Modelling of Circulation and Water Exchange in a Hypersaline Coastal Lagoon: Lagoa de Araruama, Brazil

Abstract

Coastal lagoons are common water bodies on all continents, particularly sedimentary coasts with strong wave action. Although lagoons have been centres for human habitation since prehistory, it is only in recent decades that they have experienced greatly accelerated rates of non-sustainable human development. Since many lagoons have very long residence times, the lack of adequate infrastructure support gives rise to poor lagoon water quality, eutrophication, pollution, and is also a threat to public health. To forecast the response of coastal lagoons to tides, winds, and runoff, as well as anthropogenic loading, numerical and ecological simulation models have proven to be successful analytical tools. Modelled lagoons have usually been freshwater or estuarine in nature, i.e. with salinity less than 35‰. The purpose of this investigation is to diagnose the circulation in a hypersaline coastal lagoon, Lagoa de Araruama in Brazil, with the help of a coupled numerical circulation-dispersion model.