Strongly sorbing chemicals (e.g., heavy metals, radionuclides, pharmaceuticals, and explosives) in porous media are associated predominantly with the solid phase, which is commonly assumed to be stationary. However, recent fieldand laboratory-scale observations have shown that in the presence of mobile colloidal particles (e.g., microbes, humic substances, clays, and metal oxides), colloids can...

When oocysts of the protozoan Cryptosporidium parvum contaminate drinking water supplies, they can cause outbreaks of Cryptosporidiosis, a common waterborne disease. Of the different pathways by which oocysts can wind up in drinking water, one has received little attention to date; that is, because soils are often considered to be perfect filters, the transport of oocysts through the subsoil to...

A three-dimensional numerical model is developed for the simulation of water flow and chemical transport through variably saturated porous media. The nonlinear flow equation is solved using the Galerkin finite element technique with the Picard iteration scheme and a continuous velocity field is obtained by separate application of the Galerkin technique to the flux equation. A two-site adsorptio...

Sandy sediments of tidal beaches are poor in reactive substances because they are regularly flushed by significant flow caused by tidal forcing. This transport process may significantly affect the flux of reactive solutes to the ocean. A two dimensional model coupling the Richards equation that describes the flow in permeable sediments and the conservation equation of the silicic acid was devel...

PFLOTRAN a massively parallel computer code for modeling coupled hydro-thermalchemical processes in variably saturated, non-isothermal porous media is applied to sequestration of supercritical CO2 in deep geologic formations. Two different methods of solution to the governing partial differential equations are implemented referred to as variable switching and the flash approach. Variable switch...

Chlorinated organic compounds are widespread aquifer contaminants. They known to be dense non-aqueous phase liquids (DNAPLs). Therefore, they denser than water and immiscible with other fluids. Their migration into the environment in variably saturated zones can cause severe damage. For this reason, optimizing those actions that minimize negative impact of these subsurface is essential. This pa...

Reservoir management decisions are commonly made using surface water models with simplified and/or abstracted physical processes and limited groundwater-surface water interactions. Optimizations with such models might not capture the potential importance of and feedbacks from physical processes such as evaporation and infiltration. This study details how management algorithms of the Water Evalu...