Drylands Home | Human Health | Native Lands | Public Lands

Dust Emission from Playas (Dry Lakes)

The interactions between playa type, playa hydrology, and playa-surface sediments are important factors that control the type and amount of dust emitted from playas as a result of wind erosion. The production of evaporite minerals during evaporative loss of near-surface ground water results in both the creation and maintenance of several centimeters or more of loose sediment on and near the surfaces of wet playas.

Schematic cross-sections illustrating elements of (a) wet and (b) dry playas, illustrated for a hydrologically closed basin. Modified from figure 2 in Rosen (1994, The importance of groundwater in playas: A review of playa classifications and the sedimentology and hydrology of playas, in Rosen, M.R. (ed.), Paleoclimate and basin evolution of playa systems: Geological Society of America Special Paper 289, p. 1-18.).

Observations that characterize the texture, mineralogic composition, and hardness of playa surfaces at Franklin Lake, Soda Lake, and West Cronese Lake playas in the Mojave Desert (California), along with imaging of dust emission using automated digital photography, indicate that these kinds of surface sediments are highly susceptible to dust emission. The surfaces of wet playas are dynamic-surface texture and sediment availability to wind erosion change rapidly, primarily in response to fluctuations in water-table depth, rainfall, and rates of evaporation. In contrast, dry playas are characterized by ground water at depth. Consequently, dry playas commonly have hard surfaces that produce little or no dust if undisturbed except for transient silt and clay deposited on surfaces by wind and water. Although not the dominant type of global dust, salt-rich dusts from wet playas may be important with respect to radiative properties of dust plumes, atmospheric chemistry, windborne nutrients, and human health. Examples of regionally important dust sources from dry lake beds that behave as wet playas include parts of the Aral Sea (Kasachstan and Usbekistan), Owens Lake (California, USA), and probably the Hamoun wetlands (now mostly dry) of Afghanistan and Pakistan.

Please see Reynolds, R.L., Yount, J.C., Reheis, M.C., Goldstein, H., Chavez, Jr., P., Fulton, R., Whitney J., Fuller, C., Forester, R.M., 2007, Dust Emission from wet and dry playas in the Mojave Desert: Earth Surface Processes and Landforms, v. 32, 1811-1827. DOI: 10.1002/esp.1515.