Flow dynamics in hyper-saline aquifers: hydro-geophysical monitoring and modeling
Saline–freshwater interaction in porous media is a phenomenon of practical interest particularly for the management of water resources in arid and semi-arid environments, where precious freshwater resources are threatened by seawater intrusion and where storage of freshwater in saline aquifers can b...
Main Authors: | , , , , , , , |
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Format: | Article |
Language: | English |
Published: |
Copernicus Publications
2017-03-01
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Series: | Hydrology and Earth System Sciences |
Online Access: | http://www.hydrol-earth-syst-sci.net/21/1439/2017/hess-21-1439-2017.pdf |
Summary: | Saline–freshwater interaction in porous media is a phenomenon of practical
interest particularly for the management of water resources in arid and
semi-arid environments, where precious freshwater resources are threatened
by seawater intrusion and where storage of freshwater in saline aquifers can
be a viable option. Saline–freshwater interactions are controlled by
physico-chemical processes that need to be accurately modeled. This in turn
requires monitoring of these systems, a non-trivial task for which spatially
extensive, high-resolution non-invasive techniques can provide key
information. In this paper we present the field monitoring and numerical
modeling components of an approach aimed at understanding complex
saline–freshwater systems. The approach is applied to a freshwater injection
experiment carried out in a hyper-saline aquifer near Cagliari (Sardinia,
Italy). The experiment was monitored using time-lapse cross-hole electrical
resistivity tomography (ERT). To investigate the flow dynamics, coupled
numerical flow and transport modeling of the experiment was carried out
using an advanced three-dimensional (3-D) density-driven flow-transport simulator. The simulation
results were used to produce synthetic ERT inversion results to be compared
against real field ERT results. This exercise demonstrates that the
evolution of the freshwater bulb is strongly influenced by the system's (even
mild) hydraulic heterogeneities. The example also highlights how the joint
use of ERT imaging and gravity-dependent flow and transport modeling give
fundamental information for this type of study. |
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ISSN: | 1027-5606 1607-7938 |