Chicago Harbor Lock

Chicago District
Published Jan. 9, 2024
Chicago Historic Photo Placeholder

Chicago Historic Photo

Project Description and Background

The lock was originally designed and built between 1936 and 1938 by the Metropolitan Water Reclamation District of Greater Chicago (MWRDGC). The lock was constructed as a component of the historic engineering project that reversed the flow of the Chicago River to prevent river water containing sewage from flowing into the lake and contaminating the city's drinking water. 

The lock chamber is 600 feet long x 80 feet wide x 22 feet deep. Filling/emptying is gravity-fed through partiallyopened lock gates, and there is typically a two to five-foot difference between Lake Michigan and Chicago River water levels. It takes about 12-15 minutes to cycle through the lock.  

The control house was replaced in 2007 with a more modern facility, which consolidates maintenance into one building and allows for near 360-degree visibility – improving security and speeds lockages during heavy traffic periods.  

In 2011, the Corps’ Chicago District completed a project to replace the structural steel sector gate leafs and associated hydraulic operating machinery. The new lock gates are designed to reduce repair and maintenance costs and prevent service disruptions. The new gates and operating machinery have fewer parts and are more reliable, and are modeled after the proven design of the Thomas J. O’Brien Lock.  

The Chicago Lock is fourth in the nation in terms of commercial lock usage and second in the nation in terms of recreational lock usage. On a busy day, 50-100 vessels can be locked at once. On average, the lock cycles 12,000 times annually. The lock sees an average of 711,902 commercial passenger one-way trips and 41,071 non-cargo vessel one-way trips (based on 2000 through 2010 data). In 2012, there were 10,480 lockages through the chamber - serving over 47,000 commercial, recreational, and government vessels; nearly 700,000 passengers; and 200,000 tons of commercial cargo.  

Current Status

Available funds will be used for operation and maintenance of existing structures, including Phase 3&4 Lock Chamber Wall repair, Lock Chamber Floor Repair, switchgear construction, breakwater repair, North Pier resurfacing, sector gate operating machinery repair, lock house renovations and parking lot re-pavement.

Construction activities in the lock chamber are scheduled from 16 Nov 2022 to 14 April 2023 to avoid impacts to commercial tour boats.

Funds provided through the Bipartisan Infrastructure Law (BIL) will be used for the Lock Chamber Floor Repair Phase 2 (West Floor).

Project Authorization

Rivers and Harbors Act of 1870, 1880, 1912, 1919, and 1962.