Effects of riverbed incision on the hydrology of the Vietnamese Mekong Delta

The hydrogeomorphology of the Vietnamese Mekong Delta (VMD) has been significantly altered by natural and anthropogenic drivers. In this study, spatiotemporal changes flow regime were examined analysing long-term daily, monthly, annual extreme discharges water levels from 1980 to 2018, supported further investigation sediment load (from 1960s 2015), river bathymetric data (in 1998, 2014 2017) daily salinity concentration 1990s 2015) using various statistical methods a coupled numerical model. Then, effects riverbed incision on hydrology investigated. results show that dry season discharge (i.e., in March–June) Tien River increased up 23% predam period (1980–1992) postdam (1993–2018) but level at My Thuan decreased ?46%. mean monthly June Tan Chau January June–October statistically, even though respective significantly. These instead attributed accelerated upstream Thuan, which more than three times, rate ?0.16 m/year (?16.7 Mm3/year) 1998–2014 ?0.5 (?52.5 2014–2017. This was likely caused reduction VMD 166.7 Mt/year 57.6 period) increase sand mining 3.9 Mm3 2012 13.43 2018). Collectively, is one main causes enhanced intrusion.