The data set present high-frequency data (1h-step) collected at the outlet of a 3 km length stream which flows through a boreal headwater catchment of 2.22 kilometer square and covered at 76% by an ombrotrophic dome-shaped peatland. The data set covered a period from June 2018 to May 2020. The measured parameters included physico-chemical parameters measured by an EXO2 multiparameter probe (YSI, USA) installed in the stream, at the outlet of the catchment. This multiparameter probe measured among other parameters (e.g., water temperature, pH, specific conductivity and dissolved oxygen saturation) the fluorescent dissolved organic matter (fDOM) which was used as a proxy of dissolved organic carbon (DOC) and a calibration was performed in order to determined the relashionship f(fDOM) = DOC. A hidden markov model was applied to this data set to decompose times series into low flow and high flow conditions. This was used to calculate specific DOC exports during those periods. Specific flood periods were isolated and specific indices were calculated for those periods. In addition, the stream discharge was mesured at the same site using a ultrasonic distance sensor (SR50, Campbell, USA) [from June 2018 to May 2019] and a water-level logger (U201-04, Hobo, Onset, USA) [from June 2019 to May 2020]. In the peatland area, the water table depth and the porewater temperature were measured hourly using a U20-001-04 water level logger (Hobo, Onset, USA) [2018] and a a U20l-04 water level logger (Hobo, Onset, USA) [2019] and the precipitation and air temperature were measured using a a tilting bucket rain gauge (Onset, 0.2 mm).