This work was supported by Phase 2 of the Fluvial Systems Research Group (BP, BG, Chevron, ConocoPhillips and Total). AE thanks the University of Aberdeen for additional funding and MGMS thanks the São Paulo Research Foundation (FAPESP 2014/13937‐3). The authors also wish to thank numerous residents of the Bighorn Basin for their kind hospitality and access to land, and Isobel Buchanan and Alistair Swan for assistance in the field. The authors also thank reviewers Luca Colombera and Sian Davies‐Vollum and AE Christopher Fielding for helpful comments on this manuscript.Peer reviewedPostprint