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| Titel |
Quantifying aquifer properties and freshwater resource in coastal barriers: a hydrogeophysical approach applied at Sasihithlu (Karnataka state, India) |
| VerfasserIn |
J.-M. Vouillamoz, J. Hoareau, M. Grammare, D. Caron, L. Nandagiri |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1027-5606
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| Digitales Dokument |
URL |
| Erschienen |
In: Hydrology and Earth System Sciences ; 16, no. 11 ; Nr. 16, no. 11 (2012-11-26), S.4387-4400 |
| Datensatznummer |
250013582
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| Publikation (Nr.) |
 copernicus.org/hess-16-4387-2012.pdf |
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| Zusammenfassung |
Many human communities living in coastal areas in Africa and Asia rely on
thin freshwater lenses for their domestic supply. Population growth together
with change in rainfall patterns and sea level will probably impact these
vulnerable groundwater resources. Spatial knowledge of the aquifer
properties and creation of a groundwater model are required for achieving a
sustainable management of the resource. This paper presents a ready-to-use
methodology for estimating the key aquifer properties and the freshwater
resource based on the joint use of two non-invasive geophysical tools
together with common hydrological measurements.
We applied the proposed methodology in an unconfined aquifer of a coastal
sandy barrier in South-Western India. We jointly used magnetic resonance and
transient electromagnetic soundings and we monitored rainfall, groundwater
level and groundwater electrical conductivity. The combined interpretation
of geophysical and hydrological results allowed estimating the aquifer
properties and mapping the freshwater lens. Depending on the location and
season, we estimate the freshwater reserve to range between 400 and 700 L m−2
of surface area (± 50%). We also estimate the recharge using
time lapse geophysical measurements with hydrological monitoring. After a
rainy event close to 100% of the rain is reaching the water table, but
the net recharge at the end of the monsoon is less than 10% of the rain.
Thus, we conclude that a change in rainfall patterns will probably not
impact the groundwater resource since most of the rain water recharging the
aquifer is flowing towards the sea and the river. However, a change in sea
level will impact both the groundwater reserve and net recharge. |
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