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Université de Neuchâtel

Reducing the impact of a desalination plant using stochastic modeling and optimization techniques

Alcolea, Andres ; Renard, Philippe ; Mariethoz, Gregoire ; Bertone, François

In: Journal of Hydrology, 2009, vol. 365, no. 3-4, p. 275-288

Water is critical for economic growth in coastal areas. In this context, desalination has become an increasingly important technology over the last five decades. It often has environmental side effects, especially when the input water is pumped directly from the sea via intake pipelines. However, it is generally more efficient and cheaper to desalt brackish groundwater from beach wells rather...

Université de Neuchâtel

Blocking Moving Window algorithm: Conditioning multiple-point simulations to hydrogeological data

Alcolea, Andres ; Renard, Philippe

In: Water Resources Reserach, 2010, vol. 46, no. W08511, p. 1-18

Connectivity constraints and measurements of state variables contain valuable information on aquifer architecture. Multiple-point (MP) geostatistics allow one to simulate aquifer architectures, presenting a predefined degree of global connectivity. In this context, connectivity data are often disregarded. The conditioning to state variables is usually carried out by minimizing a suitable...

Université de Neuchâtel

Three-dimensional high resolution fluvio-glacial aquifer analog - Part 1: Field study

Bayer, P. ; Huggenberger, P. ; Renard, Philippe ; Comunian, Alessandro

In: Journal of Hydrology, 2011, vol. 405, no. 1, p. 1

Describing the complex structures that exist in many sedimentary aquifers is crucial for reliable groundwater flow and transport simulation. However, hardly any aquifer can be inspected in such detail that all decimeter to meter heterogeneity is resolved. Aquifer analogs serve as surrogates to construct models of equivalent heterogeneity, and thus imitate those features relevant for flow or...

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...

Université de Neuchâtel

Impact of a stochastic sequential initiation of fractures on the spatial correlations and connectivity of discrete fracture networks

Bonneau, F ; Caumon, G ; Renard, Philippe

In: Journal of Geophysical Research: Solid Earth, 2016, vol. 121, no. 8, p. 5641-5658

Stochastic discrete fracture networks (DFNs) are classically simulated using stochastic point processes which neglect mechanical interactions between fractures and yield a low spatial correlation in a network. We propose a sequential parent-daughter Poisson point process that organizes fracture objects according to mechanical interactions while honoring statistical characterization data. The...

Université de Neuchâtel

A methodology for pseudo-genetic stochastic modelling of discrete fracture networks

Bonneau, François ; Henrion, Vincent ; Caumon, Guillaume ; Renard, Philippe ; Sausse, Judith

In: Computers & Geosciences, 2013, vol. 56, p. 12-22

Stochastic simulation of fracture systems is an interesting approach to build a set of dense and complex networks. However, discrete fracture models made of planar fractures generally fail to reproduce the complexity of natural networks, both in terms of geometry and connectivity. In this study a pseudo-genetic method is developed to generate stochastic fracture models that are consistent...

Université de Neuchâtel

Generation of 3D Spatially Variable Anisotropy for Groundwater Flow Simulations

Borghi, Andrea ; Renard, Philippe ; Courrioux, Gabriel

In: Groundwater, 2015, vol. 53, no. 6, p. 955-958

Sedimentary units generally present anisotropy in their hydraulic properties, with higher hydraulic conductivity along bedding planes, rather than perpendicular to them. This common property leads to a modeling challenge if the sedimentary structure is folded. In this paper, we show that the gradient of the geological potential used by implicit geological modeling techniques can be used to...

Université de Neuchâtel

Stochastic fracture generation accounting for the stratification orientation in a folded environment based on an implicit geological model

Borghi, Andrea ; Renard, Philippe ; Fournier, L ; Negro, François

In: Engineering Geology, 2015, vol. 187, p. 135-142

This paper presents a new approach in generating stochastic discrete fracture networks. The particularity of the approach is that it allows us to simulate the theoretical families of fractures that are expected in a folded environment. The approach produces fractures that are consistent with the local stratigraphic orientation. The fractures are modeled as simple rectangular planar objects. When...

Université de Neuchâtel

Can one identify karst conduit networks geometry and properties from hydraulic and tracer test data?

Borghi, Andrea ; Renard, Philippe ; Cornaton, Fabien

In: Advances in Water Resources, 2016, vol. 90, p. 99-115

Karst aquifers are characterized by extreme heterogeneity due to the presence of karst conduits embedded in a fractured matrix having a much lower hydraulic conductivity. The resulting contrast in the physical properties of the system implies that the system reacts very rapidly to some changes in the boundary conditions and that numerical models are extremely sensitive to small modifications in...

Université de Neuchâtel

A pseudo-genetic stochastic model to generate karstic networks

Borghi, Andrea ; Renard, Philippe ; Jenni, Sandra

In: Journal of Hydrology, 2012, vol. 414-415, p. 516-529

In this paper, we present a methodology for the stochastic simulation of 3D karstic conduits accounting for conceptual knowledge about the speleogenesis processes and accounting for a wide variety of field measurements. The methodology consists of four main steps. First, a 3D geological model of the region is built. The second step consists in the stochastic modeling of the internal...