Trends of discharge and water level variations on the Red river in the Hanoi area, Vietnam

Abstract

The present study was conducted to ascertain the characteristics of flow changes over time and to identify the dominant causes. To this end, a study of discharge and water level fluctuation trends was conducted. The study employed a 21-year data series (2004-2024) and utilized the non-parametric Mann-Kendall method, in conjunction with Sen's slope estimation, to analyze the trends and change rates of discharge and water level at Son Tay and Ha Noi hydrological stations on the Red River in the Hanoi area. The analysis process entailed a thorough examination of the annual average, annual maximum, annual minimum, and monthly average characteristics. The results definitively show that the discharge and water level at Son Tay and Ha Noi are either increasing or decreasing, or not trending. However, the majority of results clearly indicate a downward trend in water levels. This decline does not originate from discharge variations. It clearly shows the impact of riverbed change due to many different causes, including resource exploitation in the basin. This article definitively lays out the scientific foundation for managing and using water resources wisely. It also offers clear solutions to safeguard the ecosystem, traffic, and irrigation systems in the area.