A modeling study of heterogeneity and surface water-groundwater interactions in the Thomas Brook catchment, Annapolis Valley (Nova Scotia, Canada)

Abstract

Abstract.A modelling study of the impacts of subsurface heterogeneity on the hydrologic response of a small catchment is reported. The study is focused in particular on the hydraulic connection and interactions between surface water and groundwater. A coupled (1-D surface/3-D subsurface) numerical model is used to investigate, for a range of scenarios, the spatio-temporal patterns of response variables such as return flow, recharge, groundwater levels, surface saturation, and streamflow. Eight scenarios of increasing geological complexity are simulated for an 8 km 2 catchment in the Annapolis Valley (eastern Canada), introducing at each step more realistic representations of the geological strata and corresponding hydraulic properties. In a ninth scenario the effects of snow accumulation and snowmelt are also considered. The results show that response variables and significant features of the catchment (e.g. springs) can be adequately reproduced using a representation of the geology and model parameter values that are based on targeted fieldwork and existing databases, and that reflect to a sufficient degree the geological and hydrological complexity of the study area. The hydraulic conductivity values of the thin surficial sediment cover (especially till) and of the basalts in the upstream reaches emerge as key elements of the basin's heterogeneity for properly capturing the overall catchment response.

Impact of grid resolution on the integrated and distributed response of a coupled surface–subsurface hydrological model for the des Anglais catchment, Quebec

“…Bixio et al (2002) presented a modelling study of morphogenetic depression effects for a 112‐km 2 area in the Chernobyl exclusion zone. Gauthier et al (2009) applied the model to an 8‐km 2 catchment located in the Annapolis Valley (eastern Canada), characterized by a steep slope with numerous springs at its foot and strong surface–subsurface interactions. In this application, the model was verified against streamflow data and groundwater heads for a 1‐year period.…”

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.…”

A structure generator for modelling the initial sediment distribution of an artificial hydrologic catchment

“…Gascuel-Odoux et al (2010), for example, tested the impact of spatial heterogeneity of hydraulic conductivity on hydrologic model performance (HillVi, Weiler and McDonnell, 2004), showing that including lateral variation in hydraulic conductivity seems to be as important as variation in soil depth for correctly representing the fluxes and dynamics in a hillslope aquifer. In a similar study, Gauthier et al (2009) showed that only sufficiently complex scenarios of spatial heterogeneity can adequately reproduce catchment features and response variables. An evaluation of the applicability of pedotransfer functions for the spatial modelling of soil hydraulic properties (Stumpp et al, 2009) unanimously found that prediction quality increases when assuming complex spatial distributions of soil hydraulic properties.…”