3D Modelling of the Uppsala Esker

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1 3D Modelling of the Uppsala Esker Eva Jirner (SGU) Duncan McConnachie (WSP Sweden) ISO/TC211 Geographic Information/Geomatics

2 A collabrative effort

3 Orientation 3

Background Uppsala municiaplity = >200 000 inhabitants. Model area = part of the esker used for the water supply of Uppsala (294 km 2 ).

In order to increase water supply, infiltration of Fyrisåns water was initiated in the middle of the 1950 s at Tunåsen.

Further wells were constructed at Storvad, approx. 1,3 km north of Tunåsen in the early 1960 s.

4 Background Uppsala municiaplity = > inhabitants. Model area = part of the esker used for the water supply of Uppsala (294 km 2 ). Fyrisån and Uppsala esker have always been a central part of Uppsalas water supply. In order to increase water supply, infiltration of Fyrisåns water was initiated in the middle of the 1950 s at Tunåsen. Positive result infiltration beds were constructed Infiltrated water is pumped out through a series of wells located 2.1 km south at Galgbacken. Further wells were constructed at Storvad, approx. 1,3 km north of Tunåsen in the early 1960 s. A news infiltration bed was constructed in the 1970 s at Vallskog, approx. 2.5 km north of Storvad. Finally, in order to improve the reliability of the water supply and to soften the water, two new water works were commsioned at Gränby and Bäcklösa ( ). Galgbacken is now a reserve water work. Vallskog Storvad Tunåsen Galgbacken Gränby Bäcklösa

5 Background Uppsala s population is expected to grow rapidly: år 2030 / år 2050 The esker runs through the central parts of the city - highly vulnerable to potential contamination from industry and other activities. Large pressure for development of new housing and industrial areas. Artificial groundwater infiltration from Fyrisån is contributing large amounts of NOM (Natural Organic Material) to the esker (about 100 tons/year). Uppsala Water initiated a strategic project in 2013 titled Funktionsanalys Uppsalaåsen 1. Expected increased water demand 2. Sustainability of artificial infiltration with regards to NOM 3. Address existing water quality problems 4. Risk of contamination of groundwater from existing and planned urban areas

6 Activities completed Collection, analysis and digitalisation of relevant information, rapports, maps, etc. Design and construction of a system for storing and sharing data Field work (drilling, installing new groundwater observation wells, measuring of groundwater levels and temperature, conducting soil and water samples, test pumping and infiltration testing). Water and soil analyses Groundwater modelling and scenario analysis Propose prioritised goals Propose operating strategies and operating instructions Knowledge transfer and capacity building

7 Digital archive/database

8 GIS database

9 Plotting of data

10 3D modelling In order to build a 3D mathematical groundwater model, a 3D geological model is needed which describes the geometry and stratigraphy as a base for assigning hydrological boundaries and properties, such permeability and storage capacity.

11 A 3D model for groundwater modelling 42 km 294 km 2

12 The esker is often covered by clay

13 16% is not under clay

14 Quaternary map+dtm

15 Simplified classes of stratigraphy Fill Organic soil Outwash sand Silt and clay Glacial fluvial sediment Till Bedrock

16 Boreholes

17 Subsurface viewer Mx

18 Work order

19 Cross section

20 Cross section

21 Cross section in three windows

22 The deepest 160 m!

23 Example

24 The deepest 140 m!

25 A network of profiles

26 The complete block model showing the Quaternary deposits and the Bedrock

28 Information from each cross section & the entire model

30 3D printing of a generalised model

31 3D-print

33 Stratigraphy Fill Organic soil Outwash sand Silt and clay Glacial fluvial sediment Till Bedrock

34 Post-processing av stratigraphy i GIS

35 Export till FeFlow

36 What can a 3D geological modell be used for? Model can be used in physical planning, for example: Groundwater vulnerability assessment Need for protective measures connected to different types of exploitation. Knowledge and understanding of the geological stratification is important to assess the influence on groundwater levels, groundwater flow and groundwater quality from: Underground constructions Removal of confining layers Release of different types of polluting substances etc. Cross-sections, maps and 3D-illustrations can readily be shown and exported from the model and can be used in presentations and as basis for discussion and decision support.

Database and modelling Tool for an increased understanding of how the esker

37 Database and modelling Tool for an increased understanding of how the esker functions from a hydrogeological perspective and for testing different scenarios, e.g. location of new infiltration and extraction sites as well as simulating emergency situations. Analysis of contamination risks and different protection strategies and mitigation measures. Operative support to the Uppsala Water keeping a good balance between infiltration and extraction of groundwater.

38 Thank you! sgu.se wsp.com

11/22/2010. Groundwater in Unconsolidated Deposits. Alluvial (fluvial) deposits. - consist of gravel, sand, silt and clay

11/22/2010. Groundwater in Unconsolidated Deposits. Alluvial (fluvial) deposits. - consist of gravel, sand, silt and clay Groundwater in Unconsolidated Deposits Alluvial (fluvial) deposits - consist of gravel, sand, silt and clay - laid down by physical processes in rivers and flood plains - major sources for water supplies