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US Army Corps of Engineers

St. Paul District Website

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Mississippi River Locks and Dams 2–10 Miter Gates Replacement

U.S. Army Corps of Engineers, St. Paul District

Published Sept. 25, 2017

Updated: Sept. 26, 2023

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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 still being fabricated with installation planned for fiscal year 2024. New gates for Locks and Dams 6 and 7 are in fabrication and are scheduled for installation in summer of 2025.

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 2024.