1987 Wetland Delineation Manual - The Wetlands Regulation Center
1987 Wetland Delineation Manual - The Wetlands Regulation Center
1987 Wetland Delineation Manual - The Wetlands Regulation Center
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<strong>Wetland</strong> Delination <strong>Manual</strong>, <strong>1987</strong> 19<br />
(4) Physiological adaptations. Physiological adaptations include any features of the metabolic<br />
processes of plants that make them particularly fitted for life in saturated soil conditions.<br />
NOTE: It is impossible to detect the presence of physiological adaptations in plant species<br />
during onsite visits. Physiological adaptations known for hydrophytic species and species<br />
known to exhibit these adaptations are listed and discussed in Appendix C, Section 3.<br />
(5) Reproductive adaptations. Some plant species have reproductive features that enable them<br />
to become established and grow in saturated soil conditions. Reproductive adaptations known<br />
for hydrophytic species are presented in Appendix C, Section 3.<br />
Definition<br />
Hydric Soils<br />
36. A hydric soil is a soil that is saturated, flooded, or ponded long enough during the growing<br />
season to develop anaerobic conditions that favor the growth and regeneration of hydrophytic<br />
vegetation (US Department of Agriculture (USDA) Soil Conservation Service (SCS) 1985, as<br />
amended by the National Technical Committee for Hydric Soils (NTCHS) in December 1986).<br />
Criteria for hydric soils<br />
37. Based on the above definition, the NTCHS developed the following criteria for hydric<br />
soils:<br />
a. All Histosols except Folists; Soil nomenclature follows USDA-SCS (1975).<br />
b. Soils in Aquic suborders, Aquic subgroups, Albolls suborder, Salorthids great group, or<br />
Pell great groups of Vertisols that are:<br />
(1) Somewhat poorly drained and have a water table less than 0.5 ft<br />
from the surface for a significant period (usually a week or more) during the growing season,<br />
or<br />
(2) Poorly drained or very poorly drained and have either:<br />
(a) A water table at less than 1.0 ft from the surface for a significant period (usually a week or<br />
more) during the growing season if permeability is equal to or greater than 6.0 in/hr in all<br />
layers within 20 inches; or<br />
(b) A water table at less than 1.5 ft from the surface for a significant period (usually a week or<br />
more) during the growing season if permeability is less than 6.0 in/hr in any layer within 20<br />
inches; or<br />
c. Soils that are ponded for long or very long duration during the growing season; or<br />
d. Soils that are frequently flooded for long duration or very long duration during the growing<br />
season.”<br />
A hydric soil may be either drained or undrained, and a drained hydric soil may not continue to<br />
support hydrophytic vegetation. <strong>The</strong>refore, not all areas having hydric soils will qualify as<br />
25 February 1997 Environmental Techncal Services Co. 834 Castle Ridge Rd Austin, Texas 78746