The aquifer under investigation is situated on the central Bolivian Altiplano and covers 1000 km2. Perforated wells ranging in depth from 20 m to 80 m produce water whose electrical conductivity increases from upstream (0.5 mS cm-1) to downstream (5 mS cm-1). Hydrogeological modelling and interpretation of isotopic data (mainly 18O with some 2H, 3H, 14C and 13C) has been conducted on data collected over two years from groundwater, rain, the Rio Desaguadero and a core from the unsaturated zone. The aquifer presents two systems. The western low salinity zone is a consequence of infiltration from mountain runoff. Flow is northwards towards the Desaguadero and also southeastwards parallel to the mountains. The eastern zone of higher salinity results from a combination of recharge by the Desaguadero, groundwater evaporation and dissolution of salty sediments from ancient Quaternary lakes which dried up during a drier hydrological regime between 8000 and 1500 years BP.
|Number of pages||10|
|State||Published - 1995|
|Event||Proceedings of the 1994 International Symposium on Application of Tracers in Arid Zone Hydrology - Vienna, Italy|
Duration: 22 Aug 1994 → 26 Aug 1994