Staff Research Highlight - A dynamic meshing scheme for integrated hydrologic modeling to represent evolving landscapes
Hwang, H.-T., Park, Y.-J., Berg, S. J., Jones, J. P., Miller, K. L., & Sudicky, E. A. (2025). A dynamic meshing scheme for integrated hydrologic modeling to represent evolving landscapes. In Science of The Total Environment (Vol. 976, p. 179129). Elsevier BV. https://doi.org/10.1016/j.scitotenv.2025.179129
“This scheme enhances the accuracy and reliability of subsurface flow and transport simulations in HydroGeoSphere (Aquanty Inc., 2023) by incorporating temporal variations in topography caused by anthropogenic activities. Importantly, the innovative aspects of this newly suggested scheme extend its applicability beyond HydroGeoSphere, positioning it as a valuable solution for addressing challenges.”
GRAPHICAL ABSTRACT. Illustrative example of the time-varying topographic model with the dynamic meshing scheme: a) excavation and b) material placement processes.
We’re pleased to highlight this publication (co-authored by Aquanty’s Hyoun-Tae Hwang, Steve Berg, Killian L. Miller, and Edward A. Sudicky) which introduces a novel dynamic meshing scheme for integrated hydrologic modelling to better represent evolving landscapes. The approach addresses a major challenge in modelling human-altered environments, particularly in regions undergoing rapid changes such as open-pit mining sites, land reclamation zones, or urban developments. Traditional hydrologic models often rely on static mesh geometries, limiting their ability to capture changes in topography and subsurface structure over time. This research proposes a more flexible, adaptive framework capable of simulating surface and subsurface hydrologic responses to complex engineering activities.
Figure 4. Locations of aggregate mining sites in the Grand River Watershed with the Lower Nith River subwatershed (inset).
In this study, the dynamic meshing scheme was implemented within HydroGeoSphere (HGS), a fully integrated surface-subsurface hydrologic modelling platform developed by Aquanty. HGS’s governing equations solve for variably saturated subsurface flow and surface water routing using the control volume finite element method, making it well-suited for simulating coupled processes across changing terrain. The new meshing strategy allows for temporal updates to the geometry of the model— such as excavation and material placement— by adjusting nodal elevations and element configurations dynamically throughout a simulation. This capability enables more realistic representations of how large-scale anthropogenic activities alter hydrological connectivity and storage within the landscape.
To validate the method, the researchers performed benchmark tests under idealized surface and subsurface flow conditions, as well as a proof-of-concept application simulating aggregate mining operations in the Lower Nith River subwatershed of Ontario’s Grand River watershed. In these scenarios, excavation and backfilling operations were modelled over a multi-year period, with HGS capturing resulting changes in groundwater levels and surface water depths. The simulations revealed that while surface water systems tend to recover quickly after restoration activities, groundwater systems can exhibit more persistent disturbances due to altered subsurface flow paths and material properties.
Figure 7. Spatiotemporal evolution of surface-subsurface hydrologic conditions during the mining operation of Case 2: a), c) and e) for the surface water system and b), d), and f) for the groundwater system along cross-section A-A’.
This work underscores the importance of using adaptive modelling techniques when assessing environmental impacts of dynamic land use and engineering interventions. By integrating the dynamic meshing scheme with HGS, the research presents a powerful tool for evaluating hydrological responses to evolving terrain and supports more robust planning for sustainable resource and infrastructure management. This advancement expands the potential applications of HGS to include more complex, real-time engineering scenarios, providing critical insights for both the hydrological modelling community and environmental decision-makers.
Abstract:
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. Typically, fully integrated hydrologic models have been employed to analyze alterations in water availability and quality resulting from variations in climatic conditions or water extraction. In such scenarios, the structural framework of the model remains constant, with adjustments typically made to boundary conditions or material parameterizations during simulations. However, in cases of substantial landscape transformations, such as urban development, industrial expansion, and open-pit mining, accurately representing these changes in models becomes challenging due to the limitations of fixed model geometry in capturing dynamic shifts in surface water and groundwater systems. This study presents a dynamic meshing scheme integrated into the surface-subsurface model, HydroGeoSphere. The accuracy of the evolving-landscape model was verified by comparing it against groundwater seepage patterns in static hillslope conditions, demonstrating strong agreement with previous studies. Furthermore, we present a proof-of-concept application of the dynamic meshing scheme in synthetic open-pit mining sites located in the Lower Nith River subwatershed within the Grand River Watershed, Canada, effectively capturing time-dependent engineering configurations in an integrated surface-subsurface model.
“Although HydroGeoSphere currently has the capability to update spatiotemporal changes in land use and cover types, as well as evapotranspiration conditions—including evapotranspiration zones, land use/cover zones, Manning roughness coefficients, and leaf area index—parameters such as evaporation, transpiration, and vegetation influence were not primary considerations in this study, which focused on demonstrating the implementation of the dynamic meshing scheme.”