Liam N. Schenk 20250930 spreadsheet https://doi.org/10.5066/P147NJAV This model archive summary (MAS) and associated model calibration data contains two model evaluations: 1) a model validation of the prior-published sediment surrogate model at this site for WY 2019-2023, and 2) a new log-transformed turbidity-suspended sediment (SSC) regression model computing SSC from 01/17/2024 to 2/27/2025 following the drawdown of the John C. Boyle reservoir and release of large amounts of sediment from behind the dam prior to the physical removal of the dam in August 2024. The methods used follow USGS guidance as referenced in Office of Surface Water (OSW)/Office of Water Quality (OWQ) technical memoranda 2016.07 and USGS techniques and methods, book 3-chapter C4 (Rasmussen and others, 2009). The purpose of this data release is to document techniques and methods used to develop a turbidity-derived suspended sediment computation model for the Klamath River below John C. Boyle power plant near Keno, Oregon, following the drawdown and removal of the John C. Boyle dam in water year 2024. The model represents cross section composite suspended sediment concentrations. 20230913 20250227 ground condition Complete None planned -122.1954 -121.9812 42.1614 42.0105 ISO 19115 Topic Category inlandWaters USGS Thesaurus suspended material (water) USGS Metadata Identifier USGS:686d9ff2d4be026f4a0164a8 Common geographic areas Oregon GNIS Klamath River None. Users are advised to read the dataset's metadata thoroughly to understand appropriate use and data limitations. These data are in the public domain in accordance with Creative Commons Zero v1.0 Universal Public Domain Dedication (CC0-1.0) and have no use constraints. Liam Schenk mailing and physical

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Bend OR 97701 541-408-8731 gs-w-or_sciencebase@usgs.gov Pat P. Rasmussen John R. Gray G. Douglas Glysson Andrew C. Ziegler 2009 publication n/a U.S. Geological Survey USGS open file report describing techniques and methods for creating sediment surrogate models. https://pubs.usgs.gov/tm/tm3c4/ U.S. Geological Survey 20160930 Technical Memorandum publication Office of Surface Water Technical Memorandum 2016.07 Office of Water Quality Technical Memorandum 2016.10 https://water.usgs.gov/admin/memo/SW/sw.2016.07+wq.2016.10.pdf Data accuracy was evaluated by plotting the suspended sediment concentration (SSC) observations on the time series of regression-computed SSC and the 90 percent prediction intervals. The 90 percent prediction intervals represent the range in uncertainty associated with each regression-computed SSC value. Accuracy is also evaluated by examining the residual plots of regression-computed and observed values of SSC. The observed suspended sediment concentration (SSC) values fall within the 90 percent prediction intervals of the regression-computed SSC. The data represent occurrences of suspended sediment concentrations (SSC) at a specific location, USGS site ID 11510700, Klamath River below John C. Boyle power plant, near Keno, OR United States Geological Survey 1994 dataset https://www.sciencebase.gov U.S. Geological Survey https://doi.org/10.5066/f7p55kjn Digital and/or Hardcopy 20231001 20250227 observed Turbidity, streamflow, and suspended-sediment concentration data This source input is used to obtain data used in this data release. Time series of turbidity and streamflow, and discrete suspended-sediment concentration and percent fines data are obtained from the USGS National Water Information System (NWIS) and R software version 4.4.0. 20250703 The calibration dataset was generated by pairing suspended-sediment concentration (SSC) results with concurrent readings of turbidity in formazin nephelometric units (FNU) using data obtained from the USGS Water Data for the Nation and R software version 4.4.0. Model selection followed methods described in USGS Techniques and Methods 3-C4 (DOI 10.3133/tm3C4). The resulting dataset was loaded into the "wren" package version 0.0.1 (https://code.usgs.gov/water/stats/wren) to generate model statistics and plots for the final model. 20250703 1 1 Degrees, minutes, and decimal seconds North American Datum of 1927 (NAD 27) Clarke 1866 6378206.400000 294.978698 Boyle_caldata_2024_final.csv Comma Separated Value (CSV) file containing suspended-sediment,percent fines, turbidity, and streamflow data used to calibrate the surrogate model described in the model archive summary word document. Producer Defined datetime The date and time when the sample was collected, in pacific standard time Producer Defined 1/17/2024 10:50 9/4/2024 7:23 day 1 WY The water year in which the sample was collected Producer Defined 2023 2025 water year 1 SSC Suspended Sediment Concentration of the sample Producer Defined 5 5720 milligrams per liter 1 CSC Cross section coefficient. A unitless value used to change the concentration of an ISCO or GRAB sample to represent cross section suspended sediment concentration Producer Defined . Not applicable, cross section coefficient not needed because the sample is a cross section composite. Producer defined 0.81 1.01 unitless 0.01 final_SSC The final suspended sediment concentration used to calibrate the model, after the cross section coefficient is applied (if applicable) Producer Defined 4 5720 milligrams per liter 1 Fines The percent of the sample with grain size < 0.0625 mm in diameter Producer Defined 68 100 percent 1 SampleType The type of sample collected in the field for suspended sediment concentration laboratory analysis Producer Defined GRAB A sample collected by hand with an open mouth bottle near the intake tube for the pumping sampler. Producer defined ISCO A sample collected from the stream using a suction lift pumping mechanism Producer defined EDI equal discharge increment, a sample that represents cross section composite concentration of suspended sediment Producer defined Flow_Inst Instantaneous streamflow Producer Defined 345 9210 cubic feet per second 1 Turb_Inst Instantaneous turbidity Producer Defined 1.5 711.0 formazin nephelometric units 0.1 logQ log-10 transformed instantaneous streamflow Producer Defined 2.537819095 3.96425963 log10 of cubic feet per second 0.000000001 logTurb log-10 transformed turbidity Producer Defined 0.176091259 2.851869601 log10 of formazin nephelometric units 0.000000001 logSSC log-10 transformed suspended sediment concentration Producer Defined 0.602059991 3.757396029 log10 of milligrams per liter 0.000000001 Model Type The type of model the data were used for Producer Defined VAL_2019-2023 Validation model for the prior-published 2019-2023 dataset Producer defined NEW_2024-2025 The new model for the January 2024 to February 2025 model Producer defined GS ScienceBase U.S. Geological Survey mailing address

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Denver CO 80225 United States 1-888-275-8747 sciencebase@usgs.gov Unless otherwise stated, all data, metadata and related materials are considered to satisfy the quality standards relative to the purpose for which the data were collected. Although these data and associated metadata have been reviewed for accuracy and completeness and approved for release by the U.S. Geological Survey (USGS), no warranty expressed or implied is made regarding the display or utility of the data for other purposes, nor on all computer systems, nor shall the act of distribution constitute any such warranty. Digital Data https://doi.org/10.5066/P147NJAV None 20250929 Liam N Schenk Science Advisor mailing and physical

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Bend OR 97701 541-408-8731 gs-w-or_sciencebase@usgs.gov FGDC Content Standard for Digital Geospatial Metadata FGDC-STD-001-1998