Groundwater withdrawal in randomly heterogeneous coastal aquifers
We analyze the combined effects of aquifer heterogeneity and pumping operations on seawater intrusion (SWI), a phenomenon which is threatening coastal aquifers worldwide. Our investigation is set within a probabilistic framework and relies on a numerical Monte Carlo approach targeting transient...
| Hauptverfasser: | , |
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| Format: | Artikel |
| Sprache: | English |
| Veröffentlicht: |
Copernicus Publications
2018-05-01
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| Schriftenreihe: | Hydrology and Earth System Sciences |
| Online Zugang: | https://www.hydrol-earth-syst-sci.net/22/2971/2018/hess-22-2971-2018.pdf |
| Zusammenfassung: | We analyze the combined effects of aquifer heterogeneity and pumping
operations on seawater intrusion (SWI), a phenomenon which is threatening
coastal aquifers worldwide. Our investigation is set within a probabilistic
framework and relies on a numerical Monte Carlo approach targeting transient
variable-density flow and solute transport in a three-dimensional randomly
heterogeneous porous domain. The geological setting is patterned after the
Argentona river basin, in the Maresme region of Catalonia (Spain). Our
numerical study is concerned with exploring the effects of (a) random
heterogeneity of the domain on SWI in combination with (b) a variety of
groundwater withdrawal schemes. The latter have been designed by varying the
screen location along the vertical direction and the distance of the wellbore
from the coastline and from the location of the freshwater–saltwater mixing
zone which is in place prior to pumping. For each random realization of the
aquifer permeability field and for each pumping scheme, a quantitative
depiction of SWI phenomena is inferred from an original set of metrics
characterizing (a) the inland penetration of the saltwater wedge and (b) the
width of the mixing zone across the whole three-dimensional system. Our
results indicate that the stochastic nature of the system heterogeneity
significantly affects the statistical description of the main features of the
seawater wedge either in the presence or in the absence of pumping, yielding
a general reduction of toe penetration and an increase of the width of the
mixing zone. Simultaneous extraction of fresh and saltwater from two screens
along the same wellbore located, prior to pumping, within the
freshwater–saltwater mixing zone is effective in limiting SWI in the context
of groundwater resources exploitation. |
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| ISSN: | 1027-5606 1607-7938 |