Wednesday, December 5, 2007 : 10:20 a.m.

Drought Effects on the Allende-Piedras Negras Aquifer System, Northern Mexico

Carlos Gutierrez-Ojeda, Pablo Gallardo and Israel Velasco, Mexican Institute of Water Technology

With the purpose of evaluate the drought severity during the period 1993-2002 on the Allende – Piedras Negras aquifer system, Coahuila state, Northern Mexico, a precipitation analysis was carried out. Data from climatologic stations with the long term records in the area were used to estimate the standardized precipitation index (SPI) and the accumulated precipitation deficit (APD). The aquifer is located at the West side of an extensive area called “Chihuahuan Desert”. The area is characterized by its dry climate with a long term average precipitation of 517 mm/year during the period 1900-2003. However during the period 1993-2002 the average precipitation decreased to 390 mm/year. The drought analysis showed SPI values of 0-57 and -0.55 for Eagle Pass and Piedras Negras stations, respectively, which classifies the meteorological drought of the period 1993-2002 as incipient. However, its effects were accentuated by the prolonged of the extreme event. The latter was corroborated by the APD index which reached an extreme value of 1316 mm during that period. Drought effects caused a decrease of the water table on the Allende – Piedras Negras aquifer system which also affected the riparian vegetation. The extraordinary rainy season occurred in the area during the year 2003 significantly increased the average precipitation to 812 mm and the water table elevation to levels quite above those observed before the drought.

Carlos Gutierrez-Ojeda, Mexican Institute of Water Technology Master in Science (Hydrogeology) by the University of Arizona in Tucson, teacher of hydrogeology and hydrology at the Mexican Autonomous National University, head of the Hydrogeology Department of the Mexican Institute of Water Technology since February 2000, has written more than 28 papers and more than 24 technical reports. He is member of Mexican and international associations in hydrogeology and hydraulic. He has been chief scientific of research projects of the International Atomic Energy Agency.


2007 NGWA Ground Water Expo and Annual Meeting