Alexandros “Alex” Papafotiou’s professional experience has focused on water resources and environmental research and applications. He has developed and applied several conceptual models and simulation tools for solving single- and multi-phase flow problems in complex heterogeneous media for a variety of applications, including safety assessment of potential waste sites, subsurface remediation schemes, CO2 sequestration, contaminant transport in the vadose or saturated zone, design of remedial actions, and groundwater management. In support of radioactive waste disposal programs in Switzerland and France, he has developed large- and local-scale water-gas flow repository models, regional groundwater and heat flow models, as well as host rock geohydrologic models in two and three dimensions for different low-/intermediate-level waste (L/ILW) and high-level waste (HLW) repository sites. Alex’s experience includes developing large-scale models for CO2 storage in saline aquifers and depleted gas fields, as well as abandoned well risk assessment scenarios. In addition, he has developed groundwater availability models and variable density brine-water-gas flow models for risk analysis associated with mine closure activities.