The changes in physicochemical and stable isotope compositions in the lower Yellow River of China due to artificial flooding. (15th December 2020)

• Record Type: Journal Article
• Authors: Viji, Rajendran; Yi, Yujun; Song, Jie; Liu, Hongxi; Zhou, Yang; Li, Chunhui
• Is Part Of: Journal of environmental management. Volume 276(2020)
• Publication Date: 2020-12-15
• Subjects: Yellow River -- Xiaolangdi reservoir -- Stable isotopes -- Deuterium excess -- Hydro-biogeochemical cycle; Environmental policy -- Periodicals; Environmental management -- Periodicals; Environment -- Periodicals; Ecology -- Periodicals; 363.705
• DOI: 10.1016/j.jenvman.2020.111205
• Languages: English
• ISSNs: 0301-4797

Abstract

Abstract: Increasingly, modern hydrological technologies are dynamically altering river water flow and drastically affecting river hydrogeochemical cycle regimes globally. The present study focused on the reservoir discharges of artificial floodwaters that influence spatiotemporal variations in the physicochemical and stable isotope compositions in the lower Yellow River (LYR) of China. The surface water samples were collected at the nine sites along the LYR during the pre-, inter-and post-flood periods. Then, the collected samples were analysed with the following standard method. The δD and δ 18 O slopes of the waterline clearly indicated that the prolonged reservoir water and different water flows impacted the hydrological cycle in the LYR regions compared to GMWL (global meteoric water line) and LMWL (local meteoric water line). The thermal stratification processes of the water in the largest reservoir slightly enriched the heavy isotopes, and physicochemical alteration was neglected. Statistical analysis of two-way ANOVA revealed that the p -values ( p < 0.01, p < 0.05) were very strong for most of the variables between the periods, and the linear regression exhibited weak values (R 2 = 0.253, R 2 = 0.150) at the surface water temperature variations and suggested no significant influence of isotope composition. Overall, the Xiaolangdi reservoir water prolonged time rates, and artificial floodwater flow had a very small effect on the isotope composition; in particular, a large high turbidity concentration in the discharged artificial floodwaters was the only considerable ecological risk condition in the LYR. This kind of proper monitoring work is immensely important and prevents reservoirs from causing hydrological cycle impacts in the LYR and the adjacent coastal ecosystems. Highlights: The Xiaolangdi reservoir operation slightly altered the stable δD and δ18O isotope levels in the Lower Yellow River (LYR) surface water. The stable δD and δ18O isotope values in the surface water strongly deviated from the GMWL and LMWL. The river water low flow variation strongly changed the stable δD and δ18O isotope levels. The turbidity concentrations of the artificial floodwater discharges were only a major threat in the LYR. The Xiaolangdi reservoir operation has very little impact on the hydrological cycle of the LYR.