Flood Frequency Data and 2022 Observed Flood Probability for Two Streamgages in the Delta River Basin, Alaska, 1963-2022

Identification_Information:

Citation:

Citation_Information:

Originator: Best, Heather R. (ORCID: 0000-0003-0764-3060)
Publication_Date: 20230320
Title:

Geospatial_Data_Presentation_Form: tabular digital data
Publication_Information:

Publication_Place: Anchorage, Alaska
Publisher: U.S. Geological Survey, Alaska Science Center

Other_Citation_Details:

Suggested Citation: Best, H.R., 2023, Flood frequency data and 2022 observed flood probability for two streamgages in the Delta River Basin, Alaska, 1963-2022: U.S. Geological Survey data release, https://doi.org/10.5066/P9WANH3M

Online_Linkage: https://doi.org/10.5066/P9WANH3M
Larger_Work_Citation:

Citation_Information:

Originator: U.S. Geological Survey, Alaska Science Center
Publication_Date: 2022
Title:

Flood Frequency Data Collection, Alaska and Conterminous Basins in Canada

Geospatial_Data_Presentation_Form: website
Publication_Information:

Publication_Place: Anchorage, Alaska
Publisher: U.S. Geological Survey, Alaska Science Center

Other_Citation_Details:

This is a link to the publicly accessible flood frequency data collection from the U.S. Geological Survey (USGS) Alaska Science Center. Users will find links to other flood frequency data from Alaska and conterminous basins in Canada.

Online_Linkage: https://doi.org/10.5066/P9IZB7HH

Description:

Abstract:

This data release provides the source data and results of a flood frequency analysis and annual exceedance probability estimation for a flood that occurred on July 11, 2022 in the Delta River Basin, Alaska. Data are provided for two streamgages that had at least 10 years of peak-flow record. The data include streamgage information, PeakFQ input (.txt and .PSF files) PeakFQ output (.PRT, .EXP, and .JPEG files), flood frequency parameters, flood frequency estimates for the 50-, 20-, 10-, 4-, 2-, 1-, 0.5-, and 0.2-percent annual exceedance probabilities, and annual exceedance probability estimates for the flood of interest. These data were intended to support investigations of streamflow in the Delta River Basin.

Purpose:

Estimates of the magnitude and frequency of floods are needed for engineering design of transportation and water-conveyance structures, flood-insurance studies, flood-plain management, and other water-resource purposes. Previously, the U.S. Geological Survey estimated flood frequency and magnitude for selected streamgages in Alaska and conterminous basins in Canada and developed methods for estimating flood frequency and magnitude at ungaged streams (Curran and others, 2016; available at https://doi.org/10.3133/sir20165024 ). More current estimates of flood frequency are often needed for water-resource purposes, including estimating the annual exceedance probability of an observed flood peak. The U.S. Geological Survey, in collaboration with the Department of Transportation, has computed updated estimates of flood frequency through water year 2022 and annual exceedance probability for the July 11, 2022 flood for two streams in the Delta River Basin using methods and information documented in Curran and others (2016).

Time_Period_of_Content:

Time_Period_Information:

Range_of_Dates/Times:

Beginning_Date: 1963
Ending_Date: 2022

Currentness_Reference: observed

Status:

Progress: Complete
Maintenance_and_Update_Frequency: None planned

Spatial_Domain:

Bounding_Coordinates:

West_Bounding_Coordinate: -145.8730
East_Bounding_Coordinate: -145.8600
North_Bounding_Coordinate: 63.6313
South_Bounding_Coordinate: 63.4949

Keywords:

Theme:

Theme_Keyword_Thesaurus: USGS Metadata Identifier
Theme_Keyword: USGS:ASC522

Theme:

Theme_Keyword_Thesaurus: ISO 19115 Topic Category
Theme_Keyword: InlandWaters

Theme:

Theme_Keyword_Thesaurus: NASA GCMD Earth Science Keyword Thesaurus
Theme_Keyword: Terrestrial Hydrosphere
Theme_Keyword: Rivers/streams
Theme_Keyword: Drainage

Theme:

Theme_Keyword_Thesaurus: USGS Thesaurus
Theme_Keyword: Hydrographic datasets
Theme_Keyword: Hydrology
Theme_Keyword: Streamflow
Theme_Keyword: Floods
Theme_Keyword: Hazards

Place:

Place_Keyword_Thesaurus: USGS Geographic Names Information System (GNIS)
Place_Keyword: Alaska
Place_Keyword: Delta River

Access_Constraints: None
Use_Constraints:

It is requested that the authors and the USGS Alaska Science Center be cited for any subsequent publications that reference this dataset.

Point_of_Contact:

Contact_Information:

Contact_Organization_Primary:

Contact_Organization: U.S. Geological Survey, Alaska Science Center

Contact_Address:

Address_Type: Mailing and Physical
Address: 4210 University Drive
City: Anchorage
State_or_Province: Alaska
Postal_Code: 99508
Country: USA

Contact_Voice_Telephone: 907-786-7000
Contact_Electronic_Mail_Address: ascweb@usgs.gov

Data_Set_Credit: U.S. Department of Transportation
Cross_Reference:

Citation_Information:

Originator: Curran, J.H.
Originator: Barth, N.A.
Originator: Veilleux, A.G.
Originator: Ourso, R.T.
Publication_Date: 2016
Title:

Estimating flood magnitude and frequency at gaged and ungaged sites on streams in Alaska and conterminous basins in Canada, based on data through water year 2012

Geospatial_Data_Presentation_Form: publication
Series_Information:

Series_Name: U.S. Geological Survey Scientific Investigations Report
Issue_Identification: 2016–5024

Publication_Information:

Publication_Place: Reston, VA
Publisher: U.S. Geological Survey

Other_Citation_Details:

Curran, J.H., Barth, N.A., Veilleux, A.G., Ourso, R.T. 2016. Estimating flood magnitude and frequency at gaged and ungaged sites on streams in Alaska and conterminous basins in Canada, based on data through water year 2012. U.S. Geological Survey Scientific Investigations Report 2016–5024. doi:10.3133/sir20165024

Online_Linkage: https://doi.org/10.3133/sir20165024

Data_Quality_Information:

Attribute_Accuracy:

Attribute_Accuracy_Report:

Estimates of flood frequency and annual exceedance probability were visually checked after computation for consistency with data sources and for values far outside the range of expected values. Estimates of accuracy include the variance and confidence interval values included in this data release. The data were peer reviewed prior to dissemination.

Logical_Consistency_Report:

Peak data are reviewed by the U.S. Geological Survey as part of standard quality assurance procedures. Other input parameters such as perception thresholds are based on the judgment of the analyst. The data have been examined and processed for the presence of omissions and errors.

Completeness_Report: Data set is considered complete, no data were omitted.
Positional_Accuracy:

Horizontal_Positional_Accuracy:

Horizontal_Positional_Accuracy_Report:

Latitude and Longitude were retrieved from NWIS, where they are specified to the nearest 0.00000001 degree using the NAD83 datum

Lineage:

Source_Information:

Source_Citation:

Citation_Information:

Originator: Curran, J.H.
Originator: Barth, N.A.
Originator: Veilleux, A.G.
Originator: Ourso, R.T.
Publication_Date: 2016
Title:

Estimating flood magnitude and frequency at gaged and ungaged sites on streams in Alaska and conterminous basins in Canada, based on data through water year 2012

Geospatial_Data_Presentation_Form: journal article
Series_Information:

Series_Name: U.S. Geological Survey Scientific Investigations Report
Issue_Identification: 2016-5024

Publication_Information:

Publication_Place: Reston, VA
Publisher: U.S. Geological Survey

Other_Citation_Details:

Online_Linkage: https://doi.org/10.3133/sir20165024

Type_of_Source_Media: online
Source_Time_Period_of_Content:

Time_Period_Information:

Range_of_Dates/Times:

Beginning_Date: 1909
Ending_Date: 2012

Source_Currentness_Reference: publication date

Source_Citation_Abbreviation: Curran and others 2016
Source_Contribution:

This USGS flood frequency report describes the methods and data sources used to update estimates of flood frequency and magnitude. The report provides information regarding regional skew areas, regression estimates of flood magnitude and frequency, and example procedures for computing a weighted estimate for a gaged site. Table 1 lists basin characteristics (drainage area and mean annual precipitation) used in this analysis.

Source_Information:

Source_Citation:

Citation_Information:

Originator:

U.S. Geological Survey, National Water Information System (NWIS)

Publication_Date: 2022
Title: Water Data for the Nation
Geospatial_Data_Presentation_Form: online database
Publication_Information:

Publication_Place: Reston, VA
Publisher: U.S. Geological Survey

Other_Citation_Details:

U.S. Geological Survey, 2022, Annual peak streamflow data for selected streamgages, in USGS water data for the nation: U.S. Geological Survey National Water Information System database, accessed December 20, 2022, at https://doi.org/10.5066/F7P55KJN [Query parameters: Site Number = 15478093, 15478499; End Date = 2022-09-30]

Online_Linkage: https://doi.org/10.5066/F7P55KJN

Type_of_Source_Media: online database
Source_Time_Period_of_Content:

Time_Period_Information:

Single_Date/Time:

Calendar_Date: 20221220

Source_Currentness_Reference: access date

Source_Citation_Abbreviation: NWIS
Source_Contribution:

Source database for selected streamgage site information and annual peak-streamflow data used in computing flood frequency and magnitude and annual exceedance probability. (Note: Peak-streamflow data are also accessible using 'readNWISpeak' from R package 'dataRetrieval')

Source_Information:

Source_Citation:

Citation_Information:

Originator: U.S. Geological Survey
Publication_Date: 2019
Title: PeakFQ
Geospatial_Data_Presentation_Form: computer program
Series_Information:

Series_Name: PeakFQ
Issue_Identification: ver 7.4, June 28, 2022

Publication_Information:

Publication_Place: Reston, VA
Publisher: U.S. Geological Survey

Other_Citation_Details:

U.S. Geological Survey, 2022, PeakFQ: U.S. Geological Survey Water Resources of the United States Software (ver 7.4, June 28, 2022)

Online_Linkage: https://water.usgs.gov/software/PeakFQ/

Type_of_Source_Media: computer program
Source_Time_Period_of_Content:

Time_Period_Information:

Single_Date/Time:

Calendar_Date: 2022

Source_Currentness_Reference: publication date

Source_Citation_Abbreviation: PeakFQ
Source_Contribution:

U.S. Geological Survey software used for computing station estimates of flood magnitude and frequency.

Source_Information:

Source_Citation:

Citation_Information:

Originator: Flynn, K.M.
Originator: Kirby, W.H.
Originator: Hummel, P.R.
Publication_Date: 2006
Title:

User's Manual for Program PeakFQ Annual Flood-Frequency Analysis Using Bulletin 17B Guidelines

Geospatial_Data_Presentation_Form: document
Series_Information:

Series_Name: U.S. Geological Survey, Techniques and Methods
Issue_Identification: Book 4, Chapter B4

Publication_Information:

Publication_Place: Reston, VA
Publisher: U.S. Geological Survey

Other_Citation_Details:

Flynn, K.M., Kirby, W.H., and Hummel, P.R. 2006. User's Manual for Program PeakFQ Annual Flood-Frequency Analysis Using Bulletin 17B Guidelines: U.S. Geological Survey, Techniques and Methods Book 4, Chapter B4; 42 pp. doi:10.3133/tm4B4

Online_Linkage: https://pubs.usgs.gov/tm/2006/tm4b4/tm4b4.pdf

Type_of_Source_Media: publication
Source_Time_Period_of_Content:

Time_Period_Information:

Single_Date/Time:

Calendar_Date: 2006

Source_Currentness_Reference: publication date

Source_Citation_Abbreviation: Flynn and others 2006
Source_Contribution: User manual for Program PeakFQ

Source_Information:

Source_Citation:

Citation_Information:

Originator: Veilleux, A.G.
Originator: Cohn, T.A.
Originator: Flynn, K.M.
Originator: Mason, R.R., Jr.
Originator: Hummel, P.R.
Publication_Date: 2014
Title:

Estimating magnitude and frequency of floods using the PeakFQ 7.0 program

Geospatial_Data_Presentation_Form: document
Series_Information:

Series_Name: U.S. Geological Survey Fact Sheet
Issue_Identification: 2013-3108

Publication_Information:

Publication_Place: Reston, VA
Publisher: U.S. Geological Survey

Other_Citation_Details:

Veilleux, A.G., Cohn, T.A., Flynn, K.M., Mason, R.R., Jr., Hummel, P.R. 2014. Estimating magnitude and frequency of floods using the PeakFQ 7.0 program. U.S. Geological Survey Fact Sheet 2013-3108 doi:10.3133/fs20133108

Online_Linkage: https://doi.org/10.3133/fs20133108

Type_of_Source_Media: publication
Source_Time_Period_of_Content:

Time_Period_Information:

Single_Date/Time:

Calendar_Date: 2014

Source_Currentness_Reference: publication date

Source_Citation_Abbreviation: Veilleux and others 2014
Source_Contribution:

U.S. Geological Survey guidelines for computing station estimates of flood magnitude and frequency.

Source_Information:

Source_Citation:

Citation_Information:

Originator: England, J.F., Jr.
Originator: Cohn, T.A.
Originator: Faber, B.A.
Originator: Stedinger, J.R.
Originator: Thomas, W.O. Jr.
Originator: Veilleux, A.G.
Originator: Kiang, J.E.
Originator: Mason, R.R., Jr.
Publication_Date: 2018
Title:

Guidelines for determining flood flow frequency—Bulletin 17C (ver. 1.1, May 2019)

Geospatial_Data_Presentation_Form: document
Series_Information:

Series_Name: U.S. Geological Survey Techniques and Methods
Issue_Identification: Book 4, Chapter B5

Publication_Information:

Publication_Place: Reston, VA
Publisher: U.S. Geological Survey

Other_Citation_Details:

England, J.F., Jr., Cohn, T.A., Faber, B.A., Stedinger, J.R., Thomas, W.O., Jr., Veilleux, A.G., Kiang, J.E., and Mason, R.R., Jr., 2018, Guidelines for determining flood flow frequency--Bulletin 17C (ver. 1.1, May 2019): U.S. Geological Survey Techniques and Methods, book 4, chap. B5, 148 p. https://doi.org/10.3133/tm4B5

Online_Linkage: https://doi.org/10.3133/tm4B5

Type_of_Source_Media: publication
Source_Time_Period_of_Content:

Time_Period_Information:

Single_Date/Time:

Calendar_Date: 2018

Source_Currentness_Reference: publication date

Source_Citation_Abbreviation: England and others 2018
Source_Contribution:

This source provided methods and guidelines for flood frequency analysis.

Source_Information:

Source_Citation:

Citation_Information:

Originator: U.S. Geological Survey
Publication_Date: 2012
Title:

Computation of annual exceedance probability (AEP) for characterization of observed flood peaks

Geospatial_Data_Presentation_Form: document
Series_Information:

Series_Name:

U.S. Geological Survey, Office of Surface Water Technical Memorandum

Issue_Identification: 2013.01

Publication_Information:

Publication_Place: Reston, VA
Publisher: U.S. Geological Survey

Other_Citation_Details:

U.S. Geological Survey. 2012. Computation of annual exceedance probability (AEP) for characterization of observed flood peaks. U.S. Geological Survey, Office of Surface Water Technical Memorandum 2013.01

Online_Linkage: https://water.usgs.gov/admin/memo/SW/sw13.01.pdf

Type_of_Source_Media: document
Source_Time_Period_of_Content:

Time_Period_Information:

Single_Date/Time:

Calendar_Date: 2012

Source_Currentness_Reference: publication date

Source_Citation_Abbreviation: OSW Tech Memo 2013.01
Source_Contribution:

This source provided methods and guidelines for computation and presentation of estimates of annual exceedance probability for the observed flood peak.

Process_Step:

Process_Description:

Annual peak streamflow data were obtained from NWIS and used as input data to USGS PeakFQ program version 7.4 for estimating flood frequency and magnitude. Flood frequency analyses and estimation of annual exceedance probability used methods and procedures described in Curran and others (2016) and U.S. Geological Survey Office of Surface Water Technical Memorandum 2013.01 (OSW Tech Memo 2013.01), respectively.

Source_Used_Citation_Abbreviation: Curran and others 2016
Source_Used_Citation_Abbreviation: NWIS
Source_Used_Citation_Abbreviation: Veilleux and others 2014
Process_Date: 202212
Process_Contact:

Contact_Information:

Contact_Organization_Primary:

Contact_Organization: U.S. Geological Survey, Alaska Science Center
Contact_Person: Janet H. Curran

Contact_Position: Hydrologist
Contact_Address:

Address_Type: Mailing and Physical
Address: 4210 University Drive
City: Anchorage
State_or_Province: Alaska
Postal_Code: 99508
Country: USA

Contact_Voice_Telephone: 907-786-7000
Contact_Electronic_Mail_Address: ascweb@usgs.gov

Spatial_Data_Organization_Information:

Indirect_Spatial_Reference:

U.S. Geological Survey streamgage station names and numbers refer to specific geographic locations recorded in the NWIS database.

Direct_Spatial_Reference_Method: Point

Spatial_Reference_Information:

Horizontal_Coordinate_System_Definition:

Geodetic_Model:

Horizontal_Datum_Name: North American Datum of 1983 (NAD83)
Ellipsoid_Name: Geodetic Reference System 1980 (GRS80)
Semi-major_Axis: 6378137
Denominator_of_Flattening_Ratio: 298.257222101

Entity_and_Attribute_Information:

Detailed_Description:

Entity_Type:

Entity_Type_Label: floodFreq_siteInfo_deltaRvBasin_best_1963-2022.csv
Entity_Type_Definition:

Table with description of USGS streamgages used in flood frequency analysis. Includes data types used in Curran and others 2016 (Table 1). Data retrieved from NWIS [accessed December 20, 2022]. Presented in a Comma Separated Value (CSV) formatted table.

Entity_Type_Definition_Source: Author defined

Attribute:

Attribute_Label: station_no
Attribute_Definition: USGS streamgage site identification number
Attribute_Definition_Source: NWIS
Attribute_Domain_Values:

Unrepresentable_Domain:

Unique identifier: an 8 to 15 digit number of the U.S. Geological Survey site. Corresponds to the 'station_no' attribute in all tables included in with this data package.

Attribute:

Attribute_Label: station_name
Attribute_Definition: USGS streamgage name
Attribute_Definition_Source: NWIS
Attribute_Domain_Values:

Unrepresentable_Domain:

Unique identifier: a name consisting of the stream name and location references. Corresponds to the 'station_name' attribute in all tables included in with this data package.

Attribute:

Attribute_Label: data_retr_date
Attribute_Definition: Date data were retrieved from NWIS
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 12/23/2022
Range_Domain_Maximum: 2/2/2023
Attribute_Units_of_Measure: Date (mm/dd/yyyy)

Attribute:

Attribute_Label: latitude
Attribute_Definition: Latitude of streamgage, in decimal degrees
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 63.49487
Range_Domain_Maximum: 63.63126
Attribute_Units_of_Measure: Decimal degrees (NAD83)

Attribute:

Attribute_Label: longitude
Attribute_Definition: Longitude of streamgage, in decimal degrees
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: -145.86
Range_Domain_Maximum: -145.873
Attribute_Units_of_Measure: Decimal degrees (NAD83)

Attribute:

Attribute_Label: DRNAREA
Attribute_Definition:

Drainage Area: area that drains to a point on a stream (source: NWIS)

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 1.2
Range_Domain_Maximum: 4.9
Attribute_Units_of_Measure: square miles

Attribute:

Attribute_Label: PRECPRIS00
Attribute_Definition:

Mean annual basin precipitation (years: 1971-2000, for the parts of the basin in Alaska; 1961-1990 for the parts of the basin in Canada, if any). Data retrieved from Table 1 of Curran and others 2016 for streamgages used in that report or from the respective PRISM datasets using methods described in Curran and others 2016 for other streamgages.

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 27
Range_Domain_Maximum: 40
Attribute_Units_of_Measure: inches

Attribute:

Attribute_Label: tau_corr
Attribute_Definition:

Kendall tau correlation coefficient, for sites having statistically significant trends (source: PeakFQ)

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: Blank cell
Enumerated_Domain_Value_Definition: Site did not have a statistically significant trend
Enumerated_Domain_Value_Definition_Source: Author defined

Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: nan
Range_Domain_Maximum: nan

Attribute:

Attribute_Label: tau_p
Attribute_Definition: Kendall tau p-value (source: PeakFQ)
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: Blank cell
Enumerated_Domain_Value_Definition: Site did not have a statistically significant trend
Enumerated_Domain_Value_Definition_Source: Author defined

Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: nan
Range_Domain_Maximum: nan

Attribute:

Attribute_Label: skew_region
Attribute_Definition:

Regional skew area, for sites within applicable range of drainage area (source: Curran and others 2016).

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: Blank cell
Enumerated_Domain_Value_Definition: Basin is not located in a Regional Skew Area
Enumerated_Domain_Value_Definition_Source: Author defined

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: Regional Skew Area 1
Enumerated_Domain_Value_Definition: Basin is located in Regional Skew Area 1
Enumerated_Domain_Value_Definition_Source: Author defined

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: Regional Skew Area 1 basin size exclusion
Enumerated_Domain_Value_Definition:

Basin is located in Regional Skew Area 1, but outside the range of applicable basin drainage area

Enumerated_Domain_Value_Definition_Source: Author defined

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: Regional Skew Area 2
Enumerated_Domain_Value_Definition: Basin is located in Regional Skew Area 2
Enumerated_Domain_Value_Definition_Source: Author defined

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: Regional Skew Area 2 basin size exclusion
Enumerated_Domain_Value_Definition:

Basin is located in Regional Skew Area 2, but outside the range of applicable basin drainage area

Enumerated_Domain_Value_Definition_Source: Author defined

Attribute:

Attribute_Label: POR_used
Attribute_Definition: Period of record used.
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Unrepresentable_Domain:

Date ranges or multiple date ranges separated by a comma, e.g.,1918-1920,1923-1924,1926-1928,1947-1973.

Attribute:

Attribute_Label: hist_per_length
Attribute_Definition:

Historic period length, the number of years in the "period of record used", regardless of whether peaks were used for those years.

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 36
Range_Domain_Maximum: 60
Attribute_Units_of_Measure: years

Attribute:

Attribute_Label: omitted_WYs
Attribute_Definition:

Water year(s) for data omitted from analysis and explanation code.

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: Blank cell
Enumerated_Domain_Value_Definition: No water years were omitted.
Enumerated_Domain_Value_Definition_Source: Author defined

Attribute_Domain_Values:

Unrepresentable_Domain:

Year, date range, or multiple years or date ranges separated by a comma, e.g.,1918,1920, 1923-1924,1926-1928,1947-1973. Codes are shown as a letter in parentheses, e.g. (a), and are defined in Curran and others (2016).

Attribute:

Attribute_Label: no_pks
Attribute_Definition: Number of peaks in record
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 23
Range_Domain_Maximum: 26

Attribute:

Attribute_Label: percep_thresh
Attribute_Definition:

Perception threshold for water years noted and explanation code.

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: Blank cell
Enumerated_Domain_Value_Definition: Default perception threshold (0-INF).
Enumerated_Domain_Value_Definition_Source: Author defined

Attribute_Domain_Values:

Unrepresentable_Domain:

Year, date range, or multiple years or date ranges separated by a comma, e.g.,1918,1920, 1923-1924,1926-1928,1947-1973. Codes are shown as one or more letters in parentheses, e.g. (a), and are defined in Curran and others (2016).

Attribute:

Attribute_Label: interval_Q
Attribute_Definition: Interval discharge range for noted water year
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: Blank cell
Enumerated_Domain_Value_Definition: Data did not contain an interval discharge.
Enumerated_Domain_Value_Definition_Source: Author defined

Attribute_Domain_Values:

Unrepresentable_Domain:

Year followed by a colon and the lower and upper bound of the interval discharge in cubic feet per second, e.g. 1978: 0-225. Codes are shown as a letter in parentheses, e.g. (a), and are defined in Curran and others (2016).

Attribute:

Attribute_Label: PILF_thold
Attribute_Definition:

Potentially Influential Low Outlier (PILF) threshold (user-defined when followed by an x)

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: Blank cell
Enumerated_Domain_Value_Definition: No PILFs were identified.
Enumerated_Domain_Value_Definition_Source: Author defined

Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: nan
Range_Domain_Maximum: nan
Attribute_Units_of_Measure: cubic feet per second

Attribute:

Attribute_Label: no_PILFs
Attribute_Definition: Number of Potentially Influential Low Outliers (PILFs)
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: Blank cell
Enumerated_Domain_Value_Definition: No PILFs were identified.
Enumerated_Domain_Value_Definition_Source: Author defined

Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: nan
Range_Domain_Maximum: nan

Attribute:

Attribute_Label: regr_comp
Attribute_Definition: Regression equation computation method
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: online tool
Enumerated_Domain_Value_Definition:

Computed from Curran and others (2016) Application of Methods Tool, version 1.2, available online with report

Enumerated_Domain_Value_Definition_Source: Author defined

Detailed_Description:

Entity_Type:

Entity_Type_Label: floodFreq_PeakFQinputOutput_deltaRvBasin_best_1963-2022.zip
Entity_Type_Definition:

Archive file format package (.zip) with ASCII input and output files for USGS program PeakFQ used to estimate flood magnitude and frequency. Filenames are the USGS streamgage site identification numbers (i.e., 'station_no') and file extensions distinguish the type of content contained in the files. Details of file format and contents are described in the PeakFQ User's Manual (Flynn and others 2006).

.txt - input file: annual peak-flow data (retrieved from NWIS) .psf - input file: specification information for Program PeakFQ .prt - output file: flood frequency results from Program PeakFQ .exp - output file: selected flood frequency results in tabular format .jpg - output file: flood frequency curves

Entity_Type_Definition_Source: Author defined

Detailed_Description:

Entity_Type:

Entity_Type_Label: floodFreq_skew_deltaRvBasin_best_1963-2022.csv
Entity_Type_Definition:

Table with annual frequency curve parameters and skew information for peak-flow data at selected streamgages. Presented in a Comma Separated Value (CSV) formatted table.

Entity_Type_Definition_Source: Author defined

Attribute:

Attribute_Label: Station_no
Attribute_Definition: USGS streamgage site identification number
Attribute_Definition_Source: NWIS
Attribute_Domain_Values:

Unrepresentable_Domain:

Unique identifier: an 8 to 15 digit number of the U.S. Geological Survey site. Corresponds to the 'station_no' attribute in all tables included in with this data package.

Attribute:

Attribute_Label: Mean
Attribute_Definition:

Logarithmic mean of the log-Pearson type III frequency distribution (source: PeakFQ)

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 1.989
Range_Domain_Maximum: 2.497

Attribute:

Attribute_Label: StandDev
Attribute_Definition:

Logarithmic standard deviation of the log-Pearson type III frequency distribution (source: PeakFQ)

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 0.351
Range_Domain_Maximum: 0.514

Attribute:

Attribute_Label: AtSiteSkew
Attribute_Definition:

Logarithmic at-site station skew coefficient of the log-Pearson type III frequency distribution. (source: PeakFQ)

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 0.147
Range_Domain_Maximum: 0.981

Attribute:

Attribute_Label: AtSiteMSEG
Attribute_Definition:

Logarithmic mean square error of the at-site station skew coefficient of the log-Pearson type III frequency distribution (source: PeakFQ)

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 0.194
Range_Domain_Maximum: 0.410

Attribute:

Attribute_Label: RegSkew
Attribute_Definition:

Generalized skew coefficient from a regional skew coefficient analysis. All possible values are provided here for reference even if they are not present in this dataset (source: Curran and others 2016)

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: n/a
Enumerated_Domain_Value_Definition:

Not available because the basin is not located within a Regional Skew Area (Curran and others 2016) or is located within a Regional Skew Area but subject to a basin size exclusion.

Enumerated_Domain_Value_Definition_Source: Author defined

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: 0.54
Enumerated_Domain_Value_Definition: For Regional Skew Area 1 from Curran and others (2016)
Enumerated_Domain_Value_Definition_Source: Author defined

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: 0.18
Enumerated_Domain_Value_Definition: For Regional Skew Area 2 from Curran and others (2016)
Enumerated_Domain_Value_Definition_Source: Author defined

Attribute:

Attribute_Label: RegMSEG
Attribute_Definition:

Mean square error of the generalized skew coefficient from a regional skew coefficient analysis. All possible values are provided here for reference even if they are not present in this dataset (source: Curran and others 2016)

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: n/a
Enumerated_Domain_Value_Definition:

Not available because the basin is not located within a Regional Skew Area (Curran and others 2016) or is located within a Regional Skew Area but subject to a basin size exclusion.

Enumerated_Domain_Value_Definition_Source: Author defined

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: 0.449
Enumerated_Domain_Value_Definition: For Regional Skew Area 1 from Curran and others (2016)
Enumerated_Domain_Value_Definition_Source: Author defined

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: 0.116
Enumerated_Domain_Value_Definition: For Regional Skew Area 2 from Curran and others (2016)
Enumerated_Domain_Value_Definition_Source: Author defined

Attribute:

Attribute_Label: SkewUsed
Attribute_Definition:

Skew coefficient used for the frequency analysis (source: PeakFQ)

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 0.290
Range_Domain_Maximum: 0.696

Attribute:

Attribute_Label: SkewTypeUsed
Attribute_Definition: Skew type used for the frequency analysis (source: PeakFQ)
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: Station
Enumerated_Domain_Value_Definition:

The at-site station skew coefficient was used for the frequency analysis

Enumerated_Domain_Value_Definition_Source: Author defined

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: Weighted
Enumerated_Domain_Value_Definition:

The weighted skew coefficient, obtained by weighting the at-site station skew coefficient with a generalized skew coefficient from a regional skew coefficient analysis, was used for the frequency analysis

Enumerated_Domain_Value_Definition_Source: Author defined

Detailed_Description:

Entity_Type:

Entity_Type_Label: floodFreq_AEPobserved_deltaRvBasin_best_1963-2022.csv
Entity_Type_Definition:

Table with annual exceedance probability estimates computed for selected observed floods (peaks) at selected streamgages from streamgage flood frequency information in this data release. For additional details regarding computation methods, see OSW Tech Memo 2013.01. Presented in a Comma Separated Value (CSV) formatted table.

Entity_Type_Definition_Source: Author defined

Attribute:

Attribute_Label: station_no
Attribute_Definition: USGS streamgage site identification number
Attribute_Definition_Source: NWIS
Attribute_Domain_Values:

Unrepresentable_Domain:

Unique identifier: an 8 to 15 digit number of the U.S. Geological Survey site. Corresponds to the 'station_no' attribute in all tables included in with this data package.

Attribute:

Attribute_Label: pk_date
Attribute_Definition: Date of peak discharge
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 7/11/2022
Range_Domain_Maximum: 7/11/2022
Attribute_Units_of_Measure: Date (mm/dd/yyyy)

Attribute:

Attribute_Label: pk_Q_cfs
Attribute_Definition: Peak discharge
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 1140
Range_Domain_Maximum: 5520
Attribute_Units_of_Measure: cubic feet per second

Attribute:

Attribute_Label: pk_Q_rank
Attribute_Definition: Rank of peak discharge in period of record used
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 1
Range_Domain_Maximum: 1

Attribute:

Attribute_Label: no_pks_used
Attribute_Definition: Number of peaks in record used in analysis
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 23
Range_Domain_Maximum: 26

Attribute:

Attribute_Label: pk_AEP
Attribute_Definition: Annual exceedance probability of the peak discharge
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: less than 0.2
Range_Domain_Maximum: less than 0.2
Attribute_Units_of_Measure: percent

Attribute:

Attribute_Label: pk_AEP_conf_low
Attribute_Definition:

Lower bound of the 66.7 percent confidence interval for the annual exceedance probability estimate

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 0.3
Range_Domain_Maximum: 0.5
Attribute_Units_of_Measure: percent

Attribute:

Attribute_Label: pk_AEP_conf_up
Attribute_Definition:

Upper bound of the 66.7 percent confidence interval for the annual exceedance probability estimate.

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 2.9
Range_Domain_Maximum: 4.9
Attribute_Units_of_Measure: percent

Attribute:

Attribute_Label: AEP_below
Attribute_Definition:

Annual exceedance probability for the first annual exceedance probability discharge less than the observed peak discharge.

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 0.2
Range_Domain_Maximum: 0.2
Attribute_Units_of_Measure: percent

Attribute:

Attribute_Label: Q_below
Attribute_Definition:

First annual exceedance probability discharge less than the observed peak.

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 1040
Range_Domain_Maximum: 2560
Attribute_Units_of_Measure: cubic feet per second

Attribute:

Attribute_Label: Q_below_conf_low
Attribute_Definition:

Lower bound of the 90 percent confidence interval for the first annual exceedance probability discharge less than the observed peak.

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 434
Range_Domain_Maximum: 1220
Attribute_Units_of_Measure: cubic feet per second

Attribute:

Attribute_Label: Q_below_conf_up
Attribute_Definition:

Upper bound of the 90 percent confidence interval for the first annual exceedance probability discharge less than the observed peak.

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 2470
Range_Domain_Maximum: 5370
Attribute_Units_of_Measure: cubic feet per second

Attribute:

Attribute_Label: AEP_above
Attribute_Definition:

Annual exceedance probability for the first annual exceedance probability discharge greater than the observed peak discharge.

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: Blank cell
Enumerated_Domain_Value_Definition:

Observed peak discharge had annual exceedance probability smaller than 0.2 percent

Enumerated_Domain_Value_Definition_Source: Author defined

Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: nan
Range_Domain_Maximum: nan
Attribute_Units_of_Measure: percent

Attribute:

Attribute_Label: Q_above
Attribute_Definition:

First annual exceedance probability discharge greater than the observed peak.

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: Blank cell
Enumerated_Domain_Value_Definition:

Computed flow for flood event had annual exceedance probability smaller than 0.2 percent

Enumerated_Domain_Value_Definition_Source: Author defined

Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: nan
Range_Domain_Maximum: nan
Attribute_Units_of_Measure: cubic feet per second

Attribute:

Attribute_Label: Q_above_conf_low
Attribute_Definition:

Lower bound of the 90 percent confidence interval for the first annual exceedance probability discharge greater than the observed peak.

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: Blank cell
Enumerated_Domain_Value_Definition:

Computed flow for flood event had annual exceedance probability smaller than 0.2 percent

Enumerated_Domain_Value_Definition_Source: Author defined

Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: nan
Range_Domain_Maximum: nan
Attribute_Units_of_Measure: cubic feet per second

Attribute:

Attribute_Label: Q_above_conf_up
Attribute_Definition:

Upper bound of the 90 percent confidence interval for the first annual exceedance probability discharge greater than the observed peak.

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: Blank cell
Enumerated_Domain_Value_Definition:

Computed flow for flood event had annual exceedance probability smaller than 0.2 percent

Enumerated_Domain_Value_Definition_Source: Author defined

Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: nan
Range_Domain_Maximum: nan
Attribute_Units_of_Measure: cubic feet per second

Detailed_Description:

Entity_Type:

Entity_Type_Label: floodFreq_AEPestimates_deltaRvBasin_best_1963-2022.csv
Entity_Type_Definition:

Table with flood frequency estimates from Program PeakFQ for selected streamgages. Estimates include discharges, confidence intervals, and variance of prediction for a range of annual exceedance probabilities. These include data types found in Table 4 and Table 9 in Curran and others (2016). For addition details regarding Program PeakFQ estimates, see Flynn and others (2006) and Veilleux and others (2014). Presented in a Comma Separated Value (CSV) formatted table.

Entity_Type_Definition_Source: Author defined

Attribute:

Attribute_Label: Station_no
Attribute_Definition: USGS streamgage site identification number
Attribute_Definition_Source: NWIS
Attribute_Domain_Values:

Unrepresentable_Domain:

Unique identifier: an 8 to 15 digit number of the U.S. Geological Survey site. Corresponds to the 'station_no' attribute in all tables included in with this data package.

Attribute:

Attribute_Label: AEP
Attribute_Definition:

Annual exceedance probability, or the probability in any year that a flood threshold is exceeded

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 0.2
Range_Domain_Maximum: 50
Attribute_Units_of_Measure: percent

Attribute:

Attribute_Label: Qsta
Attribute_Definition:

Annual exceedance probability discharge estimated from a log Pearson type III analysis of observed station data.

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 92.1
Range_Domain_Maximum: 6400
Attribute_Units_of_Measure: cubic feet per second

Attribute:

Attribute_Label: Qsta_conf_lo
Attribute_Definition:

Lower bound of the 90 percent confidence interval for the station estimate of the annual exceedance probability discharge.

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 60.1
Range_Domain_Maximum: 3160
Attribute_Units_of_Measure: cubic feet per second

Attribute:

Attribute_Label: Qsta_conf_up
Attribute_Definition:

Upper bound of the 90 percent confidence interval for the station estimate of the annual exceedance probability discharge.

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 140
Range_Domain_Maximum: 38800
Attribute_Units_of_Measure: cubic feet per second

Attribute:

Attribute_Label: Qreg
Attribute_Definition:

Annual exceedance probability discharge estimated from the regional regression equation.

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 47.9
Range_Domain_Maximum: 624
Attribute_Units_of_Measure: cubic feet per second

Attribute:

Attribute_Label: Qreg_conf_lo
Attribute_Definition:

Lower bound of the 90 percent confidence interval for the regional regression estimate of the annual exceedance probability discharge.

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 16.7
Range_Domain_Maximum: 192
Attribute_Units_of_Measure: cubic feet per second

Attribute:

Attribute_Label: Qreg_conf_up
Attribute_Definition:

Upper bound of the 90 percent confidence interval for the regional regression estimate of the annual exceedance probability discharge.

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 137
Range_Domain_Maximum: 2030
Attribute_Units_of_Measure: cubic feet per second

Attribute:

Attribute_Label: Qwtd
Attribute_Definition:

Annual exceedance probability discharge estimated from weighting station and regression estimates.

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 84.4
Range_Domain_Maximum: 2560
Attribute_Units_of_Measure: cubic feet per second

Attribute:

Attribute_Label: Qwtd_conf_low
Attribute_Definition:

Lower bound of the 90 percent confidence interval for the weighted estimate of the annual exceedance probability discharge.

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 57.5
Range_Domain_Maximum: 1220
Attribute_Units_of_Measure: cubic feet per second

Attribute:

Attribute_Label: Qwtd_conf_up
Attribute_Definition:

Upper bound of the 90 percent confidence interval for the weighted estimate of the annual exceedance probability discharge.

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 124
Range_Domain_Maximum: 5370
Attribute_Units_of_Measure: cubic feet per second

Attribute:

Attribute_Label: Vsta
Attribute_Definition:

Variance of prediction estimated from a log Pearson type III analysis of observed station data.

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 0.0058
Range_Domain_Maximum: 0.1154

Attribute:

Attribute_Label: Vreg
Attribute_Definition:

Variance of prediction estimated from the regional regression equation.

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 0.074
Range_Domain_Maximum: 0.097

Attribute:

Attribute_Label: Vwtd
Attribute_Definition:

Variance of prediction estimated by weighting the station and regression estimates.

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 0.0054
Range_Domain_Maximum: 0.0527

Detailed_Description:

Entity_Type:

Entity_Type_Label: Supplemental_stationDataReport
Entity_Type_Definition:

Folder with two report files providing key information from this data release in a more human-readable format: (1) a .pdf format document describing the analyses and key results provided in the data release, and (2) an Excel 'Workbook' (.xlsx format) with flood frequency analysis reports for each station (one 'Worksheet' for each streamgage). The reports are compiled from the flood frequency information in this data release. Attributes are defined in the descriptions within the Workbook.

Entity_Type_Definition_Source: Author defined

Flood Frequency Data and 2022 Observed Flood Probability for Two Streamgages in the Delta River Basin, Alaska, 1963-2022

Metadata: