Abstract

CRUZ FALCON, Arturo et al. Estimation of the hydrological balance and recharge of the aquifer of la Paz, BCS, Mexico. Universidad y ciencia [online]. 2013, vol.29, n.1, pp.87-100. ISSN 0186-2979.

The need to count on a sustainable supply of fresh water for the development of the city of La Paz makes it important to define the hydrological balance of the aquifer in order to determine how to regulate the extraction of groundwater. Considering that the vertical recharge provided by rainstothe basinof La Pazoccurs mainlyinthe higher areas located to the east and southeast, the aquifer that is located in the valley is recharged mainly by underground water fow. In order to estimate this recharge, the underground fow method was used, applying Darcyss Law and piezometrical data for the area of aquifer exploitation. The horizontal recharge of freshwater, the intrusion of sea water and the vertical recharge provided by rains were estimated for an aquifer surface of 200 km² (area of aquifer exploitation). Results provided a total recharge of 22.98 Mm³ year^-1 with an intrusion of sea water of 1.73 Mm³ year^-1. The balance of the aquifer was estimated with the general hydrological balance equation including several important components. With an extraction of 30.78 Mm³ year^-1 for the year 2004 and a groundwater discharge to the Ensenada de La Paz of 1.90 Mm³ year^-1, a balance of -9.70 Mm³ year^-1 was estimated. The estimations of recharges and hydrological balances of several studies were compared. All stated that extraction is greater than rechargeand that the aquifer is over-exploited, for which reason it is necessary to take measures to preserve it.

Keywords : Aquifer of La Paz; basin of La Paz; horizontal recharge; hydrological balance; intrusion of sea water; groundwater water flow.