Total organic carbon (TOC) from terrestrial systems is transported to rivers via erosion, surface runoff, and subsurface leaching, with potential consequences for water quality and drinking water treatment. During winter, snowpack and snowmelt regulate soil thermal regimes, influencing soil moisture availability and vegetation growth over the growing season, litter production and decomposition, ultimately governing TOC export and cycling across cold-region watersheds. Snowmelt-driven spring runoff is a major driver of TOC mobilization from landscapes to river networks. The measured TOC concentrations in rivers commonly exhibit their first annual peak during spring, reflecting influences of antecedent winter hydrological and biogeochemical conditions, as well as soil organic carbon availability from prior-season biomass and litter. Watersheds across the Northern Hemisphere are increasingly impacted by climate change, with increasing TOC concentrations raising water quality concerns. Shifts in snowmelt dynamics, landscape biomass production and decomposition under warming conditions can modify organic carbon production and transport. Despite this, few studies have examined how climate-driven changes in winter hydrologic and biogeochemical processes influence springtime TOC transport and cycling in cold-regions. Using an improved Soil and Water Assessment Tool (SWAT-OCSM) and the North Saskatchewan River Basin, we simulated and compared watershed-scale responses to future climate scenarios and historical simulations to assess changes in winter-springtime TOC dynamics. These findings can be used as boundary conditions for hydrodynamic river ice models, or as a baseline against which exogenous influences, such as glacial or wildfire impacts, can be evaluated.