1987 Wetland Delineation Manual - The Wetlands Regulation Center

Wetland Delination Manual, 1987 41
• STEP 3 - Determine Whether Wetland Hydrology Is Present. When one of the following
conditions applies (STEP 2), it is only necessary to confirm that there has been no recent
hydrologic alteration of the area:
a. The entire project area is occupied by a plant community or communities in which all
dominant species are OBL (Appendix C, Section 1 or 2).
b. The project area contains two or more plant communities, all of which are dominated by
OBL and/or FACW species, and the wetland-nonwetland boundary is abrupt (e.g. a Spartina
alternifzora marsh bordered by a road embankment). * There must be documented evidence of
periodic inundation or saturated soils when the project area:
a. Has plant communities dominated by one or more FAC species;
b. Has vegetation dominated by FACW species but no adjacent community dominated by OBL
species;
c. Has a gradual, nondistinct boundary between wetlands and nonwetlands; and/or
d. Is known to have or is suspected of having significantly altered hydrology.
If either a or b applies, look for recorded evidence of recently constructed dikes, levees,
impoundments, and drainage systems, or recent avalanches, mudslides, beaver dams, etc., that
have significantly altered the area hydrology. If any significant hydrologic alteration is found,
determine whether the area is still periodically inundated or has saturated soils for sufficient
duration to support the documented vegetation (a or b above). When a or b applies and there is
no evidence of recent hydrologic alteration, or when a or b do not applv and there is
documented evidence that the area is periodically inundated or has saturated soils, wetland
hydrology is present. Otherwise, wetland hydrology does not occur on the area. Complete the
hydrology section of DATA FORM 1 and PROCEED TO STEP 4.
• STEP 4 - Determine Whether the Soils Parameter Must Be Considered. When either a or b
of STEP 3 applies and there is either no evidence of recent hydrologic alteration of the project
area or if wetland hydrology presently occurs on the area, hydric soils can be assumed to be
present. If so, PROCEED TO STEP 6. Otherwise PROCEED TO STEP 5. o STEP 5 -
Determine Whether Hydric Soils Are Present. Examine the soils data (Section B, STEP 7) and
record the soil series or soil phase on DATA FORM 1 for each community type. Determine
whether the soil is listed as a hydric soil (Appendix D, Section 2). If all community types have
hydric soils, the entire project area has hydric soils. (CAUTION: If the soil series description
makes reference to inclusions of other soil types, data must be field verified). Any portion of
the area that lacks hydric soils is a nonwetland. Complete the soils section of each DATA
FORM 1 and PROCEED TO STEP 6.
• STEP 6 - Wetland Determination. Examine the DATA FORM 1 for each community type.
Any portion of the project area is a wetland that has:
a. Hydrophytic vegetation that conforms to one of the conditions identified in STEP 3a or 3b
and has either no evidence of altered hydrology or confirmed wetland hydrology.
25 February 1997 Environmental Techncal Services Co. 834 Castle Ridge Rd Austin, Texas 78746