OBSERVATIONS ON DUNE BEHAVIOR AT GREAT SAND DUNES NATIONAL PARK, COLORADO
The NPS has used GPS and traditional surveys to map dune position and height beginning in 1992 on a few index dunes. There is also aerial imagery of the dunefield from 1998, 2005, and 2011 it was used map changes in dune location for other dunes.
The results show that regardless of dune type or size, there has been next migration toward the NE. The smaller dunes doe migrate faster, but not proportionally. These results match sand drift potential calculated from wind data and agree with previous work on dune migration rates [2].
Vertical dune growth for the largest dune is dependent on the direction of migration as accommodation space varies on either side of the dune. On large dunes in general, an increase in dune high will require the migration of smaller dunes to the crest or the migration of a large ridge up the slope of a mega dune.
References:
[1] Valdez, A. D., Development and Eolian Geomorphology of Great Sand Dunes in Quaternary Geology of Great Sand Dunes, USGS Open File Report 2007-1193 p 7-10, 2007
[2] Foreman, S. L., Episodic Late Holocene dune movements on the sandsheet area, Great Sand Dunes National Park and Preserve, San Luis Valley, Colorado, USA. Quaternary Research 66 p 97–108, 2006