Maritime activities (commercial and pleasure navigation) can induce indirect effects on the environment. The project is particularly interested in studying their effects on bank erosion (Part 1) and the navigation channel (Part 2). In Part 1, the effects of commercial and pleasure navigation will be compared. In Part 2, the aim is to predict using a 3D model the increase in turbidity and the decrease of dissolved oxygen during dredging and immersion operations. From four approaches (field measurements, laboratory tests, modeling and mathematical simulations, sociological and legal surveys on risk perception), a table of opportunities and navigation scenarios will be developed. Management solutions (new regulations for pleasure or commercial navigation) will be tested in terms of acceptability for reducing the risk of bank erosion. Turbidity and oxygenation results will be used to locate areas at risk of hypoxia and to determine durations of exposure. The project results come from these four approaches. The field measurements will allow to compare (qualitatively and quantitatively) the shipping signatures for a total of four sites in France and Quebec. Laboratory tests will determine sedimentological properties and their transport parameters or improve the formulation of laws relating to muddy sediments. Numerical modeling validated on field and laboratory measurements will be used to study different navigation scenarios (trajectory, speed or regulation) in order to reduce risks related to bank erosion or maintenance operations. Surveys on the perception (sociological with a legal insight) of the risks from collective or semi-directed interview will identify actions to improve the management practices or to change the regulations. At the end of the project, a 3D simulation tool for supporting decision will be available in open-source. Scientific analyses of the effects of commercial and recreational navigation on the risks of bank erosion or hypoxia will be available for improving practices. The project consortium involves various organizations in France and Quebec for a highly transdisciplinary approach with the involvement of universities, a public administrative institution, port authorities, actors in economic development or maritime transport, a community representing First Nations. The approach is also intersectoral (natural sciences and engineering, human and social sciences) and strongly interdisciplinary (sociology, law, civil engineering, physics and fluid mechanics, geophysics and applied mathematics). An external committee will be set up to communicate the results to international, federal, national or regional, municipal and associative bodies. Finally the scientific results will be communicated at congresses and published in international journals.