Author(s): Anh Duc Trinh; Thu Nga Do

Linked Author(s):

Keywords: Fraction of young water; Mean transit time; Sinusoidal fitting

Abstract: The water stable isotopic compositions (δ18O and δ 2H) are excellent tracers of water resources and hydrological processes. The fraction of young water (Fyw) and mean transit time (MTT) estimated from water stable isotope profiles by sine-wave fitting is useful and reliable information for the catchment hydrology. Four water stable isotopes profiles were generated at 3 upstream tributaries and delta region on the Red River from 2003 to 2019. In combination with rainwater isotope data, Fyw and MTT for different tributaries and whole river system were calculated. Range of Fyw was 0.05 - 0.32 (Fig. 1) and of MTT was 0.4 - 3.5 years (Fig. 2). The values of Fyw and MTT are negatively and positively proportional to the change of hydropower reservoir volume. These two hydrological parameters are negatively correlated over time. A decrease of Fyw (also, an increase of MTT) indicates an increase of water storage from the catchment in reservoirs. The strong variation of these catchment hydrological variables depicts the anthropogenic impact on the Red River system.

DOI: https://doi.org/10.3850/IAHR-39WC252171192022647

Year: 2022