City planners, talk to the geologists!

The Red River is flooding the northwest corner of Minnesota and North Dakota, often called "The Fargo-Moorhead area" because of the two cities across the river not far from each other. But there are many other towns that are threatened by flood-waters, and the Canadians are also in line, because the Red River flows north.

The Big Picture in Boston has some amazing photos of the scene, and there is a map at the U.S.A. article. But for the up-close, personal stories and pictures as well as the eye-witness coverage of the preparations, Bob Collins has been blogging at News Cut on MPR, as well as stacking sand bags.

If you wonder why this area is prone to flooding, this site from North Dakota State University has lots of information on the geology of the area. From Geology Professor Donald P. Schwert of the Department of Geosciences, North Dakota State University, I learned that this area is "the youngest landscape in the contiguous United States" because the glacial lake Agassiz, left behind when the last glacier retreated 12,000 years ago, did not drain until about 9,300 years ago. The rich soil left behind makes it great farmland, but also means that buildings must be built on deep pilings sunk far down into the clay. Tom Cran of MPR interviewed him, and you can listen to the podcast here. The Red River is unique in its situation; it is so young that it has not had time to carve a flood-plain that can store the waters in times of flood, and when the flood comes the waters essentially fill in what was once the bed of the glacial lake Agassiz. John Hockenberry's show The Takeaway on NPR also has a podcast of a conversation with a reporter and Schwert. Here, Schwert sheds more light on why the Red River's flooding is unique.

If you are interested in this geologist's perspective on the issues of planning and mitigation in the area, there is a link on that site to a .pdf document you can download and read. Here are some of my notes on this fascinating document (which you should really read for yourself).

As is the case for New Orleans (floods), San Francisco (earthquakes), and other areas of human habitation in the path of inevitable natural disaster (Pompeii) there are higher risks associated with settlement here than elsewhere. That doesn't mean they can't be anticipated. Erosion, slump, creep and earthflow (technical terms!) are all things that happen in certain areas along the river; experts have written reports on these issues since at least the 70s, and definitely after the big flood of 1997, yet flood management planning is too often trumped by commercial interests.

For example, the river needs to flood, it will flood, so some areas were supposed to be left as parks or parking lots to be floodable "storage areas." But people forgot or ignored this and built dikes to "protect" these areas. Residential development has been allowed in areas that were floodplain storage as recently as 1997. Two recently built low-level bridges act as obstructions for ice-jams. The public is told that all the floods in the Red River Valley are "500 year floods" yet there are no statistics going back more than 100 years, so how would we know that? (Although the author doesn't put it in these words, because there hasn't been public education on the geology of the area, residents and planners have ignored the evidence of their history and of science in their management of the land).

The author's conclusion (which follows specific suggestions for how to plan and mitigate these realities) is

"Cities like Wahpeton-Breckenridge, Fargo-Moorhead, and Grand Forks-East Grand Forks are geologic mistakes – but geographic facts. Given that these cities will never be moved in their entireties, there are still ways of accommodating to the geology and mitigating
the damages induced by flooding and slope failure. However, these require a basic understanding and acceptance of the inevitability of these geologic processes.
In planning, we should not be working toward conserving the past of these cities –instead, through wise planning and land use, we should work toward conserving their futures."

I feel terrible about the people who are working so hard to save their homes. Now isn't really the time for pointing fingers. But after what happened in 1997, why did the states, the regions and local governments not put their heads together with the scientists to come up with a plan? Maybe they did and it was ignored. Scientists do not issue building permits, but they do warn the builders. Too often their warnings are only heard after the flood.