Salinities and sediment transport in the Bolivian highlands

Abstract

Salinities and sediment loads of the rivers of the entire interior drainage basin of the Lake Titicaca, Rio Desaguadero, Lake Poopo and salars, as well as their evolution from upstream to downstream, have been characterized on the basis of the results of four samplings during runoff periods. On the other hand, the regimes of dissolved and suspended matter transport are characterized with periodic measurements and samplings at hydrometrical stations over several years. The junction of Lake Poopo and the Salar of Coipasa, since 1985 is noted, which recalls that an unique terminal lake of large area existed during some parts of the Quaternary. Mechanical and chemical erosion rates have been calculated for the basins that drain the Western (Rio Mauri) and Eastern (Rio Suches) Cordilleras of the Bolivian Andes. Most of the sediment comes from the Western Cordillera, with a mechanical erosion rate of 640 t km 2 yr −1 for the basin of the Rio Mauri. On the other hand, Lake Titicaca is the main source of dissolved matter to Lake Poopo via the Rio Desaguadero.