Resumo

ROMERO, J. Hilario; PALACIOS, Oscar L.  e  ESCOBAR, Bernardo S.. Estimation of groundwater overexploitation produced in the Celaya Valley (México). Tecnol. cienc. agua [online]. 2017, vol.8, n.4, pp.127-138. ISSN 2007-2422.  https://doi.org/10.24850/j-tyca-2017-04-08.

The Celaya Valley aquifer is located in the State of Guanajuato, Mexico, in a region known as “El Bajío”, and is the main source of water supply for eleven municipalities (Apaseo el Alto, Apaseo el Grande, Celaya, Comonfort, Cortazar, Jarral del Progreso, Juventino Rosas, San Miguel Allende, Salamanca, Tarimoro and Villagrán) with a total population of about one million inhabitants. The development of these towns strongly depends on the sustainable management of their natural resources, particularly the hydraulic resources for which there is a ban since 1949. In view of the development of the region and the many changes observed there is a need to update the hydrologic study, since the aquifer boundaries have changed and the Celaya aquifer was joined with the Apaseos’ Valley aquifer in 2003. The purpose of this study was to estimate the sources of uncertainty and the real degree of groundwater overexploitation, as the basis for establishing a sustainable management plan. Two approaches were applied: a) the method of water balance, in which the different water inputs and outputs are to be measured or calculated, and b) a method based on the analysis of the evolution in time of the aquifer water levels, since the overexploitation is equal to the mean lowering of the water levels during a giving time, multiplied by the storage coefficient. As a result of the application of the water balance method a groundwater overdraft of 440.78 Mm3 was obtained. On the other hand, by the method based on the evolution of the water levels an overdraft of 386.65 Mm3 was obtained. Actually both values are just a crude estimation of the real overexploitation because of the incompleteness of the data base of acting pumping wells, the scarcity of geohydrological information regarding the transmissivity and storage coefficient of the aquifer, and also due to the almost complete absence of information regarding the water levels and the hydraulic gradients and transmissivity in the boundaries of the aquifer, needed to assess the horizontal groundwater inputs and outputs by means of the Darcy’s Law.

Palavras-chave : Aquifer; groundwater overexploitation; water balance; water level evolution.

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