Saturday, February 20, 2010

Chuck in the Flume

In the middle of February, I decided to bolt out of (semi-cold) Anchorage for the warmth of the lower 48. It turns out that the weather in Minneapolis is just about the same at this time of year. Oh well.

I came to Minneapolis to do a few geomorphology experiments at the St. Anthony Falls Laboratory. This is a good place to do experiments since they have a huge flume here.

What is a flume, you ask? Well, this one is a big concrete ditch (6 feet deep x 9 feet wide x 250 feet long) which kind of reminds me of the big concrete waterways in LA (that you always see in any action movie with a car chase in southern CA - like the Terminator). No car chases in this one, just gravel and water.


My goal out here is to see what happens to a gravel river when you add a bunch of sand and gravel. This is kind of like what I am looking at in my project on the Sandy River, OR.

The idea is that we will take measurements over a few years in the field of what happens to the river when you let a bunch of sediment go down it, and also take measurements over a few weeks watching what happens when we shovel tons (literally) of sediment into this indoor river. For a sense of scale, this indoor river can get up to about 300 cubic feet per second but we are running it at about 30. This is about like Boulder Creek. But unlike an outdoor river, we have a 'magic cart' which takes laser scans of the river and makes millimeter-scale maps of it. With the data we get from these experiments, hopefully we will know more about how real rivers work.