| This study evaluates the use of one best management practice, vegetated filter strips, and its stormwater pollution removal performance at four road-side locations in Mobile, Alabama. Four in-ground samplers were placed at each sampled location: edge of pavement, 2 meter, 4 meter, and 6 meter downslope from the edged of pavement, within the vegetated filter strip. After sampler installation, 14 rain events were sampled in the 12 month period from January 2013 to December 2013. It was found that concentrations of stormwater constituents at the edge of pavement at all locations were similar to national averages for roadway stormwater runoff. Many constituents that were measured were found to be near background concentration levels typical in atmospheric deposition, urban and/or rural streams. Rainfall intensity was correlated with vegetative filter strip performance, especially in terms of total suspended solids (TSS). Vegetated filter strips (VFS) were effective in lowering concentrations for some constituents, but not all. For nutrients, vegetative filter strips were not effective at removing nitrate and phosphorus, as an average, but during several rain events, good phosphorus removal was observed. Concentration reductions were observed for some metals especially copper, particularly when metal concentrations at the edge of pavement were above background levels. |
