As Above, So Below: Duluth, Minnesota

The anniversary of the 2012 flood approaches. What protected much of Duluth 10 years ago?

435 miles.

8,439 football fields. The length of Minn., from North to South. That’s how far the drainage tunnels flow below Duluth’s hollow streets.

Water rushes over natural bedrock in the Brewery Creek tunnel, adjacent to the East Hillside Co-op.

“100-year-old brick arches” to brand new iron and metal grates. According to the project coordinator of Minnesota Power, Chris Kleist, the materials used to construct the historic stormwater tunnels reveal aspects of Duluth’s unique infrastructure throughout time.

“It seems like whatever they built is long-lasting,” Kleist said. “Whether or not they even knew it at the time.”

Long-lasting, however, does not mean indestructible.

Utility experts from Minnesota Power work hard to maintain these tunnels year-round. Over the years, folks like Kleist have seen ruptures in the foundations built on top of the tunnels, potholes as a result of erosion in the tunnels, hiding outlaws and even disposed human bodies.

Their work is typically responsive to infrastructural issues caused by the tunnels or to take preventative measures in instances of overhead construction. Though, they still do an annual inspection of all “accessible” points of the tunnels.

Kleist says accessible loosely–because it takes a pair of waders, high-powered spotlights and coordination to navigate the paths.

Built over major streams running down Duluth’s hillside in the late 1800s, stormwater tunnels became a necessity as a result of mainly three factors:

1. High precipitation rates
2. Rapid population influx (which was immediately followed by an increase in housing developments on the hillside)
3. The general slope of the city

In short, the tunnels protected the growing city from flooding damage–and they still do today.

As Duluth approaches the 10th anniversary of the 2012 flood, Kleist said the tunnels aided in preventing significant damage in the city because rainwater and runoff are able to run directly into lake Superior.

Not many Duluth residents have knowledge of the tunnels existing; however, Kleist says:

“They should.”

Watch the video here.

Utility workers from Minnesota Power cover a construction site directly over the tunnels, using wood to hold down the tarp from the wind.