Saltwater intrusion in the Vietnamese Mekong Delta has been significantly aggravated by both human development and adverse climate change. To curb salinization, local authorities rely heavily on structural measures (dikes, sluice gates, reservoir canals), yet their long-term environmental trade-offs remain underexplored. This study examines such environmental impacts and prioritization of measures in Tra Vinh province, Viet Nam. The research process combined field sampling of key water quality indicators at 25 sites, principal component analysis (PCA) to distil the main drivers, and in-depth interviews with ten risk-management experts. The findings reveal a potentially critical trade-off: measures provide operational benefits in reducing immediate intrusion, but this comes at the cost of elevated pollutant concentration and long-term degradation. This is evidenced by severe ecological stress, with many samples exceeding safe thresholds for DO, ORP, and TDS. Furthermore, the analysis confirmed strong interdependencies among conductivity, salinity, and total dissolved solids (correlation > 0.97). These results indicate the need for additional research on the ecosystem impacts of physical defenses, as well as consideration of non-structural approaches, including policy innovation, community engagement, and adaptive governance to support sustainable risk management against SI.