Where does the water go? Understanding geohydrological behaviour of Andean catchments in south-central Chile

ABSTRACT

Upper Diguillín and Renegado are two neighbouring Andean basins of south-central Chile, with different specific discharges that cannot be explained solely by their difference in size. To address this issue, this study considers three separate but complementary approaches: (a) long-term analysis of rainfall and flow trends; (b) determination of hydrogeological properties at the watershed scale; and (c) analysis of the temporal evolution of groundwater storage. First, a trend test detected a statistically significant discharge decrease for Renegado in summer, unrelated to a coincidental precipitation trend, which seems to be associated with an increased use of water in that season related to tourism activity in the area. Second, there were no important differences in hydraulic conductivity or drainable porosity between the two study areas. However, it was found that there is a long-term negative trend in groundwater storage for Renegado; that is, water that contributes to the lower Diguillín streamflow through numerous springs.

Editor Z. W. Kundzewicz Associate editor not assigned

KEYWORDS:

• basin-scale hydrology
• Brutsaert analysis
• trend analysis
• baseflow

Acknowledgements

The authors are grateful for the support provided by the Dirección General de Aguas-MOP, which provided streamflow and precipitation records. The paper benefited from the comments of two anonymous reviewers.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This contribution has been carried out within the framework of FONDECYT Project 1110298: Water availability in a stressed Andean watershed in central Chile: Vulnerability under climate variability”, Conicyt/Fondap/15130015: Water Research Center for Agriculture and Mining, and DIULS CD2014.