Potholes of Turnbull National Wildlife Refuge

When visiting Turnbull National Wildlife Refuge, you will find a great deal of wetlands and beautiful skies. Turnbull is located in northeastern Washington on the eastern edge of the Columbia Basin. A specific characteristic that many may not observe, is that Turnbull possess Kolk’s, or potholes, from the Great Missoula Flood. Kolk's are a geological process that took place during this flood.

"Kolk", a Dutch term which Matthes used to designate intense energy dissipation by upward vortex action (Matthes, 1947). The kolk is formed, in a groove or indentation, anywhere that a rock can be entrapped. Swirling water then intensely sucks the rocks against the side of the hollow eating a larger and larger hole. This process occurs at low pressure and low velocity (See figure 1, Patton and Baker, 1978).

The Great Missoula Floods helped to shape the beautiful landscape of Turnbull National Wildlife Refuge, with the help of the US Government (see McKenzie Small's story on the history of Turnbull). Turnbull is unique because it has acquired different types of geological processes from the floods.



Cartoon of a Kolkbmp / 1.26 MB Download