Author(s): Alberto De La Fuente S.
Linked Author(s): Alberto de la Fuente
Keywords: Salt lagoon; Hydrodynamic modelling; Stream temperature modelling
Abstract: Salt lagoons are a common feature of altiplanic desert lands of Chile, Argentina, Peru and Bolivia. They are produced by the upwelling of groundwater into closed Andean basins located at high altitudes. The characterization of the thermo-hydrodynamics of one of these Altiplanic Salt Lagoon systems, denoted VCL2, is presented in this paper, based upon field measurements and numerical simulations. Presently, Escondida Mining Company uses groundwater from Salar Punta Negra for cooper production, and then, understanding the hydrodynamics of these aquatic ecosystems is urgently needed to adequately manage and reduce the impact of inflow reduction due to the economic activity. The basic feature of this aquatic system is that the inflow water is completely evaporated, which produces a spatial gradient of salinity. The thermodynamics is controlled by heat exchange with the atmosphere and the sediments, such that the latter act as a heat reservoir, which stores heat during the day and releases it at night. The hydrodynamics is controlled by the interaction of three factors: a water pulse that travels along the system every day, the evaporation that rises the salt concentration, and the wind blowing every day from the lagoon and towards the upstream direction. Two models were implemented for the analysis, one for understanding the thermodynamics, which couples the depth averaged heat equation for the water column with the vertical heat diffusion equation for the bottom sediments, and the second one for the hydrodynamics which solves the 2D, depth averaged Saint-Venant, momentum and salt transport equations for this very shallow flow, considering evaporation losses.
Year: 2007