A decade-long federal study says that a drier climate on the Navajo Nation is causing sand dunes to grow and move, potentially threatening grazing, roads and buildings.
The study by a U.S. Geological Survey geologist found that sand dunes are growing fast and moving more, including old dunes that previously were stable. More than a third of the 27,000-square-mile reservation is covered by sand dunes and sand sheets, and it has experienced varying degrees of drought for the past 15 years.
Geologist Margaret Hiza Redsteer called the Navajo Nation — specifically the southwestern portion in Arizona — “just on the edge of being habitable,” the Farmington Daily Times (http://bit.ly/vlnVHX) reported. Her work also noted the vulnerability of indigenous people who rely heavily on the land.
“The annual moisture here has historically been just enough to get by,” she said in a statement. “When there is even a small change, there is a huge effect.”
Some of the sand dunes are moving at a rate of 115 feet per year, the report found. Faster migration of active sand dunes and the reactivation of previously immobile dunes can threaten housing, roads and the health of residents.
The study will yield data on diminished vegetation cover and the increasingly arid environment, which threatens livestock, grazing, infrastructure and livelihoods on the reservation. The areas that call for the most alarm are the lands near the Colorado Plateau, located near Flagstaff, Ariz., and surrounding the Hopi reservation.
Redsteer found that besides growth and new movement in existing dunes, new dunes were increasing in number. The new dunes form downwind from rivers and washes, largely from dry, wind-blown river sediment. For instance, the dune field outside Flagstaff, has grown by 70 percent since 1995, when the most recent drought gripped the Nation.
The dunes are moving northeast at speeds as high as 157 feet per year in 2009, which was unusually dry and windy.
Sand storms and dune movement also occurred in the northern and eastern parts of the Navajo Nation in New Mexico. The wind direction, however, was very different.
Wind blows predominantly northeast in Arizona, while it blows south in New Mexico, said Sam McCown, a meteorologist for the National Climatic Data Center.
If the trend continues, some officials warn that much of the Navajo Nation will become uninhabitable.
“The Navajo Nation is intended to be a permanent homeland for the Navajo people,” John Leeper, director of the Navajo Water Management Branch, said in a statement. “However, much of that homeland may be in jeopardy if these trends cannot be successfully mitigated.”
Geologists and Navajo officials are trying to use Redsteer’s work to find solutions, including placing barriers in dunes to stabilize them and planting seeds in the sand to encourage vegetation.