Characterizing the Size Distribution of Particles in Urban Stormwater by Use of Fixed-Point Sample-Collection Methods

摘要

The distribution of particles in runoff was characterized from six types of urban source areas (parking lot, feeder street, collector street, arterial street, rooftop, and mixed use) around Madison, Wis. The lowest median particle sizes were found at the mixed-use and parking-lot study areas (42 and 54 micrometers (im), respectively), followed by the collector street (70 im). Similar median particle sizes of approximately 95 im were found for both the arterial street and institutional roof study areas. The largest median particle size, nearly 200 im, was measured in feeder street samples. Variability in median particle size and distribution was considerable between source areas. Variability was also evident in comparisons with similar source area types from previous studies. Much of the variability can be attributed to use of different analytical techniques, sample-collection methods, and reporting between researchers. Results from this study further document the difficulty of deriving a single particle-size distribution that is representative of stormwater runoff generated from more than one source area.