Natural and Anthropogenic Emission of Soil Dust in Nellis Dunes Recreational Area, Clark County, Nevada

Nellis Dunes Recreational Area is the sole area in Clark County, Nevada, that is freely accessible to the public for off-road driving. Over 285000 people visit this 40 km² large area annually to drive their off-road vehicles in the dunes, washes, desert pavements, rock-covered hills and moon-like landscapes that characterize this part of the Mojave Desert, creating huge amounts of dust. In the same time the area experiences considerable wind erosion, which serves as an additional source for airborne dust. To investigate, monitor and control the emissions a study has been set up by the federal Bureau of Land Management (BLM) and the University of Nevada Las Vegas. Wind erosion is measured at 68 stations, located on 17 different soil types, using BSNE dust samplers. Dust production caused by off-road driving is investigated in experiments with dirt bikes, quads (4-wheelers) and dune buggies, at different driving speeds, on the same 17 soil types. The vulnerability of the 17 soil types to dust production is measured with a Portable In Situ Wind Erosion Lab (PI-SWERL) instrument. Airborne dust concentrations are recorded with a Dust Trak monitor. Wind data collected from three 20-m wind towers and one 10-m wind tower are used to calculate the wind field over the whole area using a parallel h-adaptive finite element atmospheric dispersion model. The integration of all these data will be used to estimate the contribution of wind erosion and that of off-road driving to the dust production in the area, quantify the emissions for various grain size fractions, and evaluate the potential of the 17 soil types to emit dust either by wind erosion or by off-road driving.