A computer-aided snowmelt model for augmenting winter streamflow simulation in a southern Ontario drainage basin

Abstract

A lumped-parameter mathematical model is formulated to represent the physical processes of the accumulating and melting snowpack within a drainage basin. Common theoretical descriptions of the processes represent snow accumulation and melt at a point, but computer-aided procedures facilitate spatial distribution of the model inputs and thus provide for a digital simulation of the basin-wide snowpack condition and melt with time. The model is treated on the basis of the energy flux and mass transfer processes relating to the average snowpack, across the snowpack–atmosphere and snowpack – ground surface interfaces. An awareness of the likely lack of the extensive meteorological data usually required for proper application of such models, necessitates reliance on a number of literature-cited and locally derived empirical snowmelt relationships in order to ensure a practical and viable model. Thus, auxiliary computer subroutines are formulated to provide for applicable options, depending on the availability of real-time data. The purpose of the snowmelt model is to serve as a monitor of net basin input, complementing an overall comprehensive integrated hydrologic system model for use in streamflow simulation. The model is calibrated and tested with real-time data in a Ministry of the Environment-IHD Representative Drainage Basin in southern Ontario. Its applicability in estimating maximum flood flows during spring runoff periods is demonstrated by imposing meteorological conditions favourable for continuous melting upon maximum snowpack storage conditions.