A wind-tunnel study of atmospheric boundary-layer flow over vegetated surfaces to suppress PM10 emission on Owens (dry) Lake

Dust storms on Owens (dry) Lake located 200 miles northeast of Los Angeles, California, U.S.A., have caused serious PM10 emission problems. A laboratory-based experimental study was conducted to investigate the efficiency of 'vegetation cover' on the playa to suppress dust emission rates as part of a mitigation plan. Erodible lakebed material and field vegetation (salt grass) taken from Owens (dry) Lake were placed in a wind tunnel to simulate near-surface wind flow in the atmospheric boundary layer. Vertical wind-speed profiles and vertical PM10-concentration profiles were measured over six different levels of surface vegetation cover. In order to understand the mechanism of aeolian particle transport and dust injection into the atmosphere, the roughness parameter, z(0), the friction velocity, u(*), and the surface drag coefficient, C-D, were carefully determined. An empirical equation was developed to predict PM10 emission rates as a function of wind speed and level of vegetation coverage for Owens (dry) Lake. Although the current results apply only to the effectiveness of vegetation cover to suppress PM10 emissions at Owens playa, the procedure can be employed for any arid area or region that might utilize added vegetation as a mitigation measure.