PEGASES meeting, DTU Lingby March 2003 PEGASE – Pesticides in European Groundwaters : detailled study of representative Aquifers and Simulations of possible Evolution scenarios (European project ) Martigny Site (Switzerland) : Hydrogeological Contribution Mahmoud Bouzelboudjen, Eric Di Gioia University of Neuchâtel, Switzerland In collaboration with Kirsten Meiwirth & Marc Soutter Swiss Federal Institute of Technology and Pascal Ornstein & Jean-Daniel Rouiller Centre de Recherche Alpin, Sion, Switzerland Prof. André Mermoud, PEGASE Swiss Team Leader, Swiss Federal Institute of Technology, Lausanne

CONTENTS Situation and data Water table behavior 3D Groundwater modelling with Marthe Dataset provided

PEGASE Project (Martigny, Switzerland)

3D Groundwater Model : Thickness [m]Permeability [m/s] Upper Silt (86 boreholes) Upper Silt (86 boreholes) Upper Gravel (35 boreholes) Upper Gravel (35 boreholes) Middle Silt (24 boreholes) Middle Silt (24 boreholes) Lower Gravel (24 boreholes) Lower Gravel (24 boreholes) 8.0 (cst)7.0 Thickness (M) of Upper Silt (Layer 1) and Upper gravel (Layer 2)

4.1 Aquifer system structure

Hydraulic Potential (m), High Water, July 1999

Hydraulic Potential (m), Low Water, Mach 1999

FullyD FullyG MAR Rhône river and aquifer relations : examples

Legend : Precipitations (in black) Rhône river (in blue) Piezometers (in red) Rhône river and aquifer relations

Legend : Precipitations (in black) Rhône river (in blue) Piezometers (in red) Rhône river and aquifer relations

Results of piezometric campaigns Results of piezometric campaigns

Boundary conditions for 3D groundwater modelling (explanations in) : et ftp://sitelftp.unine.ch/Bouzelboudjen/Pegase_EU_Project_2002/ ftp://sitelftp.unine.ch/Bouzelboudjen/Pegase_EU_Project_2002/

Martigny 3D Model (with Marthe Code) : Hydraulic Conductivity for upper gravel formation and for Rhône river Cell Size 50mx50m

Bleu : Rhône et Canal du syndicat Rouge : zone d étude de l infiltration des pesticides Coupe N - S Coupe W - E

Martigny groundwater 3D Model (with Marthe code) : Simulated versus observed hydraulic potential - steady state, july 1999)

Martigny groundwater 3D Model (with Marthe code) : Simulated versus observed hydraulic potential – transient state, )

Martigny groundwater 3D Model (with Marthe code) : Simulated versus observed hydraulic potential – transient state, feb. 2001)

Martigny groundwater 3D Model (with Marthe code) : Particle tracking calculated from hydrodynamic model results (transient state, jul. 2001)

Pegase area (4 km2) : Piezometry and electric conductivity (May and July 2001), source : K. Meiwirth

Pegase area (4 km2) : Electric Conductivity observed (May and July 2001), source : K. Meiwirth