Blowing dust and highway safety in the southwestern United States: Characteristics of dust emission "hotspots" and management implications

Authors: LI, JUNRAN - University Of Tulsa; KANDAKJI, TAREK - Texas Tech University; LEE, JEFFREY - Texas Tech University; Tatarko, John; BLACKWELL, JOHN - University Of Tulsa; GILL, THOMAS - University Of Texas - El Paso; COLLINS, JOE - Texas A&M University

Submitted to: Science of the Total Environment
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/13/2017
Publication Date: 11/6/2017
Citation: Li, J., Kandakji, T., Lee, J., Tatarko, J., Blackwell, J., Gill, T.E., Collins, J. 2017. Blowing dust and highway safety in the southwestern United States: Characteristics of dust emission "hotspots" and management implications. Science of the Total Environment. 621:1023-1032.

Interpretive Summary: Despite the widespread media attention of chain-reaction traffic incidents and property damage caused by windblown dust in the United States and elsewhere in the world, very few studies have investigated the relation of accident rates to windblown dust. Remote sensing and field observations reveal that wind erosion in the southwestern United States typically occurs in localized areas that are sources of dust that are sometimes called “hotspots”, while most of the surrounding landscape is not eroding. However, the space and time patterns of the hotspots and their relations to dust blowing onto highways are poorly understood. In this study, we identified the distribution patterns in space and time of hotspots that may contribute dust blowing onto highways in the southwestern United States, and we classified the hotspots for the potential of blowing dust based upon field observations and a wind erosion computer model. Our results show that of the 620 total hotspots identified, 234 (38%) were located on cropland, 164 (27%) on shrubland, and 141 (23%) on grassland. While a majority of these hotspots are located close to highways, we further investigated 55 of them that were located within 0.62 miles (1 km) to adjacent highways. Field studies and laboratory analysis showed that soils at these hotspot sites are dominated by sand and silt particles which need wind speeds ranging from 0.38-1.74 mph (0.17-0.78 m s-1) to initiate wind erosion, largely depending on the land use of the hotspot sites. A computer dust model showed that 8 hotspot sites could produce >1.1 lb per square ft (5.32 kg m-2) of dust a year, yielding highly hazardous dust conditions for ground transportation with visibility <656 ft (200 m). The location, timing, and magnitude of the dust production at the hotspots are critical information for highway authorities to make informed and timely management decisions when wind events strike.

Technical Abstract: Despite the widespread media attention of chain-reaction traffic incidents and property damage caused by windblown dust in the U.S. and elsewhere in the world, very few studies have provided in-depth analysis on this issue. Remote sensing and field observations reveal that wind erosion in the southwestern U.S. typically occurs in localized source areas, characterized as “hotspots”, while most of the landscape is not eroding. However, the spatial and temporal patterns of the hotspots and their relations to the occurrence of dust blowing to the highways are poorly characterized. In this study, we identified the spatial and temporal distribution patterns of hotspots that may contribute dust blowing to highways in the southwestern U.S., and we further classified the hotspots for the potential of blowing dust production based upon field observations and wind erosion modeling. Our results show that of the 620 total hotspots identified, 234 (38%), 164 (27%), and 141 (23%) are located on cropland, shrubland, and grassland, respectively. While a majority of these hotspots are located close to highways, we further investigated 55 of them, which are located <1km to adjacent highways and can be accessed via non-private roads. Field investigations and laboratory analysis showed that soils at these hotspot sites are dominated by sand and silt particles with threshold shear velocities ranging from 0.17-0.78 m s-1, largely depending on the land use of the hotspot sites. Dust emission modeling showed that 8 hotspot sites could produce annual emissions of >5.32 kg m-2, yielding highly hazardous dust emissions to ground transportation with visibility <200 m. Results of location, timing, and magnitude of the dust production at the hotspots are critical information for highway authorities to make informed and timely management decisions when wind events strike.