In the framework of the MAELSTROM Project, the specific objective for the Portuguese demo site Ave estuary was to understand the flow dynamics in the estuary associated with river discharge and tides, in order to estimate the transport and fate of litter and to help the detailed design of the Bubble Barrier system. Since very limited observations and no flow velocity observations were available for the Ave estuary, Deltares carried out the following activities: - A bathymetric survey was carried out to obtain bed level in the entire estuary, needed for both the set-up of the hydrodynamic model and to prepare for the implementation of the Bubble Barrier system. - Flow velocity and density variation were measured during a tidal cycle (about 13 hours) at selected locations (short-term), during the summer and the winter. - For several weeks (long-term) flow velocity and density were monitored at two locations in the estuary. - In absence of observations, a hydrological model was set-up to obtain river discharge. - Finally, a hydrodynamic model was set-up to obtain flow velocity fields in the area of interest for different tidal and river discharge conditions. This dataset consists in a time series of daily discharge in the second tab. While, the first tab gives an overview of the location and Ave catchment in Portugal. The time series was obtained by running a hydrological model that was set-up for the catchment. Using European data like rainfall, the river discharge was calculated. For more details, see MAELSTROM deliverable 2.2.

One of the aim of the MAELSTROM project was to provide a new set of integrated and advanced solutions to identify the typology of marine litter and foremost its traceability from the collection to the treatment phase through innovative app and portal. The Project developed a software and hardware tracking platform for ML data mining and sharing to narrate the in-field organization and testing of marine litter tracking, monitoring and clean up activities. The campaign conducted by Venice Lagoon Plastic Free (VLPF) of marine litter monitoring in the lagoon of Venice in Italy was devised to provide guidance and the feedback required to instruct the technical team's work involved in framing, developing, and fine-tuning the marine litter monitoring service within the MAELSTROM app. The dataset represents the results of four beach litter surveys conducted in the area of the Venice Lagoon in 2021. Data report the number of items identified on the beaches in a 100 m long transect along the beach length. The typology of items is identified using the “G code”, as per the Guidelines and forms for gathering marine litter data: beach and seafloor trawling (Galgani et al., 2021). For more information about the survey see the project deliverable 6.1.