Monitoring and modelling groundwater contributions to dependent ecoystems - The case study of the Santo André coastal lagoon.

Resumo

When the Santo André coastal lagoon (SAL) is closed to the sea, and no surface runoff is generated, its water balance is mainly controlled by the hydraulic connection between the stream network discharging into the SAL and the top detritic layer of the multi-layer Sines aquifer system, allowing the classification of this lagoon as a groundwater dependent ecosystem (GDE). A monitoring plan has been implemented to continuously register stream flow discharges in order to estimate groundwater contributions to calibrate the developed numerical flow model of the top detritic Sines aquifer. Simultaneously, the monitoring network was also continuously recording the aquifer level variation, and manual measurement of the hydraulic head of several wells installed in the top detritic aquifer were also used for the numerical flow model calibration. This paper presents estimates of groundwater contributions to the SAL obtained through monitoring and modelling and stream flow estimates contributing to the SAL water balance.

Keywords

Stream discharge, Water balance, Numerical flow model, Groundwater depending ecosystems.