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Título del libro: 19th Symposium On The Application Of Geophysics To Engineering And Environmental Problems, Sageep 2006: Geophysical Applications For Environmental And Engineering Hazzards - Advances And Constraints
Título del capítulo: 3D model of the Etla valley aquifer, Oaxaca, Mex.: Geohydrological evolution and geophysyics

Autores UNAM:
ELSA LETICIA FLORES MARQUEZ; RAYMUNDO GERARDO MARTINEZ SERRANO; RENE EFRAIN CHAVEZ SEGURA; ANDRES TEJERO ANDRADE; JAVIER URBIETA GOMEZ;
Autores externos:

Idioma:

Año de publicación:
2006
Palabras clave:

3D modeling; Aquifers; Flow of water; Groundwater resources; Landforms; Metamorphic rocks; River pollution; Sedimentary rocks; Sedimentology; Sewage; Aquifer systems; Flow direction; Groundwater system; Pumping well; Sedimentary infill; Three-dimensional ground water flow modeling; Visual MODFLOW; Water extraction; Groundwater pollution


Resumen:

The Etla valley aquifer located to the NW of the City of Oaxaca produces 80% of the total water supplied in the region. Geophysical studies characterized the basin geometry and suggested a maximum sedimentary thickness of 730 m. The Mesozoic Mylonites of the Sierra de Juarez and the metamorphic rocks of the Sierra de Oaxaca underlie the sedimentary infill. The aquifer system is embedded in Tertiary and Quaternary horizons. A three-dimensional ground water flow model, based on the interdisciplinary geophysical, geohydrological and geological studies, was computed using the Visual ModFlow program. The flow model shows a general draining from NW to SE following the axes of the valley. The simulation reveals that the present water-extraction rate produces an important abatement of groundwater level at the City of Oaxaca (SE of the valley). Another important characteristic of the groundwater system is that the flow direction of the aquifer favored the pollution by fertilizers and leakage of the sewage network, dumped to the Atoyac River, the principal drainage. A ten years later model assuming redistribution of the pumping wells, from the City of Oaxaca towards the recharge zones (flanks of the Sierras de Juárez and Oaxaca), allows a slight recovery of the aquifer system.


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