Numerically enhanced conceptual modelling (NECoM) applied to the Malta Mean Sea Level Aquifer

Lotti, Francesca; Borsi, Iacopo; Guastaldi, Enrico; Barbagli, Alessio; Basile, Paolo; Favaro, Lorenzo; Mallia, Adrian; Xuereb, Rachel; Schembri, Michael; Mamo, Julian; Sapiano, Manuel

doi:10.1007/s10040-021-02330-2

Cited by 9 publications

(5 citation statements)

References 19 publications

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“…The faults in the island were accounted for by applying HFB-Horizontal Flow Barrier package of MODFLOW-while, in our case, faults are represented by means of sudden variation in the porous media hydraulic properties. Fault isotropic hydraulic conductivities estimated in Lotti et al [24] range, for most of the cases, between an interval comprised by 8 × 10 −8 and 1 × 10 −2 m/d, which is not far from that resulting from this study and presenting horizontal conductivity values ranging from 2 × 10 −6 and 1.7 × 10 −2 m/d. Moreover, the maps of the ζ surface, resulting at the end of calibration processes (present day conditions, time at which their study stops), are comparable.…”

Section: Influence Of Faults On Groundwater Modelling Resultscontrasting

confidence: 39%

“…This is the first important outcome of the study, and the adopted approach can also be transferred to other islands where faults are widespread. Lotti et al [24] developed a 2-D model of the Mean Sea Level Aquifer focusing only on the island of Malta and including the main faults only. Their simulations were performed with the same code adopted in this study, and the calibration process was driven by using data collected in the same time window.…”

Section: Influence Of Faults On Groundwater Modelling Resultsmentioning

confidence: 99%

“…The Maltese archipelago has one of the highest population densities in the world and is one of the poorest regions globally in terms of water resources per inhabitant [23]. Potable water supply is mainly dependent on groundwater abstraction from limestone aquifers, and seawater upconing into the pumping wells is a serious problem [24]. In this study we develop a three-dimensional density dependent and heterogeneous model, working in transient conditions, in order to quantify the potential impact of predicted climate change (sea-level rise, groundwater recharge decrease and water demand increase) up to 2100 on the freshwater resources of the Maltese archipelago.…”

Section: Introductionmentioning

confidence: 99%

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The Impact of Predicted Climate Change on Groundwater Resources in a Mediterranean Archipelago: A Modelling Study of the Maltese Islands

Biase

Chidichimo

Maiolo

et al. 2021

Water

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The effects of changes in climate predicted for 2100—reduction in recharge, increase in water demand and sea-level rise—on groundwater volume and saltwater intrusion have been quantified in the Maltese Islands, an archipelago located at the center of the Mediterranean Sea. A three-dimensional density dependent and heterogeneous model, working in transient conditions, was developed based on morphological and geological information. The hydraulic conductivity and porosity of the lithological formations were derived from previous tests and studies conducted on the islands. The complex fault system intersecting the area has also been included in the model. The results show that among the three considered factors affecting groundwater resources, the most significant is the increase in water demand, which is closely followed by the decrease in groundwater recharge. Sea-level rise plays a marginal role. The 80-year simulation period showed that these combined impacts would cause a loss of more than 16% of groundwater volume.

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Section: Influence Of Faults On Groundwater Modelling Resultscontrasting

confidence: 39%

Section: Influence Of Faults On Groundwater Modelling Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

The Impact of Predicted Climate Change on Groundwater Resources in a Mediterranean Archipelago: A Modelling Study of the Maltese Islands

Biase

Chidichimo

Maiolo

et al. 2021

Water

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“…The Maltese Islands host three types of groundwater bodies (Bakalowicz and Mangion, 2003;Environment and Resources Authority, 2015;Pondthai et al, 2020;Lotti et al, 2021). The largest is the mean sea-level groundwater body, which is primarily hosted in the Lower Coralline Limestone formation.…”

Section: Regional Settingmentioning

confidence: 99%

Past and future evolution of the onshore-offshore groundwater system of a carbonate archipelago: The case of the Maltese Islands, central Mediterranean Sea

et al. 2023

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Offshore freshened groundwater (OFG) is groundwater with a salinity below that of seawater that is stored in sub-seafloor sediments and rocks. OFG has been proposed as an alternative solution to relieve water scarcity in coastal regions and to enhance oil recovery. Although OFG has been documented in most continental margins, we still have a poor understanding of the extent and flow characteristics of OFG systems, and their evolution through time. In view of the general absence of appropriate field data, paleohydrogeological models have been used. The majority of these models are based on 2D approaches, and they rarely consider the future evolution of OFG systems, especially in response to predicted climate change. Here we utilize recently acquired geological, geophysical and hydrogeological data from onshore and offshore the Maltese Islands, and employ 2D and 3D numerical models, to: (i) reconstruct the evolution of the onshore-offshore groundwater system during the last 188 ka, (ii) predict the evolution of the OFG system in response to climate-related changes. We show that the mechanisms emplacing OFG include a combination of active meteoric recharge at present as well as at sea-level lowstands. The Maltese onshore-offshore groundwater system is relatively dynamic, with 23% of groundwater being preserved in the last 18 ka. The control of geology is expressed by the more prevalent distribution of OFG north of the Great Fault, which is associated to the occurrence of low permeability units, and the asymmetry of the groundwater lens during the 18 ka lowstand. A 30% decrease in recharge predicted in the coming 100 years will diminish OFG extent by 38%, whereas sea-level rise will play a negligible role. At present the estimated volume of OFG is 1 km3, which could potentially provide an alternative supply of potable water to the Maltese Islands for 75 years. Exploitation of OFG with minimal salinization of onshore groundwater bodies would require locating pumping wells close to the coast.

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“…SI models are most useful for simulating regional‐scale seawater intrusion, where dispersion can be neglected. In island aquifers, SI models are commonly used to assess the extent of freshwater lenses and establish water budgets (Izuka et al., 2021; Lotti et al., 2021; Shuler & Mariner, 2020), while their fast simulation times also facilitate parameter estimation and quantification of predictive uncertainty (Coulon et al., 2021). Because of their rapid simulation times, SI models are widely used to optimize pumping rates in continental coastal aquifers, which are faced with the threat of lateral seawater intrusion (Kopsiaftis et al., 2019).…”

Section: Introductionmentioning

confidence: 99%

Pumping Optimization Under Uncertainty in an Island Freshwater Lens Using a Sharp‐Interface Seawater Intrusion Model

Coulon

Lemieux

Pryet

et al. 2022

Water Resources Research

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Island groundwater resources often form freshwater lenses overlying saline groundwater. When water is withdrawn from a freshwater lens by a pumping well, saline groundwater migrates upwards toward the well. This vertical seawater intrusion process, also called saltwater upconing, is a major concern when managing well fields. Freshwater lenses of island aquifers have been described as being more vulnerable than continental coastal aquifers, since vertical migration distances associated with upconing are shorter than horizontal ones (Jiao &

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Numerically enhanced conceptual modelling (NECoM) applied to the Malta Mean Sea Level Aquifer

Cited by 9 publications

References 19 publications

The Impact of Predicted Climate Change on Groundwater Resources in a Mediterranean Archipelago: A Modelling Study of the Maltese Islands

The Impact of Predicted Climate Change on Groundwater Resources in a Mediterranean Archipelago: A Modelling Study of the Maltese Islands

Past and future evolution of the onshore-offshore groundwater system of a carbonate archipelago: The case of the Maltese Islands, central Mediterranean Sea

Pumping Optimization Under Uncertainty in an Island Freshwater Lens Using a Sharp‐Interface Seawater Intrusion Model

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