Tuesday, November 8, 2011

Theodore Roosevelt and Landslides

Theodore Roosevelt National Park, North Dakota

For geologists badlands are great fun. Lots of well exposed formations and raw geomorphic processes to behold. My early geology years were all about hard rocks, mines and metamorphic processes. But I found a recent trip into some badlands had me very enthusiastic about the work I currently do on slope stability. Lots of great landslides to check out.

This bad land area is not in Washington State. Theodore Roosevelt bought and operated a ranch here in these badlands. After his first wife died he came here to heal. He drew great inspiration from this landscape. Douglas Brinkley in Wilderness Warrior titled a chapter of the book Cradle of Conservation: the Elkhorn Ranch of North Dakota. That conservation ethic had a profound impact on the Washington State landscape we know today: 8 National Wildlife Refuges and 8 National Forests covering tens of thousands of acres were set aside in Washington State by Roosevelt.

The site of Roosevelt's ranch is now part of Theodore Roosevelt National Park in southwest North Dakota. With the near complete demise of the bison on the Great Plains, the area was very attractive for cattle ranchers in the late 1800s as the grasses had been ungrazed for several years and their had been no droughts or terrible cold spells. 

Besides the history and alien like landscape, the park is full of landslides.

Landslide block. The hill in the foreground is coherent detached slide block from the slope on the left.

Another slide block with classic back slope from rotation

Cracks on road surface indicating an ongoing problem

Dip on road surface and patches mark the outer edge of a large failure involving the road.

Same failure looking down from above along the edge of the slide area.
The road was clearly constructed across an old slide surface

Expansive clay within the slide area. Bentonite swells when wet making it useful for sealing wells and landfills but a real problem for slope stability.  

This section of road is in real trouble at another slide location

Yet another slide in the early stages beginning to fracture the road

View to Little Missouri River from the headwall of new slide

This slide did not impact a road but made a trail a bit tricky

Inverted topography: Southwest North Dakota is not flat, the hills are just downward

1 comment:

Abe Jacobson said...

Argillic shale is not a good base for roadbed on hillside! What you picture here happens all the time. A roadbed there is futile.

Another good example of this is at Douglas Pass, halfway from Grand Junction to Rangely on Colorado Rt. 139.

Abe Jacobson