Snowmelt Runoff in Suburban Environments

Abstract

While snowmelt and rain-on-snow events have received considerable attention in rural watersheds they have been largely ignored in urban hydrology, despite the fact that they may result in severe flooding. The runoff responses of two subcatchments of a small drainage basin in Peterborough, Ontario were investigated for the spring snowmelts of 1984 and 1985. One of the catchments has undergone substantial suburbanization, while the other is largely in rural land use. Measurements in each catchment included snowpack water-equivalent depths, snowmelt and precipitation, fluxes of net radiation over snowpacks, infiltration capacities of pervious surface types, and streamflow. Suburban development appears to have produced substantial increases in spring quickflow yields from the entire basin. A comparison of the responses of the two subcatchments reveals that the suburban catchment reacts more rapidly to snowmelt and rain-on-snow inputs and generates larger initial quickflow response ratios than the rural basin as a result of the microclimatic, pedologic and hydraulic characteristics of built-up areas. However, the dynamic behaviour of the runoff contributing area of the rural catchment results in a marked increase in its quickflow yield as melt progresses. The results suggest that the distinct nature of the processes of snow accumulation, melt and runoff generation in built-up areas should be considered when modelling suburban snowmelt runoff.