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DSD-INT 2018 Natural and anthropogenic factors controlling the groundwater behavior of the upper Rhone valley aquifer - Christe


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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.

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DSD-INT 2018 Natural and anthropogenic factors controlling the groundwater behavior of the upper Rhone valley aquifer - Christe

  1. 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. 2. Earthquake model 2015 Situation of Canton Valais & Rhône valley 2
  3. 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? 3
  4. 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 4 Multi-layered aquifer system
  5. 5. February, 1st 2018 Geological 3D Voxel Modelling 5  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. 6. Natural vs. anthropogenic factors influencing GW-flow 6 2011-13 Mean Industrial Groundwater Use:  Today: 1 Mio m3/year  Future: + 2.5 Mio m3/year (+ 250%)
  7. 7. A9-highway: Groundwater impacting construction methods 7 PLANNING
  8. 8. Introducing engineered structures in the 3D geological model 8 Groundwater flow parameterization Kunstbauten Grosseia
  9. 9. LONZA GAMSENRIED Rhône correction: changing interaction between surface and ground-waters 9
  10. 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 10
  11. 11. 3.3 Mio m3 1.3 Mio m3 > 6 Mio m3 2016 2017 2018 Fighting with the HydRhA… 11
  12. 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 12
  13. 13. USE OBSERVE REMEDIATE  Proper assessment requires tool for spatial and temporal analysis Rapid variation of GW-levels might impact GW-quality 13
  14. 14. HydRhA model 14 Natural and anthropogenic factors controlling the groundwater behavior of the upper Rhône valley aquifer METHODS
  15. 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 15
  16. 16. “They were about to walk past it”…  Writing scenarios of the different priority simulations (GW-management).  Result will be in 3D! 16 Coming soon… PLANNING METHODS