DOI: 10.5066/p9pgal0d
title: Regional flood skew for parts of the mid-Atlantic region (hydrologic unit 02) in eastern New York and Pennsylvania

description: This data release contains annual peak-flow data through the 2013 water year, specification and output files from flood-frequency analysis of the annual peak-flow data in USGS PeakFQ software, a GIS shapefile of the basin polygons with attributes of site information, basin characteristics, results of flood-frequency analysis, and results of B-WLS/B-GLS analysis of skewness of the annual peak flows from 183 streamflow gaging stations (streamgages) operated by the U.S. Geological Survey (USGS) in parts of hydrologic unit 02 in eastern New York and Pennsylvania and the surrounding states of Connecticut, Maryland, Massachusetts, New Jersey, Vermont, Virginia, West Virginia. Also included is a comma-separated values (.csv) file containing the attributes of the GIS shapefile. Annual peak-flow data (.txt) files, specification (.psf) files for use in USGS PeakFQ flood-frequency analysis software, and PeakFQ output (.PRT) files for the 183 streamgages are provided in batch formats. B-WLS/B-GLS regression was used to relate flood skew for each streamgage to a suite of ten explanatory variables (basin characteristics), including: latitude and longitude of the basin centroids; drainage area, mean basin slope, mean basin elevation, basin compactness; mean annual precipitation, mean basin soil permeability, percentage of the basin in forested land-cover; and percentage of the basin in open water. For 156 of the 183 streamgages, basin polygons and characteristics were obtained from the GAGES II database (Falcone, 2011). For the remaining 27 streamgages-22 in New York, 2 in Pennsylvania, one in Connecticut, one in Maryland, and one in New Jersey-basin polygons were obtained from StreamStats (Ries and others, 2017) and the basin characteristics were computed using datasets and methods used in the development of GAGES II. The USGS station identification number, name, state, latitude and longitude, and 8-digit hydrologic unit code for each streamgage were obtained from the USGS National Water Information System (U.S. Geological Survey, 2020). Information from Tables 1 (Input Data Summary), 2 (Results of Multiple Grubbs-Beck and Mann-Kendall tests), and 3 (Moments and mean squared error from log-Pearson III analysis) in the PeakFQ output (.PRT) file, pseudo record length (PRL) and unbiased skew derived from results of flood-frequency analysis and used in the B-WLS/B-GLS regression, and the residual from the B-WLS/B-GLS analysis are included in the GIS shapefile and .csv file. References: Falcone, J.A., 2011, GAGES?II: Geospatial Attributes of Gages for Evaluating Streamflow: U.S. Geological Survey dataset. [available at https://water.usgs.gov/GIS/metadata/usgswrd/XML/gagesII_Sept2011.xml] Ries, K.G., III, Newson J.K., Smith, M.J., Guthrie, J.D., Steeves, P.A., Haluska, T.L., Kolb, K.R., Thompson, R.F., Santoro, R.D., and Vraga, H.W., 2017, StreamStats, version 4: U.S. Geological Survey Fact Sheet 2017?3046, 4 p., https://doi.org/10.3133/fs20173046 [Supersedes USGS Fact Sheet 2008?3067] U.S. Geological Survey, 2020, National Water Information System data available on the World Wide Web (Water Data for the Nation), accessed March 30, 2020 at http://waterdata.usgs.gov/nwis.