MEDCOAST 01, The Fifth International Conference on the Mediterranean Coastal Environment 23-27 October 2001, Hamammet, Tunisia Prediction Studies for an AUV Monitoring Mission Plan Patrícia Ramos 1,2 , Nuno Cruz 1 , Aníbal Matos 1 , Mário V. Neves 1 , Fernando L. Pereira 1 1 Faculdade de Engenharia da Universidade do Porto Rua Dr. Roberto Frias, 4200-465 Porto, Portugal Tel. + 351-225081539 Fax. +351-225081440 2 Instituto Superior de Contabilidade e Administração do Porto Rua Padre Costa, 4465-111 S. Mamede de Infesta, Porto, Portugal Tel. + 351-229050000 Fax. + 351-229025899 E-mail: {patricia, nacruz, anibal, mjneves, flp}@fe.up.pt Abstract Wastewater plumes show to be very difficult to observed in detail. The several field studies already conducted exhibit very complex and patchy structures both in vertical and horizontal sections. It is not clear yet if this plume patchiness is due to physical processes or measurement limitations. Rapid tow-yo sampling is expected to reduce the time variability during and between transects. The AUVs may be a useful instrument to detect and map wastewater plumes. This paper presents several prediction studies using time series files of actual in- situ measurements integrated in the UM3 near field model. The model predictions of the plume characteristics at the end of near field support the definition of the best sampling strategy for an AUV monitoring mission in a Portuguese west coast outfall. Introduction Several field studies using different types of techniques were already performed in order to map and detect sewage plumes (Washburn et al., 1994), (Petrenko et al., 1998)