Application of Water Stable Isotopes for Hydrological Characterization of the Red River (Asia)

Fraction of young water (Fyw) and mean transit time (MTT, τ¯) calculated from isotope profiles are valuable information for catchment hydrological assessment, especially in anthropogenically impacted region where natural conditions may not be decisive to hydrology. The calculation Fyw MTT were performed on three subsets δ18O_H2O data collected at the Hanoi meteo-hydrological station, Red River, periods; 2002–2005, 2015, 2018–2019. (min max) values rainwater over periods are, respectively, −5.3‰ (−11.0 −1.2‰), −5.4‰ (−10.7 −1.4‰), −4.5‰ (−13.9 1.7‰). corresponding river −8.4‰ (−9.8 −6.9‰), −8.5‰ (−9.1 −7.7‰), (−9.5 −7.2‰), respectively. different is 22 ± 9%, 10 5%, 8 3%. Mean 4.69 15.57, 1.65 1.53, 2.06 1.87 years. (MTT) negatively (positively) proportional change reservoir volume periods, which logical, since reservoirs tend keep more slower down flow. strong variation τ¯, two essential variables characterizing hydrology, represents an anthropogenic impact River system.