Sinkhole Problems Raising Questions in Minn.

Updated: 03/15/2013 7:43 AM KSTP.com By: Stephen Tellier

Sinkholes have been making headlines, raising questions about the ground in Minnesota. And experts say the "Land of 10,000 Lakes" could also claim to be the "Land of 20,000 Sinkholes."

Earlier this week, a sinkhole formed in the middle of Raymond Avenue in St. Paul. City officials said it was man-made, caused by a sewer line that broke. But it still took about a week, and $50,000, to repair, because of utilities beneath the ground in that area.

And experts say whether man-made or all-natural, sinkholes can, and do, pose a risk to our area.

"Dozens, and probably hundreds, of new sinkholes that form every year," said Calvin Alexander, a professor of earth sciences at the University of Minnesota, and an expert on sinkholes in the state.
 
He said at least a few of those sinkholes form right here in the Twin Cities.
 
Seven Oaks Park in Minneapolis, on the west bank of the Mississippi River, is actually a massive sinkhole.
 
"We were looking to buy a home in the area and the realtor told us that there was a sinkhole back here," said Michelle Van Kuijk, who bought a home with her husband on the edge of the park anyway.
 
She figured it was safe, because the Seven Oaks Park sinkhole has been there for about 6,000 years.
 
"It's very pretty. So it's OK. As long as it doesn't get bigger, we're good," Van Kuijk said.
 
In 2010, a man was hurt after he fell into a sinkhole that was 15 feet deep while he was simply walking on the sidewalk in downtown St. Paul.
 
"This is one of those categories of things that are rare, but are very damaging when they occur," Alexander said.
 
Alexander said the ground in our area is particularly prone to sinkholes.
 
"The bedrock is soluble. It is slowly dissolving in groundwater," Alexander said.
 
Southeastern Minnesota, including parts of the metro, hold the highest risk. And that risk heightens in the spring, when melting snow washes away even more of that bedrock.
 
But even the experts don't lose sleep over that sinking feeling.
 
"I've been studying these for 30 years and I don't stay awake at night worrying about one opening up under my house," Alexander said.
 
If you're wondering whether your homeowner's insurance policy covers potential damage caused by a sinkhole, it doesn't. But the Insurance Federation of Minnesota said adding earthquake coverage to your plan may also cover sinkholes, since it typically covers damage caused by "movement of the earth." You should talk to your insurance agent for more information.