Abstract
The objective of this work is to provide a numerical model for the hydrodynamics of a lagoon located on the chilean coastline, characterized by an intermittent connection to the sea and a regular fresh water input coming from the Andes mountains. The model consists in a two-dimensional nonlinear shallow water system, including tracer equations for the time evolution of temperature and salinity. The water circulation in the lagoon accounts for external forcings such as water exchanges (with the atmosphere, rivers and sea), wind effects and external pumping. The paper includes a validation of the numerical method with respect to an analytical solution; numerical illustrations of involved geophysical processes and realistic simulation of typical scenarios of the Tunquén lagoon are provided. Software availability. The software sources will be made available for download on a free accessible repository .