Spatio-temporal variations of sea level around the Mekong Delta: their causes and consequences on the coastal environment

Abstract

This paper presents a comprehensive analysis of sea level variations around the Mekong Delta, and their causes and consequences on the environment, based on the tidal records from several stations. The results of the analysis revealed significant spatio-temporal sea level variations along the delta coast. Tidal fluctuations showed their local peaks around the river mouth with shallow bottom areas. The prevailing winds were identified as the factor governing the remarkable seasonal variability of the mean sea levels along the southern coast of the delta. From 1985 to 2010, the relative sea level along the southern coast of the delta rose by about 3.3 mm y–1. This rate of rise combined with the effect of land subsidence renders the Mekong Delta alarmingly susceptible to frequent inundation. Moreover, the immediate impacts, including saline intrusion and occasional inundation due to seasonal sea level fluctuation, are also found to be critical and require urgent attention. These findings suggest the need to revise coastal management strategies to prioritize the immediate effects of short-term sea level fluctuations and to increase the focus on local management issues such as groundwater pumping causing land subsidence and local sea level trends in addition to the global threats.