Surge Flow In Great Sand Dunes National Park
October 22, 2007
Medano Creek, flowing east and southeast of the dunes in Great Sand Dunes National Park, Colorado, is said to be the best place in North America to observe surge flow. Surge flow is a phenomenon of shallow water flowing with a large sediment load. As underwater dunes form they create a dam over which the water breaks, creating a wave. In addition, Medano Creek exhibits braiding as it flows past the dunes. A braided stream is one that divides and recombines forming many channels. The photo on the left shows the braided Medano Creek, with dunes at the left and the Sangre de Cristo Mountains in the background. The photo on the right shows surge flow -- streamflow is to the right. Photo taken on August 2, 2007.