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Abstract

The Mekong Delta is affected by annual seasonal salinity intrusion in December–May. In this season, the discharge of the Mekong is low, and high tidal water levels cause a deep intrusion of saline water. Critical salt concentrations can be observed 50–80 km deep during high tides. These high salt concentrations cause severe problems in terms of fresh irrigation and drinking water. A quantitative knowledge of the current and likely future salinity intrusion is thus urgently required to develop adaptation plans and mitigation measures. This chapter quantifies the current salinity intrusion in the Mekong Delta, as well as a model-based estimation of the possible future salinity intrusion. The different factors affecting salinity intrusion—changing river discharge by climate change and dam development, changes in effective tidal water levels, changing ocean salinity—and their impacts are quantified by hydraulic modeling. Based on the modeling results, recommendations for future planning are derived.