Saltwater intrusion risk assessment is a foundational step for preventing and controlling salinization in coastal regions. The Vietnamese Mekong Delta (VMD) is highly affected by drought and salinization threats, especially severe under the impacts of global climate change and the rapid development of an upstream hydropower dam system. This study aimed to apply a modified DRASTIC model, which combines the generic DRASTIC model with hydrological and anthropogenic factors (i.e., river catchment and land use), to examine seawater intrusion vulnerability in the soil-water-bearing layer in the Ben Tre province, located in the VMD. One hundred and fifty hand-auger samples for total dissolved solids (TDS) measurements, one of the reflected salinity parameters, were used to validate the results obtained with both the DRASTIC and modified DRASTIC models. The spatial analysis tools in the ArcGIS software (i.e., Kriging and data classification tools) were used to interpolate, classify, and map the input factors and salinization susceptibility in the study area. The results show that the vulnerability index values obtained from the DRASTIC and modified DRASTIC models were 36–128 and 55–163, respectively. The vulnerable indices increased from inland districts to coastal areas. The Ba Tri and Binh Dai districts were recorded as having very high vulnerability to salinization, while the Chau Thanh and Cho Lach districts were at a low vulnerability level. From the comparative analysis of the two models, it is obvious that the modified DRASTIC model with the inclusion of a river or canal network and agricultural practices factors enables better performance than the generic DRASTIC model. This enhancement is explained by the significant impact of anthropogenic activities on the salinization of soil water content. This study’s results can be used as scientific implications for planners and decision-makers in river catchment and land-use management practices.

The high-resolution seismic method can provide acoustic reflectivity images of shallow marine geology structures. In South Vietnam, the demand for construction materials like sand is high; therefore, the exploration of its deposits is considered in this study. This study investigated an around 200-square-kilometer area offshore Bac Lieu using 2D seismic sub-bottom lines. We employed the processed seismic amplitude and its seismic attributes as mean and variance textures to interpret the data. The processed seismic amplitude and its attributes can represent the young Holocene sediments (i.e., sand, silt, clay, and their mixtures) thanks to their different seismic patterns. Our interpretation result consists of 3D horizons of the seabed, Holocene silt, and sand sediments, which are compatible with the prior geological information, including three nearby drill holes. The seabed gradually descends from 10.0 m to 19.0 m over a horizontal distance of around 11 km. Moreover, the interpreted results show that the sand sediments reside in the center of survey area, with a maximum thickness of around 12.0 m. Interestingly, a fill sediment channel effectively separates two different zones of young Holocene sand and silt sediments. The findings provide valuable information for Vietnamese government officers to develop sustainable policies and regulations for marine mineral exploitation and exploration.

Soil water in the coastal zones is more vulnerable to salinization. Soil-water vulnerability assessment is an effective tool for soil-water management. This study used the DRASTIC model, which is based on seven factors viz: depth to soil water, recharge, soil-water bearing layer, soil media, topography, impact of root zone, and hydraulic conductivity to evaluate soil-water salinization potentiality of Ben Tre province. The obtained soil-water vulnerability map is divided into three vulnerable zones: low vulnerability zone with 348.59 km2 of total area, moderate vulnerability zone with 1898.77 km2, and high vulnerability zone having 147.64 km2. Moreover, the DRASTIC model was validated by Total dissolved solids (TDS) over the study area. Validation results showed the low vulnerability zone of the moderate saline (TDS = 1,500–7,000 mg/L), while the moderate vulnerability zone of the moderate, high, and very high saline (TDS = 1,500–35,000 mg/L). However, the high vulnerability zone has a very high saline (TDS = 15,000–35,000 mg/L). The study results are of considerable value to land use planning and soil researchers.