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Published January 29, 2012, 08:51 PM

Living with Water: Geology behind the flooding Red River

Fargo, ND (WDAY TV) -- We continue our Living With Water special, a Forum Communications project. The next five weekends, both our broadcast and print divisions will look at flooding. Rob Kupec looks at the geology behind flooding in the Red River Valley and how the topography makes even small changes have big consequences.

Fargo, ND (WDAY TV) -- We continue our Living With Water special, a Forum Communications project. The next five weekends, both our broadcast and print divisions will look at flooding. Rob Kupec looks at the geology behind flooding in the Red River Valley and how the topography makes even small changes have big consequences.

10 thousand years ago the Red River Valley was covered with ice. As the glaciers retreated they left in their wake Lake Agassiz. When the water from that drained we were left with one of the flattest surfaces on the planet.

Don Schwert (NDSU Geology Professor): "There's no other surface like it any where else in the world."

NDSU Professor Don Schwert has spent his career studying the geology and topography of the Red River Valley and says not all flat is created equal

Don: "while it's really flat around here in Fargo, it's really, really flat when you get north of Grand Forks. In that area around Drayton and Oslo. It almost has zero gradient. Water piles up there and the flood become highly expansive and very, very slow to be processed out of there"

And the fact that the river flows north also slows the progression of a spring melt as water flows into a colder climate.

Of course the soils left behind by the lake add to the slow drainage too.

Don: " Those clays make it very difficult for those waters to penetrate into the soils"

Of course because the land is so flat here, any changes humans make have big implications on the movement of water.

Chuck Fritz (International Water Institute): "and because it's so flat, low energy such a flat system, it's incredibly hard to try to model it to say if we do this here that means that something is going to happen here or here.

So even the slightest change in road grade, dike, drain tile or flood wall can send water moving in directions that it never has before. Still with all the man made alterations

Chuck Fritz has one simple answer for the really big question.

Chuck: "when people ask me and they ask me all the time, You know how come it floods, why is it flooding and the simple answer is there's too much water.

And until this wet period we have seen for 20 years ends, flooding we be a fairly regular event.

Forum Communications newspapers and broadcast will both continue our special project, Living With Water, next weekend.

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