Long-term water level dynamics in the Red River basin in response to anthropogenic activities and climate change

• Published in: The Science of the total environment Vol. 912; p. 168985
• Main Authors: Quang, Nguyen Hao, Viet, Tran Quoc, Thang, Ha Nam, Hieu, Nguyen Trinh Duc
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 20.02.2024
• Subjects: Climate change; Dam; EOF; Red River system; Water level; Dam; Climate change; Water level; EOF; Red River system
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2023.168985

Understanding the regular variations in water levels and identifying the potential drivers under the combined pressures of anthropogenic activities and climate change can offer valuable insights into riverine management. In this study, we analyzed long-term daily observational data, including water levels and water discharge, spanning from the ~1950s to 2021 at seven gauging stations within the Red River basin. We investigated the spatiotemporal variation in mean water levels using standard analytical tools, including the Mann-Kendall (MK) test, rating curves, and Empirical Orthogonal Function (EOF). Specifically, we observed a notable and substantial decline in water levels downstream of the major tributaries, including Da, Red, and Lo Rivers, as well as at their confluence, starting at the end of 2008. Notably, a strong correlation between water levels and discharge is found, highlighting the pivotal role of discharge in influencing water levels. Surprisingly, relationships between water levels and climatic factors such as rainfall and air temperature proved less influential. This suggests that water levels are predominantly shaped by discharge and anthropogenic activities, rather than climate change. The study emphasized the substantial impact of human-induced activities, particularly dam operation and sand mining, on downstream water levels in the Red River basin. An intriguing finding revealed that upstream dynamics, particularly at the Hoa Binh dam, led to significant water level increases with the same discharge, attributed to channel deposition and reservoir water storage. The research's novelty is the comprehensive evaluation of long-term water level trends and its elucidation of the combined effects of anthropogenic activities and climate change, offering valuable insights for riverine management and emphasizing the influence of anthropogenic factors, notably dam regulation and sand mining, in driving shifts in water levels. [Display omitted] •Analyzing Red River basin's water levels (1950s–2021) and profiles (1980s–2021) assessed dam and climate impacts.•MK test, rating curves, and EOF analysis were utilized for mean water level variation assessment.•Downstream water levels declined significantly since late 2008, driven mostly by anthropogenic factors.•Significant downstream riverbed erosion due to reduced sediment supply from upstream dams and sand mining.