3d hydrogeological conceptual model building in denmark

…by I•GIS
3D hydrogeological conceptual model building in Denmark
Lessons learned from the Danish groundwater mapping campaign
Torben Bach – tob@geoscene3d.com - www.geoscene3d.com – www.geoscene3d.com/youtube
Presented at the 2017 GRA meeting in Sacramento, CA

…by I•GIS
3D hydrogeological conceptual model building in Denmark
Presentation outline
• Lessons learned working with groundwater mapping and 3D modelling
• 2 examples of 3D model conceptual models
• Rural area, regional model
• Urban area
• Future trends in 3D modelling approaches
• Summary – lessons learned as seen from IGIS
Torben Bach1 (presenter), Tom Martlev Pallesen1, Mats Lundh Gulbrandsen1
1I•GIS, Voldbjergvej 14, 1st, 8240 Risskov, Denmark

…by I•GIS mid 90’s - Pre DK-SGMA
Map based on 518 boreholes Map based on 1,400 TEM soundings
• Flow model adds up … but does not correspond to what is experienced in the field
• We needed a better geometrical 3D understanding and more data
Wells Only Geophysics Added
Lesson: Geophysics provides spatial information and is fast and cost efficient
Lesson: Build a detailed hydrogeological model, flow models alone will lack detail.

…by I•GIS Denmark – quick overview
• Densely populated
• Wide spread production of groundwater – even in major cities
• DK-SGMA: Geophysics applied on a major scale
Population
Geophysical Data
GW Interests

…by I•GIS 3D hydrogeological model building
1998 Future2017
• Hand made cross-sections
• Layers digitized and gridded in Surfer
• Import all data into a 3D modelling environment
• Build a 3D conceptual model in one environment
• Enables iterative model development
• Fast an efficient
Lesson: Use a 3D geological modelling environment. Iterative model development & Data integration

…by I•GIS Fairytale Magic ?
?? Geophysics = Magic = No hard work  ??
Not So !

…by I•GIS Geophysical Magic?
Saltwater – Clay ?
Data are ambiguous… combine more data

…by I•GIS Geophysical Magic?
The COLLECTION PROCESS and PROCESSING of data also have an
influence on the results
SkyTEM (LCI/SCI – tolkning)
Lesson: Know the strengths and weakness of your data – and combine them
Effects from processing – NOT geology

…by I•GIS 2 Model Examples
Odense
SETTING
• Urban center
DATA
• Log data
• GIS data
• Sewers/pipes
• Houses
• Roads
MODEL TYPE
• 3D Voxel Model
• Small Area
Esbjerg
SETTING
• Rural Area
DATA
• AEM data
• TEM 40
• Seismic data
• Borehole data
• Log data
• Chemical data
MODEL TYPE
• 3D Layer Model
• Regional Scale
35x30 KM = 1050 KM2
(21x19 Miles = 259460 Acres)

…by I•GIS
3D hydrogeological Modelling
3D Modelling is reduction of complexity to get to a higher Level of understanding
Complex
“Simple”

…by I•GIS
3D Geological Modelling & Data
Well Data
AEM Data
ERT Data
TEM 40 Data
Chemical Data
Lesson: Locate and develop the right tools for the job
• Wrong tool – wrong result
Lesson: Collect data to a central Data Management Storage system
• A One-stop data shop ¨- Ensures updated data
• Promote collaboration on modelling – everybody looking at the same version of data
• Traceability and history - Enable future updating of model
Seismic Data

…by I•GIS 3D Geological Modelling
AEM ERT
Borehole
Chem
Combining information example…
Non-oxidated groundwater indicates protected reservoir…combined with well data, AEM and ERT
this delineates the layer surfaces, the buried valley structure and the protecting clay cover layer
Interpretation ….
• AEM delineates bottom of the paleo channel reservoir
• Chemistry – water quality – indicates a sealed reservoir
• Borehole data shows a series of minor clay layers that acts as reservoir seal

AEM ERT
Borehole
Chem
Interpretation ….
• The geologist adds the bottom of the paleo channel based on AEM and borehole data
• Based on borehole data and chemestry, the geologist adds a seiling clay layer
Data combination and understanding is key to geological interpretation

AEM ERT
Borehole
Chem
Reduction of complexity
• From many data sources to a simplified geological geometry
• Facilitating understanding on a higher level
• The hydrogeological model based on DATA is the basis of a good hydrostrati graphical model used
in flow modelling
• Find the right balance between geometrical complexity and calibration in the hydrological model
Reduction of complexity
Lesson: Get all data into one environment
Lesson: Combine several data types in your modelling work

Lessons from building 3D Model regional hydro geological model
• an iterative and interdiciplinary process
• Combines many different geoscience disciplines (chemistry, geophysics, hydrology, geology, GIS)
• A staff with a variety of skills is needed

Some usages of the 3D hydrogeological model
Directly : Reservoir thickness, volumetric calc., protection from pesticides, new well locations,
urban development
Reservoir specific Potentiometric Maps: Used for screening of pumping impact, e.g. streams or
other pumps, general managing the resource
Export to flow modelling: For further processing, e.g. in MODFLOW, Mike She or similar…
Lesson: The 3D conceptual model is used on its own – and is the foundation for several derivatives

…by I•GIS 2 Model Examples
Odense
SETTING
• Urban center
DATA
• Log data
• GIS data
• Sewers/pipes
• Houses
• Roads
MODEL TYPE
• 3D Voxel Model
• Small Area – city
block
Esbjerg
SETTING
• Rural Area
DATA
• AEM data
• TEM 40
• Seismic data
• Borehole data
• Log data
• Chemical data
MODEL TYPE
• 3D Layer Model
• Regional Scale
35x30 KM = 1050 KM2
(21x19 Miles = 259460 Acres)

…by I•GIS Urban Modelling
Urban Environment
● The geology is “man made”
● Other data types
● Standard GIS data (roads, houses, sewers…)
● Dual-EM geophysical data
● Well and Log data

…by I•GIS
Urban Modelling Example
1. Boringer samt drikkevand- og spildevandsledninger indlæst og vist i forhold til diameter2. Bund af fyldlaget og fyld-kategorier indlæses3. Fyldet interpoleres i 3D.4. Resten af fyldlaget udfyldes med anslået ”gennemsnits fyld” (genindbygget moræneler).
5. Bygninger og øvrige strukturelle elementer indarbejdes. Lagflader fra regional model indlæses og
voxeleres
100% sand
100% ler
Voxler: 5x5x0,5 m
1. Interpolation of log and geophysical data into sand/clay fraction cells
2. Usage of GIS information to model man made structures

…by I•GIS Urban Modelling Example
Usages of an Urban Voxel Model
• Local infiltration of storm water
• Location of contamination path ways
• Protection of Groundwater
• City planning and development
Transmissivity
Lesson: Geology can be man made
Lesson: Combining “non typical” data (e.g. utility GIS data) into a model is possible

…by I•GIS Future of 3D modelling
M d
h(d,
M)
Mpred
dpred
Statistical
Model
h(d,M)
Machine Learning Automated Layer Modelling of AEM – Smart interpretation
Decistion Making Maps-
Seeking structures in Data

…by I•GIS Future of 3D modelling
Multiple Point Statistics Statistical merging of data into models
Estimating Geological Uncertainty
Merging information in a “probabilistic” sence
Modelling fine scale inheterogeniety

…by I•GIS Summary
The 3D Modelling Process
● Build a 3D conceptual model - the flow model will miss structural details
● A multidisciplinary iterative workflow - combine all information into one environment
● Facilitates collaboration between the hydrologist, hydrogeologist, geochemist and
geophysicist
Data Management
● Collect data to a central Data Management Storage system
● Start simple – and build it from there
● Secure the end results – with background data - in your DMS system
● Plan to revisit your work later – when new tools or methods become available
Geophysics
● Provides essential information on structure
● Understand the geophysical methods powers – and weaknesses
● Combine different data types – “one shoe doesn't fit all”
Primary Lesson: Embrace change!

3d hydrogeological conceptual model building in denmark

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