Dataset used for the note titled "Detection of plastic litter using an ARIS sonar."Summary:This report describes a first test in April 2021 to use an ARIS sonar to detect macro- and mesoplastic in the water column of the river Waal (a free flowing distributary of the river Rhine in the Netherlands). Tests were performed in standing water, flowing water along the shore of the river and fast flowing water in the main channel simultaneous with stow net fishing. The costs associated with the ARIS sonar were financed by Rijkswaterstaat Oost Nederland. The preliminary data acquisition and analysis were performed by the Radboud University.The dataset includes raw ARIS sonar data (.aris format) collected on two separate dates:1.Dataset collected on 16-04-2021; file names are date_time_name of the plastic litter assessed.2.Dataset collected on 19-04-2021; file names end date_time_name of the plastic litter assessed (If not included then it was a test with several items).Opens with: ARISFish software