Presentation by Pierre Christe (Environmental Protection Agency of Canton Valais, Switzerland) at the iMOD International User Day 2018, during Delft Software Days - Edition 2018. Tuesday 13 November 2018, Delft.

1. Natural and anthropogenic factors controlling the
groundwater behavior of the upper Rhône valley
aquifer (Switzerland)
Dr Pierre Christe, CHGEOLcert, EurGeol
Department of the Mobility, Territory and Environment
Service of the Environment
Head of Groundwater group
Delft, November 13th 2018

2. weinwanderungen.ch
Earthquake model 2015
Situation of Canton Valais & Rhône valley
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3.  The alpine city of Visp saw a rapid growth at the beginning of the 21st century with the opening of the
Lötschberg base tunnel, connecting to the North Canton Valais with Canton Bern in less than one hour. The
urban development saw an increase.
 Lonza, today one of the world's leading suppliers to the pharmaceutical, healthcare and life science industries
started activities in Visp around 1910. The plant in Visp is still Lonza’s largest site and one of the most
significant for production and R&D.
 Since 2010, two important projects are under construction in the area of Visp: the A9-highway connecting the
Rhône valley with Italy to the South through the Simplon railway tunnel, and the 162 km long 3rd Rhône
Correction, today’s biggest flood protection project in Switzerland.
 In 2012-13, anomalous groundwater levels were experienced in the Visp basin. A first regional groundwater
model was realized in 2015 using iMOD to help assess the situation. The model is extended now to the entire
upper Rhone valley and should run for the time period 2011-2018.
 Model results will assist authorities to critically discuss options and help define best strategies in a more
objective and efficient manner. It should be used to improve current knowledge on past conditions, present
state and future evolution.
Why a 3D GW-Model in Visp?
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4. 0 10 205
Kilometers
I
Low permeable deposits
High permeable deposits
~400 mVisp basin
Complex geometry at depth
Rhône valley aquifer and Visp basin
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Multi-layered aquifer system

5. February, 1st 2018
Geological 3D Voxel Modelling
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 3 sectors with different anisotropy
 QA and QC applied to geological models
BS_North
BS_South
Bachschutt
© swisstopo
3D Voxel Models Modelled
Parameter
Type Method
Geologisch Lithostratigraphie Discrete Nearest Neighbour
Geologisch Lithostratigraphie Continuous +
Discrete
Sequential Geological
Probabilistic Modelling
(Indicator Kriging)
Parametrisch Hydraulische
Durchlässigkeit
Continuous Co-Kriging
Side flow!
3D-transition from hard to
unconsolidated rock aquifers, means
complex distribution of GW-flow.

6. http://oss.deltares.nl/web/imod/about-imod
Natural vs. anthropogenic factors influencing GW-flow
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2011-13
Mean Industrial Groundwater Use:
 Today: 1 Mio m3/year
 Future: + 2.5 Mio m3/year (+ 250%)

7. www.a9-vs.ch
A9-highway: Groundwater impacting construction methods
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PLANNING

8. Introducing engineered structures in the 3D geological model
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Groundwater flow parameterization
Kunstbauten Grosseia

9. LONZA
GAMSENRIED
Rhône correction: changing interaction between surface and ground-waters
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10. Original Rhône river profile
2011-2015
New Rhône river profile
2016-present
 Work at the riverbed and subsequent removal of old river bank modify interaction between river and aquifer.
 This phenomenon is observed since 2016 at Lalden and still requires emergency measures.
 Risks associated to subsequent increase in groundwater levels still have to be properly assessed.
Colmated layer
“Transient” leakage factor
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11. 3.3 Mio m3 1.3 Mio m3 > 6 Mio m3
2016 2017 2018
Fighting with the HydRhA…
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12. Comparison with mean levels 1994-2003 for the same period
«GW-Excess» +0.5/+2m«GW-Deficit» -0.5/-1.5m
R3 Los 5
(seit Ende 2017)
R3 Los 7
(seit Anfangs 2016)
10’000 -30’000 m3/day
A9 Portal Tunnel
Schwarzer Graben
(2016-2017)
3’000 m3/day
Alte Deponie
Gamsenried
AltlV
Brücke SBB-ATL
(Dez. 2015-Feb. 2016)
Volkigillo
(tiefe GW-Stände
seit 2016)
2’000 m3/day A9 Anschluss-
Bauwerk Visp West
(2014-2018)
3’000 m3/day
Rovina + Partner AG, 2018
Current practice is not «sustainable» and requires collaboration between several stakeholders to transversally
address problems and discuss solutions (win-win approach).
Fassungen Lonza
(seit 70er Jahren)
Ausserbetriebnahme :
GW + 0.6 bis 1.6 m höher
± explainable through exception
winter 2018
Anthropogenic perturbation?!
Upper Rhone Valley Aquifer: situation in March 2018
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13. USE
OBSERVE
REMEDIATE
 Proper assessment requires tool for spatial and temporal analysis
Rapid variation of GW-levels might impact GW-quality
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14. HydRhA model
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Natural and anthropogenic factors controlling the groundwater behavior of the upper Rhône valley aquifer
METHODS

15.  For the management of sudden events in the Rhone valley related to groundwater, a classification is
proposed in analogy with risk assessment in natural hazards.
 Degree definition is based on the data of the cantonal groundwater monitoring network.
 Onset of degree 3 means that close evaluation of the situation is to be conducted by an expert group.
 If the risk is evolving towards degree 4 or higher, actions are taken under the authority of an executive board.
Degree 1 Degree 2 Degree 3 Degree 4 Degree 5
« Normal » average situation Alert level
DMTE
Crisis situation
No damage to infrastructures and
people
Damage risk Damage confirmed and observed
Internal
coordination +
external
communication
Realization of corrective and /or
protective measures at the local
and regional scales
Quantification of Groundwater Related Risks in the Rhone valley
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16. “They were about to walk past it”…
 Writing scenarios of the different priority simulations (GW-management).
 Result will be in 3D!
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Coming soon…
PLANNING METHODS