Big machines and bigger innovations are hard at work upgrading one of the smallest locks on the Ohio River.
The Pittsburgh District of the U.S. Army Corps of Engineers (USACE) is going big — literally — at Montgomery Locks and dam in Monaca, Pa., northwest of Pittsburgh, where one of the region's most ambitious infrastructure projects is under way: a nearly $1.6 billion project to build a new primary lock chamber in place of one roughly half its size.
The new chamber is part of the Upper Ohio Navigation project and aims to conduct major construction at the Emsworth, Dashields and Montgomery locks and dams, which are all nearly a century old and the smallest locks on the entire Ohio River.
The USACE first built the Montgomery facility in 1936, and it continues to play a critical role in regional commerce. Every year, between 12 and 20 million tons of cargo — from fuel to building materials — pass through the facility, supporting the Port of Pittsburgh and the broader inland navigation system.
Although the existing infrastructures have exceeded their 50-year operational life, Montgomery, like the others, has undergone significant rehabilitation and modernization by the district throughout the decades. However, continuing to piecemeal maintenance and rehabilitation brings risk and carries steep economic stakes.
A lock like the one at the Montgomery site works like a set of stairs for boats along the Ohio River.
"We have pools that are next to each other, and the lock chamber is like the elevator," said Col. Nicholas Melin with the USACE, the federal agency that is shepherding the structural improvements. "So, when a boat is coming upriver, it drives up to the lock chamber, it enters, the doors close, the water drops and then it drives out the other side."
The locks and dams maintain consistent water levels, so that parts of the river are not too dry in the summer or flooded during the winter, and boats pushing millions of tons of commodities can move along smoothly.
However, over the years, cracks and leaks in the structure of the Montgomery Locks threatened their ability to lock boats through, according to Melin.
"If those lock chambers shut down, no boats can move on the Ohio River to the point of Pittsburgh, [and] commerce [and recreation] stops on the river," he told public radio station WESA in the Steel City.
Were that to happen, he said, those loads shift to roads and rail, which would significantly increase emissions, traffic congestion and shipping costs. Even a single year-long closure at Montgomery could cost nearly $150 million and force shippers to reroute cargo to more than 100,000 railcars or 400,000 trucks.
The upgraded lock chamber is designed not only to support larger commercial tows than the existing river chamber can, but also to reduce delays, increase resiliency and ensure navigational reliability for decades to come, according to the USACE.
Eight Years of Work Ahead on Montgomery Locks
The Montgomery, Emsworth and Dashields locks were all rehabilitated in the 1980s, but by the early 2000s, the locks had deteriorated to the point that the USACE began looking at how to replace them.
Eventually, Congress approved the Upper Ohio Navigation Project in 2026. The work to replace the Montgomery Lock got a boost when it received $961 million in funding from the Bipartisan Infrastructure Law of 2021, and construction started in 2024, WESA noted.
As things currently stand, the three locks create a bottleneck for boats on the Ohio due to their small size. Each lock has a main lock chamber as well as a smaller, backup ancillary chamber. The main chambers are each 600 ft. long, which allows up to a nine-barge tow — about the equivalent of 1,500 trucks on the road — to pass through.
Plans call for its main chamber to remain open during construction and demolish the smaller, 360-ft.-long ancillary chamber. Construction crews will then build another 600-ft. chamber over that footprint to nearly double its capacity.
Since work started last year, the USACE said that contractors have been mobilizing construction equipment, building key infrastructure such as an on-site concrete batch plant, demolishing the existing lock chamber and laying the literal groundwork for the new chamber.
In addition, temporary field offices, fencing and power infrastructure have been installed, new stormwater drainage systems have been constructed and demolition has started on the lower guard wall.
By putting the batch plant on site, the Corps of Engineers noted, along with a quality assurance and control lab, the contractors can mix at least 150 cu. yds. of high-quality concrete per hour and minimize logistical delays.
Along the middle lock walls, the builders are also installing inclinometers — long, vertical instruments that detect subtle shifts in the earth.
"These inclinometers are designed to measure any horizontal movement of the wall during and after construction," said Andrew Aceves, a geologist with the USACE's Pittsburgh District. "Each one is installed in a cored shaft that extends several dozen feet along the lock wall, with outer casings secured to ensure long-term integrity."
More than 50 inclinometers will continuously monitor the lock wall during construction to alert engineers to any movement by providing real-time updates through an automated system. It is essential for preventing unintended structural shifts and ensuring industry vessels can continue to lock through during construction, the agency said.
Up to 10,000 Construction Jobs to Be Created
The new Cumberland Lock, downriver from Monaca in Brilliant, Ohio, is 1,200 ft. long and can handle a 15-barge tow at a time. When the tow reaches the smaller locks in southwestern Pennsylvania, however, workers have to separate the group of barges to get them through.
"We put nine barges in, [and] we break off the wires," said David Podurgiel, a member of the Waterways Association of Pittsburgh's navigation committee, in speaking with WESA Radio. "They raise [the barges], pull them out and then we come in with the rest of the tow, and they have to dewater the chamber. We come in, fill it up and we wire everything up and continue upriver."
The entire process takes approximately two and a half hours, according to Podurgiel, and can last longer if the weather is bad or the water is high. It takes only about 30 minutes, though, to get through a 1,200-ft. lock.
"When you're looking at the cost of running a boat at an average of $300 an hour, that adds up," he said.
Building the new chamber is expected to support about 10,000 jobs in the Pittsburgh region over the next six years, according to the USACE, and will include engineers, iron workers, deckhands and plumbers.
Podurgiel said he expects delays on the river during the duration of the construction, but he looks forward to its completion.
"That's gonna save time and then save money and be able to get the product to the power plant or to the steel mill or to the landings up there on the Monongahela River [in Pittsburgh]," he said.
If all goes as planned with the construction, the new lock is projected to open its chamber in 2033.
Pittsburgh is the fourth-largest port among U.S.'s inland waterways. About 50,000 barges passed through the locks and dams on the city's three rivers in 2024, pushing 140 million tons of commodities from coal to jet fuel, according to the Port of Pittsburgh, the state government agency overseeing river traffic in southwestern Pennsylvania.
