Tabular and geospatial data for the magnitude and frequency of floods at ungaged locations on streams in Tennessee, through the 2013 water year

To improve estimates of the frequency of annual peak flows for ungaged locations on non-urban, unregulated streams in Tennessee, generalized least-squares (GLS) multiple linear-regression techniques were used to relate annual peak flows from streamflow gaging stations (streamgages) operated by the U.S. Geological Survey (USGS) to physical, climatic, and land-use characteristics of their drainage basins. Geospatial data acquired since the previous study in 2003, annual peak-streamflow data through the 2013 water year, and Bulletin 17C (England and others, 2018) methods for frequency analysis of annual peak-streamflow data were used in the study. GLS regression equations were developed for four hydrologic areas with distinct hydrologic, geologic, and topographic characteristics. These regression equations can be used to estimate annual exceedance probability streamflows for ungaged locations on non-urban, unregulated streams in Tennessee. The term “unregulated” is an adjective indicating that streamflow is not appreciably influenced by regulation from reservoirs or other impoundments.

This data release contains the tabular (eight .csv files) and geospatial data used in the associated report by Ladd and Ensminger (2025), including a raster file representing percentage of impervious area, a shapefile of hydrologic areas used for regression regionalization, and shapefiles containing basin boundaries and outlet locations for streamgages used in the associated regression analysis.