Comparison of two modeling approaches for groundwater–surface water interactions

Abstract

An assessment of interactions between groundwater and surface water was carried out by applying two different modeling approaches to a small-scale study area in the municipality of Havelock, Quebec. The first approach involved a commonly used sequential procedure that consists in determining the daily recharge rate using a quasi 2D infiltration model (HELP), applied in the next step as an imposed flux to a 3D finite-element groundwater flow model. The flow model was calibrated under steadystate and transient conditions against measured water levels. The second approach was based on a recently developed physically based, 3D fully coupled groundwater-surface water flow model (CATHY) applied to the entire flow domain in an integrated manner. Implementation, calibration, and results of the simulations for both approaches are presented and discussed. For equal annual precipitation (1038 mm/y) and evapotranspiration (556 mm/y), the second approach computed a recharge rate of 233 mm/ y (8.9% higher than the first approach) and a net upward flow from the fractured aquifer (the first approach predicted a net downward flow to the rock). The simulated annual discharge was similar for the two approaches (9.6% difference). Both approaches were found to be useful in understanding the interactions between groundwater and surface water, although limitations are apparent in the sequential procedure's inability to account for surface-subsurface feedbacks, for instance near stream reaches where groundwater discharge is prevalent. The decoupled, two-model approach provides disaggregated surface, vadose, and aquifer flows, and a simple aperçu at the different components of total discharge. The fully coupled model accounts for continuous water exchanges between the land surface, subsurface, and stream channel in a more complex manner, and produces a better match against observed data.

Fully integrated modeling of surface‐subsurface solute transport and the effect of dispersion in tracer hydrograph separation

“…In order to evaluate the tracer‐based Q p , the pre‐event water, driven by hydraulic gradients in both the surface and subsurface (i.e., the hydraulic Q p ), must be quantified. Achieving this, even with modern fully integrated codes, is surprisingly difficult [ Partington et al ., ; Guay et al ., ]. For example, Renaud et al .…”

Groundwater and Surface Water Interaction at the Regional-scale – A Review with Focus on Regional Integrated Models

“…However, to the knowledge of the authors, this has only been applied to very small catchments between 0.001 and 0.1 km 2 so far (Blum et al 2002;Jones et al 2006;Mirus and Loague 2013;VanderKwaak and Loague 2001). Guay et al (2013) and Semenova and Beven (2015) list even more examples of models from the fully coupled modelling domain.…”

A field and modeling study of nonlinear storage-discharge dynamics for an Alpine headwater catchment

“…The study is undertaken by means of a process‐based hydrological model of surface‐subsurface flow calibrated and validated against a comprehensive data set of field measurements. The model couples a 3‐D RE solver with an inertia‐free approximation of the Saint Venant equations for surface flow [ Camporese et al ., ] and has been shown to be a suitable tool for simulating hydrological processes over a range of spatial and temporal scales [ Bixio et al ., ; Gauthier et al ., ; Sulis et al ., ; Guay et al ., ]. The model is general enough in its treatment of topography, parameter heterogeneity, domain geometry, and boundary conditions to allow close representation of the LCC, including the distinction between riparian and hillslope zones and the possibility of bedrock leakage.…”