Comprehensive mapping of river barriers

The environmental effects of large dams on river connectivity are well recognized and mapped globally. However, datasets describing the distribution and attributes of smaller barriers (such as weirs and culverts) are lacking or incomplete for many regions. This study critically examines barrier mapping approaches, from field survey to automated detection, showcasing recent approaches to recording, counting and classifying river barriers. We demonstrate how incomplete barrier databases, particularly those lacking many small barriers, provide a flawed basis for water management and ecological restoration planning. We discuss the efficiency and accuracy of alternative barrier mapping approaches, highlight future priorities and emphasize harmonizing barrier assessment methods to generate reliable, freely available information for effective basin-level management.

Sun, J., Lucas, M.C., Olden, J.D., Couto, T.B.A., Ning, N., Duffy, D., and L.J. Baumgartner. 2025. Towards a comprehensive river barrier mapping solution to support environmental management. Nature Water 3: 38-48. Article