Water quality modelled outputs for daily channel discharge and depth, nitrate-N, ammonium-N, suspended sediment concentration, total phosphorus, and soluble reactive phosphorus for the Mekong River basin. Baseline models for P and N were calibrated over 1998 to 2017. Predictions spanning 2018 to 2098 were modelled based on eight scenarios (2 climate x 2 socioeconomic x 2 population). Please see Whitehead et al (2019) https://doi.org/10.1016/j.scitotenv.2019.03.315 for details.