Detailed studies of groundwater-surface water systems in Hartley Creek basin show the creek to be at baseflow for only a few months in the winter when other contributions to streamflow are negligible. Following spring snowmelt, drainage of muskeg is the major contributor to streamflow along with groundwater inflow. Similar patterns of streamflow generation were observed for Firebag, Steepbank, and Muskeg rivers as well as Thickwood Creek. Quantitative hydrograph separations for these basins show that the main differences result from variable amounts of inflow from muskeg during winter. Muskeg River like Hartley Creek is close to baseflow in winter. However, in Firebag River and Thickwood Creek, drainage from muskeg may comprise as much as 40 to 50% of the streamflow in winter. Streamflow in all basins will be influenced by the disturbance of muskeg. For the particular case where muskeg is removed and replaced by mineral soils, stream discharge will tend to decrease during summer and to increase during spring runoff and stormflow periods. In cases where the local disturbance of muskeg is considerable, marked variation in streamwater chemistry can be anticipated.