Data from: Degassing emissions in a temperate hydropower reservoir driven by seasonal stratification patterns but highly sensitive to discharge variability

This dataset contains monthly data from Douglas Reservoir (Tennessee, USA) from March 2023 to March 2024 used to calculate degassing emissions of CH4 and CO2. Dissolved gas data were collected in triplicate and measured using the headspace equilibration method. Degassing fluxes were then estimated based on the difference in mean gas concentration between the forebay and tailwater, multiplied by daily discharge. Detailed methods follow those for sample collection, processing, and calculation presented in Pilla et al. 2025 (https://doi.org/10.1007/s10533-025-01211-0). Data tables include (1) replicate CH4 and CO2 dissolved gas concentrations in the forebay and tailwater; (2) CH4 and CO2 degassing fluxes, propagated uncertainty, and corresponding discharge for sampling dates; and (3) ancillary vertical sonde profiles and and water chemistry data collected in or near the reservoir forebay. The data dictionary describes all columns, elements, and units for each data table.