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. 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.