Wetland Delineation and Baseline Vegetation Assessment

As part of the Remedial Investigation/Feasibility Study process at a Department of Energy Superfund Site located in Upton, New York, Roux Associates completed a field assessment and delineation of the Peconic River wetlands to document the baseline vegetation and hydrology of the wetland resources present along sections of the river requiring sediment remediation.  Roux Associates completed a detailed inventory of the wetlands based on the installation of 55 transects along a 2.5 mile stretch of the Peconic River.  The results of the wetland assessment were be used to evaluate the Peconic River wetland functions and values, and to support the development of goals and objectives for subsequent wetland restoration plans.

Detailed vegetation surveys of each distinct plant community present were performed in accordance with the New York State Department of Environmental Conservation (NYSDEC) delineation methodology (NYSDEC, 1995).  A total of 34 transects were established perpendicular to the Peconic River.  Major plant communities along each transect were then staked on the upland and open water vegetative borders to demarcate the extent of plant community along each survey transect.  In addition to demarcating the transitions between plant communities, stakes were placed in the center of the open water region.

Along each transect, the vegetation in each plant community located within 10 feet of the transect (20-foot wide observation) was inventoried to dominant species, diversity, structure and abundance.  Vegetative species were recorded and classified using the USFWS categories as listed under Regional and National Indicator columns in the “National List of Plant Species that Occur in Wetlands” (USFWS, 1988) in which plant species have been assigned Wetland Indicator Status based upon the probability of observing each species in a wetland environment.  When observed, hydrologic wetland indicators were recorded. 

In addition to the assessment procedures outlined above, the wetland boundaries along the Peconic River were determined based upon the presence of hydrophytic vegetation and wetland hydrology and available historic baseline information.  In accordance with NYSDEC wetland delineation protocol, the presence of hydrophytic vegetation (wetland vegetation) was the primary indicator to determine jurisdiction.  Hydric soil and wetland hydrology indicators provided additional supplemental information and were only investigated if the presence of hydrophytic vegetation was questioned.  The wetland boundary line was flagged and/or staked in the field with visible colored flags.  Locations of the delineated (i.e. flagged) wetland boundaries were then determined through the use of a GPS receiver.

Subsequent activities included the evaluation of the revegetation success following remediation activities through the monitoring the baseline transects along the 2.5 mile stretch of restored Peconic River.