Detroit has tons of vacant land. But forty square miles?

Apr 18, 2012

Forty square miles.  That’s how much of Detroit lies vacant, nearly a third of the city.  You could fit Miami or San Francisco inside all that emptiness.  At least, that’s what we’ve heard for years.  The thing is, it might not be true.

This is a story about a number – an estimate, really — and how it became a fact illustrating Detroit’s decline. I’ve read about 40 square miles in the Detroit Free Press, the Detroit News, ForbesThe Wall Street JournalThe Guardian and The Washington Times. I’ve heard it on Fox and I’ve said it on the radio.

That’s when Margaret Dewar called me out.

“Wait, this can’t be true.”

Dewar is a professor of urban and regional planning at the University of Michigan. She says there’s tons of vacant land in Detroit. Just not 40 square miles, dramatic as it sounds.

“It’s too good a number to let go of,” she said. “It’s such a wonderful number, it’s so shocking.”

It makes the 139 square mile city sound so empty: an abandoned city. It’s true a million residents have left Detroit. But now, some people who’ve been using 40 square miles are rethinking the number.

So let’s rewind to early last year. That’s when I heard city official Karla Henderson speak at a public meeting of the Detroit Works Project, tasked with reimaging the city. She talked about opportunity, but she also quantified the challenge:

“Forty square miles of vacant land. So vacant land area is overwhelming for the city of Detroit.  The size and population of San Francisco would fit into the current vacant land in the city of Detroit.”

The statistics were stark. Some residents there were already anxious about the fate of their neighborhoods and their homes.

Last week I asked Henderson to revisit the vacant land numbers.

“You’ve been hearing recently 40 square miles,” she said. “We estimate there’s about 37 square miles.  I do want to put a caveat on that, that that does include our parks.”

Parks like Belle Isle and Rouge Park. By this estimate, seven square miles of parks are counted as vacant land. Plus two square miles of cemeteries. That’s nine square miles of caveats.

Karla Henderson now oversees part of the Detroit Works Project and she acknowledges this distinction got “lost in the message.”

Architect Dan Kinkead is on the Detroit Works technical planning team. He says 25 is a good number to describe the city’s vacant land. That includes 19 square miles of purely empty land, five square miles of land with vacant residential structures, and another square mile of underutilized industrial land. No parks.

It’s similar to what geo-spatial analyst Rob Linn found over at Data Driven Detroit.

“My figure is 21.39 square miles,” he said. “Just a hair over half of the 40 square mile figure.”

Which is a departure, because his boss has been citing 40 square miles for years.

Around here, demographer Kurt Metzger is known as the data guru. In 2009, his group did an important residential survey; everyone still uses its data today. Teams drove the city block by block, literally counting every house and residential lot.

They found about a third were vacant or had structures that needed to be torn down.

Metzger figured if a third of residential properties were vacant, it confirmed this idea that 30-35% of the city was too (more or less 40 square miles). The idea was already out there. But where did it come from?

“I have no idea,” Kurt Metzger told me last week. “There are a lot of numbers that we keep pushing back on, but I don’t know where that original number came from.”

While Detroit is largely residential, the new figures adjust for commercial and industrial property. Another problem with the conventional wisdom is that 30% of the city is roads: sweeping boulevards, streets, alleys, and a massive freeway system. So there’s less buildable land than is often conveyed.

Still, not everyone buys into 20 square miles of vacant land.

“In my own experience driving around, it just seems like a lot more than that,” said John Gallagher, a veteran reporter at the Detroit Free Press.

Gallagher often uses 40 square miles in his stories about land use. He says it’s reasonable given the population decline, the industrial decline, the housing survey, and the sometimes staggering return to nature.

“There’s a phrase from Willa Cather’s book My Ántonia, ‘stifled by vegetation,’” he said. “And sometimes in the height of summer, when you drive down these streets with no homes, and the trees and the weeds and the tall grass, that’s how I feel sometimes.”

In Detroit, thousands of buildings are slated for demolition. So whatever the number, the city’s vacant land is a huge challenge. If it doesn’t add up to the size of San Francisco, looks like it’s still as big as Manhattan.