smart rivers' 21 is a joint initiative among organisations from Unites States and Europe active in the field of Inland Waterway Transport (IWT). Inland waterways provide a significant transport capacity mostly under-utilized, while road and rail transport increasingly lacks on sufficient capacity (especially near big cities). The 4th smart rivers' 21 conference focuses on trends, policy, technology and science in relation to IWT with worldwide attendance of visitors, speakers and exhibitors.