Wetland Delineation Methods and Procedures
EDI conducts all federal wetland delineations in accordance with the guidelines
and procedures outlined
in the currently valid 1987 Corps of Engineers
Wetlands Delineation Manual and a multi-disciplinary
team of professionals performs each delineation. The
federal method for wetland delineation is a three-parameter
test consisting of soils, vegetation and hydrology.
An area is delineated as a federally jurisdictional wetland if
it is found to have hydric soil, hydrophytic vegetation and
wetland hydrology.
The subtle nature of some wetlands can make accurate delineations problematic.
In order to provide the greatest degree
of accuracy, EDI utilizes a multi-disciplinary team
of professionals consisting of a soil scientist and
wetland ecologist (botanist) to conduct all wetland
delineations. This unique team approach paired with EDI’s careful attention
to detail has resulted in a record of excellence.
EDI uses the quadrant transect sampling procedure for most sites that exceed
5.0 acres in size. This procedure
involves establishing a baseline from which a
representative number of parallel transects are laid out, generally 200 feet
apart between opposite property boundaries. At
200-foot intervals along each transect, EDI collects hydrologic,
soils and vegetative data at “transect data points.” Each
transect data point is evaluated according
to the data collected and the three-parameter test to
allow for a wetland determination for that point.
When an area tests positive as a wetland, the wetland boundary is defined and
delineated
with numbered flags places along the boundary. Data points
are then taken within the wetland and outside
of the wetland in order to document conditions on each side
of the boundary. The numbered boundary flags
facilitate the process of reviewing the wetland boundary
and surveying the
exact location of the boundary.
Reports
Data acquired during the field investigations is compiled and summarized in a
comprehensive wetland delineation report.
EDI structures the reports so as to facilitate U.S. Army
Corps of Engineers (Corps) and New York State Department
of Environmental Conservation (NYSDEC) determinations of
jurisdiction over each project pursuant
to Section 404 of the Clean Water Act and Article 24
(Freshwater Wetlands) of the
New York State Environmental Conservation Law.
Each report includes a project introduction, a site description, a preliminary
office review, an explanation of methods
and procedures, results and conclusions and
recommendations. The preliminary office review consists of a full
color excerpt of the U.S. Geological Survey Map, National
Wetlands Inventory Map, the Soil Conservation
Survey Map and the NYSDEC Wetlands Map with the
project site and dimensions depicted, as well as
a discussion of the information depicted on each map.
A site specific, detailed explanation
of the field investigation procedures is given.
Included in the results are a general description of the site conditions;
the field data sheets for vegetation, soils and
hydrology; a map depicting the general vegetative
communities found on-site; a map depicting the soils found
to underlay the site; a map depicting
the wetlands delineated and a discussion of each. The final
portion of the report relates the findings to the current
regulations and provides recommendations for further action
based on EDI’s experience.