Understanding groundwater use and vulnerability of rural communities in the Mekong Delta: The case of Tra Vinh province, Vietnam

Groundwater has been increasingly used for water supply to sustain local livelihood and socio-economic development in the Vietnam Mekong Delta (VMD). Yet, intensive groundwater use raises concerns on sustainability as available fresh groundwater is finite with little or limited natural recharge in the area on one hand and, on the other hand, groundwater levels have been decreasing, with induced land subsistence, increased flooding and inundation, and exacerbated salinity intrusion. This study aimed to develop understanding of groundwater use and vulnerability of rural communities in the VMD. It was motivated by both the significance and little knowledge of decentralized groundwater use of small capacity by rural communities that is not monitored and managed. In this study, we designed and conducted a structured survey in selected rural communities to collect information related to water supply and groundwater use for domestic purposes and agriculture. Combining survey data and information from different sources, our analysis found that: 1) groundwater plays a varying role in domestic water use, with a heterogeneous pattern consistent with the spatial distribution of groundwater salinity; 2) local dependence on groundwater increases spatially from inland towards coastal areas; 3) poor households in coastal areas are of high vulnerability to groundwater limitations imposed by salinity or resource depletion for domestic use; 4) groundwater use in agriculture appears to be complementary to available fresh surface water, non-essential while exhibiting a spatial pattern corresponding to groundwater salinity or availability; and 5) there is indication of groundwater depletion associated with groundwater use in agriculture. The study revealed locally developed water use behavior adapting to local water conditions and wealth level, with fresh groundwater being of strategic importance, particularly to domestic water use and poor households in coastal areas. The findings fill the knowledge gap in the literature while providing relevant information for welfare improving management decision making on groundwater in the VMD.