US Army Corps of Engineers
Chicago District Website Website

Chicago Harbor Lock – busiest in nation last year for lockages, vessels

Published March 4, 2020
Chicago Harbor Lock

Lockmaster Selwyn Tyrone Valley and Scott Kozak, Chicago Lock facility manager, conduct a group tour at the Chicago Harbor Lock during Chicago Architecture Center's “Open House Chicago," Oct. 20, 2019.

Chicago Harbor Lock

Scott Kozak, Chicago Lock facility manager, briefs a tour group at the Chicago Harbor Lock during Chicago Architecture Center's “Open House Chicago," Oct. 20, 2019.

Chicago Harbor Lock

Lockmaster Selwyn Tyrone Valley gives a group tour at the Chicago Harbor Lock during Chicago Architecture Center's “Open House Chicago," Oct. 19, 2019.

Chicago Harbor Lock

Chicago Harbor Lock, October 2019.

Chicago Harbor Lock

Lockmaster Selwyn Tyrone Valley talks Chicago and water safety to a group locking through the Chicago Harbor Lock, Oct. 19, 2019.

Chicago Harbor Lock

Chicago Harbor Lock, October 2019.

(March 4, 2020) – The Chicago Harbor Lock, located in Chicago and adjacent to Navy Pier, separates the waters of Lake Michigan from the Chicago River. It is one of two entrances from the Great Lakes to the Illinois Waterway System. And, according to its Lockmaster Selwyn Tyrone Valley, last year it hit a milestone.

“In terms of lockages and vessels, we were the busiest in the nation,” Valley said. “We had about 10,000 lockages, and saw an average of 1.16 million passengers, and almost 62,000 vessels.”

A 16-member team operates the lock 24/7. There are 10 operators, a lockmaster, a facility manager, a mechanic, an electrician, a facility services assistant, and an information technology specialist. Valley is in charge of the day-to-day operations at the Chicago Harbor Lock, and supervises the 10 operators. He also gives tours when requested, and arranges training of lock staff.

The lock chamber is 600 feet long x 80 feet wide x 23 feet deep. Filling/emptying is gravity-fed through partially-opened lock gates, and there is typically a two- to five-foot difference between Lake Michigan and Chicago River water levels. It takes about 15 to 17 minutes to cycle through the lock.

“While boaters are in the lock, we talk with them about safety and ensure they are following the rules for the lock and waterway,” Valley said.

The lock was originally designed and built between 1936 and 1938 by the Sanitary District of Chicago, which later became the Metropolitan Water Reclamation District of Greater Chicago (MWRD). It 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. Today, the Chicago River is much cleaner, but the lock continues to perform an important environmental function of separating Chicago River storm water from Lake Michigan.

MWRD operated and maintained the lock until 1984. An act of Congress transferred the operation and maintenance responsibility to the U.S. Army Corps of Engineers as part of its navigation mission. Then, in August 2014, all employees changed from contract employees to USACE employees. MWRD continues to maintain the water level in the Chicago River, and notifies Chicago Lock personnel when emergency water-level control (i.e. backflow) is needed. This is done by releasing the water from the river into Lake Michigan through the lock gates to reduce the risk of flooding.

“When we have large amount of rainfall and the river starts to rise, we work with MWRD to try to maintain the river level,” Valley said.

He explained that MWRD will open its sluice gates to start releasing water out to the lake, and if the gates are not bringing down the river level when we get to a + 2 water level on the river scale, we will open the river side gates and allow the water into the lock chamber. And if water continues to rise and gets to a + 3-3 ½, we are contacted by MWRD to open the lakeside gates to allow the river to flow to the lake. 

“We keep the gates open until MWRD contacts us to shut the gate,” Valley said. “It can go on for a few hours or a day which depends on amount of rain and time it takes for the river to drop.  During the backflow, no vessels are allowed in the chamber.”

The control house was replaced in 2007 with a more modern facility that consolidates operation into one building and, shaped like a ship, allows for near 360-degree visibility which improves security and speeds lockages during heavy traffic periods.

Valley said the biggest challenge today is the high lake levels. Also, during the boating season, he and his crew deal with “all types of impaired boaters” – especially on the big weekends like the 4th of July and Chicago Air and Water Show.

The harbor hosts a U.S. Coast Guard Station, Chicago Marine Police unit, Illinois Conservation Police unit, a Chicago Fire Department fire boat, and City of Chicago tug. The lock team, along with their partners, help promote the Corps’ water safety message as much as they can.

“Working with the Chicago Police Dept., Chicago Marine Fire Dept., Coast Guard and other partners is very important,” Valley said. “It’s important for the safety of the Chicago River and for Lake Michigan.”

“I am proud of the team for their professionalism and dedication to keeping the busiest lock in the nation operational year round,” Scott Kozak, Chicago Lock facility manager said. “And assuring the safety of the 1.2 million people that transit the lock annually.”