Sediment transport monitoring of the Yankee Fork of the Salmon River near Stanley, Idaho, 2012–15

The Yankee Fork of the Salmon River is one of the larger watersheds in the upper Salmon River subbasin of central Idaho. Mining activities since the late 19th century, specifically placer mining and associated dredging from 1940 to 1953, have left the fluvial system in a highly altered and unnatural state. To improve aquatic and terrestrial habitat in the Yankee Fork, the Bureau of Reclamation and other stakeholders collaborated on the Dredge Tailings Restoration Project and Yankee Fork Rehabilitation Project. In conjunction with these rehabilitation efforts, the U.S. Geological Survey monitored suspended-sediment transport and discharge between 2012 and 2015 at three sites in the lower reaches of the Yankee Fork. Pseudo-hydrographs were developed for the Bonanza and Confluence sites using data from the streamgage site as a surrogate. Results showed a good fit between measured and calculated discharge with R2 values of 0.96 for the Bonanza site and 0.98 for the Confluence site. Both regressions have high hypothesis test statistics (t>23) and low probability values (p