Illinois Discovers Land Cover Increases Flooding

It’s about a month old, but WUIS has a story about increased urban flooding in Illinois. There’s a lot to chew on here, but the key point I see here is how unmitigated development increases residential flooding by eliminating flood protection barriers:

That points to another reason why flooding has grown worse in Illinois: because people keep building. And that leaves less open ground to soak up rain.

According to the National Land Cover Database, Illinois had 3,238 square miles of developed land within its urban areas in 2011 — compared with 1,815 square miles in 1992. That’s an increase of 79.8 percent, or 1,423 square miles, over 19 years.

We often think about development along beachfront property eliminating natural barriers to flooding. But any time land is developed, increased land cover leaves newly fallen water fewer places to go. When there isn’t any place left, that water is going into your basement, regardless of whether you live on the declared floodplain. Further, the risk associated with some areas should be reevaluated following major development, as the development can fundamentaly change the risk profile.

Image by Center for Neighborhood Technology / Flickr.