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Titel |
Parameterization and quantification of recharge in crystalline fractured bedrocks in Galicia-Costa (NW Spain) |
VerfasserIn |
J. R. Raposo, J. Molinero, J. Dafonte |
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. 6 ; Nr. 16, no. 6 (2012-06-15), S.1667-1683 |
Datensatznummer |
250013327
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Publikation (Nr.) |
copernicus.org/hess-16-1667-2012.pdf |
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Zusammenfassung |
Quantifying groundwater recharge in crystalline rocks presents great
difficulties due to the high heterogeneity of the underground medium
(mainly, due to heterogeneity in fracture network, which determines
hydraulic parameters of the bedrock like hydraulic conductivity or effective
porosity). Traditionally these rocks have been considered to have very low
permeability, and their groundwater resources have usually been neglected;
however, they can be of local importance when the bedrock presents a net of
well-developed fractures. The current European Water Framework Directive
requires an efficient management of all groundwater resources; this begins
with a proper knowledge of the aquifer and accurate recharge estimation. In
this study, an assessment of groundwater resources in the Spanish hydrologic
district of Galicia-Costa, dominated by granitic and metasedimentary rocks,
was carried out. A water-balance modeling approach was used for estimating
recharge rates in nine pilot catchments representatives of both geologic
materials. These results were cross-validated with an independent technique,
i.e. the chloride mass balance (CMB). A relation among groundwater recharge
and annual precipitation according to two different logistic curves was
found for both granites and metasedimentary rocks, thus allowing the
parameterization of recharge by means of only a few hydrogeological
parameters. Total groundwater resources in Galicia-Costa were estimated to
be 4427 hm3 yr−1. An analysis of spatial and temporal variability of
recharge was also carried out. |
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