Basin characteristics in support of generalized least-squares (GLS) regression for 136 USGS Streamgages in urban areas in Tennessee and parts of Alabama, Georgia, Mississippi, North Carolina, and South Carolina

This data release contains a dataset of geospatial and tabular data used in support of a flood-frequency study of urban streams in Tennessee and parts of Alabama, Georgia, Mississippi, North Carolina, and South Carolina. The dataset includes data used in the development of generalized least-squares (GLS) regression equations for predicting streamflows at ungaged locations in the study area corresponding to 50-, 20-, 10-, 4-, 2-, 1-, 0.5-, and 0.2-percent annual exceedance probabilities. Included in the dataset are shapefiles of the streamgage basins and outlets used in the study packaged in a zip file (TNurbanFFreq_Basins and TNurbanFFreq_Outlets feature classes in TNurbanFFreq_Basins_and_Outlets.zip), three rasters in tiff format developed for calculation of basin characteristics packaged in a zip file (nlcd2011_developed_percent.tif, piedmont_eco_lvl3_percent.tif, and ridge_and_valley_eco_lvl3_percent.tif in Basin_Characteristic_Rasters.zip), and a table in csv format listing the basin characteristics that were tested as explanatory variables for development of the regression equations (BasinCharsTested.csv).

The data contained in the shapefiles of basin polygons and outlet locations for streamgages used in the flood-frequency analysis were derived from various sources further described in metadata document associated with this data release. The table from this data release listing the basin characteristics tested as explanatory variables predominately includes characteristics that were not used in the final GLS regression equations. The variables used in the final equations were drainage area, the percentage of developed land from the 2011 National Land Cover Database (NLCD), and the percentages of land within the Piedmont level 3 ecoregion and the Ridge and Valley level 3 ecoregion. The 3 rasters included in this data release represent the percentage of developed land derived from the 2011 NLCD and the percentages of land within the Piedmont level 3 ecoregion and the Ridge and Valley level 3 ecoregion.

For more information about the sources used for basin delineation and basin characteristic calculations, see the metadata document associated with this data release.