Metadata: 3D hydrogeologic model of Nanaimo Lowlands

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Identification

Abstract

The ""Nanaimo Lowland Groundwater Study"" is a collaboration between the British Columbia Ministry of Environment, Ministry of Forests, Lands, and Natural Resource Operations, the Regional District of Nanaimo, and the Geological Survey of Canada. The study area represents a coastal strip running from Nanoose to Deep Bay in the eastern part of Vancouver Island and covers approximately 580 km2. The groundwater flow model was based on the 3D hydrostratigraphic model (3DHSM) developed by Benoit et al. (2015). The hydrostratigraphic units were converted into a numerical grid and representative hydraulic properties were assigned to each unit. The groundwater resurgences present along the main riverbanks and at the shoreline were simulated with seepage boundary conditions allowing for a vertical hydraulic link between the main Quadra Sand aquifer and surface water. Hydraulic conductivity and groundwater recharge rate were further calibrated through numerical inversion using static hydraulic heads recorded in existing wells and estimated baseflow values.
Status:register completed
Title3D hydrogeologic model of Nanaimo Lowlands
Date2015-01-01 (register publication)
Date2015-01-01 (register creation)
Edition
Edition date
Citation group
register principalInvestigator
NameNicolas Benoît
OrganisationGovernment of Canada; Natural Resources Canada; Geological Survey of Canada - GSC Quebec
Position
Information
AddressDelivery point : 490, rue de la Couronne, 3e étage 490, rue de la Couronne, 3e étage
City : Québec Québec
Administrative region : Québec Québec
Postal code :
Country : Canada Canada
Email nicolas.benoit@canada.ca
Telephonetelephone voice; 1 (418) 6543646
Online Resource
Citation group
register originator
NameNicolas Benoît
OrganisationGovernment of Canada; Natural Resources Canada; Geological Survey of Canada - GSC Quebec
Position
Information
AddressDelivery point : 490, rue de la Couronne, 3e étage 490, rue de la Couronne, 3e étage
City : Québec Québec
Administrative region : Québec Québec
Postal code :
Country : Canada Canada
Email nicolas.benoit@canada.ca
Telephonetelephone voice; 1 (418) 6543646
Online Resource
Citation group
register custodian
NameFrancois Letourneau
OrganisationGovernment of Canada; Natural Resources Canada; Geological Survey of Canada - GSC Quebec
Position
Information
AddressDelivery point : 490, rue de la Couronne, 3e étage 490, rue de la Couronne, 3e étage
City : Québec Québec
Administrative region : Québec Québec
Postal code :
Country : Canada Canada
Email francois.letourneau@canada.ca
Telephonetelephone voice; 1 (418) 6543826
Online Resource
Citation group
register pointOfContact
Name
OrganisationGovernment of Canada; Natural Resources Canada; Geological Survey of Canada
Position
Information
AddressDelivery point :
City :
Administrative region :
Postal code :
Country :
Email nrcan.gsc-geosciencedata-donneesgeoscience-cgc.rncan@canada.ca
Telephone
Online Resource
Presentation formregister modelDigital
SeriesOpen File7845

Related publication

  • Benoit, N. and Paradis, D., 2015. Three dimensional groundwater flow model of the Nanoose-Deep Bay area, Nanaimo Lowland, British Columbia; Geological Survey of Canada, Open file 7845, 1 zip file.

Goals

The main objective of the present study is to better understand the regional groundwater flow system of the Nanoose-Deep Bay area. This is achieved using a 3D flow model of the study area.

Keyword(s)

Thesaurus
TitleGovernment of Canada Core Subject Thesaurus
Date2004 (register creation)
Date2013-05-11 (register publication)
Edition
Edition date
Citation group
register custodian
Name
OrganisationGovernment of Canada; Library and Archives Canada
Position
Information
Typeregister
TermHydrogeology
Thesaurus
TitleNRCan - GSC - Hydrogeology - Thesaurus
Date2009-01-01 (register creation)
Edition
Edition date
Citation group
register pointOfContact
Name
OrganisationCommission Géologique du Canada - Geological Survey of Canada
Position
Information
Typeregister product
Term3D Model
Thesaurus
TitleNRCan - GSC - Hydrogeology - Thesaurus
Date2009-01-01 (register creation)
Edition
Edition date
Citation group
register pointOfContact
Name
OrganisationCommission Géologique du Canada - Geological Survey of Canada
Position
Information
Typeregister theme
TermHydrogeology
Thesaurus
TitleNRCan - GSC - Hydrogeology - Thesaurus
Date2009-01-01 (register creation)
Edition
Edition date
Citation group
register pointOfContact
Name
OrganisationCommission Géologique du Canada - Geological Survey of Canada
Position
Information
Typeregister place
TermNanoose - Deep Bay area
Thesaurus
TitleNRCan - GSC - Hydrogeology - Thesaurus
Date2009-01-01 (register creation)
Edition
Edition date
Citation group
register pointOfContact
Name
OrganisationCommission Géologique du Canada - Geological Survey of Canada
Position
Information
Typeregister theme
TermGroundwater
Thesaurus
TitleNRCan - GSC - Hydrogeology - Thesaurus
Date2009-01-01 (register creation)
Edition
Edition date
Citation group
register pointOfContact
Name
OrganisationCommission Géologique du Canada - Geological Survey of Canada
Position
Information
Typeregister theme
TermGroundwater flow
Thesaurus
TitleNRCan - GSC - Hydrogeology - Thesaurus
Date2009-01-01 (register creation)
Edition
Edition date
Citation group
register pointOfContact
Name
OrganisationCommission Géologique du Canada - Geological Survey of Canada
Position
Information
Typeregister theme
TermQuaternary
Spatial representationregister grid
Languageeng; CAN
Character encodingutf8
Thematic categorygeoscientificInformation
ExtentLocalisation
-124.830000000,49.170000000;-124.500000000,49.500000000
Supplemental information

Distribution

Specific information related to data distribution
Format
NameFEFLOW
Versionnot applicable

Distributor

Contact
register distributor
NameEric Boisvert
OrganisationGovernment of Canada; Natural Resources Canada; Geological Survey of Canada - GSC Quebec
Position
Information
AddressDelivery point : 490, rue de la Couronne, 3e étage 490, rue de la Couronne, 3e étage
City : Québec Québec
Administrative region : Québec Québec
Postal code :
Country : Canada Canada
Email eric.boisvert2@canada.ca
Telephonetelephone voice; 1 (418) 6543705
Online Resource

Distributor

Contact
register pointOfContact
Name
OrganisationGovernment of Canada; Natural Resources Canada; Geological Survey of Canada
Position
Information
AddressDelivery point :
City :
Administrative region :
Postal code :
Country :
Email nrcan.gsc-geosciencedata-donneesgeoscience-cgc.rncan@canada.ca
Telephone
Online Resource

Transfer options


Quality


Quality description scope :register dataset

Lineage

Message Date lineage
Lineage is the description of the sources and steps used to create the current dataset.


Introduction
General process description
Process step Sources
The 3D hydrostratigraphic model (3DHSM) represents the conceptual model of the aquifer system architecture consisting of 7 granular units overlying 2 bedrock units. The 9 hydrostratigraphic layers built in LeapFrog Hydro were then reassigned to 14 layers. The top 7 layers of the 3DHSM represent the unconsolidated sediments, whereas the lower 7 layers represent the 2 bedrock units. All the 14 geologic layers were integrated in the 3D groundwater flow model (3DGFM) built with FEFLOW. The model includes Dirichlet and Neumann types of boundary conditions. Northwest and southeast lateral boundaries of the 3DGFM were set as no flow boundary condition to approximately represent the groundwater divides. Along the coast, all nodes with elevation greater or equal to sea level (0 m) were simulated with the seepage face boundary condition. For nodes along the coast with an elevation below sea level (0 m), a constant head equal to the sea level (0 m) was imposed, thus assuming horizontal flow at the coast. The basal layer is a no flow boundary in the model. No information was available to assess the groundwater contribution from the mountain areas. The recharge rate of the intrusive crystalline bedrock was estimated to adjust the position of the water table. This recharge rate was adjusted during the calibration process. Seepage conditions were used to represent groundwater discharge observed along the flanks of the main rivers. Thus, when simulated hydraulic heads are larger than the elevation of the ground elevation, excess water is evacuated from the model. This excess water becomes part of the baseflow in the water budget analysis. The recharge rate over the lowland area was assessed based on the separation of the baseflow from the river hydrographs and adjusted during the calibration. Recharge rate values were obtained for each watershed. In addition to the hydraulic head, a baseflow calibration was conducted for the lowland part of Nile Creek, Big Qualicum, Little Qualicum and Englishmen Rivers. Important components of a streamflow are direct precipitation, surface runoff, baseflow and hypodermic flow. Baseflow can be estimated from the analysis of streamflow records and, for assumed steady state flow condition, baseflow can be used as an estimation of the recharge rate to the aquifer. The relative proportion of baseflow in the lowland and in the mountain region was estimated for the streamflow records from two stream gaging stations located along the Big Qualicum River at the edge of the mountains and in the lowland, respectively. The same proportion was then applied in the other watersheds assuming comparable surface water and groundwater dynamics. The baseflow for each watershed was then estimated as a sum of the flux extracted from the model at nodes corresponding to seepage faces. Hydraulic conductivity (K) was used as a calibration parameter. Most initial K values for each hydrostratigraphic unit were obtained from the analyses of available pumping tests. Other K values were drawn from the literature, in particular for the low-K units. The 3DGFM was calibrated for a saturated steady state condition assuming that the model represents average annual flow conditions. The parameters adjusted during the calibration process were: K, groundwater recharge and the influx from the mountain regions. The calibration parameters were modified until a satisfactory match between the simulated and observed hydraulic heads and baseflow values. Refinement and fine adjustment was carried out applying the numerical inversion within the Pest algorithm. Hydrostratigraphic Unit [Kxy (m/s); Kz/Kxy] Lake bottom [8.3 x 10-8; 1] Capilano-Salish [3.8 x 10-4; 1] Capilano (glaciomarine) [8.1 x 10-7; 1] Vashon-Capilano (coarse) [7.7 x 10-6; 1] Vashon (till) [4.6 x 10-8; 1] Quadra [2.1 x 10-5; 1] Cowichan-Dashwood [8.1 x 10-9; 1] Dashwood-Mapleguard [1.1 x 10-7; 1] Bedrock <10 m [9.0 x 10-6; 1] Bedrock 10-20 m [7.0 x 10-6; 0.1] Bedrock 20-70 m [3.8 x 10-6; 0.94] Bedrock 70-120 m [1.3 x 10-8; 0.01] Bedrock 120-170 m [9.8 x 10-9; 0.01] Bedrock 170-220 m [1.2 x 10-9; 0.01] Bedrock 220-280 m [1.2 x 10-10; 0.01] Bedrock > 280 m [1.2 x 10-11; 0.01]
The 3D hydrostratigraphic model (3DHSM) represents the conceptual model of the aquifer system architecture consisting of 7 granular units overlying 2 bedrock units. The 9 hydrostratigraphic layers built in LeapFrog Hydro were then reassigned to 14 layers. The top 7 layers of the 3DHSM represent the unconsolidated sediments, whereas the lower 7 layers represent the 2 bedrock units. All the 14 geologic layers were integrated in the 3D groundwater flow model (3DGFM) built with FEFLOW. The model includes Dirichlet and Neumann types of boundary conditions. Northwest and southeast lateral boundaries of the 3DGFM were set as no flow boundary condition to approximately represent the groundwater divides. Along the coast, all nodes with elevation greater or equal to sea level (0 m) were simulated with the seepage face boundary condition. For nodes along the coast with an elevation below sea level (0 m), a constant head equal to the sea level (0 m) was imposed, thus assuming horizontal flow at the coast. The basal layer is a no flow boundary in the model. No information was available to assess the groundwater contribution from the mountain areas. The recharge rate of the intrusive crystalline bedrock was estimated to adjust the position of the water table. This recharge rate was adjusted during the calibration process. Seepage conditions were used to represent groundwater discharge observed along the flanks of the main rivers. Thus, when simulated hydraulic heads are larger than the elevation of the ground elevation, excess water is evacuated from the model. This excess water becomes part of the baseflow in the water budget analysis. The recharge rate over the lowland area was assessed based on the separation of the baseflow from the river hydrographs and adjusted during the calibration. Recharge rate values were obtained for each watershed. In addition to the hydraulic head, a baseflow calibration was conducted for the lowland part of Nile Creek, Big Qualicum, Little Qualicum and Englishmen Rivers. Important components of a streamflow are direct precipitation, surface runoff, baseflow and hypodermic flow. Baseflow can be estimated from the analysis of streamflow records and, for assumed steady state flow condition, baseflow can be used as an estimation of the recharge rate to the aquifer. The relative proportion of baseflow in the lowland and in the mountain region was estimated for the streamflow records from two stream gaging stations located along the Big Qualicum River at the edge of the mountains and in the lowland, respectively. The same proportion was then applied in the other watersheds assuming comparable surface water and groundwater dynamics. The baseflow for each watershed was then estimated as a sum of the flux extracted from the model at nodes corresponding to seepage faces. Hydraulic conductivity (K) was used as a calibration parameter. Most initial K values for each hydrostratigraphic unit were obtained from the analyses of available pumping tests. Other K values were drawn from the literature, in particular for the low-K units. The 3DGFM was calibrated for a saturated steady state condition assuming that the model represents average annual flow conditions. The parameters adjusted during the calibration process were: K, groundwater recharge and the influx from the mountain regions. The calibration parameters were modified until a satisfactory match between the simulated and observed hydraulic heads and baseflow values. Refinement and fine adjustment was carried out applying the numerical inversion within the Pest algorithm. Hydrostratigraphic Unit [Kxy (m/s); Kz/Kxy] Lake bottom [8.3 x 10-8; 1] Capilano-Salish [3.8 x 10-4; 1] Capilano (glaciomarine) [8.1 x 10-7; 1] Vashon-Capilano (coarse) [7.7 x 10-6; 1] Vashon (till) [4.6 x 10-8; 1] Quadra [2.1 x 10-5; 1] Cowichan-Dashwood [8.1 x 10-9; 1] Dashwood-Mapleguard [1.1 x 10-7; 1] Bedrock <10 m [9.0 x 10-6; 1] Bedrock 10-20 m [7.0 x 10-6; 0.1] Bedrock 20-70 m [3.8 x 10-6; 0.94] Bedrock 70-120 m [1.3 x 10-8; 0.01] Bedrock 120-170 m [9.8 x 10-9; 0.01] Bedrock 170-220 m [1.2 x 10-9; 0.01] Bedrock 220-280 m [1.2 x 10-10; 0.01] Bedrock > 280 m [1.2 x 10-11; 0.01]


Technical details and constraints

File identifiere0b61f1b-5fd4-b6b1-dba2-987004860caf
Languageeng; CAN
Character encodingregister utf8
Hierarchical classificationregister dataset
Date2017-10-27
Metadata standardNorth American Profile of ISO 19115:2003 - Geographic information - Metadata
VersionCAN/CGSB-171.100-2009
Constraints
Update frequencyregister asNeeded

Regionalisation

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Language code Pays Encodage
register Frenchregister Canadaregister utf8

Geographic Reference System

Reference System codeEPSG:26910
Registerhttp://www.epsg-registry.org/
Version6.14

Metadata Contact

register pointOfContact
NameFrancois Letourneau
OrganisationGovernment of Canada; Natural Resources Canada; Geological Survey of Canada - GSC Quebec
Position
Information
AddressDelivery point : 490, rue de la Couronne, 3e étage 490, rue de la Couronne, 3e étage
City : Québec Québec
Administrative region : Québec Québec
Postal code :
Country : Canada Canada
Email francois.letourneau@canada.ca
Telephonetelephone voice; 1 (418) 6543826
Online Resource
register pointOfContact
Name
OrganisationGovernment of Canada; Natural Resources Canada; Geological Survey of Canada
Position
Information
AddressDelivery point :
City :
Administrative region :
Postal code :
Country :
Email nrcan.gsc-geosciencedata-donneesgeoscience-cgc.rncan@canada.ca
Telephone
Online Resource