Macomb flooding mystery solved after crews discover sandbags beneath culvert

(FOX 2) - Candice Miller remembers when she got the call from one of her workers. It started with "you aren't going to believe it."

The commissioner for public works in Macomb County spends a lot of time around stormwater drains. But the discovery inside a culvert in Chesterfield Township was one of "the most dramatic" her team has ever made.

"Our crews found not just one, not just two, but actually three different sandbag walls!" she announced in a posting on Facebook.

It solved the mystery of horrendous flooding at one busy intersection. But why a blockade of sand was even there in the first place is still a puzzle.

Big picture view:

Macomb County manages over 500 drains in their jurisdiction. 

But the drain near 23 Mile and I-94 has proven to be an issue recently — leading to severe flooding that has damaged buildings and blocked roads.

"Chesterfield in the last few years has had rainstorms that have brought localized, biblical rain," Miller told FOX 2. "Sometimes up to four inches of rain."

For managers like Miller, ensuring stormwater has a place to go is a game she plays throughout the year. Occasionally, solutions prove expensive because infrastructure improvements cost a lot of money.

And sometimes, it's as simple as removing walls of sand bags that have dammed drains for decades.

The backstory:

"You can't imagine what we do find in drains," Miller said.

The department spends enough time clearing out obstructions that it even created an unofficial show: "What we find in our drains."

"We cleaned up one in Fraser that is by CN rail tracks and this whole area gets all this flooding. So we went under the culvert, and it was full of railroad ties," she said. "Almost packed in so tight nothing could get through."

In another case, under Groesbeck, chunks of concrete and construction debris were found jammed inside.

"The guys out doing drain maintenance — you just can't believe what people throw in these drains," said Miller.

Sand Bags causing flooding

The culvert in question belongs to the Sutherland Oemig Drain, which traverses throughout Chesterfield Township and eventually moves stormwater into Lake St. Clair.

It's technically under the jurisdiction of the Michigan Department of Transportation, which is why Miller told them ahead of time they would be performing maintenance at the site.

"That's how we got into the culvert and discovered walls of sand bags," she said.

A photo posted by the commissioner included bags of sand covered in what Miller could only describe as "muck." In the image, dark-colored sludge surrounds the bags, with several feet of water held back. 

It looks like a scene out of a horror movie.

That means the cleanup operation is not a short one. Crews used pickaxes, shovels and a vacuum truck to remove some of the sediment that had built up.

The cleanup, which includes several thousand feet of drain upstream and downstream from the culvert, is going faster than expected.

Dig deeper:

So what were the sand bags doing there in the first place?

Miller theorizes they could have been left during construction activities to prevent flow during work before being inadvertently left in place. It is possible they were left intentionally, but no obvious reason presents itself as to why.

According to MDOT, which operates the culvert, it was built in 1971 before being extended around 2000. It is routinely inspected every two years because of its size.

The Macomb Transportation Service Center's division under MDOT said an inspection report placed a "high priority" on having the culvert dredged to ensure water could continue to flow. 

The department has since partnered with Macomb County to clean up the culvert. The work was completed on Dec. 7.

Macomb CountyInfrastructureMichigan Department of Transportation