Reply to “Water table variations in Atacama Desert alluvial fans”*

Abstract

Viguier et al. propose an alternative conceptual model to the one presented by Scheihing to explain observed groundwater table variations at the foothills of the Andean piedmont in the Pampa del Tamarugal. It is demonstrated that the conceptual model of Viguier et al. is deficient. New findings underline that the confined aquifer of the Pampa del Tamarugal exhibits a hydraulic continuity over regional scales as proposed by Scheihing. Accordingly, short hydraulic response times of several months to distant recharge events can be confirmed. It is suggested that the investigated confined aquifer exhibits transient easterly boundary conditions, with easterly boundaries located in the Andean piedmont. These boundaries underly a periodic forcing due to occasional recharge. Several arguments are presented that support that alluvial fan channel recharge is in the investigated cases likely not a significant recharge mechanism (not to be confused with fan apex recharge).