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Université de Neuchâtel

Stochastic Hydrogeology: What Professionals Really Need?

Renard, Philippe

In: Ground Water, 2007, vol. 45, no. 5, p. 531-541

Quantitative hydrogeology celebrated its 150th anniversary in 2006. Geostatistics is younger but has had a very large impact in hydrogeology. Today, geostatistics is used routinely to interpolate deterministically most of the parameters that are required to analyze a problem or make a quantitative analysis. In a small number of cases, geostatistics is combined with deterministic approaches to...

Université de Neuchâtel

La fin des certitudes ?

Renard, Philippe

In: Bulletin d’Hydrogéologie, 2008, vol. 22, p. 1-20

2006 fut l’année anniversaire des 150 ans de la naissance de l’hydrogéologie quantitative. La théorie des variables régionalisées, ou géostatistique, est beaucoup plus jeune mais a eu un impact majeur. Aujourd’hui, tout étudiant manie avec brio le krigeage que ce soit pour cartographier une contamination, un champ de transmissivité, ou le toit d’une nappe. Mais la géostatistique...

Université de Neuchâtel

Forecasting the Number of Soil Samples Required to Reduce Remediation Cost Uncertainty

Demougeot-Renard, Hélène ; de Fouquet, Chantal ; Renard, Philippe

In: Journal of Environmental Quality (JEQ), 2004, vol. 33, p. 1694-1702

Sampling scheme design is an important step in the management of polluted sites. It largely controls the accuracy of remediation cost estimates. In practice, however, sampling is seldom designed to comply with a given level of remediation cost uncertainty. In this paper, we present a new technique that allows one to estimate of the number of samples that should be taken at a given stage of...

Université de Neuchâtel

Environmental Isotopes as Indicators for Ground Water Recharge to Fractured Granite

Ofterdinger, U.S. ; Balderer, Werner ; Loew, S ; Renard, Philippe

In: Ground Water, 2004, vol. 42, no. 6, p. 868-879

To assess the contribution of accumulated winter precipitation and glacial meltwater to the recharge of deep ground water flow systems in fracture crystalline rocks, measurements of environmental isotope ratios, hydrochemical composition, and in situ parameters of ground water were performed in a deep tunnel. The measurements demonstrate the significance of these ground water recharge components...

Université de Neuchâtel

Approximate discharge for constant head test with recharging boundary : Technical Note

Renard, Philippe

In: Ground Water, 2005, vol. 43, no. 3, p. 439-442

The calculation of the discharge to a constant drawdown well or tunnel in the presence of an infinite linear constant head boundary in an ideal confined aquifer usually relies on the numerical inversion of a Laplace transform solution. Such a solution is used to interpret constant head tests in wells or to roughly estimate ground water inflow into tunnels. In this paper, a simple approximate...

Université de Neuchâtel

Dealing with spatial heterogeneity

de Marsily, Gh. ; Delay, F. ; Gonçalvès, J. ; Renard, Philippe ; Teles, V. ; Violette, S.

In: Hydrogeology Journal, 2005, vol. 13, no. 1, p. 161-183

On peut aborder le problème de lhétérogénéité en sefforçant de définir une perméabilité équivalente homogène, par prise de moyenne, ou au contraire en décrivant la variation dans lespace des propriétés des roches à partir des observations géologiques et des mesures locales. Les techniques disponibles pour une telle description sont soit continues, comme lapproche Géostatistique,...

Université de Neuchâtel

Study of stable isotopes in the Kouris catchment (Cyprus) for the description of the regional groundwater flow

Boronina, Anastasia ; Balderer, Werner ; Renard, Philippe ; Stichler, Willibald

In: Journal of Hydrology, 2005, vol. 308, no. 1-4, p. 214-226

The stable isotopes of oxygen and hydrogen in groundwater and precipitation were integrated for the description of groundwater flow in the Kouris catchment (Cyprus). The catchment consists of an ophiolitic complex in the North and sediments in the South. It is characterized by strong heterogeneity of the underground media and steep slopes of the topography. The regression line,...

Université de Neuchâtel

Groundwater resources in the Kouris catchment (Cyprus) : data analysis and numerical modelling

Boronina, Anastasia ; Renard, Philippe ; Balderer, Werner ; Christodoulides, Andreas

In: Journal of Hydrology, 2003, vol. 217, no. 1-4, p. 130-149

The Kouris catchment in Cyprus is currently experiencing a scarcity of water resources due to the semi-arid climate across the southern part of the region, a series of dry years, and recent surface/subsurface water over-extraction. The catchment consists of the upper part of an ophiolitic complex in the North, which is considered a very significant aquifer for Cyprus, and an overlying sedimentary...

Université de Neuchâtel

The problem of salt recycling and seawater intrusion in coastal irrigated plains : an example from the Kiti aquifer (Southern Cyprus)

Milnes, Ellen ; Renard, Philippe

In: Journal of Hydrology, 2004, vol. 288, no. 3-4, p. 327-343

In coastal aquifers which are exploited for agricultural purposes, salinisation by salt recycling from irrigation is superimposed on the effects of seawater intrusion. Water quality degradation of irrigation pumping wells caused by seawater intrusion further enhances salinisation by irrigation, as the extracted solute mass is recycled and is not withdrawn from the system. The main...

Université de Neuchâtel

A dynamic model of the Aral Sea water and salt balance

Benduhn, François ; Renard, Philippe

In: Journal of Marine Systems, 2004, vol. 47, no. 1-4, p. 35-50

The Aral Sea is shrinking rapidly since the 1960s mainly because of the diversion of the Amu Darya and Syr Darya rivers for irrigation purposes. Since then, the evaporation became the most important component of the water balance of the Sea and led to a concentration of the remaining salts. In this article, we investigate through a coupled mathematical model of water and salt balance of the Aral...