Summary of basin characteristics for National Hydrography Dataset, version 2 catchments in the southeastern United States, 1950 - 2010

This dataset provides numerical and categorical descriptions of 46 basin characteristics for 957 basins with observed streamflow information and 9,314 ungaged basins coinciding with 12-digit hydrologic unit code pour points that drain to the Gulf of Mexico. Characteristics are indexed by National Hydrography Dataset (NHD) version 2 COMID and USGS site number (streamflow-gaging station), where applicable. The variables represent mutable and immutable basin characteristics and are organized by characteristic type: physical (5), hydrologic (6), categorical (12), climate (6), landscape alteration (7), and land cover (12). Mutable characteristics such as climate, land cover, and landscape alteration variables are reported in decadal increments (for example, average percent forest for the decade 1950-1959, 1960-1969, etc). The majority of basin characteristics in this dataset were calculated using divergence-routing methods and are often referred to as 'network-accumulated'. This method uses a modified routing database to navigate the NHDPlus reach network to aggregate (accumulate) the values derived from the reach catchment scale (Schwarz and Wieczorek, 2016). In four instances, values are also provided for the entire catchment above a site and area designated using the "CAT_" prefix.

本数据集为957个拥有实测径流观测资料的流域，以及9314个未布设径流监测站的流域，提供了46项流域特征的数值与分类描述。这些未监测流域与汇水至墨西哥湾的12位水文单元代码汇流点相匹配。流域特征通过美国国家水文数据集（National Hydrography Dataset, NHD）第二版的COMID，以及适用情况下的美国地质调查局（USGS）径流测站编号进行索引。本数据集的变量涵盖可变与不变流域特征，并按特征类型分为六类：物理特征（5项）、水文特征（6项）、分类特征（12项）、气候特征（6项）、景观扰动特征（7项）以及土地覆盖特征（12项）。其中气候、土地覆盖与景观扰动等可变特征以十年为间隔进行统计，例如1950-1959年、1960-1969年等时段的森林覆盖率平均值。本数据集的多数流域特征采用分流汇流算法（divergence-routing methods）计算，这类特征通常被称为“网络累积型”特征。该方法通过改进的汇流路径数据库，遍历NHDPlus河段网络，对河段集水区尺度的数值进行聚合（累积）处理（Schwarz与Wieczorek，2016）。另有四种情形下，数据集还提供了测站以上全集水区，以及以"CAT_"为前缀标识的区域的特征数值。