We proposed a novel model conceptualization to simulate the dynamic freezing-thaw processes of permafrost at watershed-scale for the purpose of decreasing large-scale modeling complexity and meanwhile maintaining the accuracy in the estimation of integrated hydrologic metrics. The model conceptualization includes four main components: decomposition of watershed to sub-catchments, parameterization of sub-catchments to 2D hillslopes, hillslope-scale permafrost modeling using the Advanced Terrestrial Simulator (ATS), and external river routing based on hillslopes discharges through Model for Scale Adaptive River Transport (MOSART). We applied this model conceptualization to a catchment in Sagavanirktok River basin, resulting in significant overestimation of discharge during snowmelt dominated period, but zero discharge in spring, partially caused by the inappropriate representation of infiltration-runoff partitioning. We improved this issue by updating the relative permeability model to allow for water moving deeper instead of just keeping saturated at top surface, and modifying aerodynamic resistance to account for microtopography effect which further affects soil evaporation. Extending the model conceptualization to the whole Sagavanirktok River basin is on going.