Hydrogeomorphic (HGM) Approach

A functional assessment method that compares a wetland’s
condition to similar wetland types (as defined by HGM
classification) that are relatively unaltered. HGM functions
normally fall into one of three major categories: (1) hydrologic
(storage of surface water), (2) biogeochemical (removal of
elements and compounds), and (3) habitat ( maintenance of plant
and animal communities). Hydrogeomorphic classes include
riverine, depressional, slope, mineral soil flats, organic soil
flats, estuarine fringe, and lacustrine fringe.