Twin Cities locks and dams scoping documents


Lower St. Anthony Falls (LSAF) Lock and Dam is located on the Mississippi River, near river mile 853, in Minneapolis, Minnesota. LSAF was constructed and in operation in September 1956. The dam consists of a 275-foot-long concrete spillway and is 56 feet wide by 400 feet long and has four Tainter gates. The structure is connected to a short earth embankment owned by Xcel Energy Company.

Lock and Dam 1 (LD1) is located on the Mississippi River, near river mile 847, in Minneapolis, Minnesota.  LD1 was constructed in 1917 and reconstructed in 1929. The main lock was completed in May 1932. The dam consists of a 574-foot-long Ambursen concrete overflow structure, the lock chamber is 56 feet wide by 400 feet long. LD1 is the only lock within the St. Paul District that is a twin lock. The twin, or river lock is also 56 feet wide by 400 feet long.  

Congress directed the closure of Upper St. Anthony Falls (USAF) Lock and Dam in 2014, traffic ceased in June 2015. Both LSAF and LD1 have been affected by the decrease in demand for navigation services stemming from the closure of USAF Lock and Dam. Commercial navigation traffic had a steady flow enroute to the Minneapolis Harbor located upstream of USAF.

A disposition study was reinitiated on LSAF and LD1 in August 2022. The disposition study will evaluate whether LSAF and LD1 should be deauthorized, and if the associated real property and government-owned improvements should undergo disposal. This study is authorized by Section 216 of the Flood Control Act of 1970 (33 U.S.C. § 426 et seq.) as amended.

Current Status:

In October 2022, the Corps held meetings with the public, resource agencies and non-governmental agencies to begin the scoping process. A summary of scoping comments received was developed and posted to the project website in May 2023. Other ongoing actions include assessing the current recreational use of LD1 and LSAF. A summary of the recreational assessment will be shared upon completion in Spring 2024. 

A draft disposition study report and recommendations will be prepared following receipt of federal funds. LSAF and LD1 have not been deauthorized by Congress. The Corps continues to maintain the LSAF and LD1 sites for navigation.

Lower St. Anthony Falls Lock and Dam and Lock and Dam 1 Section 216 Disposition Study Scoping

Scoping Document (PDF)
Appendix A Information on Scoping Events (PDF)
Appendix B Frequently Asked Questions (PDF)
Appendix C Scoping Comments (PDF)
Appendix D Pulbic Comments Part 1 (PDF)
Appendix D Public Comments Part 2 (PDF)
Appendix E Summary of Scoping Comments (PDF)


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U.S. Army Corps of Engineers
Project Management
Minneapolis Locks Disposition
332 Minnesota St., Suite E1500
St. Paul, MN 55101

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