Data Source: National Resources Conservation Service (NRCS) Gridded Soil Survey Geographic (gSSURGO) Database, November 2023.
This data represents Hydrologic Soil Groups, or soils with similar hydrologic characteristics that influence absorbance and runoff of precipitation. Therefore, this data can help estimate potential stream flow after a storm event.
Hydrologic Soils Definitions from NRCS
Hydrologic Soil Group A - Soils having high infiltration rates even when thoroughly wetted, consisting chiefly of deep, well to excessively drained sand and/or gravel. These soils have a high rate of water transmission and would result in a low runoff potential.
Hydrologic Soil Group B - Soils having moderate infiltration rates when thoroughly wetted, consisting chiefly of moderately deep or deep, moderately well or well drained soils with moderately fine to moderately coarse textures. These soils have a moderate rate of water transmission.
Hydrologic Soil Group C - Soils having slow infiltration rates when thoroughly wetted, consisting chiefly of (1) soils with a layer that impedes the downward movement of water, or (2) soils with moderately fine or fine textures and slow infiltration rate. These soils have a slow rate of water transmission.
Hydrologic Soil Group D - Soils having very slow infiltration rates when thoroughly wetted, consisting chiefly of (1) clayey soils with high swelling capacity or potential, (2) soils with a high permanent water table, (3) soils with claypan or clay layer at or near the surface, and (4) shallow soils over nearly impervious materials. These soils have a very slow rate of water transmission.
Date Creation
Data was downloaded from the November 2023 gSSURGO Database for the Continental US, combined with the gSSURGO attribute table field Hydrologic Group - Dominant Conditions (hydgrpdcd), converted to polygon, simplified, and clipped to the boundary of North Carolina. For more information on creating soil maps, visit the
NRCS site for gSSURGO. This data is static.
This data is intended for use in the ATLAS (Advancing Transportation through Linkages, Automation, and Screening) Tool for the Hydraulics Unit at NCDOT.
Metadata Reference
Point of Contact
NCDOT EAU ATLAS Business Team
Contact Information:
ATLAS@ncdot.gov
Contact instructions: Please send an email with any issues, questions, or comments regarding Hydrologic Soils. If it is an immediate need, please
indicate as such in the subject line in an email.