Detail Abstract

Dynamics of salt intrusion in the Mekong Delta and future projections

Abstract

The low-lying and rapidly urbanizing Mekong Delta is experiencing land subsidence rates in the order of 1-4cm/yr, in response to excessive ground water extraction, that are exceeding sea level rise. Furthermore, within the Rise and Fall Project, by analyzi9ng noble historical records of water level, discharge and stationary salinity measurements, we have shown that sand mining is changing the channel geometries; hence, tidal propagation is changing in the estuarine channel system. By accelerated dam construction further upstream in Cambodia, Laos and China, the sediment supply has declined, resulting in coastal, channel bed and bank erosion. All above mechanisms contribute to increased salt intrusion. <br> Here we will show how various environmental trends influence dynamics of salt intrusion in the Mekong Delta and we project how all the drivers such as climate change, land subsidence and land use influence salt intrusion in the future of the Mekong Delta. We use state of the art 2DV-3D models, backed by extensive observations to display the changes in the delt.<br> The observed trends and the modelled physical processes raise grave concerns over the long-term livelihood of the delta and reveal that anthropogenic activities out-pace global climate change effects on the region. The fate of this mega delta solely depends on bold, integrated, inter-disciplinary and trans-boundary governance and management measures that require immediate actions.