Université de Neuchâtel

Assessing the impact of thermal feedback and recycling in open-loop groundwater heat pump (GWHP) systems : a complementary design tool

Milnes, Ellen ; Perrochet, Pierre

In: Hydrogeology Journal, 2013, vol. 21, no. 2, p. 505-514

Thermal feedback and thermal recycling in open-loop groundwater heat pump (GWHP) systems occurs when a fraction of the injected water in a well doublet returns to the production well. They reflect two different mathematical representations of the same physical process. Thermal feedback assumes a constant injection temperature, while thermal recycling couples the injection and...

Université de Neuchâtel

Fracture characterisation using geoelectric null-arrays

Falco, Pierik ; Negro, François ; Szalai, Sándor ; Milnes, Ellen

In: Journal of Applied Geophysics, 2013, vol. 93, p. 33-42

The term “geoelectric null-array” is used for direct current electrode configurations yielding a potential difference of zero above a homogeneous half-space. This paper presents a comparative study of the behaviour of three null-arrays, midpoint null-array (MAN), Wenner-γ null-array and Schlumberger null-array in response to a fracture, both in profiling and in azimuthal mode. The main...

Université de Neuchâtel

Modelling Discharge Rates and Ground Settlement Induced by Tunnel Excavation

Preisig, Giona ; Dematteis, A. ; Torri, R ; Monin, N. ; Milnes, Ellen ; Perrochet, Pierre

In: Rock Mechanics and Rock Engineering, 2014, vol. 47, no. 3, p. 869-884

Interception of aquifers by tunnel excavation results in water inflow and leads to drawdown of the water table which may induce ground settlement. In this work, analytical and numerical models are presented which specifically address these groundwater related processes in tunnel excavation. These developed models are compared and their performance as predictive tools is evaluated. Firstly, the...

Université de Neuchâtel

Process-based groundwater salinisation risk assessment methodology: Application to the Akrotiri aquifer (Southern Cyprus)

Milnes, Ellen

In: Journal of Hydrology, 2011, vol. 399, no. 1-2, p. 29-47

Groundwater salinisation is a major groundwater contamination issue world-wide and can be caused by different processes, such as seawater intrusion, agrochemical pollution, geogenic contamination and irrigation-induced salinisation. In many areas, several salinisation processes are superimposed. Since remedial measures vary for different salinisation processes, correct identification is...

Université de Neuchâtel

Markierungsversuche und Modellierung zur Bewertung der Gefährdung eines Trinkwasserbrunnens = Tracer experiments and modelling for risk assessment of a drinking water well

Goldscheider, Nicola ; Milnes, Ellen ; Fries, W. ; Joppen, M.

In: Grundwasser, 2008, vol. 13, no. 4, p. 220-230

A tracer experiment with uranine in a gravel aquifer aimed to assess the risk of a drinking water well near Pratteln, Switzerland, resulting from a contaminated site 760 m further upgradient. The experiment revealed a maximum linear flow velocity of 127 m/d and a mass recovery of 0.93 %. The tracer was also detected at two intermediate monitoring wells. This paper discusses the causes of...

Université de Neuchâtel

Simultaneous identification of a single pollution point-source location and contamination time under known flow field conditions

Milnes, Ellen ; Perrochet, Pierre

In: Advances in Water Resources, 2007, vol. 30, no. 12, p. 2439-2446

A theoretical framework is presented that allows direct identification of a single point-source pollution location and time in heterogeneous multidimensional systems under known flow field conditions. Based on the concept of the transfer function theory, it is shown that an observed pollution plume contains all the necessary information to predict the concentration at the unknown pollution source...

Université de Neuchâtel

Direct simulation of solute recycling in irrigated areas

Milnes, Ellen ; Perrochet, Pierre

In: Advances in Water Resources, 2006, vol. 29, no. 8, p. 1140-1154

Solute recycling from irrigation can be described as the process that occurs when the salt load that is extracted from irrigation wells and distributed on the fields is returned to the groundwater below irrigated surfaces by deep percolation. Unless the salt load leaves the system by means of drains or surface runoff, transfer to the groundwater will take place, sooner or later. This can lead to...

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

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...