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| Titel |
Groundwater vulnerability mapping in Guadalajara aquifers system (Western Mexico) |
| VerfasserIn |
L. David Rizo-Decelis, Ana I. Marín, Bartolomé Andreo |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250135779
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| Publikation (Nr.) |
 EGU/EGU2016-16684.pdf |
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| Zusammenfassung |
| Groundwater vulnerability mapping is a practical tool to implement strategies for land-use
planning and sustainable socioeconomic development coherent with groundwater
protection. The objective of vulnerability mapping is to identify the most vulnerable
zones of catchment areas and to provide criteria for protecting the groundwater
used for drinking water supply. The delineation of protection zones in fractured
aquifers is a challenging task due to the heterogeneity and anisotropy of hydraulic
conductivities, which makes difficult prediction of groundwater flow organization and flow
velocities.
Different methods of intrinsic groundwater vulnerability mapping were applied in the
Atemajac-Toluquilla groundwater body, an aquifers system that covers around 1300 km2. The
aquifer supplies the 30% of urban water resources of the metropolitan area of Guadalajara
(Mexico), where over 4.6 million people reside.
Study area is located in a complex neotectonic active volcanic region in the Santiago
River Basin (Western Mexico), which influences the aquifer system underneath the
city. Previous works have defined the flow dynamics and identified the origin of
recharge. In addition, the mixture of fresh groundwater with hydrothermal and
polluted waters have been estimated. Two main aquifers compose the multilayer
system. The upper aquifer is unconfined and consists of sediments and pyroclastic
materials. Recharge of this aquifer comes from rainwater and ascending vertical
fluids from the lower aquifer. The lower aquifer consists of fractured basalts of
Pliocene age. Formerly, the main water source has been the upper unit, which is a
porous and unconsolidated unit, which acts as a semi-isotropic aquifer. Intense
groundwater usage has resulted in lowering the water table in the upper aquifer.
Therefore, the current groundwater extraction is carried out from the deeper aquifer and
underlying bedrock units, where fracture flow predominates. Pollution indicators have
been reported in some monitoring wells, which have been related to anthropogenic
activity.
Vulnerability maps were produced using different parametric methods (e.g.: DRASTIC,
GOD, DISCO, AVI), then the results are compared and assessed. Since each one of these
methods use different number of parameters and weights, relatively different results were
obtained, although the results have been evaluated with common cartographic inputs. The
comparison between selected methods shows that the GOD method results are more
correlated with the other methods and produces vulnerability maps comparable with
them.
Even though groundwater vulnerability is a critical issue around the world, no protection
zones have been delineated in Guadalajara city, one of the biggest in Latin America. The
groundwater contamination in the study area poses a serious risk for a large population and
the environment.
This work aims to propose an approach for groundwater protection cartography,
based on the application and the comparison of results from different contamination
vulnerability methods. These outcomes may assist water authorities to identify the
higher vulnerable zones of the aquifers, in order to improving and adapting the land
planning and management according to the protection of the own water resources. |
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