A dynamic meshing scheme for integrated hydrologic modeling to represent evolving landscapes.

The influence of human activities on water resources has gained significant attention from water resource regulatory authorities, stakeholders, and the public. Anthropogenic activities, such as alterations in land use, agricultural practices, and mining operations, have a profound impact on the sustainability and quality of both surface water and groundwater systems. Evaluating the influence of a continually evolving engineered environment on surface water and groundwater systems demands the utilization of adaptive landscape models that can consider changing surface and subsurface topography, geometry, and material properties.

Improving monitoring network design to detect leaks at hazardous facilities: Lessons from a CO storage site.

Exploring the challenges posed by uncertainties in numerical modeling for hazardous material storage, this study introduces methodologies to improve monitoring networks for detecting subsurface leakages. The proposed approaches were applied to the Korea CO Storage Environmental Management (K-COSEM) test site, undergoing calibration, validation and uncertainty analysis through hydraulic and controlled-CO release tests. The calibration phase involved inter-well tracer and multi-well pumping tests, leveraging the Parameter ESTimation (PEST) model to determine the aquifer flow and solute transport properties of the K-COSEM site.

Effects of soil heterogeneity and preferential flow on the water flow and isotope transport in an experimental hillslope.

Soil water movement plays vital roles in hillslope runoff generation and groundwater and surface water interaction. However, there are still knowledge gaps about the impacts of soil heterogeneity and preferential flow on the internal water flow and transport process. In this study, the vertical soil heterogeneity focused on the variations in soil retention capacity, and the consideration of lateral preferential flow emphasized the higher hydraulic conductivity.

Natural Stimuli Calibration with Fining Direction Regularization in an Integrated Hydrologic Model.

The interaction between surface water and groundwater during flood events is a complex process that has traditionally been described using simplified analytical solutions, or abstracted numerical models. To make the problem tractable, it is common to idealize the flood event, simplify river channel geometry, and ignore bank soil heterogeneity, often resulting in a model that only loosely represents the site, thus limiting its applicability to any specific river cross-section. In this study, we calibrate a site-specific fully-integrated surface and subsurface HydroGeoSphere model using flood events for a cross-section along the South River near Waynesboro, VA.

Determination of rate constants and branching ratios for TCE degradation by zero-valent iron using a chain decay multispecies model.

The applicability of a newly-developed chain-decay multispecies model (CMM) was validated by obtaining kinetic rate constants and branching ratios along the reaction pathways of trichloroethene (TCE) reduction by zero-valent iron (ZVI) from column experiments. Changes in rate constants and branching ratios for individual reactions for degradation products over time for two columns under different geochemical conditions were examined to provide ranges of those parameters expected over the long-term. As compared to the column receiving deionized water, the column receiving dissolved CaCO3 showed higher mean degradation rates for TCE and all of its degradation products.

A semi-analytical solution for simulating contaminant transport subject to chain-decay reactions.

We present a set of new, semi-analytical solutions to simulate three-dimensional contaminant transport subject to first-order chain-decay reactions. The aquifer is assumed to be areally semi-infinite, but finite in thickness. The analytical solution can treat the transformation of contaminants into daughter products, leading to decay chains consisting of multiple contaminant species and various reaction pathways.

Numerical simulation of DNAPL emissions and remediation in a fractured dolomitic aquifer.

This study presents a numerical model of a large aqueous phase plume of a mixture of chlorinated solvents that has penetrated the fractured dolomitic bedrock near Smithville, Ontario, Canada several decades ago which, since 1989 has been hydraulically controlled by a pump-and-treat remediation system. A multiphase compositional model CompFlow is first applied to simulate the migration of DNAPLs in a discretely fractured porous medium with hydrostratigraphy representing the Smithville site. Results from CompFlow are used to estimate the pure-phase DNAPL distribution in the discrete fractures and rock matrix.

Ambiguous hydraulic heads and 14C activities in transient regional flow.

A regional flow and transport model is used to explore the implications of significant variability in Pleistocene and Holocene climates on hydraulic heads and (14)C activity. Simulations involve a 39 km slice of the Death Valley Flow System through Yucca Mountain toward the Amargosa Desert. The long-time scale over which infiltration has changed (tens-of-thousands of years) is matched by the large physical extent of the flow system (many tens-of-kilometers).