Groundwater recharge in the Azul aquifer, central Buenos Aires Province, Argentina

A comparison is made of several methodologies for groundwater recharge esti mation in a water-table aquifer from a flat-land basin in central Buenos Ai res Province, Argentina. It has been found that the potential evapotranspir ation estimates from the Thornthwaite equation are underestimated, which ma kes the soil-water budgets based on them lead to excessive recharge values. Recharge estimates based on chloride ion mass balance and groundwater now modeling are comparable, more realistic, and indicate that recharge is alwa ys less than 10% of the annual input by rainfall. (C) 1999 Elsevier Science Ltd. All rights reserved.