Development of a
3D geological/Hydrological Model As
Basis for the Urban Water Cycle
Synthesis report
Susie Mielby, Carsten Emil Jespersen,
Christian Ammitsøe, Gert Laursen,
Jan Jeppesen, Johan Linderberg,
Knud Søndergaard, Margrethe Kristensen,
Martin Hansen, Niels-Peter Jensen,
Peter Sandersen and Tom Martlev Pallesen
GEOLOGICAL SURVEY OF DENMARK AND GREENLAND
MINISTRY OF ENERGY, UTILITIES AND CLIMATE
Development of a 3D Geological/
Hydrogeological Model as Basis
for the Urban Water Cycle
Synthesis Report
Susie Mielby
Carsten Emil Jespersen
Christian Ammitsøe
Gert Laursen
Jan Jeppesen
Johan Linderberg
Knud Søndergaard
Margrethe Kristensen
Martin Hansen
Niels-Peter Jensen
Peter Sandersen
Tom Martlev Pallesen
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Development of a 3D Geological/Hydrogeological Model as Basis for the Urban Water Cycle
Authors: Susie Mielby, Carsten Emil Jespersen, Christian Ammitsøe, Gert Laursen, Jan Jeppesen, Johan
Linderberg, Knud Søndergaard, Margrethe Kristensen, Martin Hansen, Niels-Peter Jensen, Peter Sandersen and Tom Martlev Pallesen.
Model on front page: Tom Martlev Pallesen
Special edition
Cover: Henrik Klinge
Repro: GEUS
September 2015
Translated to English by Bente F. Nedergaard, 2016
The report is available in Danish and English on the Internet: www.geus.dk
©
De Nationale Geologiske Undersøgelser for Danmark og Grønland, GEUS
The Geological Survey of Denmark and Greenland
Øster Voldgade 10
DK-1350 København K
Telephone: +45 38 14 20 00
E-mail: [email protected]
The project is based on funding from The Foundation for Development of Technology (VTU) and is conducted in collaboration with the Municipality of Odense, VCS Denmark, I-GIS and Alectia A/S.
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GEUS, OK, VCS, I-GIS, ALECTIA
Foreword
In 2012 The Municipality of Odense, VCS Denmark and GEUS entered into a collaboration
aiming to develop a 3D geological/hydrogeological model of the subsurface beneath Odense.
Consequently a two-year long project, based on funding from The Foundation for Development of Technology in the Danish Water Sector, in short called “VTU-Fonden”, was
launched in 2013 by The Municipality of Odense, the local water utility (VCS Denmark), IGIS A/S, Alectia A/S and GEUS.
A project group and a steering committee have been set up to support the project.
The Project group consisted of
 Susie Mielby
 Carsten Emil Jespersen


Christian Ammitsøe
Gert Laursen

Jan Jeppesen




Johan Linderberg
Knud Søndergaard
Margrethe Kristensen
Martin Hansen


Niels-Peter Jensen
Peter Sandersen
Project manager, hydrogeologist, GEUS
Responsible for Climate Adaptation, The Municipality of Odense
Project director, VCS Denmark
Hydrogeologist, Climate Adaptation, The Municipality of Odense
Head of Marketing and Development, Climate
Adaptation, Alectia A/S
Hydrogeologist, VCS Denmark
Head of department, The Municipality of Odense
Specialist in GeoScene3D, GIS and data, GEUS
Section manager for the Database section,
GEUS
Director and specialist in IT/GIS, I-GIS A/S
Senior advisor, Specialist in geological modelling, GEUS
The Steering committee consisted of:
 Christian Ammitsøe
Project director, VCS Denmark
 Knud Søndergaard
Head of department, The Municipality of Odense
 Thomas Vangkilde-Pedersen
Head of department, GEUS
The Basis for Collaboration
Managing the urban aquatic environment demands knowledge of surface hydrology, sewage transport, geology and groundwater conditions. The construction of a detailed subsurface model in three dimensions systematically using existing and new data is a necessary
condition for this.
The municipalities have not been systematically collecting and updating geological
/hydrological mappings. The existing mapping results are fragments of a whole, and there
5
are often more geological/hydrostratigraphical models present, made for various purposes,
years apart and made on a variety of data sets. Therefore, it is necessary to consider which
of the previous models that are usable, and if collection of new data is needed.
Quite often the modelling work is starting all over again when new knowledge or the need
for a model occurs, and it is a big and time demanding job providing a new basis for decisions.
A better knowledge of the urban geology and a better use of subsurface data will lead to an
improved basis for decisions related to climate adaptations in the future, thereby to carry
out the climate adaptations with better efficiency and substantial savings in relation to the
following cost-heavy decisions, when planning in the end must be converted to buildings,
sewage systems, roads and trenches etc.
A needs-oriented, systematic maintenance and extension of a basic geological/ hydrogeological model will lead to faster, better and more robust decisions for the municipalities and
the supply companies.
A common 3D geological/hydrogeological/GIS-system for handling the mapping results will
furthermore provide the basis for a more homogeneous workflow, and allow the various
municipal administrations to access the same updated basis for decisions - at all times.
International Collaboration
Denmark is not the only country needing knowledge and modelling of the subsurface beneath the cities. GEUS and The Municipality of Odense has concurrent with this project
been participating in an EU COST-project aiming to improve knowledge on an international
scale (“SUB-URBAN: A European Network to Improve the Understanding and Use of the
Subsurface beneath Our Cities”).
The joint effort has been an advantage for both the COST-project and the VTU-project.
Dissemination of Results
Results from the project have been disseminated at a large number of conferences, professional meetings and at meetings with potential users.
In addition to the established 3D model, the constructed model concept with related recommendations will be a useful pioneer model for setting up other future municipality models
for public authorities.
A wide range of different experiences have been made together with development of methods and collecting of relevant knowledge for modelling of the subsurface during the project
period. This knowledge has been assembled in a number of sub-reports, all sharing the
same overall project title.
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The sub-reports are:






The 3D-model as Basis for Handling the Urban Water Cycle
Collation and Assessment of Data
Geotechnical Data for Planning and Administration
3D Geological/Hydro-Stratigraphic Modelling
Interactive Modelling of Anthropogenic Layers
Technical Handling and Storage of Urban Geological Data and Models
Each sub-report is concluded with a number of recommendations, compiled in the present
synthesis report.
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Contents
1.
Introduction
1.1
1.2
1.3
1.4
2.
Background and Purpose.......................................................................................11
Analysis of Requirements ......................................................................................12
Methods ..................................................................................................................13
Reporting ................................................................................................................14
The Main Project Results
2.1
2.2
2.3
2.4
2.5
2.6
3.
4.
5.
6.
31
Updated Model versus New Model ........................................................................31
Consequence of Missing Knowledge – Example from Odense ............................31
International Cooperation and Experiences
6.1
6.2
6.3
6.4
6.5
28
Managing the Further Course ................................................................................28
New Mappings in the Municipality ..........................................................................29
Maintenance of the Municipality Model ..................................................................29
Storing the Model Results ......................................................................................30
Economy
5.1
5.2
24
The Utility Value of the Model – The Urban Water ................................................24
The Utility Value of the Model – Other Users in the Municipality ..........................25
Necessary Improvement of Data and Model .........................................................26
Perspectives for the Model.....................................................................................27
Technical Management and Maintenance
4.1
4.2
4.3
4.4
15
Modelling ................................................................................................................15
Model and Data Tools ............................................................................................19
Administrative Practice and Basis for Decisions....................................................21
Results and Recommendations from the Project ..................................................21
Dissemination of Results ........................................................................................22
What We Didn’t Achieve – Re-Prioritizations.........................................................23
The Model as Basis for Planning
3.1
3.2
3.3
3.4
11
34
Object .....................................................................................................................34
Where are we in Relation to Data ..........................................................................35
What is our Position Regarding Modelling? ...........................................................35
What is our Position Regarding Planning? ............................................................36
General Views from SUB-URBAN .........................................................................36
7.
A National Perspective
38
8.
References
39
9
Appendix – Summary of Recommendations
9.
9.1
9.2
9.3
9.4
9.5
9.6
9.7
10
41
Synthesis Report .................................................................................................... 42
3D-model as Basis for Management of the Urban Water Cycle ........................... 43
Collation and Assessment of Data ......................................................................... 44
Geotechnical Data for Planning and Administration .............................................. 45
3D Geological/Hydro-Stratigraphical Modelling ..................................................... 46
Interactive Modelling of Anthropogenic Layers...................................................... 47
Technical Handling and Storage of Urban Geological Data and Models .............. 50
GEUS, OK, VCS, I-GIS, ALECTIA
1. Introduction
This report contains the main results from the VTU-project and the underlying rationale
behind the 3D geological/hydrogeological model being used together with its data as a tool
for management and administration of the urban water cycle.
The report and the related sub-reports constitute the documentation of the VTU-project and
its recommendations, and are supposed to support further maintenance and development
of the model. An essential scope is to let others benefit from the experience and the results.
The report contains a short description of the products gained from the project, and the
adjustments that have been made compared to the original ideas in the project plan.
Furthermore, the report explains the usefulness of the 3D model (and the developed data)
related to planning and administration within the municipality, concerning the urban water
cycle but also in other contexts. Also professional considerations have been described related to potential future improvements and maintenance of the model (together with related
data) for the continued use as an administration tool.
To guarantee the continued integrity of the model as an administrative basis for the municipality, the report contains a description of what is needed technologically to maintain this
municipality model. The report also describes different economic considerations and estimates that may be useful to keep in mind.
Finally, the technological development in other countries in comparison to Denmark is described. The experiences from abroad are based on the EU COST-project, in which several
of the partners have participated simultaneously.
1.1 Background and Purpose
Since the late 1970s when Ellen Louise Mertz performed a geotechnical mapping in selected larger cities, there has not been conducted a systematic mapping of the cities. Therefore, The Municipality of Odense, VCS Denmark and GEUS strategically decided that the
mapping of the subsurface was needed, and that it advantageously could be conducted in
Odense.
An application for a VTU-project was made and granted using Odense as an example with
the overall scope of developing a 3D model to establish:

A 3D geological/ hydrogeological municipality model for contribution to the mapping
of geology and the urban water cycle beneath cities.

A better basis for planning of the future work on infiltration and drainage of water.
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
Recommendations for a national tool, enabling the establishment of detailed geological/hydrogeological municipality models for other areas.
In connection with climate adaptation detailed knowledge is required to tell specifically
where handling of excess rain water outside the sewage system is needed, and in these
areas to clarify exactly where to infiltrate surface water. Finally, it is necessary to calculate
where the infiltration will create changes to the water level, and in that way cause flooding
or increased humidity in basements.
An overall modelling is crucial to foresee the consequences of intervention in the urban
water cycle. It is obvious that this task is requiring great accuracy of the model on small
areas, and at the same time the model must be operable on catchment scale; that is on
larger areas.
Even though the project was launched for a relatively limited number of users, it was the
intention that the coming product should be widely used and disseminated, both in the municipality to obtain a larger and shared data volume for the administrations, and outside the
municipality for a better use of the achieved experiences – and in a way to allow collaboration on common solutions nationwide.
Throughout the ages, several geological/hydrogeological models have been built and then
left inactive to gradually become more and more irrelevant, because the owner of the model not considered whether it had a purpose and pays to maintain the model. The lesson
learned often was to start all over again.
One of the aims for this project has been to specifically consider how to update and maintain the model concept, and this report contains considerations on how to maintain a municipality model and the related costs. This effort of course must be compared to the usefulness.
1.2 Analysis of Requirements
The project is highly inter-disciplinary. Consequently, from the start it has been important to
spend time on an analysis of requirements to balance needs and technological abilities.
(Mielby, 2013)
Firstly, the analysis of requirements has uncovered what is demanded for modelling of the
urban water cycle in its broadest sense, including other user’s need for a model and related
data (Figure 1).
Secondly, the analysis of requirements has included a systematic review of both the project
stages and the methods that can be used to provide better access to data and modelling,
and in this way ensure an updated and more reliable basis for decisions.
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Figure 1. The primary needs related to modelling of hydrostratigraphical and anthropogenic
layers (yellow). The text states the 4 main requirements of the model in order to be able to
function as basis for the urban water cycle. The blue line illustrates the water level.
The analysis of requirements has revealed a need for stakeholders to perform far more
tasks than possible in this VTU-project, but it has throughout the entire process made it
possible to prioritize and select the main focus areas.
The analysis of requirements has shown a central need to establish:
 A geological (municipality) model showing aquifer layers
 A model containing information on both geology and man-made layers and objects
(man-made fill and infrastructure)
 A model that is able to contain the largest amount of information in detailed areas
 A model also containing information about the groundwater table.
1.3 Methods
VCS Denmark and the former Fyn County had a yearlong tradition for collecting hydrogeological data, leaving the municipality with a unique collection of data that is not available for
other cities and municipalities to the same extent. This makes the City of Odense very suitable as focus area for this development project.
From the beginning it was decided that the model should be built in 3D and be based on
the present available data, methods and guides to the National Groundwater Mapping using methods and tools established in connection to the water resource mapping made by
Fyn County and obtained from international networking.
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In selected model areas, results from other study fields (e.g. performed in connection to
water supply, soil contamination and geotechnical studies) that were not stored in databases, will be included in selected model areas, if a new digital data basis can be provided
within the financial frames for the project. In addition, digital information from Odense Municipality and VCS Denmark concerning city plan data and water pipes etc. will be included.
Any other information about earth fill, sandy infill around buried infrastructure/buildings and
covered areas etc. should be included too. An inclusion of data regarding organogenic deposits will also be considered, for instance groundwater table and wetland maps (possible
water-logged areas) that in addition to geological layers and structures can be of importance for the water flow both in the subsurface and on the surface.
The reason for organizing and making “unconventional” data available for the modelling is
to develop a new and better basic knowledge about the upper man-made fill and earth layers beneath our cities, thereby contributing to an improved basis for planning basis for decisions for the suburban administration and management of the subsurface and groundwater etc.
The products from the geological/hydrogeological modelling project are GIS-maps and 3D–
models for spatial visualisation and administration. The 3D–modelling has been focused on
handling a great level of detail and on the need for a uniform hydrogeological basis, especially in the surface-near layers.
Tests will be performed in detail areas to ensure that the model and the developed concept
meet the requirements.
As the problems in many cases are expected to be generally well known in other parts of
the country, the results from this project will be formulated as recommendations for development of a common model concept and maintenance to be used by other municipalities,
water companies and water works.
1.4 Reporting
As mentioned in the foreword several experiences, method developments and collections
of relevant knowledge for modelling of the subsurface have been made. This knowledge is
assembled in this main report and in a number of technical reports.
Please note that detailed descriptions of the use of geotechnical data for planning and administration, and of the 3D model as basis for managing the urban water cycle are available. These two reports address the administrative part of the model concept.
The other more technical reports deal with data collection and management, modelling of
anthropogenic and geological layers and finally data storage.
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2. The Main Project Results
In this chapter the main results from the VTU-project is presented.
The chapter contains brief summaries of the results from the work with modelling, data and
tools. It also contains a description of the detailed recommendations for managing the geotechnical data as well as the use of the 3D geological/hydrogeological model as basis for
the hydrological cycle and a listing of dissemination activities related to the project.
Finally, the changes that have been a necessary consequence from the learned experiences during the project will be commented.
2.1 Modelling
The geological modelling is described in Sub-Report 4 (Sandersen et al. 2016), the anthropogenic modelling is described in Sub-Report 5 (Pallesen & Jensen, 2015), and the relations between the two are described in Sub-Report 1 (Mielby et al. 2015).
As the required level of detail is depending on the purpose of the modelling, the VTUproject has been working with a municipal model and detailed local models which in both
cases are based on the same underlying data and geological interpretations.
Spatial Geological Modelling
With models from the National Groundwater Mapping Project as a starting point a spatial
geological model based on available borehole data and geophysics has been made. The
model has its border just outside the municipality (Figure 2).
Hydro-Stratigraphical Modelling
Based on the geological interpretation, a hydrostratigraphical model with grid cells on 100 x
100 m has been built. The hydrostratigraphical model is based on the spatial geological
model and is built with a number of layers corresponding to the existing national “DKmodel” (See Figure 3).
Anthropogenic Modelling
The anthropogenic deposits consist of man-made fill layers around basements, pipelines
and underground passages etc. A detailed interpretation of both man-made fill layer and
infrastructure has been conducted within a local area at Thomas B. Thriges Gade in Odense (See Figure 4).
15
Figure 2. Illustration of the model area with fixed interpretation profiles established in GeoScene 3D. Figure from Sub-Report 4 (Sandersen et al. 2015).
Figure 3. A Profile SW-NE through the VTU-model for the Municipality of Odense. Aquifer
Layer 3 (pink), Aquifer Layer 5 (yellow), Aquifer Layer 7 (red) and Aquifer Layer 9 (green).
Example from Sub-Report 4 (Sandersen et al., 2015).
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Figure 4. Anthropogenic modelling incorporating fill layers and basements etc. The brown
colours are clay, the red colour is sand and black-brown is corresponding to hydraulic impermeable layers (basements and building foundations). Example from Sub-Report 5
(Pallesen & Jensen, 2015).
The Use of Different Scales and Concepts
Based on the user requirement analysis, there is a need to build only one model that is
capable of being used at different scales. Consequently, concepts for handling larger detail
(more layers in the hydrostratigraphical model) have been described in Sub-Report 4, just
as methods for handling the detailed digital information on man-made fill layers and infrastructure have been described in Sub-Report 5. Thus the model concept on the same basis
can be used with both large and small levels of detail (See figure 5). At the moment it is the
computational capabilities that define the size limitations for the model.
Figure 6 shows an example of a merge of the anthropogenic and the geological model from
the detailed modelling of Thomas B. Thriges Gade.
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Figure 5. Flow diagram showing the process of merging the hydrostratigraphical model
and the anthropogenic model. Illustration from Sub-Report 1 (Mielby et al., 2015).
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Figure 6. An example showing the merged geological and anthropogenic models from
Thomas B. Thriges Gade. (Also see figure 3 and 4).
2.2 Model and Data Tools
Managing “Non-Digital Data”
Some of the geotechnical boreholes performed over time are not available as digital data,
but merely as analogue information of lithology on “paper” (pdf-files). This has led to development of facilities in the modelling tool GeoScene3D to digitize those pdf-files. This facility
has among other things been used for the detailed interpretation of the man-made fill layers, where the drill log usually contains more information than would normally be digitized.
Managing Anthropogenic Data
The anthropogenic information comes from specifications of layers from geotechnical drillings and indirectly from infrastructural data containing information on buildings, basements,
electric supply mains, sewage systems, roads and underground passages etc. This information partly consists of the datasets for buildings and distribution systems themselves,
and partly of information on excavations influencing on the water flow in the area of interest. See the example in figure 7.
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As anthropogenic data have a chronological hierarchy, the order of their application is important: New buildings may have been built, and the original soil may have been replaced
repeatedly by fill materials. In connection with the project a set of rules has been established for arranging age and spatial extent of the various objects. Corresponding facilities
for managing this information have been set up in GeoScene 3D to draw up voxels containing the “lithological” interpretation.
Figure 7. An example of distribution systems and buildings from the detailed anthropogenic
modelling of Thomas B. Thriges Gade.
Storage Facilities in Jupiter
Until now it has only been possible to manage standard drilling information and not geotechnical parameters in the Jupiter database. In connection with the project such facilities
have been set up to enable storage and access to these data types for the authorities who
may require it.
Visualization
Finally, the project has worked towards an improved visualization of the modelling result,
partly by the use of modelling in GeoScene 3D (see examples in Sub-Report 1) and partly
by the model stored in the Model database at GEUS. In both cases, we haven’t succeeded
completely due to limitations in storage capacity of the National Model database (among
other things the large amounts of data, new data types and finally because voxels still cannot be stored in the Model database).
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2.3 Administrative Practice and Basis for Decisions
Access to Geotechnical Information
It was originally assumed that the project should be based on the existing digital geotechnical borehole data with no funding of acquired digital data. This assumption, however,
didn’t hold true and it turned out to be complicated and cost the project many hours and
delays to access the existing digital geotechnical data owned by the private companies.
A thorough analysis of the users of the geotechnical data has been made revealing a wide
and uncoordinated use and management of the geotechnical data. The experiences from
the work has led to a special report - Sub-Report 3 (Laursen et al., 2015), outlining the existing management of geotechnical data and pointing out the potential for rationalization.
The 3D-Model as Basis for Managing the Urban Water Cycle
One of the initial conditions or the VTU-project was that the established model should be
able to manage the urban water cycle and in this connection, as an example, infiltration of
water. During the project focus was also on the other needs for the urban water management. Sub-Report 1 (Mielby et al., 2015) describes the typical influences of the aquatic environment in the urban area, and focus on how to solve the hydrogeological tasks and problems. The sub-report explains management of various scales, the use of anthropogenic
data etc., and it also contains the identification of a big potential for improving the basis for
decisions in the urban area. Among these, the report also describes the professional and
technical connection between the different VTU-project elements and how it is held together as a whole.
2.4 Results and Recommendations from the Project
A number of general tools and recommendations have been established to make the results and experiences from the VTU-project available both for the Odense area, and for
other cities in the country.
Important results:

A description of essential influences on the water cycle in the urban subsurface

Analysis of working procedures in connection with data management of the water
cycle

A systematic collection and assessment of data

A mapping of the potential for improving the working procedure concerning geotechnical data

Working flows for scale independent 3D modelling
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
Working flows and tools for 3D modelling of anthropogenic deposits

Working flows for the merging of the geological and the anthropogenic modelling

Establishing an ability to store geotechnical information, when it is reported to the
Jupiter database.
Important recommendations:

The work load with the data from urban areas is big and must be managed strategically in order not to be too cost-intensive.

Nowadays the geotechnical borings aren’t managed effectively. The users work
with their own data; which consequently leads to a “silo approach”. An improved
access to data is required.

A statutory reporting duty for geotechnical data should be introduced, preferably for
all geotechnical borings, but initially at least for geotechnical data ordered by public
authorities and public companies.

Access to all basic data in shared databases is important to prevent erroneous corrections of the model caused by non-synchronised data (databases that are not corrected or miss reporting).

The anthropogenic and geological modelling must be made consecutively and focused.

One and the same basic model should be achieved by setting up a consecutive
maintenance of the established model concept starting with quality-assured data –
setting up a 3D geological model – setting up a 3D hydrostratigraphical model –
setting up a 3D anthropogenic voxel model – merging the geological and the anthropogenic models – and finally saving the model. The sequential order is important.

The rational systematic workflow is important to ensure the technical and geological
update of the model concept successively and efficiently, and coherently with adjacent areas.

It is important from the outset to determine the objective, the priority and the management of the work with the municipality model if it should be able to function as a
shared municipality administrative basis for the future.
The detailed recommendations and their background are described in the sub-reports from
the project, and the recommendations are summarized in the appendix to this report.
2.5 Dissemination of Results
The project results have been presented during the project period on various conferences
like Hydrology Forum, Danish Water Conference and Danish Water Forum. Also interna-
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tionally presentations of several project results have been given on the IAH conference in
Rome and especially in the EU COST-project Sub-Urban, where The Municipality of Odense is partner.
In-house the municipality, the project has been presented the office for management of
construction projects, to the archaeologists and to the GIS-section, just as the Groundwater
department and the Climate department are actively participating in the project. The Region
of Southern Denmark has participated at the common project meetings as observer.
2.6 What We Didn’t Achieve – Re-Prioritizations
As mentioned earlier in this chapter, the use of all geotechnical data was assumed, and in
spite of expectations to access these data several times, we didn’t succeed. Therefore it
has been impossible to use the geotechnical parameters in the model work, making the
project more data weak than expected at the planning of the project.
However, it turned out that digital infrastructure data from the municipality and public utilities were available in large numbers, and it was decided to give a greater priority to the
automated handling of these data in GeoScene 3D.
Storing the resulting city modelling voxels in the Model database at GEUS is not possible
for the time being, and therefore only the spatial geological model and the hydrostratigraphical model will be uploaded there.
Trying to obtain the geotechnical data took much more time than expected thus delaying
the start-up of modelling. Due to the delay of the modelling, the final model for municipalities and water supplies was published after the final presentation at the end of the project.
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3. The Model as Basis for Planning
This chapter deals with the utility value of the 3D geological/hydrogeological model for
managing the urban water and its potential for other users.
Many urban areas are rapidly developing and the use of the subsurface is intensified these
days by road, houses, sewage systems, tunnels, utilization for water abstraction and energy storage as well as waste storage. The same applies to the City of Odense.
Managing these tasks at a high professional level requires:
 Exact knowledge
 Knowledge of time-related development
 Knowledge of consequences of changes made (results from model scenarios)
 Compiled information
3.1 The Utility Value of the Model – The Urban Water
Due to climate adaptation water companies and municipalities are faced with increasing
rigorous demands to manage rain water at both local and city scale. Everyday rain as well
as excessive rain must be managed in the city in a way keeping damages to houses and
surroundings to a minimum.
Climate adaptation is leading to initiation of activities to affect the urban water cycle locally.
An inadequate or completely missing knowledge of local conditions in the subsurface may
cause many problems, e.g. groundwater pollution, damaged building constructions or
changes to the water cycle creating unintentional impacts elsewhere in the water catchment area.
When infiltration through soakaways or wadis is included in the planning processes of urban areas – whether existing or new – it is important to ensure that it is planned in areas
where infiltration is possible (Jeppesen, 2014), and that aquifers underneath aren’t polluted
by rain water from roofs and roads.
At the same time municipalities and supply companies have a wide range of management
tasks related to the urban water. The municipality and the supply company must protect the
groundwater interests, manage infiltration, establish retention basins and recreational areas, estimate the impact of increasing precipitation and abstraction changes etc., all factors
of great consequence to the urban areas and its surroundings.
In future a better management of city water will demand more knowledge of surface hydrology, sewage systems, geology and groundwater condition, and that this ideally is based on
information from databases and model tools, thereby making it possible to carry out necessary estimates and calculations across the traditional disciplines, geology/groundwater
modelling and surface water-modelling/hydraulic modelling of sewage systems.
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A precondition for this handling can take place effectively is a systematic integration of
these many and different activities. The various data used together with a 3D geological/hydrogeological model will constitute a very strong tool for managing and modelling the
many data, necessary to support decisions for these tasks.
3.2 The Utility Value of the Model – Other Users in the Municipality
In relation to data collection in the example from Odense there has been held a number of
meetings, and other users who might be able to contribute with data and information for the
model building have been contacted. It turned out that other areas within the municipality,
which could benefit from the improved access to data and the compiled model.
The archaeologists are typically interested in information on the fill layer and the geology
near to the surface. They use 3D visualization and could achieve a benefit from showing
their digitized information in connection with geotechnical borings and geological data.
Technicians working with construction, road and railway projects mainly have an interest in
the stability of the construction works. They often use geotechnical borehole information
(cpt, etc.) and are especially interested in information about organic layers and other geological layers with reduced strength.
Water supply companies are typically interested in potential abstraction of water and the
protection of well fields. They mainly use the models from the National Groundwater Mapping, but also within the municipality and urban area they may have an interest in
knowledge of the detailed geology. In addition both they and people working with sewage
are interested in knowing about the municipal infrastructural data from construction works.
People working with raw materials typically have an interest in the top 15 meters of the
subsurface, and especially in the peripheral area of the municipality where the national
groundwater mapping has not been performed.
People working with soil contamination are typically interested in the geological structure
near the point sources in order to carry out the best possible remediation and protection of
the surrounding environment. They typically use the results from the national groundwater
mapping, but as point sources very often are placed in the urban areas that aren’t mapped
by the national groundwater mapping, they are especially interested in mapping of the cities
and a detailed mapping of the urban area.
Technicians working with GIS and infrastructural data are suppliers to the municipal administration and to the operators working with the municipal infrastructure. It is of mutual interest that the geological model and infrastructural data are in accordance, not to mention the
potential for increasing collaboration.
Planners in the municipality are typically using maps worked out by the municipal technical
departments. The planners will have a better basis and opportunity to evaluate the underly-
25
ing data for their planning in the future. Besides, a volumetric mapping (i.e. spatial and 3D)
of the total subsurface beneath the urban area may prove to be useful to the planners in
the future.
Figure 8 shows 3 different information layers, which in future will be useful to handle in
combination.
Figure 8. Every 3D geological/hydrogeological model should be able to manage the following 3 information layers: Land use (population, land use, land use plan), infrastructure and
geologic subsurface (presentation COST Sub-Urban by M. van der Meulen).
3.3 Necessary Improvement of Data and Model
Even though the elaborated 3D geological/hydrogeological model today (year 2015) constitutes the best basis for decisions, experience from the work shows that there are many
places in Odense with a sparse data foundation which should be optimized to make a better basis for decisions.
The reason for the sparse data foundation is that there hasn’t been performed as many
geophysical surveys in the urban area as in the open country. Moreover, as mentioned in
the geotechnical sub-report, there isn’t free and easy access to geotechnical borehole information, and finally there is a need - as the example with estimating the possibility for
infiltration of rain water shows (Jeppesen, 2014) – for working with a large degree of detail
where local conditions are influencing.
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Ideally, each assessment based upon the hydrogeological foundation should be initiated
with a screening of the available subsurface information, in order to evaluate, if the data
foundation is sufficient for the requirements. If the evaluation shows that the subsurface
data must be improved, further information must be gathered to document the consequences of the requested initiatives.
It is vital that the new information is entered into the model to bring it up to date, thereby
also entering the collected data into the basis for decisions henceforth. It may also be included in the evaluations of later impacts on the surrounding environment, and act as legal
basis if necessary.
3.4 Perspectives for the Model
An integrated modelling is essential to understand the consequences of interventions in the
urban water cycle. In 2015, the model developed is considered the best basis for a unified
setting for managing the urban water cycle in Odense, and so it must remain. The challenge is to ensure that the model continues to be based on the latest and most relevant
data in the future.
The experiences in Odense showed that the underlying basis for planning can be improved. This requires a continued combined updating of the model, utilizing all existing and
new subsurface data.
It is therefore crucial that the model constitutes the basis for the future collection and elaboration of data, and that it acts as a unifying setting for managing the water cycle.
All together, the conclusion is that we have come a long way in managing the urban geology, but we have also disclosed a need for further development before we achieve a full
geological/hydrogeological planning basis for our urban areas.
“This is not the end.
It is not even the beginning of the end.
But it is – perhaps - the end of the beginning.”
W. Churchill, 1942
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4. Technical Management and Maintenance
Maintenance of a 3D geological/hydrogeological model is a challenging task due to the way
that municipalities, advisors and supply companies work.

It is difficult to reuse data (especially geotechnical data) due to the issue of rights.

There is no natural connection between collection of data and producing of information (in this case modelling). Data is not fully applied.

The mapping projects are often limited to larger or smaller areas making a systematic workflow for the total model area difficult.

We are in a technological interim phase using both maps (2D) and models (3D).
These challenges must be considered carefully to make the modelling work. This chapter
describes the organizing needed to maintain a 3D geological/hydrogeological model as an
active basis for decisions to the municipality and other users.
4.1 Managing the Further Course
In order to establish a complete administrative basis by way of a geological/hydrogeological
municipality model working as reference and tool to the municipality, advisors etc., procedures must be set up to ensure the work towards establishing the required data foundation.
This is needed:
 New data must be collected as basis for administration and planning
 Authorities must require the reporting of collated new geological and geotechnical
data to open databases.
 These data must be incorporated in the model.
 The model must be elaborated according to the need that arises for an updated geological model.
If work is done systematically, we will obtain:
 A model with all the geological/hydrogeological data that are needed for the urban
management.
 A basis for the hydrological modelling that is needed for management of the urban
water cycle.
It is important that work is targeted and systematically performed. Often the financial resources for work and development are limited, which makes it even more important to focus the management of the maintenance and development tasks.
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Initially, the maintenance and model update must be carefully and properly anchored. If
doubt about who is technically and organizationally responsible for the model arises, the
integrity for the model will fade very rapidly. Therefore, it must be ensured that an overview
is present, that the responsibilities for the various tasks are delegated, that a timeframe has
been made and that a vision for the future life and development of the model is present. To
manage a project this big in the best possible manner, a steering committee consisting of
the main stakeholder, users and technicians working with the model is suggested.
4.2 New Mappings in the Municipality
At this writing it is expected that the results from the 3D modelling will provide a basis for
more projects between the Southern Denmark Region, VCS Denmark and the Municipality
of Odense (The detailed mapping of infiltration possibilities in the Skibhus district, establishing a general climate model for Odense, protection of Bolbro and Eksercermarken well
fields).
Especially in the Municipality of Odense and VCS Denmark the model will be used for new
mappings and provide a better basis for decisions. It is also expected that the model will
raise new research project due to the new and better data already present that directly and
without further costs will enable the use for new innovatory purposes.
It is anticipated that particular during the first years, where the model is new, new detailed
mappings must be carried out regularly.
It is advisable to evaluate whether this detailed mapping should be performed as a direct
update of the existing model, or if it is relevant to conduct it as a separate mapping.
In the first case the detailed mapping should be performed according to guidelines mentioned in the model instructions. If the mapping is performed by persons with no experience
in the specific built 3D geological/hydrogeological model, the new mapping should be subject to a quality assessment before updating the model with the results.
In the latter case all the data and results from the detailed mapping should be available for
a traditional updating of the municipality model.
4.3 Maintenance of the Municipality Model
When building a municipality model, all available data from common public databases (Jupiter, GERDA and the Model databases) should in to the greatest possible extent be taken
into consideration. At the time of establishment, the model will therefore be consistent with
these.
29
As time goes new knowledge spread out across the municipal area must be anticipated
and it will be of great importance to enter it into the modelling. It may be results form later
hydrological models showing new connections in the geology, the subsurface and the
deeper geological layers, but it may also come from new borings and geophysical data.
None the less the model requires updating to ensure that the basis for decisions continuously is up to date (Korsgaard, 2015).
A distinct task will be to evaluate if there are areas with weak data and where the model
needs strengthening, comprising how new data – e.g. geotechnical data and significant
infrastructural data – can be obtained and incorporated.
The strategy for updating should be according to the guidelines and the sequence for the
geological and anthropogenic modelling.
4.4 Storing the Model Results
After updating the municipality model the results should be reported to the Model Database
at GEUS, in order to make it possible for all to use the updated basic model.
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5. Economy
This chapter will go through the financial rationale concerning the building and maintenance
of the 3D geological/hydrogeological municipality model.
After that we show examples of costs arising in a situation with inadequate basis for decisions leading the construction builder to have to do over the work already performed, or to
make a completely new construction.
Finally, this chapter shows other examples of costs related to drainage and climate adaptation.
5.1 Updated Model versus New Model
At the completion of the VTU-project well over 3 mills DK kr. have been spent on setting up
an administrative basis for the municipality. The price clearly exceeds what is normally paid
for a geological/hydrogeological model. However, a considerable development effort and
documentation work has been made, and the model has been designed to be bigger and
more detailed than usually for similar model. Furthermore, a tool for modelling of the anthropogenic layers beneath the city has been developed.
If the municipal model is to be kept up-to-date, maintenance must be done regularly, i.e.
one or two times yearly, and at least every three years. When too much time passes without maintenance, the update will of course be more comprehensive.
If instead – as today – ad hoc modelling is made, there may have to be made two new detailed models per year in the municipality. The costs for that should be compared to the
price of maintaining a municipal model – in addition to the fact that more models exist instead of only one which can lead to confusion about which one is the “right” one.
This leads to an argument for using the same amount of money to maintain and extend the
common basis for decisions.
5.2 Consequence of Missing Knowledge – Example from
Odense
In certain cases the basis for decisions for carrying out a construction work proves to be
wrong (e.g. missing data), leading to additional costs that might have been avoided.
A relevant example is the parcelling out at Stenløsevej/Dahlsvej in the southern part of the
Municipality of Odense. The area comprised in all ca. 80 lots divided between one-family
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houses and low-rise buildings. According to the local development plan the rainwater
should be managed within the area. From each lot VCS Denmark should manage 50 % of
the rainwater in a common rainwater drain system for the total built-up area, while the
house owners should manage the remaining rainwater on their lots in fachines. Water from
the roads and common areas etc. should be managed in the common rainwater drain system. See figure 9.
Figure 9. Principle of soakaway and drainage of Dahlsvej.
From earlier made geotechnical investigations and infiltration tests, it was expected that the
area was suitable for infiltration. In connection with the construction works in year 2011-12
further filtration tests were made showing strongly fluctuating infiltration conditions within
short distances, and it turned out that many of the soakaways and wadis etc. that were
made in actual practice could not drain off the rainwater sufficiently. This required a row of
revisions of project plans and overflow from the infiltration elements to VCS Denmark’s
sewage system. The original assumption that rainwater to the extent possible should be
managed within the area turned out to be difficult in practice.
A very rainy summer lead to further costs for the project, and finally the costs for advisors
were higher than expected due to the fact that the advisors back then didn’t have much
experience with local drainage of rainwater.
A detailed mapping of infiltration conditions and the building of a combined geological model for the area might have provided a much better overview of the options for handling the
rainwater in the area, and a row of revisions of project plans could probably have been
avoided.
The total project costs amounted to 12.5 mills DK kr. of which contractor costs amounted to
8.7 mills kr. It is estimated that 1 – 1.5 mills DK kr. of the contractor costs are referred to
insufficient knowledge of the actual geological conditions. Furthermore VCS Denmark estimates that these conditions have led to increased advisory costs for 0.5 mills DK kr.
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In all, VCS Denmark estimates that the extra costs due to insufficient knowledge of geological conditions accounts for 10 - 15 % of the total project costs.
This cost surplus can be compared to the costs that initially could have been spent on a
detailed mapping of the area and an up-date of the geological and anthropogenic municipality model. This detailed mapping could comprise digitizing of existing geotechnical boreholes, establishing of new boreholes, gauging of water level, data analysis, mapping of fill
layers and infrastructure etc. (Jeppesen, 2014).
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6. International Cooperation and Experiences
Running parallel with the VTU-project the participants from GEUS, The Municipality of
Odense, I-GIS A/S and VCS Denmark have joined a EU COST Action: TU1206 “SUBURBAN – A European Network to Improve Understanding and Use of the Ground Beneath
our Cities” (COST, 2015). The project runs from year 2013 – 2017.
In this chapter is described on which level, Odense Municipality/Denmark is compared to
our neighbour countries.
6.1 Object
The object of the COST-Network is to improve understanding and use of the subsurface
beneath our cities. Denmark participates in the project together with 27 other partner countries, mainly from Europe. The COST-project contributes to provide an excellent overview
of the situations in other European cities.
The main objective for SUB-URBAN is to focus on the need for knowledge to be used by
the decision-makers in the cities, because in many places – like Odense – there hasn’t
been performed a systematic mapping to build a basis for decisions for managing the subsurface in the urban areas. The object for SUB-URBAN is, as shown beneath, successively
to point out the recent (low) state, and the need for development of improved tools for
managing the subsurface in the cities (see figure 10).
Figure 10: Stepwise knowledge building focusing on establishing a basis for decisions for
management of the subsurface (ref. COST, 2015).
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6.2 Where are we in Relation to Data
Not all countries use groundwater for drinking water like Denmark does. The countries using groundwater have access to knowledge of the subsurface from the established wells.
Denmark has an extra advantage, as statutory reporting of water wells are required as well
as certification of the well borers, so that not just information but also comparable geological data are reported. Generally Denmark has a considerable knowledge of the subsurface
outside urban areas due to the national groundwater mapping, where boreholes and geophysical investigations have been implemented to protect the groundwater resources.
GEUS’ effort to ensure digital access and common public data is far advanced.
Geotechnical borings will often be the primary source of information within urban areas.
The access to this geological information differs considerably. The access possibilities to
the geotechnical data has been mapped by the SUB-URBAN project. The mapping shows
that some places (e.g. the State Administration for Hamburg) have a systematic collection
of geotechnical data while in other places a formally cooperation between advisors and the
public administration has been established, e.g. Glasgow (ASK). Denmark has no tradition
for shared storage of geotechnical information, and geotechnical data must be digitized by
one self, collected from partners or alternatively bought from advisors. So we are not similarly up to date.
6.3 What is our Position Regarding Modelling?
Generally there are many set-ups of modelling of the subsurface outside urban areas in
Denmark due to the National Groundwater Mapping, and Denmark therefore is of high
standing. An overall national hydrostratigraphical model, the DK-model, is also available. A
unique access to these model data is available at the Model Database at GEUS.
Ad hoc modelling has been set up within the urban areas in connection with protection of
well fields and remediation of contamination.
In many places abroad, modelling of the urban areas has been set up like in the Odense
City, but only relatively few are targeted at establishing a future administrative basis for the
incorporating infrastructural data. Helsinki, though, is one.
In the Netherlands modelling of geology is incorporated in the legislation for the geological
survey (TNO). In other cases partnerships between cities and the geological surveys have
been established, like seen between Glasgow City and the British Geological Survey.
In most cases there is no continuous financing of maintenance of a geological model as
administrative basis.
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6.4 What is our Position Regarding Planning?
Generally around the world only limited planning involving the subsurface beneath cities is
seen, and there are several examples of conflicting subsurface use and planning.
Oslo, Hamburg and Hong Kong are good examples of cities where the authorities – as a
part of the organization – have incorporated 3D geological modelling in the administration
of the city. Rotterdam Municipality has also worked with 3D planning of the subsurface, but
it is not fully implemented in the planning basis for the municipality. Glasgow has collaborated closely with The British Geological Survey to establish an information flow which supports both planning, as well as research and administration, see figure 11 below.
Figure 11: Connection between new knowledge (data), science, modelling and planning
(ref. British Geological Survey).
6.5 General Views from SUB-URBAN
During the past 200 years, the cities have increased their population leading to expanding
development of the urban areas.
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The urban subsurface plays a significant factor for sustainable development of the cities,
but management of the subsurface has not been adequately developed, causing a great
need for access to information, databases, knowledge and tools.
The purpose of developing and procuring access to knowledge of the subsurface beneath
our cities and the necessary technology should according to SUB-URBAN chairman S. D.
Campbell be to support those who are planning and administrating the cities and the city
policies, including:

To maximize the economic, social and environmental benefits of sustainable development of the subsurface and its natural resources, especially concerning groundwater, geothermal energy as well as opportunities for Sustainable Urban Drainage
systems (SUDS).

To acknowledge and responsibly manage the contradictory demands that the increasing use of the subsurface including nature-based solutions are causing - and
which demands state-of-the-art static and dynamic 3D and also predictive 4D modelling of the subsurface based on research, effective monitoring and 3D as well as
4D information systems.

To protect the ecosystem of the subsurface which the cities are depending on
(though often with limited recognition), their sustainability as well as protecting them
against naturally generated incidents that cities can be exposed to - and which demands robust systems like for instance volumetric 3D planning of the subsurface of
the cities.
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7. A National Perspective
In Denmark we have specifications for the way planning and regulatory tasks must be carried out in the countryside in connection with e.g. groundwater mapping, blue/green climate
adaptation solutions etc., that end in plans for the respective areas. But a similar planning
for the urban subsurface and the water cycle beneath urban areas are missing.
The existing models for urban areas at present have other (and more) specific targets than
seen in this project. I may be for building a metro, a motorway, climate modelling of water
run-off, mapping of contaminated areas, building of larger constructions and protection of
well fields. These models are often reused for other purposes, but seldom maintained with
the attention that is required to enter as a planning tool for water infiltration as described in
this project.
The VTU-project has obtained a long row of results that are central for the possibility to
establish an integrated 3D geological/hydrogeological model for the management of the
subsurface beneath the City of Odense and over time also other urban areas.
At the present time there is no coherent management of the urban geology related to sustainable use of the subsurface beneath the cities. There is an immediate need on national
level to collaborate on the collection and access to geotechnical data, on access to suitable
geological data and the use of infrastructural data.
An agreement between all actors involved to collaborate on a shared tool, and to establish
a technical professional and managerial organization, is required.
Locally, it could be relevant to involve the following actors:
 The local planners
 The local administrators of groundwater
 Water supply companies
 Other users (important operators, the Regions etc.)
 The persons responsible for infrastructure (GIS)
 Model administration (data, model and hydrogeological relation)
On a national scale additional actors may be relevant:
 Ministry of Environment and Food of Denmark (to ensure and enforce the legislation and data)
 Professional data centres (to ensure borehole data of good quality)
 Professional data centres (To ensure data and model quality and coherence)
To promote the development of geological/hydrogeological models in urban areas for management of the subsurface, it is necessary to improve the legislation to ensure an ongoing
reporting of especially geotechnical data and also access to infrastructural data in a way to
make these data usable for the future management of the subsurface.
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8. References
COST, 2015:
http://www.cost.eu/COST_Actions/tud/Actions/TU1206
Hansen, M., Wiese, M. B., Gausby, M.. & Mielby, S., 2015:
Udvikling af en 3D geologisk/hydrogeologisk model som basis for det urbane
vandkredsløb. Delrapport 6 - Teknisk håndtering og lagring af bygeologiske data og
modeller. Udarbejdet i VTU-projektet.
Häggqvist, E. & Söderholm, P., 2014:
The economic value of geological information: Synthesis and directions for future
research, Resources Policy 43 (2015). P. 91–100
Jeppesen, J., 2014:
Udvikling af en urban-hydrologisk model til simulering af af nye innovative LARløsninger til lokal håndtering af både regnvand og grundvand (LARG). Afrapportering
af VTU-projekt 29. December 2014.
Korsgaard, A., 2015:
Rådgivernes anvendelse af kortlægningen. Vintermøde
Grundvandsforurening, Vingsted 10.-11. marts 2015. P. 11-12.
om
Jord-
og
Kristensen, M., Sandersen, P. & Mielby, S., 2015:
Udvikling af en 3D geologisk/hydrogeologisk model som basis for det urbane
vandkredsløb. Delrapport 2 – Indsamling og vurdering af data. Udarbejdet i VTUprojektet
Laursen, G., Mielby, S. & Kristensen, M., 2015:
Udvikling af en 3D geologisk/hydrogeologisk model som basis for det urbane
vandkredsløb. Delrapport 3 - Geotekniske data til planlægning og administration.
Udarbejdet i VTU-projektet
Mertz, E.L, 1974:
Odense og omegns jordbundsforhold: En ingeniørgeologisk beskrivelse. DGU
Rapport Nr. 9, 1974.
Mielby, S., 2013:
Behovsanalyse, Status pr 2013.10.16, Udarbejdet i VTU-projektet i forbindelse med
MP1-afrapportering
Mielby, S., Laursen, G., Linderberg, J., Sandersen, P. & Jeppesen, J., 2015:
Udvikling af en 3D geologisk/hydrogeologisk model som basis for det urbane
vandkredsløb. Delrapport 1 - 3D-modellen som basis for håndteringen af det urbane
vandkredsløb. Udarbejdet i VTU-projektet
Pallesen, T. M. & Jensen, N.-P., 2015:
Udvikling af en 3D geologisk/hydrogeologisk model som basis for det urbane
vandkredsløb. Delrapport 5 - Interaktiv modellering af antropogene lag. Udarbejdet i
VTU-projektet
Sandersen, P., Kristensen, M. & Mielby, S., 2015:
Udvikling af en 3D geologisk/hydrogeologisk model som basis for det urbane
vandkredsløb. Delrapport 4 - 3D geologisk/hydrostratigrafisk modellering i Odense.
Udarbejdet i VTU-projektet
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9. Appendix – Summary of Recommendations
This Appendix contains the complete collection of recommendations from the entire VTUProject. Initially, for each subsection there is a reference to the sub-report, where detailed
background and information can be found.
Particularly important recommendations:
 The work load with the data from urban areas is big and must be managed strategically in order not to be too cost-intensive.

At moment the geotechnical borings aren’t managed effectively as each party works
with their own data which consequently leads to a “silo approach”. An improved access to geotechnical data is required.

A statutory reporting duty for geotechnical data should be introduced, preferably for
all geotechnical borings, but initially at least for geotechnical data ordered by public
authorities and public companies.

Access to all basic data in shared databases is important to prevent erroneous corrections of the model caused by non-synchronised data (databases that are not
corrected or to missing reports of data).

The anthropogenic and geological modelling must be made consecutively and focused.

One and the same basic model should be achieved by setting up a consecutive
maintenance of the established model concept starting with quality-assured data –
then setting up a 3D geological model – setting up a 3D hydrostratigraphical model
– setting up a 3D anthropogenic voxel model – merging the geological and the anthropogenic models – and finally saving the model. The sequential order is important.

The rational systematic workflow is important to ensure the technical and geological
update of the model concept successively, efficiently and coherently with adjacent
areas.

It is important from the outset to determine the objective, the priority and the management of the work with the municipality model if the model should be able to
function as a shared administrative basis for the future.
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9.1 Synthesis Report
The example from Odense shows that the 3D geological/hydrogeological model, built in the
VTU-Project, is at the time of completion (year 2015) providing the best basis for management of the subsurface in the Municipality of Odense.
In spite of that, the underlying data for the built model have turned out to be insufficient in
several places when working on cadastral plot level. The model should therefore be fortified
with more data if it is to function as sufficient basis for the administration of the urban water
cycle in parts of the Municipality of Odense.
At decisions involving the subsurface, a screening of the relevant data should be made
from the very beginning in order to evaluate, if data is sufficient and knowledge for making
decisions and impact assessment is present.
It is important continuously to elaborate and improve the 3D model in order to constitute the
best basis for administration and planning at all times.
Therefore, it is recommended:
 That new data henceforward is collected as basis for the planning.

That the authorities require reporting of collated new geological and geotechnical
data to open databases.

That the authorities advise private contractors to require reporting of geological and
geotechnical data to open databases.

That these data are entered into the model.

That the model is continuously elaborated and maintained according to the newest
requirements.

That requirement is imposed on national scale for reporting of geological and geotechnical data.

There are several challenges in managing and maintaining the 3D geological/hydrogeological model:
 It is difficult to reuse certain data (especially geotechnical data) as a consequence
of legal rights.
42

There is no natural linkage between collection of data and producing of information
(in this case the modelling).

The work is often performed as separate mapping projects for larger or smaller areas, which complicates a systematic information flow for the entire model area.

At present time we find ourselves in a technological interim phase using maps (2D)
and models (3D).
GEUS, OK, VCS, I-GIS, ALECTIA
We recommend taking these challenges into account:
 By establishing a systematic technical work flow to technologically/geologically update the model concept successively and effectively in coherence with the neighbouring areas.

By determining an objective and a priority of the work with the municipal model in
order to make it function as a future shared municipal administrative basis.

By elaborating and updating the model, preferably each year and at least every
three years.

By ensuring that the updates are made according to a definite procedure for modelling, as it forms the basis for future administration.

By agreeing upon coordinated development that ensures the models integrity (one
and only one model) as basis for administration.

By assigning time and finances to the updating tasks and coordination.

By budgeting according to acquired data, if the result of the project is depending on
specific data. It is important when working in urban areas because many “new” data
can be collected (e.g. geotechnical data and anthropogenic data), that are not
available in an easily accessible format.

By establishing a technical and administrative organization responsible for the
maintenance of the model (steering committee and technical project management).
9.2 3D-model as Basis for Management of the Urban Water
Cycle
The following recommendations have been worked for the Sub-Report 1 – 3D model as
Basis for Management of the Urban Water Cycle (Mielby et al. 2015). The background for
the recommendations can be found in the sub-report mentioned.
The following hydrogeological premises set the framework for the 3D geological/hydrogeological modelling of the urban water cycle:

Climate actions must be seen in connection to other human and natural influences
on the hydrological water cycle.

Impacts must be clarified for specific areas – and not just limited to places where
the actions are taken, and it must sum up on all relevant actions and impacts in the
entire hydrological catchment area.

Changes of the hydrological cycle and impacts must be watched for several years.

The water level and geology are important parameters for estimating the effect of
impacts.

Modelling of the anthropogenic layers and the geology must be made in connection.
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One and the same basic model should be achieved by establishing a consecutive maintenance of the model concept starting with – quality ensured data - building a 3D geological
model – building a 3D hydrostratigraphical model – building a 3D anthropogenic voxel
model – combining the geological and anthropogenic models – and finally storing the model
results. The sequence is important.
Often more data is required to solve problems at a detailed level - or more data must be
collected to ensure a sufficient basis for decisions. It is recommended to establish a work
flow to collect data systematically for the municipal model.
A work flow should be established to ensure that the municipal model will be updated systematically with relevant detailed data to make the model meet both a use on municipal
scale as well as detailed use.
Including anthropogenic data into the modelling of the subsurface
 There are many anthropogenic data (information on filling and infrastructure) – this
information is updated more frequently than the geology and should be managed
automatically.

Anthropogenic data are chronological. The sequence is important. New construction elements may have been added, and the original soil may have been replaced
by filling carried out in several steps.

Urban data (information on infrastructure) are not always sufficient, e.g. if information on position and depth of basements isn’t accurate enough for the predictions of flooded basement problems.
There is a need for further work to visualize the results of the model in a practical manner –
both with the results of the model, and also in connection with complementary hydrogeological themes.
9.3 Collation and Assessment of Data
The following recommendations have been worked for the Sub-Report 2 – Collation and
Assessment of Data, (Kristensen et al. 2015). The background for the recommendations
can be found in the sub-report mentioned.
Initially, it is important to evaluate which data that can be used and for what purpose they
can be used. It is also important to prioritize data in relation to their expected application.
An overview of data will provide an overview and a strong tool to prioritize, from where it
will general be most important to collect data. The overview stating priority and quality of
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the collected data will provide a useful tool for projects involving many different data (see
appendix 1 in Sub-Report 2).
Time to analyse and validate borehole data and for collection of borehole data from other
sources than GEUS must be anticipated.
Borehole data is important, but also incomplete and therefore labour-intensive to bring up
to date. It is vital to report all corrections to the individual borehole to the common public
database, to make certain that they are correct for future updates of the modelling.
It is an advantage to distinguish between anthropogenic data and geological data and to
manage them separately.
An overview of the sequence of subjects used for the anthropogenic layer should be applied. It is important that the sequence is made in such a way that the youngest part always
is ‘uppermost’ in the final anthropogenic model.
When working in urban areas, where no digital models have been made earlier, many new
data can be collected (e.g. geotechnical data and anthropogenic data) in a format not easily
accessible. Budgeting according to data acquisition is therefore important, if the result from
the project is depending on certain data types.
9.4 Geotechnical Data for Planning and Administration
Referring to Sub-Report 3 – Geotechnical Data for Planning and Administration (Laursen et
al. 2015), the following recommendations has been worked out. The background for the
recommendations can be found in the sub-report mentioned.
A future shared access to the geotechnical data must be ensured for planning, authorizations and follow-up (monitoring).
The management of urban related information must be more effective:

It is recommended that geotechnical data is collected at each boring (and not per
project), so that all detailed information is available at once, when working on cadastral plot level.

It is important that the collected geotechnical data is only collected and digitized
once.

It is important that all geotechnical data is accessible at all times, in order to make
the full data set available, when the model is updated.
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
All found errors in the Jupiter database must be corrected in order not to cause errors at later updating of the model.
Geotechnical data should be prioritized according to their age as the latest data generally
are more correctly interpreted/encoded, digitized and levelled.
9.5 3D Geological/Hydro-Stratigraphical Modelling
The following recommendations have been worked for the Sub-Report 4 – 3D Geological/Hydrostratigraphical Modelling in Odense (Sandersen et al. 2015). The background for
the re-commendations can be found in the sub-report mentioned.
On the basis of the geological modelling, it is recommended:
46

To make a number of preliminary model considerations:
o What is the purpose of the planned model?
o Is it expected to be able to solve all or just some specific problems?
o What problems can we expect during the modelling and what can be addressed from the beginning?

To select focus for the geological modelling:
o Is there anything in the geological structure that requires a special focus related to the specific model task?
o Is a special focus on parts of the model required related to our preliminary
knowledge of data?
o Will there be parts of the model less important (e.g. areas where the
groundwater is not being used, (saline aquifers, marginal model parts where
less exact modelling is required etc.)?

To balance requirements and expectations:
o The modeller might be aware of potential difficulties in the model area, e.g.
data coverage and details, but do the end users know this?
o Is the modeller completely aware of what the end users will be using the
geological model for? Do we know their requirements and expectations?
o Our expectations to the possible modelling of the geology may be changed
during modelling (something we believed we could do turns out to be impossible, or the end users requirements and expectations may alter during
the process).

To prioritize when selecting data:
o Prioritizing between easily accessible data sets/ complex data sets.
o Coordinating resources and level of ambitions.
o Evaluate the risk of deselecting data.
GEUS, OK, VCS, I-GIS, ALECTIA

To estimate, if collection of supplementary data is necessary:
o If it is clear from the start that supplementary data is decisive, it should be
considered when making the earliest estimations and decisions.

To be attentive to uncertainties related to the final model:
o The strengths and weaknesses of the model should be known.
o What is possible to do / impossible to do with the model?
o Scale problematics:
 Which scales of the geology can we hope to dissolve?
 What does it take to achieve a high dissolution, if this is what we
want?
 Evaluation of data quality/data density/method capacity related to
the required geological detail.
o Data problems: Do we know the weaknesses of the data (e.g. inadequate
borehole data, large areas with no data etc.).

To elaborate focal points for the further planned model work:
o Evaluating how best to use the model in future work.
o What to do in the long term for the model to maintain its relevance.
o Outlining procedures for future model updates.
o Describing how to ensure that the latest version of the model is available to
others and how to ensure updates to be incorporated continuously into the
model.
o Ensuring that the model enters into a regional and/or national context (DKmodel, National 3D geological model…)
9.6 Interactive Modelling of Anthropogenic Layers
The following recommendations have been worked for the Sub-Report 5 – Interactive Modelling of Anthropogenic Layers (Pallesen & Jensen, 2015). The background for the recommendations can be found in the sub-report mentioned.
Data overview, data utilization and prioritizing
Input data should to the greatest possible extent be quality-assured with relation to content,
errors and omissions. It can be particularly difficult at the utilization of vector-themes (piping
etc.) together with related attributes (pipe dimension, type of material, year of construction
etc.).
It is important to prioritize data in relation to the expected utilization. A review of data provides a good overview and a strong tool to prioritize wherefrom it is most important to collect data. A review of data stating priority and quality of the collected data is a usable tool
for projects involving many different data.
47
Distinguishing and managing separately between anthropogenic data and geological data
will be an advantage.
An overview should be used containing the priority of subjects to be used for the anthropogenic model layer. The sequence is important. New construction elements may have been
added, and the original soil may have been replaced by fillings carried out in several steps.
It is therefore essential that the sequence is set up placing the youngest element ‘uppermost’ in the final anthropogenic model.
Categorization of filling types and geology
In this project the individual voxels have been attributed to a filling type reflecting a claysand relation, and thereby a form of lithology. In the end these evaluations are transformed
to hydraulic flow characteristics. The evaluations behind are subjective, and in addition they
are based on descriptions of filling, which are also subjective and uncertain because of
great variations of filling material both vertically and horizontally. This makes it essential to
set up a categorization system that is as simple as possible and including only a few general filling type categories.
The density of filling type points (interpretation points) are significant for the input generated
via interpolation to the voxel grid. Interpolation is especially important on a local scale. A
systematic approach to evaluation and management of the filling layer is essential.
Besides, the applied average filling type that has been entered into the voxel grid where
interpolation hasn’t generated any data is very important, but also widely uncertain.
Future anthropogenic modelling – level of detail
Due to the experiences gathered in this project, it is estimated that it is both possible and
realistic to carry out a detailed urban geological modelling. The urban area, chosen as test
area for the model, is complex, and the time available for the modelling was not sufficient to
carry out a full modelling by involving all data. But data, software and work flow has now
been developed, tested and optimized.
For future models it is essential to act accordingly to the required and necessary level of
details related to the model purpose and customer. By using more voxel grids during the
modelling process, several parameters may be added simultaneously, e.g. lithology, age
and transmissivity.
It is important to consider whether a high level of detail can be provided for at the further
work, e.g. hydrological calculations.
Model maintenance
Due to the software and work methods developed in connection to this project, it will be a
manageable task to make continuous updates to the urban model. It is therefore recom-
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GEUS, OK, VCS, I-GIS, ALECTIA
mended to prepare a specific description of work flow and to incorporate it in the municipal
work flow. The extent of this task is difficult to estimate, but will impose that new data will
be included when it emerges. A well-defined work flow description will ensure a homogeneous and smooth model update in the future as new data emerges or existing data is revised.
Involving local knowledge
Involving local knowledge will provide a valuable supplement for further detailing and adjustment of the original model. As an example it could be evaluating a construction on a
detailed level, or the presence of sand fillings and their size. There will probably be local
differences due to soil conditions, traditions etc., which should be evaluated for each place.
An involvement of expertise, e.g. the municipal construction authority, will be an advantage.
The same applies for collection and use of other data. For instance, there may be local
knowledge about piping, roads and other areas of importance that would be useful to collect.
Historical maps showing the urban development through the time could advantageously be
introduced when working on the identification of the bottom of the fill layer. In this project
the bottom is only identified by using bore data. The borings are unevenly scattered within
the area, and therefore there are also areas where there is actually no knowledge of the
bottom of the filling layer. These maps might have provided valuable information.
Uncertainties
It is important to consider the strengths and weaknesses of the model. For instance, there
are parts of the model which are based on very subjective estimations and assumptions,
e.g. categorizing of fill layers in concerning clay/sand relation – and the consequences of
that.
Several of the involved data sets are being used knowing that they are subject to uncertainties to a greater or lesser extent. For instance, building basements and foundations are
placed in relation to the terrain surface in the model. This, however, is a problem seen from
a local perspective as the buildings in the used data set are represented as combined units
often larger than each building per se. Each individual unit is positioned in relation to a centre value related to the terrain, which leads to parts of the building lying too high or too low
in particularly hilly areas. This has consequences for the voxels chosen on the basis of the
facts of the building theme.
In calculating the value of each voxel using a "relative" and a "blend" feature are used.
These allow the use of particularly small elements but also lead to a smoothing of detail in
the model. This is a consequence of some model technical functions - including by virtue of
a upper limit on the number of voxels in a single voxel grid, and thus among others indirectly a lower limit for how small voxels that can be used within a given area.
49
Others
There should be drawn up lists of geotechnical and hydraulic parameters of anthropogenic
layers. In the developed model, these values are estimated from an overall knowledge
about different fillings elements, but there are no studies or applied literature that can quantify and detail these.
It could be considered to develop some specific products, for example a number maps
showing the geology at different depths, for example in the intervals 0-1, 1-2, 2-3 and so on
meters below terrain. Such maps will be easier to distribute and use in other contexts, for
example for urban planners. This is not possible with direct use of GeoScene3D right now.
Conclusively evaluated, we have developed a methodology and a dynamic tool, which allows relatively easy to set up, modify and update voxel models for anthropogenic layers in
urban-areas. However, there will be a larger initial work in data preparation. The extent of
this work depends partly on the level of ambition in relation to such, e.g. degree of detail.
When the initial data preparation is in place, the new plants or future proposed plant could
be easily incorporated into the model in order, for example scenario runs and impact analyzes.
The tools in GeoScene3D also allows the user to make manual adjustments in the voxel
model, for example inserting a hydraulic barrier in a wire trace or, if a drain / trace with a
high hydraulic conductivity. At the moment it is not possible to use single 3D objects (e.g.
buildings) for the selection of the voxels in the model.
There is a lack at the moment of experience in relation to the extent to which the high level
of detail can be utilized by subsequent flow calculations. It is recommended to investigate
these matters, which could possibly lead to a simplified workflow in relation to the data included in the voxel model since some small / local data types may only have minimal impact on the resulting model.
The voxel model with the anthropogenic layers can be joined with a more regional voxel
model that for example is based on an existing hydrostratigrafisk layer model.
9.7 Technical Handling and Storage of Urban Geological Data
and Models
The following recommendations have been worked for the Sub-report 6 - Technical handling and storage of urban data and models (Hansen et al, 2015). The background for the
recommendations can be found in the sub-report mentioned.
Jupiter Data
Many of the boreholes carried out in urban areas are performed for public authorities, for
example in connection with public works and regional survey of soil contamination. At the
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GEUS, OK, VCS, I-GIS, ALECTIA
same time many other public authorities lack access to geological / geotechnical information in urban areas, and will be forced to use resources to collect and convert / digitize
data from other sources.
A system for digital reporting of borehole data to the Jupiter database exist and this is being
developed to include geotechnical parameters. To make geotechnical data available, it is
obvious to recommend that one or another form of obligation to report to Jupiter is established. The reporting obligation could, for instance be for all boreholes performed for public
authorities (see also Sub-Report 3 Geotechnical data for planning and administration).
Such a reporting will contribute to the follow-up to the intent of the data responsibility
agreement drawn up under the auspices of the National Environmental Portal and signed
by the Ministry of Environment, Local Government Denmark and Danish Regions to other
ministries and to ensure a higher degree of data sharing between the public authorities.
Model Data
It should be encouraged to store developed urban models in the model database, so they
are for benefit of other players.
The National Model database should be updated with a facility for storing voxel data.
51
ISBN: 978-87-7871-459-6
Danish Ministry
of Energy, Utilities and
and Climate
GEUS is a research and advisory institution in the
Danish Ministry of Energy, Utilities and Climate
9
788778
714596
DEVELOPMENT OF A 3D GEOLOGICAL/HYDROGEOLOGICAL MODEL AS BASIS FOR THE URBAN
WATER CYCLE
SYNTHESIS REPORT
There is an increased focus on the urban geology in these years.
Municipalities and water companies are faced with new tasks in
climate adaptation, the establishment of renewable energy,
action plans etc., as well as the urban regeneration, infrastructure and construction projects require detailed knowledge of geological conditions. Insufficient knowledge can lead to a risk of
erroneous planning and investments.
On this background, The Municipality of Odense, VCS Denmark
and GEUS in 2012 initiated a collaboration to develop a 3D geological / hydrogeological model of the subsurface beneath Odense
municipality. In 2013 a two-year project was launched based on
funds from The Foundation of Development of Technology (VTU)
with the participation of Odense Municipality, VCS Denmark, I-GIS,
Alectia A/S and GEUS.
Also at the national level, the issue is well known. Therefore from the
beginning, it has been assumed that the results from this project will be used
as recommendations for a nationwide model concept comprising a systematic
model construction and maintenance for the benefit of municipalities, water companies and advisors.
The project is finished, and this reporting of the project is presenting important factors
to the management of the urban water cycle, for example data acquisition (geotechnical,
infrastructure etc.), how a local geological / hydrogeological model is constructed and
maintained, how the uppermost layer (the Anthropocene) can be modelled, how the
overall models contribute to climate change adaptation and so on.
Denmark is not alone in the need for knowledge and for a modelling of subsurface
below the city. GEUS and The Municipality of Odense have parallel to this project
attended a EU-project, with the purpose of building knowledge on an international level
("SUB-URBAN - A European network to improve the understanding and use of the
subsurface beneath our cities "). This also provides an opportunity to have an international reflexion in the VTU report.
De Nationale Geologiske Undersøgelser
for Danmark og Grønland (GEUS)
Geological Survey of Denmark and Greenland
Øster Voldgade 10
DK-1350 København K
Denmark
Phone
Fax
E-mail
Hompage
+45 38 14 20 00
+45 38 14 20 50
[email protected]
www.geus.dk