The delta of the Mekong River in Vietnam has been heavily impacted by anthropogenic stresses in recent years, such as upstream dam construction and sand mining within the main and distributary channels, leading to riverbank and coastal erosion. Intensive bathymetric surveys, conducted within the Tien River branch during the dry and wet season 2018, reveal a high magnitude of sand mining activities. For the year 2018, an analysis of bathymetric maps and the local refilling processes leads to an estimated sand extraction volume of 4.64 $$\pm $$± 0.31 Mm $${}^{3}$$3 /yr in the study area, which covered around 20 km. Reported statistics of sand mining for all of the Mekong’s channels within the delta, which have a cumulative length of several hundred kilometres, are 17.77 Mm $${}^{3}$$3 /yr for this period. Results from this study highlight that these statistics are likely too conservative. It is also shown that natural sediment supplies from upper reaches of the Mekong are insufficient to compensate for the loss of extracted bed aggregates, illustrating the non-sustainable nature of the local sand mining practices.

Sustainable livelihood development is an ongoing challenge worldwide, and has regained importance due to threats of water shortages and climate change. To cope with changing climatic, demographic and market conditions in Vietnam’s Mekong Delta (VMD) an agricultural transformation process has been suggested in the recent Mekong Delta Plan. This agricultural transformation process requires the implementation of alternative livelihood models. The majority of current agricultural livelihood models in the VMD have been introduced by the government in a top-down manner. In this study, we applied a bottom-up approach to understand the motivations and abilities of local farmers to adopt alternative livelihood models. It is based on the MOTA methodological framework, which is further tested with the use of multivariate analyses. The study was conducted in Ben Tre coastal province. Results showed that farmers’ motivations and abilities to apply alternative models vary substantially among different groups, driven by their perceptions on triggers and opportunities. Acknowledging this diversity is essential to the development of agricultural transformation plans. Furthermore, based on the analysis, a projection of the precise support that communities need to supplement their knowledge, skills and financial capacities, as well as interventions to reduce the risks of new livelihood models, is given.