Foz do Arelho outfall plume predictive study

A seawater quality monitoring program for Foz do Arelho outfall has already started in May 2006 to evaluate the background seawater quality around the vicinity of the sea outfall and to follow the impacts of wastewater discharge in the area. Seven monitoring campaigns were already performed between 2006-2007 in which CTD and ADCP measurements were obtained in the vicinity of the wastewater discharge. Predictions of the plume behavior for several times of the year were obtained using a near field model with the monitoring data as input. The plume behavior was mostly influenced by density stratification. During stratified conditions the plume was trapped with dilutions always above 270 to 1. During unstratified conditions the plume was surfacing with dilutions above always 375 to 1. It is concluded that the outfall is behaving as expected.