $18,000,000
Installation of LDs 5A & 8 Gates $1,800,000
FY 2023:
Award of Gates at LDs 3, 4 & 5 $19,000,000
Upgrade of LDs 3 & 4 Anchorages $1,000,000