Revisiting recharge and sustainability of the North-Western Sahara aquifers

Gonçalvès, Julio; Deschamps, Pierre; Hamelin, Bruno; Vallet‐Coulomb, Christine; Petersen, Jade; Chekireb, Amine

doi:10.1007/s10113-020-01627-4

Cited by 18 publications

(9 citation statements)

References 28 publications

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“…Considering the recharging fluxes at the western and southern boundaries of the system, a constant value of 2.6 m 3 •s −1 was estimated for the Triassic flux by means of a hydrogeological model [OSS, 2006]. Using an approach combining water stable isotopes, geostatistical and reservoir simulations, and a simple hydrological model based on piezometric levels, Gonçalvès et al [2015Gonçalvès et al [ , 2020 obtained a temporal variation for the recharging flux from the CI to the Djeffara aquifers showing a decline from 1.8 m 3 •s −1 in 1950 to 0.6 m 3 •s −1 in 2009 due to the overexploitation of the CI aquifer. In addition, global rainfall rates Piezometric information available from OSS [2006] is mostly made of cumulative drawdown ∆h values in 2003, and drawdown (not absolute piezometric levels) time series but for a small fraction of piezometers.…”

Section: Hydrological Datamentioning

confidence: 99%

Coastal aquifer recharge and groundwater–seawater exchanges using downscaled GRACE data: case study of the Djeffara plain (Libya–Tunisia)

Gonçalvès¹,

Séraphin²,

Chekireb³

et al. 2021

Comptes Rendus. Géoscience

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The Djeffara plain, extending over Tunisia and Libya (48,000 km 2 ), experiences unsustainable exploitation of groundwater, the severity of which needs to be determined. Here, we used data from Gravity Recovery and Climate Experiment (GRACE) and Global Land Data Assimilation System (GLDAS) to assess the groundwater storage variation (∆GWS) for the period 2002-2016. ∆GWS values, downscaled over a 0.5°× 0.5°grid using pumping wells spatial distribution and rates, were introduced in a discrete set of groundwater and salt budget equations to ascertain the recharge and the coastal fluxes. An average recharge of 4.3 ± 2.7 mm•yr −1 representing 2.2 ± 1.4% of the domain-averaged annual rainfall was obtained. A saline intrusion of 147.3 × 10 6 and 46.9 × 10 6 m 3 •yr −1 was calculated for the Tripoli (Libya) and Djerba (Tunisia) areas, respectively. The overall Submarine Groundwater Discharge (SGD) of freshwater along the 450 km long Djeffara coast represents about 339.6 × 10 6 m 3 •yr −1 for the 2002-2016 period.

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Section: Hydrological Datamentioning

confidence: 99%

Coastal aquifer recharge and groundwater–seawater exchanges using downscaled GRACE data: case study of the Djeffara plain (Libya–Tunisia)

Gonçalvès¹,

Séraphin²,

Chekireb³

et al. 2021

Comptes Rendus. Géoscience

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“…In such areas, the opposing trends of decreasing groundwater recharge and increasing abstraction will further lead to dropping groundwater levels. This effect is even more noticeable in deep aquifers that experience very little or no recharge and are therefore considered as nonrenewable, fossil groundwater resources, as for example in a few aquifers in Jordan (Charalambous 2016), Saudi Arabia or Libya (Gonçalvès et al 2020;Khater et al 2003). This means that sufficient availability of groundwater for future generations is at risk.…”

Section: Introductionmentioning

confidence: 99%

Quantification and possible causes of declining groundwater resources in the Euro-Mediterranean region from 2003 to 2020

Xanke

Liesch

2022

Hydrogeol J

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Groundwater resources in Euro-Mediterranean countries provide a large part of the population’s water supply and are affected to varying degrees by anthropogenic use and climatic impacts. In many places, significant groundwater-level declines have already been observed, indicating an imbalance between natural groundwater recharge and groundwater abstraction. The extent of changes in groundwater storage (GWS) in the period 2003–2020 is quantified for the Euro-Mediterranean region using the latest data from the Gravity Recovery and Climate Experiment (GRACE/GRACE-FO) satellite mission and recently reanalyzed ERA5-Land climate data from the European Centre for Medium-Range Weather Forecasts. The results are set in relation to the prevailing climate, the regional hydrogeological setting, and annual groundwater recharge and abstractions on country level. Analysis of the mean annual trends over the study period shows significant decreases in GWS in many countries of Europe, Northern Africa and the entire Arabian Peninsula. Overall, there are significantly negative trends in about 70% of the study region. The mean of the trends across the Euro-Mediterranean region is –2.1 mm/year. The strongest negative trends in GWS per country are observed in Iraq and Syria (–8.8 and –6.0 mm/year, respectively), but also countries in central and eastern Europe are affected by depleting aquifers. The results are a clear indicator of the already medium-term groundwater stress in the Euro-Mediterranean region, which is expected to increase in the future, and demonstrate the need for adapted strategies for sustainable groundwater management on a transregional scale in the context of climate change and population growth.

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“…Nevertheless, present-day recharge is required for hydrogeological modeling implementations where a pre-industrial steady-state is often postulated but not argued. The high reactivity of the CI was already discussed by Petersen (2014) and Gonçalvès et al (2020). Here we can examine in the same way the global characteristic time for the CT.…”

Section: Tablementioning

confidence: 57%

“…These formations are separated (discontinuously at large scale but effectively at lower scale) by dolomite and clays of the Aptian. Recharge occurs at the outcrops of this regional‐scale aquifer representing about 200,000 km 2 (20% of the total surface area of the CI), of which the Atlas area contributes about 70% (Gonçalvès et al., 2020). The most recent value of overall recharge for the CI was estimated at 9.4 m 3 s −1 by hydrogeological modeling (Baba Sy, 2005).…”

Section: Hydrological and Climatic Context Of North Africa Aquifers A...mentioning

confidence: 99%

Analytical Expressions of Radiocarbon Distribution in Transient State Unconfined Aquifers and Their Application to Determination of Past and Present Recharges of North Africa Aquifers

Chekireb

Gonçalvès

Hamelin

et al. 2021

Water Resources Research

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Determining groundwater recharge is fundamental for the understanding and management of groundwater systems, especially for renewability analysis. Assessing the long-term recharge rate is pivotal to understand aquifers' behavior and predict potential effects of recent climate and land use changes on groundwater resources. Recharge rate can be defined as the amount of water that effectively flows across the unsaturated zone and reaches the water table of an aquifer over a given time. Among the different methods to identify the recharge, such as numerical modeling (unsaturated or saturated zone) and water table fluctuation, the use of geochemical tracers is one of the most appropriate approaches especially in arid environments where recharge is low and sporadic (

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Revisiting recharge and sustainability of the North-Western Sahara aquifers

Cited by 18 publications

References 28 publications

Coastal aquifer recharge and groundwater–seawater exchanges using downscaled GRACE data: case study of the Djeffara plain (Libya–Tunisia)

Coastal aquifer recharge and groundwater–seawater exchanges using downscaled GRACE data: case study of the Djeffara plain (Libya–Tunisia)

Quantification and possible causes of declining groundwater resources in the Euro-Mediterranean region from 2003 to 2020

Analytical Expressions of Radiocarbon Distribution in Transient State Unconfined Aquifers and Their Application to Determination of Past and Present Recharges of North Africa Aquifers

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