This dataset contains high-frequency measurements of nitrate (NO3-) and dissolved organic carbon (DOC) in the Kervidy-Naizin catchment Agrhys . Kervidy-Naizin is part of the environmental research observatory Aghrys, where several environmental compartments – hydrosphere, pedosphere, biosphere – and farming practices have been monitored since 1990 (Fovet et al., 2018). Here, we describe the high frequency NO3- and DOC concentrations measured by the S::SCAN spectrolyser from 2010/10/20 to 2023/09/06 (thirteen water years). The dataset contains the raw data and data corrected with reference measurements obtained through laboratory analysis of 2561 grab samples.