Flood frequency statistics for streamgages and methods for estimating flood frequency statistics at ungaged sites in Alaska and conterminous basins in Canada are presented in U.S. Geological Survey Scientific Investigations Report 2016-5024. This report revised methods for obtaining basin characteristics and regional skew, and presents new streamflow magnitude and frequency statistics for gaged basins and new regression equations for estimating these statistics for ungaged basins.
Return to Water >> Alaska Streamflow Statistics
Basin characteristics
Basin characteristics are physical and climatic features used as independent variables for estimating streamflow. Basin characteristics for an ungaged site that are substituted in the estimating equations should be determined by the same methods as those used to develop the equations. USGS SIR 2016-5024 uses two basin characteristics for estimating flood frequency:
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Drainage area (DRNAREA) is obtained from a drainage area boundary for the site in question. Drainage area delineations are based on the Watershed Boundary Dataset.
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Basin average mean annual precipitation for 1971–2000 from the PRISM climate dataset (PRECPRIS00) is obtained for areas in Alaska from Gibson (2009) (tip: no password is required when accessed from Internet Explorer) and for areas in Canada from PRISM Climate Group (2002).
Basin characteristics have been computed for selected streamgages and can be downloaded as a table from USGS SIR 2016-5024 Appendix A , also available as an ESRI geodatabase.
Regional skew areas
Flood frequency estimates for a streamgage are improved by using a weighted average of the station skew and a regional skew. USGS SIR 2016-5024 presents regional skew and standard error of the regional skew for two new regional skew areas (see figure 5, table 5, and table 6). Areas outside the regional skew areas are considered skew exclusion areas where station skew is used.
Statistics/equations
Flood frequency statistics for streamgages in Alaska and conterminous basins in Canada with at least 10 years of record through water year 2012 are shown in table form in USGS SIR 2016-5024 table 4 and can be obtained from a map view in StreamStats.
Tools for estimating flood frequency statistics are available in spreadsheet form in the USGS SIR 2016-5024 Applications Tool and in the USGS National Streamflow Statistics (NSS) program. For sites within Cook Inlet Basin, StreamStats provides tool for delineating a drainage area, computing basin characteristics, and computing the flood frequency estimation equations.
Below are other science projects associated with this project.
Alaska Streamflow Statistics
Flood Frequency Data Collection for Alaska and Conterminous Drainage Basins in Canada
Flow Duration and Low-Flow Frequency Studies in Alaska
- Overview
Flood frequency statistics for streamgages and methods for estimating flood frequency statistics at ungaged sites in Alaska and conterminous basins in Canada are presented in U.S. Geological Survey Scientific Investigations Report 2016-5024. This report revised methods for obtaining basin characteristics and regional skew, and presents new streamflow magnitude and frequency statistics for gaged basins and new regression equations for estimating these statistics for ungaged basins.
Return to Water >> Alaska Streamflow Statistics
Basin characteristics
Basin characteristics are physical and climatic features used as independent variables for estimating streamflow. Basin characteristics for an ungaged site that are substituted in the estimating equations should be determined by the same methods as those used to develop the equations. USGS SIR 2016-5024 uses two basin characteristics for estimating flood frequency:
-
Drainage area (DRNAREA) is obtained from a drainage area boundary for the site in question. Drainage area delineations are based on the Watershed Boundary Dataset.
-
Basin average mean annual precipitation for 1971–2000 from the PRISM climate dataset (PRECPRIS00) is obtained for areas in Alaska from Gibson (2009) (tip: no password is required when accessed from Internet Explorer) and for areas in Canada from PRISM Climate Group (2002).
Basin characteristics have been computed for selected streamgages and can be downloaded as a table from USGS SIR 2016-5024 Appendix A , also available as an ESRI geodatabase.
Sources/Usage: Public Domain. Visit Media to see details.Links to PDF version(Public domain.) Regional skew areas
Flood frequency estimates for a streamgage are improved by using a weighted average of the station skew and a regional skew. USGS SIR 2016-5024 presents regional skew and standard error of the regional skew for two new regional skew areas (see figure 5, table 5, and table 6). Areas outside the regional skew areas are considered skew exclusion areas where station skew is used.
Statistics/equations
Flood frequency statistics for streamgages in Alaska and conterminous basins in Canada with at least 10 years of record through water year 2012 are shown in table form in USGS SIR 2016-5024 table 4 and can be obtained from a map view in StreamStats.
Tools for estimating flood frequency statistics are available in spreadsheet form in the USGS SIR 2016-5024 Applications Tool and in the USGS National Streamflow Statistics (NSS) program. For sites within Cook Inlet Basin, StreamStats provides tool for delineating a drainage area, computing basin characteristics, and computing the flood frequency estimation equations.
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- Science
Below are other science projects associated with this project.
Alaska Streamflow Statistics
The USGS conducts various studies of streamflow statistics for data collected at streamflow-gaging stations. Streamflow statistics for gaged streams and methods for estimating those statistics for ungaged streams are used by water resource planners and managers for designing infrastructure, managing floodplains, and protecting life, property, and aquatic resources. The most recent USGS studies of...Flood Frequency Data Collection for Alaska and Conterminous Drainage Basins in Canada
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. In 2016, the U.S. Geological Survey estimated flood frequency and magnitude for selected streamgages in Alaska and conterminous basins in Canada and developed methods for...Flow Duration and Low-Flow Frequency Studies in Alaska
Flow duration and low-flow frequency statistics for streamgages and methods for estimating flow-duration and low-flow frequency statistics at ungaged sites in Alaska and conterminous basins in Canada are presented in U.S. Geological Survey Water Resources Investigations Report 2003-4114. - Data
- Web Tools
- Software