| The mesh and maps were primarily created in ArcGIS and Triangle. Watflow software (Molson et al., 2002) was used to simulate groundwater flow of the Chaudière River watershed.
The surface of the three-dimensional (3D) model corresponds to the digital elevation model (DEM). The base of the model is set to a depth of 300 m with respect to the DEM. This depth is considered below the large fractured zone, where groundwater is almost immobile. The model has 29 finite element layers of which 10 represent the bedrock, 18 represent the unconsolidated deposits, and the last one represents the surface layer (recharge spreading layer). The mesh of the model is composed of 119,447 two-dimensional (2D) triangular elements on the horizontal plane thus forming a total of 3,463,963 3D prismatic triangular elements with 1,815,720 nodes.
The boundary conditions of the model are represented by groundwater divides, which results in a no flow boundary in the model. Constant head corresponding to the DEM elevations were imposed on the Chaudière River and its main tributaries. A no flow condition has been imposed at the lower limit of the model.
On the surface of the model, a recharge rate was imposed according to the estimates obtained by Benoît et al. (2012) with the HELP infiltration model (Schroeder et al., 1994). The major municipal wells with available information were integrated into the model as localized pumping, while water consumption from private and agricultural wells was converted into an uniform water quantity removed directly from the recharge.
Horizontal hydraulic conductivity and vertical anisotropy are the calibration parameters of the model. Seven hydrostratigraphic units were identified in the unconsolidated deposits. The hydraulic conductivities of each unit were calibrated with hydraulic head.
Unit [Kx (m/s) / Kz (m/s)]
Organics [1x 10-5 / 1x10-5]
Sand [1x10-6 / 1x10-6]
Clay [1x 10-9 / 1x 10-9]
Gravel [1x 10-3 / 1x 10-3]
Permeable till [1x 10-6 / 1x 10-6]
Till [7x10-7 / 5x10-7]
Bedrock [1x10-7 / 1x10-7]
The bedrock at the bottom of the unconsolidated deposits represents the highly fractured bedrock and is considered as a unit of unconsolidated deposits. Estimated hydraulic conductivity values generally range from 1x10-7 to 1x10-5 m/s for the first 100 meters of bedrock. The hydraulic conductivity values down to the model base (300 m) were defined by linear extrapolation and decreased to 1x10-10 m/s at the lower limit.
The unconsolidated units are represented by 18 layers of elements. The layers of the model do not necessarily correspond exactly to the various hydrostratigraphic units and each layer of elements of the model may contain different hydrostratigraphic units. When hydrostratigraphic units are defined, the layers of elements follow these units as much as possible. |
| The mesh and maps were primarily created in ArcGIS and Triangle. Watflow software (Molson et al., 2002) was used to simulate groundwater flow of the Chaudière River watershed. The surface of the three-dimensional (3D) model corresponds to the digital elevation model (DEM). The base of the model is set to a depth of 300 m with respect to the DEM. This depth is considered below the large fractured zone, where groundwater is almost immobile. The model has 29 finite element layers of which 10 represent the bedrock, 18 represent the unconsolidated deposits, and the last one represents the surface layer (recharge spreading layer). The mesh of the model is composed of 119,447 two-dimensional (2D) triangular elements on the horizontal plane thus forming a total of 3,463,963 3D prismatic triangular elements with 1,815,720 nodes. The boundary conditions of the model are represented by groundwater divides, which results in a no flow boundary in the model. Constant head corresponding to the DEM elevations were imposed on the Chaudière River and its main tributaries. A no flow condition has been imposed at the lower limit of the model. On the surface of the model, a recharge rate was imposed according to the estimates obtained by Benoît et al. (2012) with the HELP infiltration model (Schroeder et al., 1994). The major municipal wells with available information were integrated into the model as localized pumping, while water consumption from private and agricultural wells was converted into an uniform water quantity removed directly from the recharge. Horizontal hydraulic conductivity and vertical anisotropy are the calibration parameters of the model. Seven hydrostratigraphic units were identified in the unconsolidated deposits. The hydraulic conductivities of each unit were calibrated with hydraulic head. Unit [Kx (m/s) / Kz (m/s)] Organics [1x 10-5 / 1x10-5] Sand [1x10-6 / 1x10-6] Clay [1x 10-9 / 1x 10-9] Gravel [1x 10-3 / 1x 10-3] Permeable till [1x 10-6 / 1x 10-6] Till [7x10-7 / 5x10-7] Bedrock [1x10-7 / 1x10-7] The bedrock at the bottom of the unconsolidated deposits represents the highly fractured bedrock and is considered as a unit of unconsolidated deposits. Estimated hydraulic conductivity values generally range from 1x10-7 to 1x10-5 m/s for the first 100 meters of bedrock. The hydraulic conductivity values down to the model base (300 m) were defined by linear extrapolation and decreased to 1x10-10 m/s at the lower limit. The unconsolidated units are represented by 18 layers of elements. The layers of the model do not necessarily correspond exactly to the various hydrostratigraphic units and each layer of elements of the model may contain different hydrostratigraphic units. When hydrostratigraphic units are defined, the layers of elements follow these units as much as possible. |
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