Characterization and temporal variation of urban runoff in a cold climate - design implications for SuDS

Abstract

This paper characterizes stormwater runoff in a coastal cold climate urban area regarding metal fractionation and particle size distribution to understand the implications for sustainable urban drainage system (SuDS) design. Strong temporal and spatial variations were found for all studied parameters. Suspended and dissolved solids showed up to 10-fold and 44-fold increase, respectively, during salting periods (air temperature <0 °C). Metals were nearly solely associated with the suspended fraction (>1.2 µm), which increased during the salting periods (>97%). Use of snow-tyres and de-icers (gritting sand and NaCl) are more likely to explain the temporal fluctuations, rather than contributions from nearby snow piles. Residential streets might serve as a source of pollutants during the winter months when street sweeping is minimal. These results imply that protection against clogging from excessive sediment loads and use of salts during winter should be the primary focus for SuDS design.