Université de Neuchâtel

Uncertainty propagation and global sensitivity analysis in multi-layered hydrogeological models of flow and lifetime expectancy

Deman, Grégory ; Perrochet, Pierre (Dir.) ; Kerrou, Jaouher (Codir.)

Thèse de doctorat : Université de Neuchâtel, 2015.

The main focus of this thesis is the uncertainty propagation (UP) and global sensitivity analysis (GSA) in complex hydrogeological numerical models. Various methods are presented with applications on numerical models for the groundwater flow and mean lifetime expectancy (MLE) in the scope of Andra's (French National Radioactive Waste Management Agency) project for the geological disposal of...

Université de Neuchâtel

Recharge quantification and continental freshwater lens dynamics in arid regions : application to the Merti aquifer (eastern Kenya)

Blandenier, Lucien ; Perrochet, Pierre (Dir.) ; Milnes, Ellen (Codir.) ; Brunner, Philip (Codir.)

Thèse de doctorat : Université de Neuchâtel, 2015.

The Dadaab refugee camp, the largest refugee camp in the world with a population of approximately 400’000 persons, is located in the arid to semi-arid eastern Kenya, close to the Somali border. The only permanent water resource for the refugees and the host communities comes from the Merti aquifer which consists in a large continental freshwater lens of 250 km by 50 km surrounded by salty...

Université de Neuchâtel

Sondages géoélectriques "null-arrays" pour la caractérisation des structures de subsurface

Falco, Pierik ; Perrochet, Pierre (Dir.) ; Milnes, Ellen (Codir.)

Thèse de doctorat : Université de Neuchâtel, 2013.

The term "geoelectric null-array" is used for those geoelectrical configurations measuring a zero potential difference above a homogenous half-space. This thesis presents a study of the behaviour of three of these null-arrays - the midpoint null-array, the Wenner-γ null-array and the Schlumberger null-array - above different vertical structures, using profiling and azimuthal measurements. A...

Université de Neuchâtel

Regional simulation of coupled hydromechanical processes in fractured and granular porous aquifer using effective stress-dependent parameters

Preisig, Giona ; Perrochet, Pierre (Dir.)

Thèse de doctorat : Université de Neuchâtel, 2013.

Field observations and laboratory experiments have clearly demonstrated that heavily perturbed / exploited aquifers are subject to 3D deformations, which may cause significant socio-economic impacts at regional scale. Most common examples include: (1) excessive pumping of groundwater from deep aquifers leading to land subsidence; (2) deep excavation of tunnels in permeable geological units...

Université de Neuchâtel

Field experimentation and modelling of salt transfer in Korba coastal plain : impact of seawater intrusion and irrigation practices

Slama, Fairouz ; Perrochet, Pierre (Dir.) ; Bouhlila, R. (Codir.)

Thèse de doctorat : Université de Neuchâtel, 2010 ; 2197.

Seawater intrusion and agricultural pollution are the major sources of groundwater contamination and salinization in coastal irrigated areas. The Korba coastal aquifer, located in the Cap Bon peninsula, North-East of Tunisia, has been intensively exploited since the seventies. Several studies reported the sharp piezometric drop and groundwater salinization. Seawater intrusion was presented as the...

Université de Neuchâtel

Groundwater flow, heat and mass transport in geothermal systems of a Central Alpine Massif. : The cases of Lavey-les-Bains, Saint-Gervais-les-Bains, and Val d'Illiez

Sonney, Romain ; Perrochet, Pierre (Dir.) ; Vuataz, François-David (Codir.)

Thèse de doctorat : Université de Neuchâtel, 2010.

Groundwater flow, heat and mass transport in geothermal or hydrothermal systems locally occurs in the Alps Range where a series of precise conditions are met such as active downflow, permeability at depth, concentrated and fast upflow and favorable geomorphological surface patterns. Advanced studies of the regional and local geology, thermal water chemistry, mixing processes, infiltration area,...

Université de Neuchâtel

Towards improved numerical modeling of karst aquifers : coupling turbulent conduit flow and laminar matrix flow under variably saturated conditions

Rooij, Rob de ; Perrochet, Pierre (Dir.)

Thèse de doctorat : Université de Neuchâtel, 2007 ; Th.1984.

Numerical models for simulating groundwater flow based on full saturation do not account for moving water tables and the infiltration and storage processes in unsaturated zones. Strictly speaking these models are based on the concept of a confined aquifer with well known boundary conditions. Nonetheless, models based on full saturation are also used for more complicated problems such as the...

Université de Neuchâtel

Analyse des processus advectifs-dispersifs en milieux poreux sous contraintes hydrologiques périodiques : implications pour la protection des captages d’eaux souterraines

Badoux, Vincent ; Perrochet, Pierre (Dir.)

Thèse de doctorat : Université de Neuchâtel, 2007 ; Th.1976.

Water protection is written in the Swiss Federal Consitution. On that basis, the Federal Assembly enacted laws that aim to protect water from any kind of contamination. It establishes groundwater protection schemes around water supply wells, such as the protection zones S1, S2 and S3 and the area of contribution Zu. The aims of the present thesis, on the one hand, was to study the influence of...

Université de Neuchâtel

Modelling groundwater salinisation in irrigated coastal areas : from solute recycling concepts to quantitative risk assessment

Milnes, Ellen ; Perrochet, Pierre (Dir.)

Thèse de doctorat : Université de Neuchâtel, 2005 ; 1814.

The main objective of this thesis is the quantitative investigation of groundwater salinisation induced by solute recycling from irrigation, and its implications for the overall salinisation in coastal settings. Since the modelling approaches proposed in literature to simulate seawater-intruded areas rarely account for the coupled and superimposed effects of solute recycling and seawater...

Université de Neuchâtel

Une approche déterministe des distributions des temps de transit de l'eau souterraine par la théorie des réservoirs

Etcheverry, David ; Perrochet, Pierre (Dir.)

Thèse de doctorat : Université de Neuchâtel, 2001 ; 1585.

The applicability of the reservoir theory is explored through a deterministic approach of groundwater transit time distributions in purely advective conditions. The theory is reformulated in a probabilistic framework and supported by the Gauss divergence theorem. This emphasizes the relationship between ages at the outlet and the flux vector field within the system. The concept of residual...