Using Stable Isotopes to Assess Groundwater Recharge and Solute Transport in a Density-Driven Flow-Dominated Lake–Aquifer System
Saline lakes are mostly located in endorheic basins in arid and semi-arid regions, where the excess of evaporation over precipitation promotes the accumulation of salts on the surface. As the salinity of these lakes increases, their mass balance changes, and biogeochemical processes may be intensifi...
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| Format: | Article |
| Language: | English |
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MDPI AG
2022-05-01
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| Series: | Water |
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| Online Access: | https://www.mdpi.com/2073-4441/14/10/1628 |
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| author | Nicolas Valiente Iordanka Dountcheva David Sanz Juan José Gómez-Alday |
| author_facet | Nicolas Valiente Iordanka Dountcheva David Sanz Juan José Gómez-Alday |
| author_sort | Nicolas Valiente |
| collection | DOAJ |
| description | Saline lakes are mostly located in endorheic basins in arid and semi-arid regions, where the excess of evaporation over precipitation promotes the accumulation of salts on the surface. As the salinity of these lakes increases, their mass balance changes, and biogeochemical processes may be intensified. In that sense, Pétrola Lake (SE Spain) is a terminal lake located in an endorheic basin with elevated anthropic pressure, mainly derived from agricultural inputs and wastewater discharge. The goal of this study was to evaluate the interaction between groundwater and saline water from Pétrola Lake to improve our knowledge of groundwater recharge processes by density-driven flow (DDF) in terminal lakes. A combination of hydrochemical (chloride concentration) and stable isotope (δ<sup>18</sup>O<sub>H<sub>2</sub>O</sub> and δ<sup>2</sup>H<sub>H<sub>2</sub>O</sub>) data were used. In order to test the conceptual model, a simple numerical experiment was performed using a one-dimensional column that represents the relationship between the lake and the aquifer incorporating the variable density coupling control in solute migration. The isotopic composition of 190 groundwater and surface water samples collected between September 2008 and July 2015 provides a regression line (δ<sup>2</sup>H<sub>H<sub>2</sub>O</sub> = 5.0·δ<sup>18</sup>O<sub>H<sub>2</sub>O</sub> − 14.3‰, R<sup>2</sup> = 0.95) consistent with dominant evaporation processes in the lake. The DDF towards the underlying aquifer showed a strong influence on the mixing processes between the groundwater and surface water. Nevertheless, groundwater chemistry at different depths beneath the lake remains almost constant over time, suggesting an equilibrium between DDF and regional groundwater flow (RGF). Modelling isotope changes allowed inferring the temporal pattern of saline water recharge, coinciding with the summer season when water loss through evaporation is most significant. Consequently, the transport of solutes suitable for chemical reactions is then feasible to deeper zones of the aquifer. |
| first_indexed | 2024-03-10T01:34:45Z |
| format | Article |
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| institution | Directory Open Access Journal |
| issn | 2073-4441 |
| language | English |
| last_indexed | 2024-03-10T01:34:45Z |
| publishDate | 2022-05-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Water |
| spelling | doaj.art-a60c17c6ab4942aeb1324748d630895b2023-11-23T13:35:24ZengMDPI AGWater2073-44412022-05-011410162810.3390/w14101628Using Stable Isotopes to Assess Groundwater Recharge and Solute Transport in a Density-Driven Flow-Dominated Lake–Aquifer SystemNicolas Valiente0Iordanka Dountcheva1David Sanz2Juan José Gómez-Alday3Division of Terrestrial Ecosystem Research, Centre for Microbiology and Environmental Systems Science, University of Vienna, Djerassiplatz 1, 1030 Vienna, AustriaBiotechnology and Natural Resources Section, Institute for Regional Development (IDR), University of Castilla–La Mancha (UCLM), Campus Universitario s/n, 02071 Albacete, SpainBiotechnology and Natural Resources Section, Institute for Regional Development (IDR), University of Castilla–La Mancha (UCLM), Campus Universitario s/n, 02071 Albacete, SpainBiotechnology and Natural Resources Section, Institute for Regional Development (IDR), University of Castilla–La Mancha (UCLM), Campus Universitario s/n, 02071 Albacete, SpainSaline lakes are mostly located in endorheic basins in arid and semi-arid regions, where the excess of evaporation over precipitation promotes the accumulation of salts on the surface. As the salinity of these lakes increases, their mass balance changes, and biogeochemical processes may be intensified. In that sense, Pétrola Lake (SE Spain) is a terminal lake located in an endorheic basin with elevated anthropic pressure, mainly derived from agricultural inputs and wastewater discharge. The goal of this study was to evaluate the interaction between groundwater and saline water from Pétrola Lake to improve our knowledge of groundwater recharge processes by density-driven flow (DDF) in terminal lakes. A combination of hydrochemical (chloride concentration) and stable isotope (δ<sup>18</sup>O<sub>H<sub>2</sub>O</sub> and δ<sup>2</sup>H<sub>H<sub>2</sub>O</sub>) data were used. In order to test the conceptual model, a simple numerical experiment was performed using a one-dimensional column that represents the relationship between the lake and the aquifer incorporating the variable density coupling control in solute migration. The isotopic composition of 190 groundwater and surface water samples collected between September 2008 and July 2015 provides a regression line (δ<sup>2</sup>H<sub>H<sub>2</sub>O</sub> = 5.0·δ<sup>18</sup>O<sub>H<sub>2</sub>O</sub> − 14.3‰, R<sup>2</sup> = 0.95) consistent with dominant evaporation processes in the lake. The DDF towards the underlying aquifer showed a strong influence on the mixing processes between the groundwater and surface water. Nevertheless, groundwater chemistry at different depths beneath the lake remains almost constant over time, suggesting an equilibrium between DDF and regional groundwater flow (RGF). Modelling isotope changes allowed inferring the temporal pattern of saline water recharge, coinciding with the summer season when water loss through evaporation is most significant. Consequently, the transport of solutes suitable for chemical reactions is then feasible to deeper zones of the aquifer.https://www.mdpi.com/2073-4441/14/10/1628saline lakedensity-driven flowstable isotopesgroundwater rechargesolute transport |
| spellingShingle | Nicolas Valiente Iordanka Dountcheva David Sanz Juan José Gómez-Alday Using Stable Isotopes to Assess Groundwater Recharge and Solute Transport in a Density-Driven Flow-Dominated Lake–Aquifer System Water saline lake density-driven flow stable isotopes groundwater recharge solute transport |
| title | Using Stable Isotopes to Assess Groundwater Recharge and Solute Transport in a Density-Driven Flow-Dominated Lake–Aquifer System |
| title_full | Using Stable Isotopes to Assess Groundwater Recharge and Solute Transport in a Density-Driven Flow-Dominated Lake–Aquifer System |
| title_fullStr | Using Stable Isotopes to Assess Groundwater Recharge and Solute Transport in a Density-Driven Flow-Dominated Lake–Aquifer System |
| title_full_unstemmed | Using Stable Isotopes to Assess Groundwater Recharge and Solute Transport in a Density-Driven Flow-Dominated Lake–Aquifer System |
| title_short | Using Stable Isotopes to Assess Groundwater Recharge and Solute Transport in a Density-Driven Flow-Dominated Lake–Aquifer System |
| title_sort | using stable isotopes to assess groundwater recharge and solute transport in a density driven flow dominated lake aquifer system |
| topic | saline lake density-driven flow stable isotopes groundwater recharge solute transport |
| url | https://www.mdpi.com/2073-4441/14/10/1628 |
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