Hydrogeomorphic (HGM) Functional Assessment Model and Guidebook for Tidal Fringe Wetlands in the New Jersey Meadowlands


Peg McBrien, P.E., P.W.S., Principal Environmental Scientist, The Louis Berger Group, Inc., East Orange, NJ 

     mmcbrien@louisberger.com, 973-678-1960 x469



On behalf of the New Jersey Meadowlands Commission (NJMC), the Louis Berger Group, Inc. (Berger) is completing a hydrogeomorphic (HGM) functional assessment model and guidebook for tidal fringe wetlands in the Hackensack Meadowlands. The HGM model will be used as a tool to help determine wetland functions and values and to approximate compensatory wetland mitigation.  Other assessment methodologies include the Wetland Evaluation Technique (WET), Habitat Evaluation Procedure (HEP) and Indicator Value Assessment (IVA) assessment methodologies.


The HGM effort is being coordinated with an Advisory Team (A-Team) including representatives of the New York District of the U.S. Army Corps of Engineers, U.S. Environmental Protection Agency, U.S. Fish and Wildlife Service, New Jersey Department of Environmental Protection, Rutgers University, NJMC and Berger.  Existing HGM methods are being adapted to apply to the unique urban estuarine nature of the tidal fringe wetlands in the Meadowlands.


To initiate the HGM effort, extensive field data were collected by Rutgers University.  The data were used to develop initial models of functions provided by the wetlands. These models have been tested for accuracy and sensitivity by assessing eight reference wetlands, selected to represent a range of degraded to desirable conditions within the Meadowlands.  Both map-based variables, such as amount of aquatic edge and channel density, and field variables, such as vegetation structure and soil texture, have been collected.  The data were analyzed to calibrate the model variables. The data were applied to ten functional models and the resulting functional capacity indices were assessed. Based on the results, a Draft Regional Guidebook is being developed. The Guidebook identifies which functions are most likely to be performed by wetlands in the New Jersey Meadowlands, discusses the ecosystem and landscape characteristics that influence the capacity of wetlands to perform functions, and provides the models for assessing these functions. The Calibrated Draft Regional Guidebook for Tidal Fringe Wetlands in the Meadowlands should be completed in early 2004.