Dust Sources in Utah

Background and Implications

Dust storms are an increasingly prevalent problem in Utah. Dust emitted from playas has a variety of potentially harmful effects on the environment and human health, causing diseases such as valley fever, asthma, and pneumonia in humans, earlier snowmelt and decreased runoff from mountain snowpack, and carrying many organisms and metals that affect air quality and water resources. Understanding dust sources will help us mitigate the hazard moving forward.

To identify likely dust sources, we considered soil type, slope, and soil moisture, focusing on smaller grain sizes, flat terrain, and areas with little to no vegetation.

The Model

I created a model that used a 30m DEM, polygon soil data from the state GIS database, and Landsat 8 imagery from Earth Explorer to identify likely dust sources. I converted the final output to KML and viewed changes over time in Google Earth (images below).

12 Landsat 8 images (B4 RED and B5 NIR) were taken from Summer 2020, mosaicked in ArcGIS, and used to calculate NDVI (soil moisture)
30m DEM was used to identify slopes <5%
Resulting NDVI, slope, and selected soils were reclassified and weighted against each other for the final output shown above

Application

The Great Salt Lake has experienced a dramatic change in its water levels over the past 35 years, exposing 2000 square miles of dry lakebed. The images below show how current dust sources along the lakeshore (calculated from our model) are increasing as lake levels continue to drop. Dust sources around the lake today would not have existed 40 years ago due to higher lake levels. As lake levels continue to drop, we expect to see an increase in intensity and frequency in dust storms for this area.

1984

1998

2006

2020

Future Work

I am currently working on expanding this map to include the entire state of Utah. I plan to overlay the locations where I currently have MWAC dust samplers (shown on the left) to see if those were placed in areas that are major dust sources (according to my model)
Land-use type can have a significant affect on dust production for an area. I would like to overlay a land-use type layer on my dust source map to see if there's any correlation

Dust storm moving into SLC (Spring 2016)

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