Abstract

CRUZ-FALCON, A et al. Rainfall and recharge in the basin of La Paz, BCS, Mexico. Universidad y ciencia [online]. 2011, vol.27, n.3, pp.251-263. ISSN 0186-2979.

Over the last years, the aquifer of La Paz, BCS has been seriously affected by over-exploitation generated by population growth, that has resulted in its pollution by salt water intrusion. It may thus be seen that the management of the resource has been inadequate, as more water than that provided by natural recharges from rainfall has been extracted. In order to estimate the volumes of some of the main components of the hydrologic system of the La Paz basin, the hydrologic equilibrium general equation applied to a geographical information system (GIS) was used, and digital models were produced for rainfall, temperature, evapotranspiration, runoff and recharge, with climate data for 25 years (1980 to 2004). Estimated data were a rainfall of 410 Mm³ year⁻¹, 330 Mm³ year⁻¹ of evapotranspiration, 15 Mm³ year⁻¹ of surface runoff, and a potential rainfall recharge of 65 Mm³ year⁻¹. Rainfall recharge mainly takes place in the mountain heights located to the east and southeast of the basin (Las Cruces and El Novillo mountain ranges) and is equivalent to 15.9% of the rainfall. The sub-basin of El Novillo covers the larger surface and receives more than 50% of the total rainfall.

Keywords : La Paz basin; rainfall; hydrologic balance; rainfall recharge; geographical information system; climate data.