Interbasin Underflow Between Closed Altiplano Basins in Chile

Abstract

Interbasin ground water movement of 200 to 240 L/sec occurs as underflow beneath a mountainous surface water divide separating the topographically higher Salar de Michincha from the topographically lower Salar de Coposa internally drained basins in the Altiplano of northern Chile. Salt-encrusted flats (salars) and saline lakes occur on the lowest parts of the basin floors and comprise the principal evaporative discharge areas for the basins. Because a surface water divide separates the basins, surface water drainage boundaries do not coincide with ground water drainage boundaries. In the region, interbasin ground water movement is usually not recognized, but occurs for selected basins, and at places is an important component of ground water budgets. With increasing development of water for mining industry and potential exportation of ground water from the Altiplano for use at coastal cities, demonstration and quantification of interbasin movement is important for assessment of sustainable ground water development in a region of extreme aridity. Recognition and quantification of interbasin ground water underflow will assist in management of ground water resources in the arid Chilean Altiplano environment.

Recharge to groundwater in the Turi Basin, northern Chile: An evaluation based on tritium and chloride mass balance techniques

“…The chloride (Cl) mass balance technique (Allison and Hughes, 1978;Dettinger, 1989) has been shown to provide an additional approach to the estimation of recharge that has not previously been applied in the Andean Cordillera. Interbasin groundwater transfer has not been widely reported, probably as a result of political considerations, but as Montgomery et al (2003) and this study show, is probably more widespread in this environment than previously acknowledged.…”

Unraveling complex hydrogeological processes in Andean basins in south‐central Chile: An integrated assessment to understand hydrological dissimilarity

“…This phenomenon coincides with the observed behavior in the Chillán–Renegado–Diguillín system. Along the same lines, Zanon et al (), Montgomery, Rosko, Castro, Keller, and Bevacqua (), and Langman and Ellis () have found similar patterns in different sites around the globe, all of which were located in volcanic mountainous areas.…”

Architecture of the aquifers of the Calama Basin, Loa catchment basin, northern Chile

“…1). Those volcanic peaks overlie laterally extensive Miocene and Pliocene pyroclastic volcanic deposits and interbedded epiclastic sands and gravels (de Silva, 1989;Montgomery et al, 2003;Houston, 2007) that compose aquifers in some of the upland basins (Mardones Perez, 1998;Montgomery et al, 2003;Houston, 2007;DGA, 2003). A reasonable but unproven extrapolation is that some water recharged east of the surface catchment divide flows as groundwater westward into the surface water Loa catchment (Pourrut and Covarrubias, 1995;Houston, 2007).…”

“…Although locally at least part of the 1-100-m-thick ignimbrites is welded tuff, more widely the ignimbrites are not welded. The effectiveness of these ignimbrites to impede water flow is unresolved: common vertical fractures may serve as flow paths (Montgomery et al, 2003), yet water-pressure data in the Llalqui area demonstrate that the Sifón Ignimbrite locally confines an artesian aquifer (Houston, 2004(Houston, , 2007.…”