1987 Wetland Delineation Manual - The Wetlands Regulation Center

Wetland Delination Manual, 1987 58
b. Make as many additional wetland determinations as necessary to find the wetland
boundary. NOTE: The completed DATA FORM 1's for the original two observation points
often will provide a clue as to the parameters that change between the two points.
c. When the wetland boundary is found, mark the boundary location on the base map and
indicate on the DATA FORM 1 that this represents a wetland boundary. Record the distance
of the boundary from one of the two regular observation points. Since the regular observation
points represent known distances from the baseline, it will be possible to accurately pinpoint
the boundary location on the base map. PROCEED TO STEP 19.
• STEP 19 - Make Wetland Determinations at All Other Required Observation Points Along
All Transects. Continue to locate and sample all required observation points along all
transacts. NOTE: The procedure described in Step 18 must be applied at every position where
a wetzand boundary occurs between successive observation points. Complete a DATA FORM
1 for each observation point and PROCEED TO STEP 20.
• STEP 20 - Synthesize Data to Determine the Portion of the Area Containing Wetlands.
Examine all completed copies of DATA FORM 1 (STEP 19), and mark on a copy of the base
map the locations of all-observation points that are wetlands with a W and all observation
points that are nonwetlands with an N. Also, mark all wetland boundaries occurring along
transacts with an X. If all the observation points are wetlands, the entire area is wetlands. If all
observation points are nonwetlands, none of the area is wetlands. If some wetlands and some
nonwetlands are present, connect the wetland boundaries (X) by following contour lines
between transacts. CAUTION: -If the determination is considered to be highly controversial, it
may be necessary to be more precise in determining the wetland boundary between transacts.
This is also true for very large areas where the distance between transacts is greater. If this is
necessary, PROCEED TO STEP 21.
• STEP 21 - Determine Wetland Boundary Between Transects. Two procedures may be used
to determine the wetland boundary between transacts, both of which involve surveying:
a. Survey contour from wetland boundary along transacts. The first method involves
surveying the elevation of the wetland boundaries along transacts and then extending the
survey to determine the same contour between transacts. This procedure will be adequate in
areas where there is no significant elevational change between transacts. However, if a
significant elevational change occurs between transacts, either the surveyor must adjust
elevational readings to accommodate such changes or the second method must be used.
NOTE: The surveyed wetland boundary must be examined to ensure that no anomalies exist.
If these occur, additional wetland determinations will be required in the portion of the area
where the anomalies occur, and the wetland boundary must be adjusted accordingly.
b. Additional wetland determinations between transacts. This procedure consists of traversing
the area between transacts and making additional wetland determinations to locate the wetland
25 February 1997 Environmental Techncal Services Co. 834 Castle Ridge Rd Austin, Texas 78746