1987 Wetland Delineation Manual - The Wetlands Regulation Center

Wetland Delination Manual, 1987 47
established--one at 200 ft, one at 600 ft, and one at 1,000 ft from the baseline starting point.
CAUTION: All plant community types must be included. This may necessitate relocation of
one or more transect lines. PROCEED TO STEP 20.
• STEP 20 - Sample Observation Points Along the First Transect. Beginning at the starting
point of the first transect, extend the transect at a 90-deg angle to the baseline. Use the
following procedure as appropriate to simultaneously characterize the parameters at each
observation point. Combine field-collected data with information already available and make
a wetland determination at each observation point. A DATA FORM 1 must be completed for
each observation point.
a. Determine whether normal environmental conditions are present. Determine whether
normal environmental conditions are present by considering the following:
(1) Is the area presently lacking hydrophytic vegetation and/or hydrologic indicators due to
annual or seasonal fluctuations in precipitation or ground-water levels?
(2) Are hydrophytic vegetation indicators lacking due to seasonal fluctuations in temperature?
If the answer to either of these questions is thought to be YES, PROCEED TO Section G. If
the answer to both questions is NO, PROCEED TO STEP 20b.
b. Establish an observation point in the first plant community type encountered. Select a
representative location along the transect in the first plant community type encountered. When
the first plant community type is large and covers a significant distance along the transect,
select an area that is no closer than 300 ft to a perceptible change in plant community type.
PROCEED TO STEP 20c.
c. Characterize parameters. Characterize the parameters at the observation point by
completing (1), (2), and (3) below:
(1) Vegetation. Record on DATA FORM 1 the dominant plant species in each vegetation
layer occurring in the immediate vicinity of the observation point. Use a 5-ft radius for herbs
and saplings/shrubs, and a 30-ft radius for trees and woody vines (when present). Subjectively
determine the dominant species by estimating those having the largest relative basal area
(woody overstory) This term is used because species having the largest individuals may not be
dominant when only a few are present. To use relative basal area, consider both the size and
number of individuals of a species and subjectively compare with other species present.,
greatest height (woody understory), greatest percentage of areal cover (herbaceous
understory), and/or greatest number of stems (woody vines). NOTE: Plot size may be
estimated, and plot size may also be varied when site conditions warrant. Record on DATA
FORM 1 any dominant species observed to have morphological adaptations (Appendix C,
Section 3) for occurrence in wetlands, and determine and record dominant species that have
known physiological adaptations for occurrence in wetlands (Appendix C, Section 3). Record
on DATA FORM 1 the indicator status (Appendix C, Section 1 or 2) of each dominant species.
25 February 1997 Environmental Techncal Services Co. 834 Castle Ridge Rd Austin, Texas 78746