Geology topics

Research about Stanley, Idaho

Source-linked reports with geographic coverage including Stanley, Idaho.

4 recordsLinked to original sources

USGS2021

Sediment transport in the Yankee Fork of the Salmon River near Stanley, Idaho, water years 2012–19

Placer and dredging operations in the Yankee Fork Basin, Idaho, have left more than 5 miles of the lower Yankee Fork of the Salmon River (Yankee Fork) in a highly altered fluvial condition, resulting in poor habitat quantity and quality for native fish species. Since 2011, the Bureau of Reclamation and other stakeholders have implemented a series of restoration efforts to improve the connectivity of the river with its floodplain and to improve aquatic and terrestrial habitat in the Yankee Fork. In conjunction with these rehabilitation efforts, the U.S. Geological Survey monitored streamflow and suspended-sediment and bedload transport during water years 2012–19 at four sites in the affected lower reach of the Yankee Fork. The objectives of the monitoring were to (1) identify source areas of sediment, (2) quantify sediment transport in the lower Yankee Fork, and (3) provide a benchmark to evaluate the effects of rehabilitation efforts in the basin. During the 8 years of sampling, the annual flow-weighted suspended-sediment concentrations (SSCs) were largest at the most downstream Clayton site, ranging from a low of 11 milligrams per liter (mg/L) in 2015 to 145 mg/L in 2017. The Clayton site also had the largest flow-weighted concentrations of suspended sand and suspended fines. At relatively low streamflow, the fine-grained fraction of the suspended sediment was the dominant component of the SSC at all sites, with an increase in the sand-size fraction as streamflow increased during snowmelt runoff. Each of the three main-stem Yankee Fork sites indicated a large amount of hysteresis in SSCs during snowmelt runoff, with concentrations on the rising limb of the hydrograph larger than concentrations on the falling limb at similar streamflow. Hysteresis was particularly evident in the fine-grained fraction of suspended sediment, indicating that sediment transport in the lower Yankee Fork is more limited by the supply of fine-grained sediment as compared to coarser-grained sediment.

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USGS2020

Rupture process of the M6.5 Stanley, Idaho, earthquake inferred from seismic waveform and geodetic data

The 2020 M 6.5 Stanley, Idaho, earthquake produced rupture in the north of the active Sawtooth fault in the northern basin and range at depth, without any observable surface rupture. Global Positioning System (GPS) and Interferometric Synthetic Aperture Radar (InSAR) data yield several millimeters of static offsets out to ∼100 km from the rupture and up to ∼0.1 m of near‐field crustal deformation. We combine the GPS and InSAR data with long‐period regional seismic waveforms to derive models of kinematic slip and afterslip. We find that the coseismic rupture is complex, likely involving up to 2 m combined left‐lateral strike slip and normal slip on a previously unidentified ∼south‐southeast‐striking fault. This slip is predominantly left‐lateral strike slip, different from the dominant east‐northeast–west‐northwest normal faulting of the region. At least one ∼northeast‐trending fault, likely associated with the Trans‐Challis fault system, is inferred to have accommodated a few decimeters of right‐lateral afterslip, consistent with vigorous aftershock activity at depth along northeast‐trending lineations.

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USGS2018

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<0.0001), indicating a strong linear correlation. Suspended-sediment samples collected mostly during snowmelt runoff showed a positive correlation with stream discharge. Hysteresis in the sample results indicates a supply-limited suspended-sediment transport regime. Percent sand by weight of suspended-sediment samples identified a possible discharge threshold for sand suspension at about 400 cubic feet per second (ft 3 /s) at the Bonanza site and about 1,000 ft 3 /s at the Confluence and Gage sites.

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USGS2004

Instream flow characterization of upper Salmon River Basin streams, Central Idaho, 2003

Anadromous fish populations in the Columbia River Basin have plummeted in the last 100 years. This severe decline led to Federal listing of chinook salmon ( Oncorhynchus tshawytscha ) and steelhead trout ( Oncorhynchus mykiss ) stocks as endangered or threatened under the Endangered Species Act (ESA) in the 1990s. Historically, the upper Salmon River Basin (upstream from the confluence with the Pahsimeroi River) in Idaho provided migration corridors and significant habitat for these ESA-listed species, in addition to the federally listed bull trout ( Salvelinus confluentus ). Human development has modified the original streamflow conditions in many streams in the upper Salmon River Basin. Summer streamflow modifications, as a result of irrigation practices, have directly affected the quantity and quality of fish habitat and also have affected migration and (or) access to suitable spawning and rearing habitat for these fish. As a result of these ESA listings and Action 149 of the Federal Columbia River Power System Biological Opinion of 2000, the Bureau of Reclamation was tasked to conduct streamflow characterization studies in the upper Salmon River Basin to clearly define habitat requirements for effective species management and habitat restoration. These studies include the collection of habitat and streamflow information for the Physical Habitat Simulation (PHABSIM) model, a widely applied method to determine relations between habitat and discharge requirements for various fish species and life stages. Model results can be used by resource managers to guide habitat restoration efforts in the evaluation of potential fish habitat and passage improvements by increasing streamflow. Instream flow characterization studies were completed on Pole, Fourth of July, Elk, and Valley Creeks during 2003. Continuous streamflow data were collected upstream from all diversions on each stream. In addition, natural summer streamflows were estimated for each study site using regression equations. PHABSIM results are presented for bull trout, chinook salmon, and steelhead trout over a range of summer streamflows. Habitat/discharge relations are summarized for juvenile, adult, and spawning life stages at each study site. Adult fish passage and discharge relations are evaluated at specific transects identified as a potential low-streamflow passage barrier at each study site. Continuous summer water temperature data for selected study sites also are summarized and compared with Idaho Water Quality Standards and various temperature requirements of targeted fish species. Results of these habitat studies can be used to prioritize and direct cost-effective actions to improve fish habitat for ESA-listed anadromous and native fish species in the basin. These actions may include acquiring water during critical low-flow periods by leasing or modifying irrigation delivery systems to minimize out-of-stream diversions.

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