Dune Reactivation: A Looming Threat in the Great Plains
Historical Dune Activity
The Great Plains, once known as the Great American Desert, were once a vast expanse of active dunes and sheet sand. However, over the past 150 years, vegetation has stabilized these dunes, giving rise to the agricultural landscapes we see today.
Recent research by U.S. Geological Survey geologist Daniel Muhs and his colleagues has revealed that dune activity has been far more prevalent in the past 1,000 years than previously believed. Carbon-dating of soils, bones, and artifacts has identified significant dune movement during this period, including within the past century and during the drought of the 1930s.
Causes of Dune Reactivation
Dunes require two key factors to become active: a lack of vegetation to hold them in place, and strong winds to transport the sand. Drought is the primary driver of dune reactivation, as it weakens vegetation and exposes bare sand to the wind.
Climate change models predict an increase in the frequency and severity of droughts in the Great Plains. This could create the conditions necessary for widespread dune reactivation, with potentially devastating consequences.
Consequences of Dune Reactivation
Reactivated dunes can have a significant impact on infrastructure and agriculture. As Muhs notes, “If that sand ever starts moving, this Interstate is history.” Dunes can bury fences, roads, rangeland, and even entire towns.
In addition, dune reactivation can disrupt ecosystems and wildlife habitats. The Nebraska Sand Hills, for example, are home to a unique ecosystem that has adapted to the presence of active dunes. Dune reactivation could threaten this ecosystem and the species that depend on it.
Monitoring and Mitigation Strategies
Scientists are closely monitoring dune activity in the Great Plains to assess the risk of reactivation. They are using a variety of techniques, including satellite imagery, ground-based surveys, and carbon-dating to track dune movement and identify areas that are most vulnerable to reactivation.
Mitigation strategies are also being developed to reduce the risk of dune reactivation. These strategies include planting vegetation to stabilize dunes, constructing windbreaks, and implementing drought management plans.
Conclusion
The potential for dune reactivation in the Great Plains is a serious threat that requires careful monitoring and mitigation strategies. By understanding the causes and consequences of dune reactivation, we can take steps to protect our communities and ecosystems from this natural hazard.