This research aims to apply deterministic models in northern Manitoba in order to observe the ability and the appropriateness of the models in simulating runoff in northern Manitoba. The conceptual, deterministic models chosen for this research are the SLURP model and the WATFLOOD model. The Sapochi River Basin in the Northern Study Area of the Boreal Ecosystem-Atmosphere Study (BOREAS) is the river basin chosen as the study area for this research. Archived data for 1994 and 1995 were used to calibrate and verify the SLURP and WATFLOOD models in the Sapochi River Basin. The model is first calibrated with 1994 data and then verified with 1995 data. Furthermore, 1995 data is used as a calibration year and 1994 data as the verification year. Finally, both models are optimized on 1994 and 1995 together. The application of each model in the Sapochi River Basin produced different results with the SLURP model achieving a Nash and Sutcliffe efficiency of 80% over 1994 and 1995. WATFLOOD produces about 70% for 1994 and 1995. Parameters associated with snowmelt and slow storage are the most influencing parameters for SLURP simulations, with the latter dominating summer and fall runoff. Parameters associated with the upper and lower zone, specifically the upper zone specific retention, are the most influential on WATFLOOD simulation for this region. The northern Boreal forest region is dominated by snowmelt and slow discharge from interflow. The research also indicates that the ASA concept from the SLURP model is more representative than the GRU concept in depicting the natural condition of watershed. One ASA was sufficient to simulate runoff in SLURP adequately while a 5km x 5 km GRU was necessary in the WATFLOOD simulations.