Bouwes, N., Weber, N., Jordan, C.E., Saunders, W.C., Tattam, I.A., Volk, C., Wheaton, J.M. and Pollock, M.M. (2016). “Ecosystem experiment reveals benefits of natural and simulated beaver dams to a threatened population of steelhead (Oncorhynchus mykiss).” Scientific Reports, 6, 28581. https://doi.org/10.1038/srep28581
In 2009 the team installed 76 beaver dam analogues over 3.4 km of Bridge Creek, an incised tributary of the John Day River, and kept building to replace failures until 121 were working in 2012. Treatment reaches were compared with control reaches in Bridge Creek and with Murderers Creek as a watershed control, using fish data from 2007 to 2009 before treatment and 2010 to 2013 after. Juvenile steelhead density, survival and production rose in the treated stream, with no effect on upstream or downstream migration. Baseflow was not reported. The wiki cites it as the best controlled design in the retention literature and as a model for monitoring, while noting that it measured fish and habitat and left water volume unmeasured.