Minnesota and Feds Pass Hidden Wall Controversy at St. Anthony Falls

The Critical Cutoff Wall Beneath St. Anthony Falls

Scientists are currently conducting the first comprehensive inspection of a vital piece of infrastructure that has been largely overlooked for decades — the cutoff wall beneath St. Anthony Falls in downtown Minneapolis. This structure, which is over 150 years old, plays a crucial role in preventing the waterfall from collapsing. If it were to fail, the resulting flood could be catastrophic.

The federal government and the state of Minnesota have recently found themselves at odds over who is responsible for maintaining this critical infrastructure. The cutoff wall, built by the Army Corps of Engineers between 1874 and 1876, is located within state waters. However, the federal study released this summer suggested that the responsibility for its maintenance lies with the state. This claim has sparked controversy among environmental groups and the Department of Natural Resources (DNR).

Colleen O’Connor Toberman, director of the land use and planning program at Friends of the Mississippi River, expressed surprise at the Corps' assertion that the wall is the state's responsibility simply because it was constructed in state waters. "Wait, where’s your proof? You can’t just say that in a sentence and assume everyone’s gonna let that go by," she said.

The DNR responded with its own statement, emphasizing that the state had no legal obligation to maintain the wall. According to DNR Assistant Commissioner Jess Richards, the state did not have the authority to regulate public waters until 1925. He argued that there is no evidence that the state authorized the construction of the cutoff wall, making the Corps' claim legally unfounded.

A Historical Perspective

The cutoff wall was originally built in the 19th century as an emergency measure to prevent the total collapse of St. Anthony Falls. At the time, the milling industry was central to Minneapolis’ development, and private power companies had blasted numerous tunnels into the falls’ limestone banks to harness hydropower. One of these tunnels was poorly constructed, leading to rapid erosion. The cutoff wall was a dramatic intervention to stabilize the waterfall.

Over time, the wall fell into obscurity. The Corps claims it was never inventoried as government property, and no known maintenance has been conducted since its construction. This makes it unique among other structures that support the falls, such as the dam spillway, which is regularly inspected.

The cutoff wall also plays a key role in maintaining the Minneapolis water supply. If it were to fail, river levels could drop too low for the city to take in water. In response to this risk, Rep. Sydney Jordan introduced a bill in 2023 that allocated $750,000 to the University of Minnesota to study the condition of the wall.

Risk and Responsibility

Minneapolis provides water to over a dozen cities, including hospitals and an international airport. The city maintains a three-day drinking water reserve, according to city spokesperson Allen Henry. "The idea that it is an orphan project, everyone’s going to say it’s not mine, so we’re just going to ignore it, leaves our state at a tremendous risk," said Rep. Ginny Klevorn, highlighting the potential dangers of neglecting the wall.

Republicans supported the study but were concerned about funding the inspection, fearing it might imply the state would assume responsibility for any repairs. "We can’t do this on our own if we don’t actually understand who owns it," said Rep. Jim Nash. "If no other outside force acts on it, we’re going to have to come back and say well, we have to do it because we paid for the study."

The Inspection Efforts

Last year, the inspection team began researching historical records on the wall and launched a geophysical investigation using ground-penetrating radar. However, spring flooding forced them to pause their work and request a one-year extension from the legislature. Fieldwork has not resumed this summer, according to Bridget Mendel, spokesperson for the St. Anthony Falls Laboratory.

"They continue to have meetings with the project team and continue to plan for future steps, but there hasn’t been any physical work happening out there," Mendel said. "It’s slow going. ... Since we have that extension, I think they’re working it into their schedule."

The inspection report is due to the Legislature by July 1, 2026. Scientists plan to eventually build a scale model of St. Anthony Falls to simulate what would happen if critical infrastructure at the site failed. Their findings will inform Hennepin County Emergency Management’s creation of a risk assessment.

Eric Waage, director of emergency management for Hennepin County, asked, "Which roads, bridges, pipelines, water intakes and other infrastructure would be impacted by cutting erosion upstream?" The goal is to create a detailed map of what remains of the limestone caprock and assess the damage sustained since the industrial era.