Groundwater Model Visp: An iMOD application in an alpine setting

Dr Pierre Christe Environmental Protection Agency (SPE)

Head Groundwater Group

Delft Software Days Tuesday, 1st November 2016

Dpartement des transports, de l'quipement et de l'environnement Departement fr Verkehr, Bau und Umwelt

Oversight by FOEV Protection of Surface and

Groundwater (quantitative +

qualitative)

Facilitate access to quality

geological and hydrogeological

information / data

Collaboration with FOEN

swisstopo

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Walliser Bote, February 2013

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Walliser Bote, June 2013

GW-Model Visp: It all started with a little political and ideological controversy.

Climate change

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Switzerland, Valais and the hotspot Visp

weinwanderungen.ch

Earthquake model 2015

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mammut.ch

Groundwater recharge in the Rhone valley influenced by groundwater circulations at different depths through highly heterogeneous (hard) rock masses

Rhone-Valley

Southern Alps

Northern Alps

Visp is surrounded by steep mountains

Ground elevation model: swissAlti3D

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Visp belongs to the geothermal system Oberwallis

Geothermal systems locally influence groundwater temperatures in the Rhone Valley (thermal anomalies)

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Geographical extent and structure of the Rhone Valley aquifer

Lower Valais Central Valais

Upper Valais

Low permeable deposits

High permeable deposits

~400 m

Max.100 m Average 40 m

Glacial + torrential + slope deposits Rhone alluvium (unconsolidated, water-bearing) vs. Flood

deposits (consolidated, low permeability) Multi-layered aquifer system

1 2

3

B B

A

A

Visp hydrogeological setting

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Data: 1994-2003

Data: 2004 - 2013

Mountain water inflow

Juli

Rhone

Janu

ar F

ebru

ar

Direct GW-recharge

Juli

Vispa

Juni

Juli

GW-Recording

Juli

Evaluating groundwater recharge in the Rhone-Valley: summer and winter peaks

Geotechnisches Institut, 2016

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Supra-regional considerations REGIONAL MODELLING! Climatic vs. Hydrogeological processes Snow Water Equivalent (SWE)

Area of interest Mountain water inflow

+ 1.8 m

+ 2.5 m

+ 5 m

Particular geometrical relationships Stronger apparent differences in GW-amplitudes in Vispertal doesnt necessarily mean that the cause of the observed phenomenon has its origin there.

Visp hydrological years 2012-2013: What has been exactly observed?

Geotechnisches Institut, 2016

Differences (2013) (2012)

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Aquifer sections

Inflow profiles in Visp: where does the groundwater come from?

Total budget: 400 l/s = 24000 l/min

(35000 m3/day)

Outflow in %

Geotechnisches Institut, 2016

Inflow in %

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~ 15000 m3/day (10500 l/min)

Data: SPE

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Realized and projected major underground infrastructures and construction in the area of interest Confronting cumulative impacts of :

1. Permanent ground foundations2. Temporary groundwater retentions

Visp: questionning land use practice and planning, ensure proper coordination

Water bearing layers

North

South

North South

Low permeable layers

Lonza extraction

Underground infrastructures

Direction of groundwater flow

Hard-rock

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Deltares, 2015

Visp: using iMOD to simulate different scenarios

Parameter Min. Average Max. Parameter Min. Average Max. KF 382.0 432.0 487.0 SF 0.181 0.300 1.122 KV 25.0 45.0 60.0 BF 0.073 1.300 15.321 LF 0.18 0.2 0.22 P 0.040 0.050 0.070

SS 4.32E-6 6.2E-5 6.23E-4 Computed parameter confidence intervals (96%).

LF Leakage Factor [d] P Porosity [-] SS Specific Storage [-] KV Permeability Vispertal [m/d] KF Permeability Rhone Valley [m/d] SF Sideflow [-] BF Bottom flow [mm/d]

Small uncertainty

Larger uncertainty

Large variability

Results: causes of the strong GW-level rise in the years 2012 /2013 in Visp

First approach with the methodological concept.

Expected model-improvements:

Introduction of the respective GW-contributions from distinct geological andhydrogeological units;

Introduction of a weighting factor forsnowmelt rates to differentiate betweenwinter and spring times;

Introduction of better rain and snowmeltmodels both at the local and regionallevels;

Model-construction of channels andagricultural drainage;

Inventory of all existing constructionsreaching or below GW-level;

Better knowledge of the undergroundand groundwater structure below

What can regional groundwater models help us solve.

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Area of interest

Current iMOD model (1. Feb. 2011 to 31. Dec. 2012)

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Transient 3D-model for GW-fluctuation

Area of interest New area of

interest

Extended iMOD model (summer 2015 to summer 2016)

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Conflict prevention and management

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No, I hate YOU!!

I hate you!

How can we actually still love them?!

Excavation below piezometric level

Public safety: construction sites

Modification of hydrological relationships

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Combined effects from industrial and agricultural activities on groundwater over decades!

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Public safety: site remediation

Grossgrund-channel

Industrial site Lonza

Waste disposal Gamsenried

mysafetysigns.com

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Public health: drinking water ressource

High damage susceptibility Site effects, non-linear phenomena in liquefiable soils, related pore pressure effects

Burjanek et al. (2012)

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Public security: example of the 1855 Visp M6.2 earthquake

Ground velocity NS component

COupled seismogenic GEohazards in Alpine Regions (COGEAR)

Drawing Hands, M.C. Escher, 1948

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Responsible decision, responsible actions

Prediction

Model

Uncertainties

Effective measures

Many thanks to..

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See you soon in Visp?

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