Abstract

The drylands of the 8 th region in south-central Chile are characterized by granitic soils and Mediterranean climate, where water scarcity is the main constrain for local development. Farmers obtain small amounts of water from shallow wells, barely enough for domestic consumption. In this study, monthly hydrological balances were carried out in two subwatersheds of the San Jose watershed, located in the commune of Ninhue, to estimate aquifer recharge and potential groundwater sources. The model used is a modification of Thornthwaite's balance. The balance was carried out using in-situ measurements of water flow and precipitation, and evapotranspiration was estimated by the Penman-Monteith method. The resulting recharge was sensitized regarding evapotranspiration and soil humidity retention capacity to detect data errors in the model. The results indicated that recharge can reach up to 6% of the annual precipitation, with minimum values of 1%. That means 22 mm/year with a minimum of 6.3 mm/year, which would triplicate water availability in shallow wells. By doing this, the peasant's quality of life will be improved as water availability increases.