COS 35-4 - Wind erosion in groundwater dependent vegetation communities

Tuesday, August 9, 2011: 2:30 PM
Ballroom F, Austin Convention Center
Kimberly R. Vest1, Andrew J. Elmore1, James M. Kaste2 and Gregory S. Okin3, (1)Appalachian Laboratory, University of Maryland Center for Environmental Science, Frostburg, MD, (2)Department of Geology, The College of William and Mary, Williamsburg, VA, (3)Department of Geography, UCLA, Los Angeles, CA

Arid and semi-arid vegetation communities are vulnerable to water resource management practices such as groundwater pumping. Groundwater pumping below the root zone of groundwater dependent vegetation (GDV) leads to a decrease in vegetation cover exposing bare soil to wind erosion. Many groundwater dependent areas contain playa lakes that are large sources of global dust emission, and an increase in groundwater pumping below the root zone of GDV in these areas might exacerbate that dust emission. Although research into dust emissions from playas has been extensively studied, there is a lack of research into dust emission in areas of GDV. To enhance our understanding of the mechanisms behind wind erosion in GDV regions, we examined the relationship between chronic groundwater pumping and vegetation cover change and its effects on soil erosion and compared these results to other wind erosion areas. The work was conducted in Owens Valley, California, where a long history of groundwater pumping and surface water diversion has lead to documented vegetation changes.


We examined hydrological and ecological factors across thirteen groundwater dependent alkali meadow sites in Owens Valley. We analyzed vegetation and gap size and installed Big Spring Number Eight (BSNE) catchers to calculate mass transport of aeolian sediment across sites spanning a gradient in vegetation structure and depth to water. The average mass transport across our sites was compared to the mass transport across other sites in the Chihuahuan desert and Minquin County, China. Results across three field seasons show that sediment collected in the BSNE catchers was positively correlated with site gap size. Further, areas that were the most heavily pumped have higher total horizontal flux (Qtot) than sites that were not pumped. The average Qtot from our sites is approximately half of the Qtot produced in the Chihuahuan and Minquin sites. By extrapolating the average Qtot from our sites over the area of impacted alkali meadow (i.e., due to groundwater pumping) in Owens Valley, the Qtot is comparable to the Qtot from Owens Lake. Our results support the hypothesis that loss of vegetation cover due to groundwater decline leaves behind bare soil areas that are easily eroded and might become a significant source of dust emission.

Copyright © . All rights reserved.
Banner photo by Flickr user greg westfall.