| Hydrometric, isotopic and hydrochemical data were used to investigate runoff generation in a discontinuous permafrost headwater catchment. Research was undertaken between 10 April and 8 July, 2008 within Granger Basin, a 7.6 km2 sub-catchment of the Wolf Creek Research Basin, Yukon Territory, Canada. The main objectives of this research were to determine: i) the main components of the water balance and their values throughout the snowmelt period; ii) the role of aufeis and channel ice on streamflow quantity and quality and iii) the magnitude and timing of runoff components during the spring melt period. The main components of the water balance in Granger Basin were snowmelt (152 mm), precipitation (68 mm), evaporation (88 mm), discharge (173 mm) and change in storage (-41 mm) Aufeis and channel ice represented less than 1% of total streamflow, however, they did alter streamflow pathways and the timing of discharge. Pre-event water represented ∼73% of total streamflow during the snowmelt period. End-member mixing analysis enabled the determination of three contributing end-members to streamflow. Initially, the groundwater end-member dominated streamflow, followed by soil water end-member, the snowmelt water and then back toward the groundwater end-member chemistry. Concentration versus discharge plots elucidated the dilution of weathering ions by snowmelt water and the chemostatic behaviour of ions that originated in organic soils. The potassium to calcium ratio (K:Ca) of streamwater indicated an early contribution of pre-event soil water during snowmelt generation. The combined use of hydrometric, isotopic and hydrochemical data demonstrated the importance and timing of the pre-event soil water contribution to snowmelt runoff generation in Granger Basin. These insights advance our knowledge and understanding of runoff generation in Granger Basin and demonstrate the value of a mixed methods approach to tracer based investigations. |
