The Hydrogeomorphic (HGM) Approach for Assessing Wetland Functions begins with a classification of wetlands based on hydrogeomorphic factors. This classification is intended to lay a foundation for and support ongoing efforts to develop methods for assessing the physical, chemical, and biological functions of wetlands. The approach includes a development phase and an application phase. The assessment procedure, as the final product, can be used to compare project alternatives, determine impacts, mitigation requirements, etc. A growing number of reports can be downloaded from http://el.erdc.usace.army.mil/wetlands/hgmhp.html. Software to run the guidebook models is under development.
Within EMRIS, the section on "Selecting a Wetland Assessment Procedure" contains information on several function assessment approaches, some of which contain models.