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February 20, 2008

I was part of a special field trip today, a once in twenty years photo opportunity. This is the Mississippi River where it passes over Saint Anthony Falls near downtown Minneapolis. The bridge in this picture is the "Stone Arch Bridge", a National Historic Monument and part of the grain mill scene that defined our "Mill City", back in the mid-nineteenth century. The Army Corps of Engineers still operates and maintains Lock & Dam Number One here, the first lock you will encounter travelling south from the headwaters of the Mississippi to Minneapolis. The Lock & Dam are designed to allow boat traffic (especially barges, which are still often filled with grain) to move up or downstream over the 49 ft. difference in elevation. So it goes that every twenty years the "The Corps" open the gates at the Ford Dam a few miles downstream and lower the water levels at St. Anthony to check the structural integrity of the various spillways and inlets that feed the lock, and today was that day!
It's interesting because my friends at Friends of the Mississippi River decided to offer a tour of the event guided by National Parks Historians, and 75 people signed up in the few hours of the news release. After adding two more tours, which both filled up the same day, they ended up with three tours of 45 people each, plus 200 on the waiting list. And all to go out on a day that started out at -12 F, with a -24 F wind chill to look at a river with no water in it. Hey, we love our river. And we want to see what it looks like without much water in it. Who wouldn't?
In the above photo, the normal water level is up to the lighter colored stone on the bases of the arches. None of the snow & ice covered earth is visible under the bridge. The water level has been lowered around 13 ft. It doesn't sound like much, but that's 13 ft. across the entire span of the river for miles.The morning found the Muddy Miss not so muddy, but steamy in the cold temps. Ice covered the exposed rock, and big sheets and cups of it caved in around the edges where the water had receeded.Mini-marshmallows of ice developed in the spillways. With the wind at our backs, the hiking was fine, but after the turn-around and heading back into the wind, the moisture from the dam and wind-chill was really punishing. Successful clothing combinations were the "hot-topic" of the day.
I think some birds like this Red-tailed Hawk welcomed the lack of deep water to provide more hunting grounds, while the geese and ducks were looking a bit perplexed about having to share their pools with relatives and squawked their grievances as the tours filed by.

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