Elena Abarca

AMPHOS 21 Consulting S.L | AMPHOS21

Key Points The intertidal saline cell is not a permanent feature of a coastal aquifer The intertidal saline cell cycle is linked to the lunar cycle of tides The cell cycle modulates the fresh and salt groundwater fluxes to the ocean

The seawater intrusion process is characterized by the difference in freshwater and seawater density that causes freshwater to float on seawater. Many confined aquifers have a large horizontal extension with respect to thickness. In these cases, while buoyancy acts in the vertical direction, flow is confined between the upper and bottom boundaries...

The Henry problem has played a key role in our understanding of seawater intrusion into coastal aquifers and in benchmarking density dependent flow codes. This paper seeks to modify Henry’s problem to ensure sensitivity to density variations and vertical salinity profiles that resemble field observations. In the proposed problem, the “dispersive He...

Seawater intrusion in coastal aquifers is a 3-D phenomenon. However, 3-D regional aquifer models are often limited by insufficient geological and hydrological data, the large horizontal to vertical scales ratio, and by numerical constraints. We present an effective formulation for modeling seawater intrusion that relies on a dimensional reduction o...

Carbon mineralisation is currently one of the most promising Carbon Capture and Storage (CSS) options for permanent gas sequestration since it ensures a rapid conversion of carbon from the gas phase to a carbonate mineral. Mafic and ultramafic rocks are the best geological options for mineral carbonation due to the relatively fast dissolution rates...

Reactive transport numerical modelling is used to explore chemical interactions between fluids and solids associated with a broad range of subsurface processes. It is a powerful tool extensively used in geoscientific applications. However, simulations often require large computational times. This is due to the fact that they typically involve slow...

CO2CRC has made a significant investment into establishing the feasibility of conducting a CO2 injection experiment into a shallow fault at the CO2CRC Otway International Test Centre. Two appraisal wells drilled and cored through Brumbys Fault indicate the fault extends to the base of the upper 2 m thick Hesse Clay layer, which forms a seal to the...

Dolomitization of carbonate reservoirs is considered a major process for porosity enhancement and is therefore of great relevance in hydrocarbon exploration. Despite the ubiquitous occurrence of massive dolostones, the question of whether reasonable amounts of dolomitizing fluid and Mg supply are capable of substantial porosity generation remains....

Radionuclide accumulation patterns in quaternary sediments are key for the safety evaluation of a nuclear waste repository. The retention capacity of the regolith (loose sediments) is evaluated considering that radionuclides would migrate from deep bedrock to the surface and will eventually interact with these sediments. In a studied area in Sweden...

Renewable energies fluctuate, resulting in temporary mismatches between demand and supply. The conversion of surplus energy to hydrogen and its storage in geological formations is one option to counteract this energy imbalance. This study evaluates the feasibility of seasonal storage of hydrogen produced from wind power in Castilla-León region (nor...

Abstract Dissolution of carbon-dioxide into formation fluids during carbon capture and storage (CCS) can generate an instability with a denser CO2-rich fluid located above the less dense native aquifer fluid. This instability promotes convective mixing, enhancing CO2 dissolution and favouring the storage safety. Convective mixing has been extensive...

The Swedish Nuclear Fuel and Waste Management Company (SKB) has developed conceptual and quantitative models for the reactive transport of selected radionuclides in the near-surface system or regolith (Grandía et al., 2007; Sena et al., 2008; Piqué et al., 2010). However, the description of hydrological processes and the model geometries were simpl...

An extension of the Swedish final repository for short-lived radioactive waste (SFR) is planned and a safety assessment has been performed as part of the licensing process. Within this work, steps have been taken to advance the modelling environment to better integrate its individual parts. It is desirable that an integrating modelling environment...

The future nuclear spent fuel repository in the Forsmark area in Sweden, constructed at a depth of 500 meters, is designed to be isolated from people and nature for at least 100.000 years. As part of the safety assessment of the repository, it is necessary to simulate the interaction of the repository compounds with the surrounding groundwater and...

Eleven separate vault-scale submodels have been extracted from the geometries of the SFR 1 and SFR 3 repository-scale models. The submodels are implemented in separate COMSOL files and run for the Base case (shoreline positions 1, 2 and 3). As a verification of the correct implementation, the results of the vault-scale submodels are postprocessed a...

The present work is a part of the safety assessment SR-PSU and deals with the future hydrogeological conditions in the near-field of SFR 1 (the existing facility) and SFR3 (the planned extension). The term near-field refers to the rock vaults, their components and barriers, as well as the surrounding rock in the vicinity of the repository. Three st...

The Duero basin in NW Spain is one the most promising basin for CO2 storage in the Iberian Peninsula due to the existence of favourable deep aquifers close to large CO2 emission point sources. A number of projects are presently active either for scientific research (e.g., the Hontomín site, OXI-CFB300 EPRR project) or commercial purposes (e.g., Sah...

A configuration of denser CO2-enriched brine overlying a lighter water leads to convective flow and the formation of gravity fingers of dense fluid sinking into the resident brine. This process has been acknowledged as an enhancer of supercritical CO2(g) dissolution in saline aquifers. Given the non-linear feedback between reactive transport (disso...

Flow modeling of CO2 sequestration projects must be able to confidently predict CO2 plume migration-which affects a sequestration project's Area of Review as well as its pore space access requirements-despite geologic uncertainties stemming from heterogeneity in the subsurface. We present our study of the effect of heterogeneity in porosity and per...

Ocean forces have a critical impact on the magnitude and temporal evolution of Submarine Groundwater Discharge (SGD). Here, we analyze the groundwater discharge response to changes in the tidal signal at Waquoit Bay, Cape Cod, Massachusetts. We present a conceptual and numerical model that predicts that both fresh and saltwater components of SGD ar...

We study the long-term temporal and spatial evolution of fresh and saltwater fluxes across the seaside boundary in an aquifer subject to small tide oscillations. Our estimates are based in the unconfined aquifer at Waquoit Bay, Cape Cod, Massachusetts. Here, the tidal amplitude is small, ranging between 0.2 m at neap tide and 0.5 m at spring tide....

Modeling seawater intrusion has evolved from a tool for understanding to a water management need, but it remains a challenge. Inherent difficulties of solute transport modeling (e.g., assessment of dispersion coefficients; three-dimensional complexity of aquifer geometries and heterogeneity in hydraulic parameters) are combined with the concentrati...

1] The mixing zone between freshwater and seawater in a coastal aquifer is an important transition region that controls regional groundwater flow dynamics and reactive transport processes. While experimental procedures have been developed to study the movement of salt wedges in aquifers, so far no one has attempted to exclusively map the mixing zon...

Electrical resistivity imaging has been used in coastal settings to characterize fresh submarine groundwater discharge and the position of the freshwater/salt-water interface because of the relation of bulk electrical conductivity to pore-fluid conductivity, which in turn is a function of salinity. Interpretation of tomograms for hydrologic process...

We present a multidisciplinary approach to characterize submarine groundwater discharge in Waquoit Bay, Cape Cod, USA. We focus on the fluctuations in fresh and saline discharge over tidal cycles and spring-neap cycles of tidal magnitude. Geophysical (electrical resistivity), chemical (salinity and basic chemical parameters) and hydrological data (...

In coastal states, the injection of treated wastewater into deep saline aquifers offers a disposal alternative to ocean outfalls and discharge directly into local waterways. The density of treated wastewater is similar to that of freshwater but is often much lower than the ambient density of deep aquifers. This significant density contrast can caus...

Stream-aquifer interaction has been the subject of much research for cases of good hydraulic connection (continuous saturated zone) between a river and an aquifer. Under these conditions, floods do not represent a very large net input to the aquifer because most of the water that enters the aquifer during the flood returns to the river when its sta...

The European Water Framework Directive establishes the basis for Community action in the field of water policy. Water authorities in Catalonia, together with users are designing a management program to improve groundwater status and to assess the impact of infrastructures and city-planning activities on the aquifers and their associated natural sys...

Numerous studies have been devoted to the optimization of groundwater management strategies in coastal aquifers. However, little has been done to address the problem of initially contaminated aquifers, the subject of this paper. Corrective measures need to be optimally designed to improve water quality while minimizing changes in the existing pumpi...

Steady-state distributions of water potential and salt concentration in coastal aquifers are typically modelled by the Henry problem, which consists of a fully coupled system of flow and transport equations. Coupling arises from the dependence of water density on salt concentration. The physical behaviour of the system is fully described by two dim...

Modeling seawater intrusion has evolved from a tool for understanding to a water management need. Yet, it remains a challenge. Inherent difficulties of solute transport modeling (e.g., assessment of dispersion coefficients; three-dimensional complexity of aquifer geometries and heterogeneity in hydraulic parameters) are combined with the concentrat...

European Parliament establishes the basis for Community action in the field of water policy by Water Framework Directive (WFD) 2000/60/EC. Water authorities in Catalonia (Agència Catalana de l'Aigua) are designing a management program to improve groundwater status and to assess the impact of infrastructures and city-planning activities on the Llobr...

Steady-state distributions of water potential and salt concentration in coastal aquifers are typically illustrated by the Henry problem, which consists of a fully coupled system of flow and transport equations. Coupling is caused by the dependence of water density on salt concentration. While the Henry problem often serves as a benchmark for numeri...

Dispersivity is the most significant and difficult parameter to assess in seawater intrusion models. It is well established that dispersion is enhanced by spatial heterogeneity. While real aquifers in general are heterogeneous, most models describing saltwater intrusion into coastal aquifers do not take into account spatial heterogeneity. One of th...

In a coastal aquifer with a valley-shaped impermeable bottom, the seawater convection cell is essentially horizontal rather than vertical as is usually assumed, with seawater entering inland across the whole thickness of the aquifer in the central (deepest) portion. This causes a marked increase in the saltwater intrusion along such a section and a...

A very large amount of water has been pumped, in particular during the 1970s, from the Llobregat Delta main aquifer (Barcelona, Spain). This caused the salinization of important areas of this aquifer. This contamination process was accelerated by the construction of a new inland dock of the Barcelona Harbor. Since then, big efforts have been undert...