A New Normalized Groundwater Age-Based Index for Quantitative Evaluation of the Vulnerability to Seawater Intrusion in Coastal Aquifers: Implications for Management and Risk Assessments

The vulnerability of coastal aquifers to seawater intrusion has been largely relying on data-driven indexing approaches despite their shortcomings depict the complex processes groundwater flow and mass transport under variable velocity conditions. This paper introduces a modelling-based alternative technique normalized saltwater age index post-processed from results density simulation. distributed is obtained steady-state distribution salinity restriction mean distribution. approach provides novel way shift concentration space into assessment evaluate threats aquifers. method requires only sequential numerical solution two steady state sets equations. Several variants hypothetical Henry problem case study in Lebanon are selected for demonstration. Results highlight this ability rank, compare, validate different scenarios water resources management. A concept zero-vulnerability line/surface delineating area threatened by shown be relevant optimal management risk assessments. Hence, work new tool sustainably manage protect resources.