Regional flood skew for the Tennessee and parts of the Ohio and Lower Mississippi River basins (hydrologic unit codes 06, 05, and 08, respectively) in Tennessee, Kentucky, western Virginia, western West Virginia, far western Maryland and parts of North Carolina, Georgia, Alabama, and Mississippi

This dataset contains site information, basin characteristics, results of flood-frequency analysis, and results of Bayesian weighted least-squares/Bayesian generalized least-squares (B-WLS/B-GLS) analysis of regional skewness of the annual peak flows for 785 streamflow gaging stations (streamgages) operated by the U.S. Geological Survey (USGS) in the Tennessee and parts of the Ohio and Lower Mississippi River basins (hydrologic unit codes 06, 05, and 08, respectively) in Tennessee, Kentucky, western Virginia, western West Virginia, far western Maryland and parts of North Carolina, Georgia, Alabama, and Mississippi. Annual peak-flow data through the 2021 water year (a water year is defined as the period October 1-September 30 and named for the year in which it ends) were used in the study. For regional skew analysis, 283 of the 785 candidate streamgages were removed for pseudo record length (PRL; Veilleux and Wagner, 2021) less than 30 years, 108 were removed for redundancy, 4 were removed for regulation and 2 were removed for urbanization (see file "VAskew_Region2.csv" in this dataset). For the remaining 387 of 785 candidate streamgages, B-WLS/B-GLS regression (Veilleux and Wagner, 2021) was used to relate flood skew to a suite of 32 explanatory variables. None of the explanatory variables tested had sufficient predictive power in explaining the variability in skew in the region; thus, a constant model of regional skew, 0.048 (average variance of prediction 0.16, standard error 0.4) was selected for the study area (Messinger and others, 2025). For the 785 candidate streamgages, annual peak-flow data through the 2021 water year ("VAskew_region2.pkf") and specification ("VAskew_region2.psf"), output ("VASKEW_REGION2.PRT"), and export ("VASKEW_REGION2.EXP") files from flood-frequency analysis in version 7.4.1 of USGS PeakFQ software (hereafter referred to as "PeakFQ"; Veilleux and others, 2014; Flynn and others, 2006) are provided. Two .csv files are provided, one describing the basin characteristics tested ("BasinCharsTested.csv") and the other ("VAskew_Region2.csv") containing site information (U.S. Geological Survey, 2023), results of flood-frequency analysis in PeakFQ, and, for the 387 streamgages used in the B-WLS/B-GLS regression, PRL, unbiased at-site skew, unbiased mean squared error of the at-site skew, the B-WLS/B-GLS residual, and metrics of leverage and influence. A geographic information systems (GIS) shapefile ("VA_SkewRegion2.shp") containing a polygon representing the geographic extent of the skew region is also included.

本数据集包含美国地质调查局（U.S. Geological Survey, USGS）在覆盖田纳西流域、俄亥俄流域部分区域与密西西比河下游流域（水文单元代码分别为06、05、08），涉及田纳西州、肯塔基州、弗吉尼亚州西部、西弗吉尼亚州西部、马里兰州极西部，以及北卡罗来纳州、佐治亚州、阿拉巴马州和密西西比州的部分区域内运营的785个流量监测站（streamgage）的站点信息、流域特征、洪水频率分析结果，以及年最大流量区域偏度的贝叶斯加权最小二乘/贝叶斯广义最小二乘（Bayesian Weighted Least-Squares/Bayesian Generalized Least-Squares, B-WLS/B-GLS）分析结果。
本研究使用了截至2021水文年的年最大流量数据（水文年定义为10月1日至次年9月30日，以其结束年份命名）。在区域偏度分析中，785个候选流量监测站中有283个因伪记录长度（Pseudo Record Length, PRL; Veilleux与Wagner, 2021）不足30年被剔除，108个因数据冗余被剔除，4个因受径流调节影响被剔除，2个因受城市化影响被剔除（详见本数据集内的"VAskew_Region2.csv"文件）。
针对剩余387个候选流量监测站，研究采用B-WLS/B-GLS回归法（Veilleux与Wagner, 2021），将洪水偏度与32个解释变量集进行关联。经检验，所有解释变量均无足够的预测能力解释研究区域内偏度的变异性；因此，为该研究区域选定了恒定的区域偏度模型值0.048（预测平均方差为0.16，标准误差为0.4）（Messinger等, 2025）。
针对785个候选流量监测站，本数据集提供了截至2021水文年的年最大流量数据（"VAskew_region2.pkf"）、洪水频率分析的配置文件（"VAskew_region2.psf"）、输出文件（"VASKEW_REGION2.PRT"），以及美国地质调查局PeakFQ软件7.4.1版（以下简称"PeakFQ"; Veilleux等, 2014; Flynn等, 2006）进行洪水频率分析得到的导出文件（"VASKEW_REGION2.EXP"）。
本数据集还提供了两个.csv文件：其一为所测试的流域特征说明文件（"BasinCharsTested.csv"）；其二为"VAskew_Region2.csv"，包含站点信息（U.S. Geological Survey, 2023）、PeakFQ软件的洪水频率分析结果，以及用于B-WLS/B-GLS回归的387个流量监测站的伪记录长度、无偏站点偏度、无偏站点偏度均方误差、B-WLS/B-GLS残差，以及杠杆率和影响度指标。
本数据集还包含一个地理信息系统（Geographic Information Systems, GIS）形状文件（"VA_SkewRegion2.shp"），其中包含表征该偏度区域地理范围的多边形要素。