Towards a new methodology to evaluate the environmental impact of a marine outfall using a lightweight AUV

This paper describes a new methodology to analyze the effect of a marine outfall and its toxic waste on the surrounding submarine ecosystems, combining divers and a lightweight Autonomous Underwater Vehicle (AUV) deployed and controlled from a small recreational boat. The innovation here is twofold: a) the relatively low cost equipment and human resources used in the overall process and the subsequent minimization of human risks, b) the application of all the technology that implies the use of an autonomous vehicle in this particular application, (automatic geo-localization, accurate mission programming and execution, increasing mission time or diverse sensorial data recollection). The process intends to go one step beyond the current methods employed to inspect marine industrial infrastructures, shipwrecks, geological or benthic zones of special interest, based on the participation of divers and, in some cases, Remotely Operated Vehicles (ROVs). The case study presented in this paper corresponds to the inspection of the sewage outfall in Palma de Mallorca, started after the detection of Cyanobacterium on the surrounding seafloor, a living organism which appearance indicates elevated concentration of nitrates and pollution in the water.