HYDRIC SOILS LIST FOR RHODE ISLAND

Hydric Soil Definition: A hydric soil is a soil that formed under conditions of saturation, flooding, or ponding long enough during the growing season to develop anaerobic conditions in the upper part.

Hydric soils develop under conditions sufficiently wet to support the growth and regeneration of hydrophytic vegetation.  Some areas of these soils may have been drained and therefore do not support predominantly hydrophytic vegetation and are not wetland.  Only those soils that are saturated, flooded, or ponded long enough during the growing season to develop anaerobic conditions in the upper part are considered hydric.   The criteria used to determine which soil map units are composed dominantly of hydric soils are based on selected soil properties.  These properties are documented in Soil Taxonomy and the State Soil Survey Database.

 This list of Rhode Island soil map units that qualify as hydric soils has applications for agriculture and nonagricultural purposes.  These applications include land-use planning, mapping, classifying and delineating wetlands, mitigation planning, and hydrophytic vegetation and hydrology indicators, are part of the procedure for identifying wetlands as described in the Federal Manual for Identifying and Delineating Jurisdictional Wetlands.

HYDRIC SOIL CRITERIA (Federal Register 1995):

 Criteria 1.       All Histosols except Folist, or

 Criteria 2.       Soils in aquic suborders, great group, or subgroup, Albolls suborder, Aquisalids, Pachic subgroups, or Cumulic subgroups that are:

 a.)    Somewhat poorly drained with a water table equal to 0.0 feet from the surface during the growing season, or
 b.)    Poorly drained or very poorly drained soils that have either:

 (1)   water table at equal to 0.0 feet from the surface during the growing season if textures are coarse sand, sand, or fine sand in all layers within 20 inches, or for other soils

 (2)   water table at less than or equal to 0.5 feet from the surface during the growing season if permeability is equal to or greater than 6.0 inches/hour in all layers within 20 inches, or

 (3)   water table at less than or equal to 1.0 feet from the surface during the growing season if permeability is less than 6.0 inches/hour in any layer within 20 inches, or

 Criteria 3.  Soils that are frequently ponded for long duration or very long duration during the growing season, or

 Criteria 4.  Soils that are frequently flooded for long duration or very long duration during the growing season.

Hydric Soils List

The list of soil map units on the following page (link below) is referenced to the Soil Survey of Rhode Island (USDA, Natural Resources Conservation Service , July 1981) or any updates thereof.

Note:  This list constitutes both of the "State" list of hydric soil map units and the "County" hydric soil map unit list for each of Rhode Island's five counties.

Link to Hydric Soil List for RI