Anthropogenic Aquifer Recharge Effect on Groundwater Resources in an Agricultural Floodplain in Northeastern Tunisia: Insights from Geochemical Tracers and Geophysical Methods

Author(s):  
Anis Chekirbane ◽  
Omeyma Gasmi ◽  
Ammar Mlayah ◽  
Hakim Gabtni ◽  
Samia Khadhar ◽  
...  
2019 ◽  
Vol 28 (1) ◽  
pp. 175-192
Author(s):  
Phil Hayes ◽  
Chris Nicol ◽  
Andrew D. La Croix ◽  
Julie Pearce ◽  
Sebastian Gonzalez ◽  
...  

AbstractThe Precipice Sandstone is a major Great Artesian Basin aquifer in the Surat Basin, Queensland, Australia, which is used for water supply and production of oil and gas. This report describes use of observed groundwater pressure responses to managed aquifer recharge (MAR) at a regional scale to test recent geological descriptions of Precipice Sandstone extent, and to inform its hydrogeological conceptualisation. Since 2015, two MAR schemes have injected over 20 GL of treated water from coal seam gas production into the Precipice Sandstone, with pressure responses rapidly propagating over 100 km, indicating high aquifer diffusivity. Groundwater modelling of injection and inversion of pressure signals using PEST software shows the spatial variability of aquifer properties, and indicates that basin in-situ stresses and faulting exert control on permeability. Extremely high permeability, up to 200 m/day, occurs in heavily fractured regions with a dual-porosity flow regime. The broader-scale estimates of permeability approach an order of magnitude higher than previous studies, which has implications for the management of water resources in the Precipice Sandstone. Results also show the Precipice Sandstone to have broadly isotropic permeability. The results also support a recent geological interpretation of the Precipice Sandstone as having more limited lateral extent than initially considered. The study shows the effective use of MAR injection data to improve geological and hydrogeological understanding through groundwater model inversion. It also demonstrates the utility of combining hydrogeological and reservoir-engineer datasets in areas explored and developed for both groundwater resources and oil and gas resources.


2017 ◽  
Vol 6 (2) ◽  
Author(s):  
Stefano Bernardinetti ◽  
Stefano Maraio ◽  
Pier Paolo Gennaro Bruno ◽  
Valentina Cicala ◽  
Serena Minucci ◽  
...  

The need to obtain a detailed hydrogeological characterization of the subsurface and its interpretation for the groundwater resources management, often requires to apply several and complementary geophysical methods. The goal of the approach in this paper is to provide a unique model of the aquifer by synthesizing and optimizing the information provided by several geophysical methods. This approach greatly reduces the degree of uncertainty and subjectivity of the interpretation by exploiting the different physical and mechanic characteristics of the aquifer. The studied area, into the municipality of Laterina (Arezzo, Italy), is a shallow basin filled by lacustrine and alluvial deposits (Pleistocene and Olocene epochs, Quaternary period), with alternated silt, sand with variable content of gravel and clay where the bottom is represented by arenaceous-pelitic rocks (Mt. Cervarola Unit, Tuscan Domain, Miocene epoch). This shallow basin constitutes the unconfined superficial aquifer to be exploited in the nearly future. To improve the geological model obtained from a detailed geological survey we performed electrical resistivity and P wave refraction tomographies along the same line in order to obtain different, independent and integrable data sets. For the seismic data also the reflected events have been processed, a remarkable contribution to draw the geologic setting. Through the k-means algorithm, we perform a cluster analysis for the bivariate data set to individuate relationships between the two sets of variables. This algorithm allows to individuate clusters with the aim of minimizing the dissimilarity within each cluster and maximizing it among different clusters of the bivariate data set. The optimal number of clusters “K”, corresponding to the individuated geophysical facies, depends to the multivariate data set distribution and in this work is estimated with the Silhouettes. The result is an integrated tomography that shows a finite number of homogeneous geophysical facies, which therefore permits to distinguish and interpret the porous aquifer in a quantitative and objective way.


2020 ◽  
Author(s):  
Emanuel Zarate ◽  
Alan MacDonald ◽  
Russell Swift ◽  
Jonathan Chambers ◽  
Japhet Kashaigili ◽  
...  

<p>Drylands (semi-arid/arid regions) represent >35% of the Earth’s surface, support a population of around 2 billion people, and are forecast to be increasingly water stressed in coming decades. Groundwater is the most reliable source of water in drylands, and it is likely that the structure and hydraulic properties of superficial geology play a crucial role in controlling groundwater recharge in these regions.  However, the spatio-temporal hydrogeological controls on the rates of groundwater recharge, and their sensitivity to environmental change are poorly resolved.</p><p>In the Makutapora groundwater basin (Tanzania), an analogue for semi-arid tropical areas underlain by weathered and fractured crystalline rock aquifers, we conducted a series of geophysical surveys using Electrical Resistivity Tomography (ERT) and frequency domain electromagnetic methods (FDEM). Using these data, in conjunction with borehole logs, we identify and delineate five major lithological units in the basin: 1) Superficial deposits of coarse sand (>200 Ω m) 2) Highly conductive smectitic clays (1-10 Ω m) 3) Decomposed pedolitic soils (30-100 Ω m) 4) Weathered saprolite (100-700 Ω m) and 5) Fractured granitic basement (>700 Ω m). We also identify 10-50m wide zones of normal faulting extending across the basin and cutting through these units, interpreted with the aid of analysis of a digital elevation model alongside the geophysics data.</p><p>These results are combined with existing long-term hydrological and hydrogeological records to build conceptual models of the processes governing recharge. We hypothesise that: 1) Zones of active faulting provide permeable pathways enabling greater recharge to occur; 2) Superficial sand deposits may act as collectors and stores that slowly feed recharge into these fault zones; 3) Windows within layers of smectitic clay underlying ephemeral streams may provide pathways for focused recharge via transmission losses; and 4) Overbank flooding during high-intensity precipitation events that inundate a greater area of the basin increases the probability of activating such permeable pathways.</p><p>Our results suggest that configurations of superficial geology may play a crucial role in controlling patterns, rates and timing of groundwater recharge in dryland settings. They also provide a physical basis to improve numerical models of groundwater recharge in drylands, and a conceptual framework to evaluate strategies (e.g. Managed Aquifer Recharge) to artificially enhance the availability of groundwater resources in these regions.</p>


2017 ◽  
Vol 15 (4) ◽  
pp. 644-657 ◽  
Author(s):  
M. F. El-Shahat ◽  
M. A. Sadek ◽  
W. M. Salem ◽  
A. A. Embaby ◽  
F. A. Mohamed

The northwestern coast of Sinai is home to many economic activities and development programs, thus evaluation of the potentiality and vulnerability of water resources is important. The present work has been conducted on the groundwater resources of this area for describing the major features of groundwater quality and the principal factors that control salinity evolution. The major ionic content of 39 groundwater samples collected from the Quaternary aquifer shows high coefficients of variation reflecting asymmetry of aquifer recharge. The groundwater samples have been classified into four clusters (using hierarchical cluster analysis), these match the variety of total dissolvable solids, water types and ionic orders. The principal component analysis combined the ionic parameters of the studied groundwater samples into two principal components. The first represents about 56% of the whole sample variance reflecting a salinization due to evaporation, leaching, dissolution of marine salts and/or seawater intrusion. The second represents about 15.8% reflecting dilution with rain water and the El-Salam Canal. Most groundwater samples were not suitable for human consumption and about 41% are suitable for irrigation. However, all groundwater samples are suitable for cattle, about 69% and 15% are suitable for horses and poultry, respectively.


1969 ◽  
Vol 17 ◽  
pp. 41-44 ◽  
Author(s):  
Ingelise Møller ◽  
Verner H. Søndergaard ◽  
Flemming Jørgensen

Groundwater mapping in Denmark has high priority. It was initiated in the 1990s when the pressure on groundwater resources increased due to urban development and pollution from industrial and agricultural sources. In some areas, the groundwater mapping included survey drillings, modelling based on existing knowledge and geophysical mapping with newly developed methods that made area coverage on a large scale possible. The groundwater mapping that included development of new geophysical methods showed promising results, and led to an ambitious plan to significantly intensify the hydrogeological mapping in order to improve the protection of the Danish groundwater resources. In 1999 the Danish Government initiated the National Groundwater Mapping Programme with the objective to obtain a detailed description of the aquifers with respect to localisation, extension, distribution and interconnection as well as their vulnerability to pollution (Thomsen et al. 2004). This mapping programme covers around 40% of the area of Den - mark designated as particularly valuable water abstraction areas. Water consumers fi nance the mapping programme by paying 0.04 € per cubic metre of consumed water. At the end of the programme in 2015, the total cost is estimated to be about 250 000 000 € with a significant part spent on geophysical mapping.


Author(s):  
Nejmeddine Ouhichi ◽  
Radhouane Hamdi ◽  
Lachaal Fethi ◽  
Hakim GABTNI ◽  
Olivier grunberger

In semiarid regions, dams are useful for surface water storage, sediment sequestration, and aquifer recharge. Built in 1987 on the Cap Bon peninsula (in northeastern Tunisia), the Lebna Dam is considered a good example of a multifunctional reservoir. The dam feeds two important irrigation networks, stores large sediment quantities, and allows a significant recharge flow to the underlying aquifer. This work suggests new leakage flow and dam-aquifer interaction characterizations through the development of an approach that combines a water balance calculation, geological field observations, groundwater monitoring, and geophysical research. The hydrological balance calculation performed over the 27-year monitoring period, from 1990 to 2017, shows that an estimated water volume of 3.7 Mm3y-1 has leaked from the Lebna reservoir to the coastal aquifer. Geological mapping of the Lebna Dam basin in summer 2019 revealed the existence of permeable layers of sands to sandstones exposed along the southern banks of the reservoir and extending to an elevation that included the water level when the dam is full; these rocks outcrop at approximately 16 m.a.s.l. A geophysical survey based on 67 vertical electrical soundings and 8 electrical resistivity tomography profiles in the area downstream of the reservoir was carried out to identify the lateral continuity of the recharge zones. Piezometric campaigns consisting of four field surveys in 2019 and 2020 were conducted in the region downstream of Lebna Dam, consisting of 71 water well samples. An interpretation of these geophysical data coupled with available borehole logging and piezometric measurements was used to define the leakage geometry from the reservoir dam to the coastal aquifer. The collected evidence led to the conclusion that concentrated recharge occurs in the downstream sections, especially on the right bank of the aquifer.


2022 ◽  
Author(s):  
Omeed H. Al-Kakey ◽  
◽  
Arsalan A. Othman ◽  
Broder J. Merkel ◽  
◽  
...  

Excessive extraction, uncontrolled withdrawal of groundwater, and unregulated practices have caused severe depletion of groundwater resources in the Erbil basin, Iraq. This situation has had a number of negative consequences on human settlement, agricultural activities, clean water supply, and the environment. Runoff harvesting and artificial groundwater recharge play a significant role in the sustainable management of water resources, particularly in arid and semi-arid regions. This study aims to: (1) delineate groundwater recharge zones using multiple thematic layers that control the groundwater recharge process, and (2) identify prospective sites and structures to perform artificial groundwater recharge. In order to generate a potential map for groundwater recharge zones, seven thematic layers are considered in this study, namely, topographic position index, geomorphology, lithology, land cover, slope, drainage-length density, and lineament-length density. After that, the analytic hierarchy process was applied to weight, rank, and reclassify these seven thematic layers. All maps are then integrated within the ArcGIS environment for delineating groundwater recharge zones. Accordingly, the resulting map categorizes the study area into five zones: extremely high, high, moderate, low, and extremely low potential for groundwater recharge. As expected, areas along the Greater Zab river show the highest possibility for groundwater recharge. Likewise, rugged eastern hills demonstrate an encouraging capacity for artificial aquifer recharge, whereas the least effective area is represented by built-up land. Based on the generated map, two dams are proposed as promising artificial recharge structures for harvesting runoff water east of Erbil city. Lastly, the resulting map of the potential groundwater recharge zones is verified using static water level data, where the coefficient of determination (R2) achieved a satisfactory result (0.73). These findings provide crucial evidence for implementing a sustainable management plan of surface and groundwater resources. The applied method is eventually valid for regions where appropriate and adequate field data availability is a serious issue.


2021 ◽  
Author(s):  
Staša Borović ◽  
Matko Patekar ◽  
Josip Terzić ◽  
Marco Pola ◽  
Marina Filipović ◽  
...  

<p>Vis, a small remote island in the Adriatic Sea, inhabited since the time of ancient Greeks and Romans, exhibits a unique historical and natural environment. With an area of 89.7 km<sup>2</sup>, the island is mostly composed of karstified carbonate rocks and belongs to Dinaric karst region, locus typicus for karst landforms. Its distance from the mainland is around 50 km from the city of Split, 147 km from the Italian coastline and 18 km from neighbouring Hvar island. The climate on the island is Mediterranean with dry and hot summer and mild, rainy and humid winter (Csa). Vis island, due to its remote location, is not connected to the mainland by submarine water pipeline so it has autonomous water supply due to favourable geological and hydrological conditions which enabled the formation of excellent karst aquifers. The majority of water is abstracted from drilled wells in the central part of the island (Korita extraction site), around 40 l/s, while additional quantities are obtained from coastal spring of Pizdica. Although predominantly of good quality, existing groundwater quantities on Vis are extremely vulnerable to the effects of climate change, namely increase in temperature, quantitative and temporal variability in precipitation trends as well as seawater intrusion. Moreover, Vis island is an attractive location for summer bathing tourism which causes the highest pressure on drinking water resources precisely during the hydrological minimum. An idea to apply artificial recharge of karst aquifer on Vis emerged during the 1970s, however, only on the theoretical level.</p><p>Through the scope of the DEEPWATER-CE project, funded by Interreg Central Europe Programme, the aim is to develop implementation frame for managed aquifer recharge (MAR) solutions. Simplified, MAR is a process by which excess surface water is directed into the ground — either by spreading on the surface, by using recharge wells, or by altering natural conditions to increase infiltration to replenish an aquifer (DILLON et al., 2019). Globally, various designs of MAR schemes have successfully been implemented in unconsolidated aquifers, but there is little experience with artificially recharging karst aquifers (ROLF, 2017). A particular challenge for the technical implementation and operation of MAR is posed by strong hydraulic anisotropy and heterogeneity of karst aquifers and by their high vulnerability to contamination (XANKE, 2017). To investigate whether a MAR operation is feasible and suitable for karst aquifer on Vis, a detailed field and laboratory investigations were carried out. Field investigations included in-situ measurements of physicochemical parameters on water samples from springs and boreholes, groundwater monitoring (conductivity, temperature and water levels), geophysical methods (ERT, magnetotellurics, and seismic refraction) and structural measurements. Laboratory analyses included measurements of stabile water isotopes, and principal cations and anions. Hence, by conducting extensive investigations, coupled with historical data and previous research, a foundation for implementing efficient and sustainable management of karst aquifer through MAR on Vis island will be provided. </p>


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