This U.S. Geological Survey (USGS) data release contains batch formatted annual peak streamflow data (PkFlows_AllSites.txt) through the 2020 water year for six selected USGS streamgages (01321000, 01342797, 01343060, 01346000, 01347000, and 01348000) that recorded the flood of October 31 – November 3, 2019, which severely affected the Mohawk Valley and southern Adirondack region in central New York State. This data release also contains batch formatted specification (PkFlows_AllSites.psf) and output (PEAKFLOWS_ALLSITES.PRT) files from log-Pearson type III (LPIII) flood-frequency analysis of the annual peak streamflow data in version 7.4 of the USGS PeakFQ software (Flynn and others, 2006), which implements the Bulletin 17C (England and others, 2018) methodology for determining flood flow frequency. A comma separated values file (FloodFrequencyEstimates.csv) with estimates of flood magnitudes for selected annual exceedance probabilities from three different types of flood-frequency analysis (LPIII, regional regression equations, and weighted LPIII) is also included. The basins of the selected streamgages include the Sacandaga River basin (located within the upper Hudson River basin), and the East and West Canada Creek basins (located within the Mohawk River basin). Annual peak streamflow data were obtained from the USGS National Water Information System (U.S. Geological Survey, 2016). Considerations that informed the PeakFQ specifications for all six streamgages (including the effect of regulation, differences in station and regional skew, and other considerations) are discussed in Graziano and others (2024). Regional regression equation estimates were obtained for the locations of the four streamgages where streamflow is unregulated (01321000, 01342797, 01343060, and 01348000) using the StreamStats web application (U.S. Geological Survey, 2019), which presently utilizes equations in Lumia and others (2006). Weighted LPIII estimates (for the same four streamgages where streamflow is unregulated) were computed by weighting the (at-site) LPIII estimates with the regional regression equation estimates (Lumia and others (2006), equation 3). The weighted LPIII estimates are considered the most accurate of the three types of flood-frequency estimates. For this analysis, stationarity in the annual peak streamflow records was assumed after visual inspection of the records indicated no clear trends.

This U.S. Geological Survey (USGS) data release contains batch formatted annual peak streamflow data (PkFlows_AllSites.txt) for the respective periods of record (through the 2020 or 2021 water year) for seven USGS streamgages in the upper Esopus Creek watershed in upstate New York. This data release also contains batch formatted specification (PkFlows_AllSites.psf) and output (PEAKFLOWS_ALLSITES.PRT) files from log-Pearson type III (LPIII) flood-frequency analysis of the annual peak streamflow data from version 7.3 of the USGS PeakFQ software (https://water.usgs.gov/software/PeakFQ/), and a csv file (FloodFrequencyEstimates.csv) with estimates of flood magnitudes for selected annual exceedance probabilities from three different types of flood-frequency analysis (LPIII, regional regression equations, and weighted LPIII). Annual peak streamflow data were obtained from the USGS National Water Information System (https://nwis.waterdata.usgs.gov/usa/nwis/peak). The station skew option was used in the PeakFQ LPIII analyses of all seven streamgages. Regional regression estimates were obtained for the locations of the streamgages using the StreamStats web application (https://streamstats.usgs.gov/ss/), which utilizes the regional regression equations presented in Lumia and others (2006). The weighted LPIII estimates are the LPIII estimates weighted with the regional regression estimates (Lumia and others (2006), equation 3) and are considered the most accurate of the three types of flood-frequency estimates . For this analysis, stationarity in the annual peak streamflow records was assumed after visual inspection of the records indicated no clear trends.

This U.S. Geological Survey (USGS) data release contains batch formatted annual peak streamflow data (PkFlows_AllSites.txt) for the respective periods of record (through the 2020 or 2021 water year) for seven USGS streamgages in the upper Esopus Creek watershed in upstate New York. This data release also contains batch formatted specification (PkFlows_AllSites.psf) and output (PEAKFLOWS_ALLSITES.PRT) files from log-Pearson type III (LPIII) flood-frequency analysis of the annual peak streamflow data from version 7.3 of the USGS PeakFQ software (https://water.usgs.gov/software/PeakFQ/), and a csv file (FloodFrequencyEstimates.csv) with estimates of flood magnitudes for selected annual exceedance probabilities from three different types of flood-frequency analysis (LPIII, regional regression equations, and weighted LPIII). Annual peak streamflow data were obtained from the USGS National Water Information System (https://nwis.waterdata.usgs.gov/usa/nwis/peak). The station skew option was used in the PeakFQ LPIII analyses of all seven streamgages. Regional regression estimates were obtained for the locations of the streamgages using the StreamStats web application (https://streamstats.usgs.gov/ss/), which utilizes the regional regression equations presented in Lumia and others (2006). The weighted LPIII estimates are the LPIII estimates weighted with the regional regression estimates (Lumia and others (2006), equation 3) and are considered the most accurate of the three types of flood-frequency estimates . For this analysis, stationarity in the annual peak streamflow records was assumed after visual inspection of the records indicated no clear trends.

This dataset contains site information, basin characteristics, results of flood-frequency analysis, and a generalized (regional) flood skew for 76 selected streamgages operated by the U.S. Geological Survey (USGS) in the upper White River basin (4-digit hydrologic unit 1101) in southern Missouri and northern Arkansas. The Little Rock District U.S. Army Corps of Engineers (USACE) needed updated estimates of streamflows corresponding to selected annual exceedance probabilities (AEPs) and a basin-specific regional flood skew. USGS selected 111 candidate streamgages in the study area that had 20 or more years of gaged annual peak-flow data available through the 2020 water year. After screening for regulation, urbanization, redundant/nested basins, drainage areas greater than 2,500 square miles, and streamgage basins located in the Mississippi Alluvial Plain (8-digit hydrologic unit 11010013), 77 candidate streamgages remained. After conducting the initial flood-frequency analysis to generate at-site (station) skew and its mean squared error (MSE) for development of the regional flood skew, four streamgages with less than 20 years of pseudo effective record length (PRL) and two streamgages with an excessive amount of censored annual peak flows were removed, leaving 71 streamgages (44 in Arkansas and 27 in Missouri) for use in the study. Flood-frequency analysis was done using the Expected Moments Algorithm (EMA) in version 7.3 of USGS software PeakFQ (Veilleux and others, 2014; England and others, 2019). Ten basin characteristics were tested as explanatory variables in a generalized additive model (GAM) of flood skew, but a lack of statistical significance of the variables, including two-dimensional smooths of the locations of the streamgages and the centroids of their basins, indicated that a weighted mean flood skew of -0.132, with a mean squared error of 0.160 and standard error of 0.400, was appropriate. The regional flood skew agrees well with regional flood skew previously developed for Arkansas and Louisiana(skew -0.17, MSE 0.12) using Bayesian generalized least-squares (B-GLS) regression and most of the streamgages in this study (Wagner and others, 2016, appendix 1). The regional flood skew was incorporated in a final flood-frequency analysis in PeakFQ software using a weighted skew (England and others, 2019). In addition to the 71 streamgages used to develop the regional flood skew, five active streamgages that were screened for redundancy (four in Missouri and one in Arkansas) were included in the final flood-frequency analysis. The final estimates of streamflows corresponding to the selected AEPs (0.5, 0.2, 0.1, 0.04, 0.02, 0.01, and 0.002) were weighted with estimates of the same AEPs computed using regional regression equations (Southard and Veilleux, 2014; Wagner and others, 2016) to generate the final weighted estimates, their variances, and 95-percent confidence intervals.

This dataset contains site information, basin characteristics, results of flood-frequency analysis, and a generalized (regional) flood skew for 76 selected streamgages operated by the U.S. Geological Survey (USGS) in the upper White River basin (4-digit hydrologic unit 1101) in southern Missouri and northern Arkansas. The Little Rock District U.S. Army Corps of Engineers (USACE) needed updated estimates of streamflows corresponding to selected annual exceedance probabilities (AEPs) and a basin-specific regional flood skew. USGS selected 111 candidate streamgages in the study area that had 20 or more years of gaged annual peak-flow data available through the 2020 water year. After screening for regulation, urbanization, redundant/nested basins, drainage areas greater than 2,500 square miles, and streamgage basins located in the Mississippi Alluvial Plain (8-digit hydrologic unit 11010013), 77 candidate streamgages remained. After conducting the initial flood-frequency analysis to generate at-site (station) skew and its mean squared error (MSE) for development of the regional flood skew, four streamgages with less than 20 years of pseudo effective record length (PRL) and two streamgages with an excessive amount of censored annual peak flows were removed, leaving 71 streamgages (44 in Arkansas and 27 in Missouri) for use in the study. Flood-frequency analysis was done using the Expected Moments Algorithm (EMA) in version 7.3 of USGS software PeakFQ (Veilleux and others, 2014; England and others, 2019). Ten basin characteristics were tested as explanatory variables in a generalized additive model (GAM) of flood skew, but a lack of statistical significance of the variables, including two-dimensional smooths of the locations of the streamgages and the centroids of their basins, indicated that a weighted mean flood skew of -0.132, with a mean squared error of 0.160 and standard error of 0.400, was appropriate. The regional flood skew agrees well with regional flood skew previously developed for Arkansas and Louisiana(skew -0.17, MSE 0.12) using Bayesian generalized least-squares (B-GLS) regression and most of the streamgages in this study (Wagner and others, 2016, appendix 1). The regional flood skew was incorporated in a final flood-frequency analysis in PeakFQ software using a weighted skew (England and others, 2019). In addition to the 71 streamgages used to develop the regional flood skew, five active streamgages that were screened for redundancy (four in Missouri and one in Arkansas) were included in the final flood-frequency analysis. The final estimates of streamflows corresponding to the selected AEPs (0.5, 0.2, 0.1, 0.04, 0.02, 0.01, and 0.002) were weighted with estimates of the same AEPs computed using regional regression equations (Southard and Veilleux, 2014; Wagner and others, 2016) to generate the final weighted estimates, their variances, and 95-percent confidence intervals.

This dataset contains site information and results of flood-frequency analysis for 139 urban streamflow gaging stations (streamgages) operated by the U.S. Geological Survey (USGS) in Tennessee and parts of Alabama, Georgia, Mississippi, North Carolina, and South Carolina. Developed imperviousness in the basins, based on the 2011 National Land Cover Database, was at least 10 percent (Homer and others, 2015). Drainage areas of the streamgage basins ranged from 0.15 - 161 square miles. Annual peak-flow data from the 1947 - 2022 water years were used in the study (U.S. Geological Survey, 2024). Peak-flow (.pkf), specification (.psf), output (.PRT), and export (.EXP) files from flood-frequency analysis in USGS PeakFQ software (Veilleux and others, 2014; Flynn and others, 2006) are provided. Site information and results of flood-frequency analysis are provided in .csv format.

This dataset contains site information and results of flood-frequency analysis for 139 urban streamflow gaging stations (streamgages) operated by the U.S. Geological Survey (USGS) in Tennessee and parts of Alabama, Georgia, Mississippi, North Carolina, and South Carolina. Developed imperviousness in the basins, based on the 2011 National Land Cover Database, was at least 10 percent (Homer and others, 2015). Drainage areas of the streamgage basins ranged from 0.15 - 161 square miles. Annual peak-flow data from the 1947 - 2022 water years were used in the study (U.S. Geological Survey, 2024). Peak-flow (.pkf), specification (.psf), output (.PRT), and export (.EXP) files from flood-frequency analysis in USGS PeakFQ software (Veilleux and others, 2014; Flynn and others, 2006) are provided. Site information and results of flood-frequency analysis are provided in .csv format.

The U.S. Geological Survey (USGS), in cooperation with the New Mexico Department of Transportation, estimated the magnitude and frequency of floods corresponding to the 50-, 20-, 10-, 4-, 2-, 1-, 0.5-, and 0.2-percent annual exceedance probabilities (AEPs; otherwise known as the 2-, 5-, 10-, 25-, 50-, 100-, 200-, and 500-year floods, respectively) for 346 selected streamgages in New Mexico and parts of Arizona, Colorado, Oklahoma, Texas, and Utah using data through water year 2020. An updated regional flood skew, -0.145, standard error 0.454, was computed for the study area. Regression equations were developed which can be used to estimate the magnitude and frequency of floods at ungaged locations on unregulated streams in the study area. The methods and results of the study are published in the parent report (Bell and others, 2022, https://doi.org/10.5066/XXXXXXXX). For the 346 selected streamgages, this dataset includes peak-flow (*.pkf) and specification (*.psf), output (*.PRT), and export (*.EXP) files from version 7.3 of USGS PeakFQ software (Veilleux and others, 2014; Flynn and others, 2006). Within PeakFQ software, the Expected Moments Algorithm (EMA) was used to conduct frequency analyses to estimate stream discharges corresponding to the 0.5, 0.2, 0.1, 0.04, 0.02, 0.01, 0.005, and 0.002 AEPs. When appropriate, the updated regional skew was used to weight the at-site skew in the frequency analyses. Results of the frequency analyses were used in generalized least-squares (GLS) regression to generate equations that predict discharges corresponding to selected AEPs at ungaged locations on streams in the study area (Bell and others, 2022).

This data collection of U.S. Geological Survey data releases provides the source data and results of flood frequency analyses and annual exceedance probability estimation for selected observed floods in Alaska and conterminous basins in Canada. The data include streamgage information, PeakFQ input and output, flood frequency parameters, flood frequency estimates for selected annual exceedance probabilities, and annual exceedance probability estimates for selected observed flood events.

This data collection of U.S. Geological Survey data releases provides the source data and results of flood frequency analyses and annual exceedance probability estimation for selected observed floods in Alaska and conterminous basins in Canada. The data include streamgage information, PeakFQ input and output, flood frequency parameters, flood frequency estimates for selected annual exceedance probabilities, and annual exceedance probability estimates for selected observed flood events.