New Lock at the Soo

Sault Ste. Marie, Michigan

Detroit District
Published Jan. 10, 2024
Updated: Jan. 12, 2024
The New Lock at the Soo Artistic Rendering depicts how the Soo Locks will look once the New Lock at the Soo is complete in Sault Ste. Marie, Mich.

The New Lock at the Soo Artistic Rendering depicts how the Soo Locks will look once the New Lock at the Soo is complete in Sault Ste. Marie, Mich.

Aerial image of the Soo Locks facility looking west at the New Lock at the Soo construction to the north of the facility.
SLIDESHOW | 5 images | New Lock at the Soo major construction continues The U.S. Army Corps of Engineers New Lock at the Soo project remains on schedule as major construction continues with phases 2 and 3 this season in Sault Ste. Marie, Michigan.
The project will provide much-needed resiliency at the Soo Locks with the construction of the New Lock at the Soo. The New Lock at the Soo will be the same dimensions as the Soo Locks’ largest lock, Poe Lock, 1,200 feet long, 110 feet wide and 32 feet deep. 

The New Lock at the Soo is being built in the footprint of the existing Sabin Lock, the northern most lock of the four on the Soo Locks facility, opened in 1919. The construction program, which includes improvements to the northern approach channel, is occurring in three phases of work. 
-Phase 1 work included deepening the upstream approach to the northern channel from 24 feet to 30 feet deep so modern vessels can approach the New Lock at the Soo. 
-Phase 2 work includes rehabilitating the upstream approach walls to guide vessels into the New Lock at the Soo and will allow the vessels to moor on the wall. The existing approach walls in the northern channel are the same age as the existing Sabin and Davis Locks, over 100 years old. 
-Phase 3 work includes demolishing the existing Sabin Lock, infilling the Davis Lock, constructing a new pump well and constructing the New Lock at the Soo chamber. 

Soo Locks Hydro Plant Tail Race Closures

The Soo Locks Hydro Plant Tail Race is currently closed Mondays at 6 a.m. to Saturdays at 6 p.m. and open Saturdays at 6 p.m. to Mondays at 6 a.m.

The closure is necessary as New Lock at the Soo construction will have many large marine-based construction barges and equipment in the area, causing an unsafe area for recreational boaters. 

To be added to the Tail Race alert notification system, contact 906-259-2841. 


The Soo Locks are often called the lynch pin of the Great Lakes Navigation System. 88% of the commercial commodities are carried by ships transiting the Soo Locks and are limited by size to the Poe Lock. Due to aging and deteriorating infrastructure, unscheduled outages are increasing. The economic impact of a 30-day unscheduled closure of the Soo Locks is $160 million (in 2015 numbers).

1986: Water Resources Development Act of 1986: Authorized Construction. 

2005: A Limited Reevaluation Report (LRR) completed in 2005 calculated a Benefit to Cost Ratio (BCR) of 0.73 associated with construction of a second Poe-sized lock. The report assumed that current rail infrastructure could handle commodities impacted by an outage of the Poe lock. It also assumed negligible probabilities of failure, based on past performance.                

2005: Benefit Cost Ratio Issues:

  • Assumption that 100 percent of commodities are delivered
  • Rail capacity was assumed as sufficient
  • Assumption of major overhaul in 2017
  • Probabilities of component failures have increased
  • Assumption of new vessels being Mac Lock-Sized                                                                                          

2007: Water Resources Development Act of 2007: Construction at 100 percent federal expense.

2014: The U.S. Army Corps of Engineers conducted a Partial Benefits Analysis to determine if some benefit categories were not captured or insufficient information was used. Partial Benefits Analysis: Expert elicitation held with two dozen stakeholders reliant on Soo Locks to determine how lock closures affect business and what their response would be to a significant lock outage Due to the results of the Partial Benefits Analysis, the U.S. Army Corps of Engineers decided that an Economic Reevaluation was needed.

2018: Economic Validation Study Complete

2018: Water Resources Development Act of 2018: Project authorized.

The U.S. Army Corps of Engineers utilizes a planning process in evaluating sustainable solutions for the Nation’s Civil Works projects. This planning process follows the six-step process defined in the federal Principles and Guidelines (P&G) for Water and Related Land Resources.

In planning Corps’ Civil Works projects, the National Environmental Policy Act (NEPA) and the P&G require that an array of reasonable alternatives be evaluated. The P&G further requires that the alternative plan with the greatest net economic benefit consistent with protecting the nation’s environment (the NED Plan) is to be selected.

Benefit Cost Analysis is the most common method for comparing alternatives and exploring net effects of each alternative. Comparing possible alternatives (or different plans) is important to identify the most important effects and to compare those effects between alternatives (advantages and disadvantages of each plan).

This presentation is current as of Sept. 7, 2023. All data are subject to change after Sept. 7, 2023.

Visit the Soo Locks project page to learn about the history and significance of the Soo Locks.

See the world-renowned Soo Locks in person! Visit our recreation page to learn more.

New Lock at the Soo Project Team