Abstract:
This report aims the presentation of the conceptual model, the mathematical model, and the
computed results that allowed the quantification and mapping of the groundwater flow discharge, per
kilometre of coastal line, towards Santos Estuary, in Brazil.
The physical data of the Santos Estuary watershed is presented in terms of geology,
hydrogeology, altimetry and precipitation.
From the results it can be concluded that groundwater discharge to Santos Estuary depends on
the watershed location, area and land use. Flow discharge is lower on a well drained basin, because
groundwater contributions are mainly to the drains. There is a high fresh water discharge to the Atlantic
Ocean, from Praia Grande and Santos area. Lower values are related with crystalline rock outcrop and
small islands. Total groundwater discharge to the land-Estuary boundary from precipitation is about 8%,
besides, other 17% flows as base flow to the drains.
From the simulation it can be concluded that Boturoca watershed, São Vicente and Santo Amaro
Island are the main contributors of fresh water from the sedimentary aquifer to the estuary. The results
showed important groundwater discharges, higher from January to May. Lower discharges to the
estuary were observed in Cubatão watershed. In this basin groundwater from the sedimentary aquifer
flows to the drains and, afterwards as surface water, to the estuary.
