SEPARATING STREAMFLOW INTO GROUNDWATER, SOLUM AND UPWELLING FLOW AND ITS IMPLICATIONS FOR HYDROCHEMICAL MODELING

A chemical hydrograph separation technique based on the mass-balance a pproach was extended to separate streamflow into three components in a small forested catchment in the southern Laurentians, Quebec. Using l inear correlation analysis to identify chemical tracers capable of div iding a hydrograph for the Hermine catchment, streamflow was separated into groundwater, solum and upwelling flow. This new approach which c alculated upwelling flow, i.e. solution forced from the groundwater up through the solum prior to reaching the stream, allowed us to determi ne the chemical behaviour of the tracers used in this particular study . Dissolved silicon was reactive since its concentration was modified by the pathway to the channel whereas total aluminium, hydronium, mono meric aluminium, fluoride and magnesium were non-reactive since their concentrations were controlled by the source of the solution.