Université de Neuchâtel

Conditioning groundwater flow parameters with iterative ensemble smoothers : analysis and approaches in the continuous and the discrete cases

Lam, Dan-Thuy ; Renard, Philippe (Dir.) ; Kerrou, Jaouher (Codir.)

Thèse de doctorat : Université de Neuchâtel, 2019.

Data assimilation (DA) consists in combining observations and predictions of a numerical model to produce an optimal estimate of the evolving state of a system. Over the last decade, DA methods based on the Ensemble Kalman Filter (EnKF) have been particularly explored in various geoscience fields for inverse modelling. Although this type of ensemble methods can handle high-dimensional systems,...

Université de Neuchâtel

Hydrogeological and topographical controls on catchment dynamics and their implications for low flows

Carlier, Claire ; Brunner, Philip (Dir.) ; Hunkeler, Daniel (Codir.)

Thèse de doctorat : Université de Neuchâtel, 2018.

Periods with scarce precipitation will likely occur more frequently and last longer under changing climatic conditions, even in relatively humid regions like Switzerland. To assess the sensitivity of water resources to dry spells and to identify regions that might experience water scarcity issues, a thorough understanding of the mechanisms governing catchment dynamics in the absence of rain is...

Université de Neuchâtel

Application of carbon-chlorine isotopic analysis to determine the origin and fate of chlorinated ethenes in groundwater

Badin, Alice ; Hunkeler, Daniel (Dir.) ; Schirmer, Mario (Codir.)

Thèse de doctorat : Université de Neuchâtel, 2015.

Chlorinated ethenes are ubiquitous groundwater contaminants posing a threat to one of our main drinking water sources. Despite their spill history dating back to more than 40 years ago, these contaminants are still found in groundwater in numerous industrially developed countries due to their persistence, difficult characterisation in the subsurface and resulting challenging remediation. When...

Université de Neuchâtel

Groundwater dynamics and streamflow generation in a mountainous headwater catchment : process understanding from field experiments and modeling studies

Freyberg, Jana von ; Schirmer, Mario (Dir.) ; Hunkeler, Daniel (Codir.)

Thèse de doctorat : Université de Neuchâtel, 2015.

Groundwater systems in mountainous headwater catchments significantly sustain downstream freshwater bodies and therefore play an important role in the regional water cycle. Complex interactions between atmospheric, subsurface and ecological variables occur that determine groundwater quantity and quality as well as streamflow-generation mechanisms at different spatiotemporal scales. An integrated...

Université de Neuchâtel

Investigating the origin of chloroform in soils and groundwater using carbon and chlorine stable isotopes analysis

Breider, Florian ; Hunkeler, Daniel (Dir.)

Thèse de doctorat : Université de Neuchâtel, 2013.

Chloroform (CHCl3) has been considered for a long time as an anthropogenic contaminant which is known to be possibly carcinogenic to humans. Chloroform is also an important contributor to gaseous chlorine in the atmosphere and may catalyze some chemical reactions in the lower atmosphere. The presence of chloroform in aquatic and terrestrial environments has been widely demonstrated....

Université de Lausanne

Usages de l'eau à Gaya (Niger) : entre fortes potentialités et contraintes majeures

Dambo, Lawali ; Winistorfer, Jörg (Dir.)

Thèse de doctorat : Université de Lausanne, 2007.

The department of Gaya, in which this study was done, is located in the SW area of the Republic of Niger. It has an important hydrological potential composed of surface water (approximately 100 permanent ponds, 106 km of the Niger River) and 7 bodies of underground water sources including sub-surface and artresan wells. This study of the exploitation of wtaer in Gaya has been carried out...

Université de Neuchâtel

Les isotopes radioactifs de la série de l’uranium-238 (222Rn, 226Ra, 234U et 238U) dans les eaux thermales de Suisse : sites d’Yverdon-les-Bains, Moiry, Loèche-les-Bains, Saxon, Val d’Illiez, Bad Ragaz, Delémont, Lavey-les-Bains, Brigerbad et Combioula

Gainon, François ; Zwahlen, François (Dir.)

Thèse de doctorat : Université de Neuchâtel, 2008 ; Th.2029.

Isotopes of the 238U series are naturally occurring in groundwater. The aim of this work is to measure 4 isotopes of this series (222Rn, 226Ra, 238U and 234U) in the context of deep groundwater, to study their geochemical behavior and finally to use this information for a better understanding of deep aquifers. The test sites are situated in...

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...