Navajo Land Use Planning ProjectUSGS interdisciplinary studies, in collaboration with the Navajo Nation, monitor and document the rate and magnitude of changes in sand dune mobility and impacts on the associated rangeland One third of the Navajo Nation is blanketed with sand dunes (eolian deposits), much of it stabilized to varying degrees by vegetation that is dependent on the amount of moisture available and the amount of wind. Some of the dunes are very old; others date from the 1950s, when drought and wind mobilized sediment from floods on the Little Colorado River. Persistent drought has affected the region with varying degrees of severity from 1996 to 2012, and newly mobilized dunes are increasing in number. In addition, new dunes form downwind from rivers and washes, largely from dry, wind-blown river sediment. In the Grand Falls area of the southwest Navajo Nation, the area covered with mobile dunes has grown 70 percent since 1995. These dunes are moving northeast at a rate of 115 feet per year (see USGS Fact Sheet 2011-3085).
Increased dune mobility can threaten roads, buildings, and the rangeland that is vital to the Navajo economy and indispensable to its culture. Because dune stability is influence by climate patterns, this project established a series of stations that recording wind, precipitation, temperature, and soil moisture in an otherwise unmonitored region. Seasonal vegetation surveys are conducted in locations of increased sand dune mobility, and wind measurements are coupled with sand transport data from BSNE's to improve our understanding of the variability of the eolian system.
Why is this research important?
Increased aridity has significant impacts on residents of drylands across the globe, particularly within societies with limited resources and economic means. The reactivation of stabilized sand contributes to myriad problems for the Navajo people, including loss of rare and endangered native plants, degradation of farming and grazing land, and lower air quality from periodic dust storms. Some communities in the southern and western areas of the Navajo Nation may be forced to relocate because the recent mobilization of dunes has encroached upon their homes and blockied roadways.
Because aridity and changes in sand dune mobility are influenced strongly by climate, prolonged droughts have the potential to shift regional dune fields to a perpetually mobile state, altering the ecosystems that form the basis for the livelihoods of many members of the Navajo Nation. Our documentation of rates and extents of ongoing changes is intended to provide a basis to predict future changes under different climate scenarios and to help Navajo leaders develop sustainable management plans.
Principal Investigator: Margaret Hiza Redsteer