Staff Directory

John Ewing’s experience has focused on the development, calibration, and application of numerical models of single- and multi-phase fluid flow and transport in the subsurface. He uses models to address a variety of water resource management, radioactive waste isolation, and environmental investigation and remediation issues. Working for federal and state agencies responsible for the management, preservation, and protection of water resources, his experience includes developing regional-scale groundwater availability models (GAMs) of aquifers to support long-term planning and aquifer management. He has also used more local-scale models to help locate and design water supply wells and evaluate the impacts of groundwater pumping in the context of major water development and delivery projects. John has applied his modeling expertise to support national programs in the US, Switzerland, and France established to safely dispose of low-, intermediate-, and high-level radioactive wastes in deep geologic repositories. In support of site characterization and suitability evaluations, repository performance and safety assessments, and facility licensing, he has developed and applied process and system models to evaluate issues such as heat and gas evolution resulting from the storage of wastes and the performance of engineered barrier systems (EBS) designed to isolate wastes within a repository. As part of environmental protection and restoration activities at US Department of Energy, US Department of Defense, federal Superfund, and commercial mining operations and petroleum refining plants, John has used models to determine the nature, extent, and migration of subsurface contaminants, evaluate the feasibility of various remedial alternatives, define regulatory boundaries, design monitor well networks, and design and optimize remedial systems that include injection/extraction well systems for surfactant floods, soil vapor extraction systems, and interceptor trenches. His work has addressed soils and groundwater contaminated by chlorinated solvents, petroleum hydrocarbons, metals, and radionuclides. John has experience applying a variety of public domain and proprietary modeling codes that include the MODFLOW suite of codes, TOUGH, FEHM, UTCHEM, MUFTE UG, SWIFT II, UTSTREAM, IHM, and SWAT and he is an expert in applying automated calibration codes including PEST, ITOUGH, and UCODE, and in running models and conducting sensitivity and uncertainty analyses on computing clusters using parallelization software.