Every year, a river’s channel shifts as water, waterborne sediment, and freeze/thaw forces erode its banks and deposit sediment in its path. Some rivers, such as ones bedded in rock, shift very slowly, over thousands or millions of years. On the other hand, soft-bedded rivers can shift their beds by several feet a year.
I’m particularly aware of these fast-shifting “sand-bed” rivers because there’s one visible from my studio window. Wunachích t’aakhéen (the Salmon River) makes its loopy way across the flat sweep of glacial outwash on which the town of Gustavus is built.
As sand-bed rivers shift, they leave beautiful traces on the landscape. Sometimes those fossil channels are visible in aerial and satellite photos. But because they’re elevationally subtle, fossil channels are often hidden under forests or human development.
LIDAR technology is a way to expose a river’s fossil channels–there are some particularly beautiful examples out there for the Mississippiand the Willamette.
I recently built an art/science lesson around this story of meandering rivers. It starts with basic earth science background: erosion and deposition, river migration. Then students use the art elements of line, shape, and color, and the design principles of emphasis, rhythm, and movement, to create artworks that convey river channel migration over time. Here’s an example:
So far I’ve taught the lesson three times: once to teachers, and twice to 7th grade classes. I’m still working out the details, but I’m getting some positive initial reactions! Teachers: if you’re interested in learning more about this “River Rhythms” art/science lesson, let me know.
Katherine Hocker 