Haylie M. Brown Seth A. Siefken 20250428 text file Reston, Virginia U.S. Geological Survey https://doi.org/10.5066/P1449JPM Seth A. Siefken Tara Williams-Sether Nancy A. Barth Katherine J. Chase Mark A. Cedar Face 2025 publication Scientific Investigations Report 2025-5019 Reston, Virginia U.S. Geological Survey https://doi.org/10.3133/sir20255019 This file contains peak-flow data in tab-delimited format for selected streamgages based on data through water year 2022. The file was retrieved from the USGS NWIS peak-flow database (https://nwis.waterdata.usgs.gov/usa/nwis/peak). This file provides peak-flow data input to the U.S. Geological Survey peakfq software package used for peak-flow frequency analyses. 19101001 20240930 ground condition Complete Unknown -116.0492 -114.3137 48.9508 47.5919 ISO 19115 Topic Category inlandWaters USGS Thesaurus computational methods statistical analysis time series analysis stream-gage measurement hydrologic processes floods streamflow hazards USGS-CC Natural Hazards hazard preparedness watershed management General peak-flow frequency annual exceedance probability streamflow hydrology USGS Metadata Identifier USGS:67c9bba5d34ed3737708c94f Common geographic areas Land North America United States Montana Upper Kootenai Lower Kootenai Yaak Lower Clark Fork none None. Users are advised to read the dataset's metadata thoroughly to understand appropriate use and data limitations. Seth Siefken U.S. Geological Survey Wyoming-Montana Water Science Center Hydrologist mailing and physical

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Helena MT 59601 US 406-475-4626 ssiefken@usgs.gov This analysis was completed by the U.S. Geological Survey, in cooperation with the Montana Department of Natural Resources and Conservation. Siefken, S.A., Crouch, S., Rucker, S., Wavra, H. N., Faunce, K. E., Boles, C. 2024 application/service Reston, Virginia U.S. Geological Survey https://doi.org/10.5066/P14NQH6T Water Resources Division, U.S. Geological Survey 2003 publication U.S. Geological Survey Open-File Report 2003-123 Reston, Virginia U. S. Geological Survey https://doi.org/10.3133/ofr03123 U.S. Geological Survey 2024 application/service Reston, Virginia U.S. Geological Survey http://nwis.waterdata.usgs.gov/usa/nwis/peak No formal attribute accuracy tests were conducted. No formal logical accuracy tests were conducted. Data set is considered complete for the information presented, as described in the abstract. Users are advised to read the rest of the metadata record carefully for additional details. No formal positional accuracy tests were conducted. No formal positional accuracy tests were conducted. U.S. Geological Survey 2024 application/service Reston, Virginia U.S. Geological Survey http://nwis.waterdata.usgs.gov/usa/nwis/peak annual peak-flow data 19101001 20240930 see dates NWIS Peak-flow data for selected streamgages were obtained from NWIS in tab-delimited format. Data obtained from NWIS and exported in tab-delimited format. NWIS 2024 To distinguish between multiple analyses performed for the same streamgage, the USGS streamgage identification number is appended with an analysis designation in the format XXXXXXXX.AB, where XXXXXXXX is the USGS streamgage identification number, A is the alteration status for the analysis, and B is the type of peak-flow frequency analysis. Values of A (alteration status) are defined as: A = 0, unaltered; A = 1, altered (either major or minor alteration); A = 2, total, where the “Total” analysis is based on all available peak-flow records, including both unaltered and altered peak-flow records for streamgages with peak-flow records before and after the start of alteration; and A = 3, Urbanized. Values of B (type of peak-flow frequency analysis) are defined as: B = 0, at-site peak-flow frequency analysis conducted on recorded data; B = 1, peak-flow frequency analysis conducted on combined recorded and synthesized data; synthesized data from Maintenance of Variance Extension Type III (MOVE.3) record extension procedure; B = 2, peak-flow frequency analysis determined from regional regression equations (RREs); B = 3, at-site peak-flow frequency analysis weighted with results from RREs; and B = 4, analysis with paleoflood data. For streamgages where multiple analyses were desired, the data for that streamgage were duplicated and the appropriate suffixes were added to the duplicate data. 2024 In some cases, peak flows obtained from NWIS were modified using one of the three methods described in Siefken and others, 2025, Sections "Data Combination" and "Data Correction". 2024 1.0E-4 1.0E-4 Decimal degrees North American Datum of 1983 (NAD 83) Geodetic Reference System 1980 6378137.0 298.257223563 wymt_ffa_2024Lincoln_nwis_peak.txt Annual peak-flow data in tab-delimited format. The file was retrieved from the USGS peak-flow database (https://nwis.waterdata.usgs.gov/usa/nwis/peak). Rows in the file starting with the "#" character in the first column contain the date and time of download, a disclaimer statement, a list of fields contained in the file, a list of site numbers in the file, and lists of streamflow and gage-height qualification codes. The tab-separated data that follow begin with two header rows; the first contains the field names and the second lists the number of characters in the field and a letter representing the data type, either "s" (serial) or "d" (date). Field names are described below. USGS agency_cd Agency code USGS The agency code is either USGS or, if the records were furnished by another agency, the code associate with that respective agency. site_no Streamgage identification number and analysis designation USGS U.S. Geological Survey streamgage identification number appended with analysis designation XXXXXXXX.AB where XXXXXXXX is the streamgage identification number; A is the alteration status for the analysis, and B is the type of peak-flow frequency analysis. Values of A (alteration status) are defined as: A = 0, unaltered; A = 1, altered (either major or minor alteration); A = 2, total, where the “Total” analysis is based on all available peak-flow records, including both unaltered and altered peak-flow records for streamgages with peak-flow records before and after the start of alteration; and A = 3, Urbanized. Values of B (type of peak-flow frequency analysis) are defined as: B = 0, at-site peak-flow frequency analysis conducted on recorded data; B = 1, peak-flow frequency analysis conducted on combined recorded and synthesized data; synthesized data from Maintenance of Variance Extension Type III (MOVE.3) record extension procedure; B = 2, peak-flow frequency analysis determined from regional regression equations (RREs); B = 3, at-site peak-flow frequency analysis weighted with results from RREs; and B = 4, analysis with paleoflood data. peak_dt Date of peak streamflow (format YYYY-MM-DD) USGS The date of the annual peak flow is expressed as yyyy-mm-dd. If only the year and month are known, it is expressed as yyyy-mm-00; if only the year is known, it is expressed as yyyy-00-00. peak_tm Time of peak streamflow (24 hour format, 00:00 - 23:59) USGS The time of the annual peak flow is expressed in 24 hour format, ranging from 00:00 - 23:59. If the time is unknown, the field is blank. peak_va Annual peak streamflow value in cubic feet per second USGS defined 1 123000 cubic feet per second peak_cd Peak discharge-qualification code USGS (see https://help.waterdata.usgs.gov/codes-and-parameters/peak-streamflow-special-conditions-peak.peak_cd) 1 discharge is a maximum daily average USGS (see https://help.waterdata.usgs.gov/codes-and-parameters/peak-streamflow-special-conditions-peak.peak_cd) 2 discharge is an estimate USGS (see https://help.waterdata.usgs.gov/codes-and-parameters/peak-streamflow-special-conditions-peak.peak_cd) 3 discharge affected by dam failure USGS (see https://help.waterdata.usgs.gov/codes-and-parameters/peak-streamflow-special-conditions-peak.peak_cd) 4 discharge less than indicated value, which is the minimum recordable discharge at this site USGS (see https://help.waterdata.usgs.gov/codes-and-parameters/peak-streamflow-special-conditions-peak.peak_cd) 5 discharge affected to an unknown degree by regulation and diversion USGS (see https://help.waterdata.usgs.gov/codes-and-parameters/peak-streamflow-special-conditions-peak.peak_cd) 6 discharge affected by regulation or diversion USGS (see https://help.waterdata.usgs.gov/codes-and-parameters/peak-streamflow-special-conditions-peak.peak_cd) 7 discharge is an historic peak USGS (see https://help.waterdata.usgs.gov/codes-and-parameters/peak-streamflow-special-conditions-peak.peak_cd) 8 discharge actually greater than indicated value USGS (see https://help.waterdata.usgs.gov/codes-and-parameters/peak-streamflow-special-conditions-peak.peak_cd) 9 discharge due to snowmelt, hurricane, ice-jam or debris-dam breakup USGS (see https://help.waterdata.usgs.gov/codes-and-parameters/peak-streamflow-special-conditions-peak.peak_cd) A Year of occurrence in unknown or not exact USGS (see https://help.waterdata.usgs.gov/codes-and-parameters/peak-streamflow-special-conditions-peak.peak_cd) Bd Day of occurrence is unknown or not exact USGS (see https://help.waterdata.usgs.gov/codes-and-parameters/peak-streamflow-special-conditions-peak.peak_cd) Bm Month of occurrence is unknown or not exact USGS (see https://help.waterdata.usgs.gov/codes-and-parameters/peak-streamflow-special-conditions-peak.peak_cd) C all or part of the annual peak-flow record affected by urbanization, mining, agricultural changes, channelization, or other USGS (see https://help.waterdata.usgs.gov/codes-and-parameters/peak-streamflow-special-conditions-peak.peak_cd) D Base discharge changed during this year USGS (see https://help.waterdata.usgs.gov/codes-and-parameters/peak-streamflow-special-conditions-peak.peak_cd) E Only the annual maximum peak is available for this year USGS (see https://help.waterdata.usgs.gov/codes-and-parameters/peak-streamflow-special-conditions-peak.peak_cd) F Peak supplied by another agency USGS (see https://help.waterdata.usgs.gov/codes-and-parameters/peak-streamflow-special-conditions-peak.peak_cd) O Opportunistic annual peak not from systematic data collection USGS (see https://help.waterdata.usgs.gov/codes-and-parameters/peak-streamflow-special-conditions-peak.peak_cd) R Revised USGS (see https://help.waterdata.usgs.gov/codes-and-parameters/peak-streamflow-special-conditions-peak.peak_cd) gage_ht Gage height for the associated peak streamflow, in feet relative to gage datum USGS defined 0.03 123.4 feet 0.01 gage_ht_cd Gage height qualification code USGS (see https://help.waterdata.usgs.gov/codes-and-parameters/peak-streamflow-special-conditions-peak.peak_cd) 1 Gage height affected by backwater USGS (see https://help.waterdata.usgs.gov/codes-and-parameters/peak-streamflow-special-conditions-peak.peak_cd) 2 Gage height not the maximum for the year USGS (see https://help.waterdata.usgs.gov/codes-and-parameters/peak-streamflow-special-conditions-peak.peak_cd) 3 Gage height was at a different site and/or datum USGS (see https://help.waterdata.usgs.gov/codes-and-parameters/peak-streamflow-special-conditions-peak.peak_cd) 4 Gage height below minimum recordable elevation USGS (see https://help.waterdata.usgs.gov/codes-and-parameters/peak-streamflow-special-conditions-peak.peak_cd) 5 Gage height is an estimate USGS (see https://help.waterdata.usgs.gov/codes-and-parameters/peak-streamflow-special-conditions-peak.peak_cd) 6 Gage height datum changed during this year USGS (see https://help.waterdata.usgs.gov/codes-and-parameters/peak-streamflow-special-conditions-peak.peak_cd) 7 Debris, mud, or hyper-concentrated flow USGS (see https://help.waterdata.usgs.gov/codes-and-parameters/peak-streamflow-special-conditions-peak.peak_cd) 8 Gage height tidally affected USGS (see https://help.waterdata.usgs.gov/codes-and-parameters/peak-streamflow-special-conditions-peak.peak_cd) Bd Day of occurrence is unknown or not exact USGS (see https://help.waterdata.usgs.gov/codes-and-parameters/peak-streamflow-special-conditions-peak.peak_cd) Bm Month of occurrence is unknown or not exact USGS (see https://help.waterdata.usgs.gov/codes-and-parameters/peak-streamflow-special-conditions-peak.peak_cd) F Peak supplied by another agency USGS (see https://help.waterdata.usgs.gov/codes-and-parameters/peak-streamflow-special-conditions-peak.peak_cd) R Revised USGS (see https://help.waterdata.usgs.gov/codes-and-parameters/peak-streamflow-special-conditions-peak.peak_cd) year_last_pk Peak streamflow reported is the highest since this year USGS The annual peak streamflow assigned a year in this column is the largest in magnitude since the assigned year. ag_dt Date of maximum gage-height for water year (if not concurrent with peak) USGS The maximum gage-height can occur on a different date than the maximum streamflow; for example, during a period of backwater. ag_tm Time of maximum gage-height for water year (if not concurrent with peak) USGS The maximum gage-height can occur at a different time than the maximum streamflow; for example, at an index velocity site where the velocity peak can precede the gage-height peak. ag_gage_ht Maximum Gage height for water year in feet relative to gage datum (if not concurrent with peak) USGS defined 1.53 8.79 feet 0.01 ag_gage_ht_cd Maximum gage height code USGS defined 1 Gage height affected by backwater producer defined GS ScienceBase U.S. Geological Survey mailing and physical

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Denver CO 80225 US 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 on any other system or for general or scientific purposes, nor shall the act of distribution constitute any such warranty. Digital Data https://doi.org/10.5066/P1449JPM None Users should be familiar with hydrologic and statistical methods used for calculating, interpreting, and applying these data. 20250428 Seth Siefken U.S. Geological Survey Wyoming-Montana Water Science Center Hydrologist mailing and physical

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Helena MT 59601 US 406-475-4626 ssiefken@usgs.gov Content Standard for Digital Geospatial Metadata FGDC-STD-001-1998