Dams suggest progress — they are a way of arresting the flow of water (and that which it contains) to convert its potential energy into something useable. But in so doing, dams reconfigure the multiple lives and non-lives within which riparian residents live. But this is a transformation, not simply an erasure: as multiple scholars have shown, modernity gives rise to new magics, and new ways of being. This lecture explores these new ways of negotiating power and potency on a changed river, asking what new horizons open as old ones close, and exploring how these new potentials disturb webs of being and dwelling on the river.