Urban Snowmelt Runoff Responses to the Temperature‐Hydraulic Conductivity Relation in a Cold Climate

ABSTRACT Urban winter runoff management was mainly regulated by temperature variations and the snow‐removing measures, but the underlying mechanism of the temperature‐hydraulic conductivity (T‐K) relation was seldom studied for urban environments and far from clearly understood. It is imperative to consider the T‐K relation for snowmelt runoff calculation especially when the compound effects with the snow‐removing measures and low impact development (LID) need to be considered. This work investigated the temperature regulation on urban infiltration and snowmelt runoff by a proposed modelling framework. A series of hydrologic model experiments revealed a crucial link between the hydraulic conductivity and snowmelt runoff emphasising the role of temperature in the partitioning between percolation and runoff. The inclusion of a T‐K relation in the SWMM model resulted in a 26.0%–37.1% decrease in infiltration and a 12.7%–25.8% increase in runoff. The effects of the T‐K relation were found to become more significant when the anthropogenic interventions such as snow‐clearing measures and LID were applied. After the T‐K mechanism was modelled, the infiltration and the runoff caused by the snow‐clearing measures were reduced by 33.7%–48.2% and raised by 19.7%–35.6%, respectively, and LID would further reduce infiltration by 46.2%–65.2% and increase runoff by 71.0%–105.2%. This study serves as one of the first a few attempts to improve the understanding of the freeze–thaw cycles of land surface in urban environments.