DOC is a substrate for stream heterotrophs, and high DOC availability is known to inhibit nitrification. We evaluated how watershed configuration (watershed area, lake area and stream length) affects DOC quantity and quality. We hypothesized that DOC quantity would be most influenced by aspects of watershed size, while quality would be most influenced by lakes. We tested this hypothesis by 1) measuring inflow and outflow DOC concentration and quality in 5 watersheds of differing configuration and 2) conducting more detailed assessment of temporal changes in DOC quantity and quality in one watershed (Bull Trout). DOC concentrations were similar in all inflows, whereas outflow concentrations decreased with increased lake area. DOC quality increased with lake area but decreased with watershed area and stream length. Bull Trout outflow DOC concentrations were consistent (~1.4mgC/L) while the inflow decreased steadily (~0.9mgC/L to 0.4mgC/L) throughout the summer. In both locations, DOC quality increased over time, but was consistently higher in the inflow. Nitrification rates were lower in inflows than outflows (p=0.05), thus DOC quality appears to exert a stronger control on nitrification than DOC quantity. Understanding relationships between watershed configuration and DOC dynamics may provide insight in nitrate regeneration in complex mountain watersheds.