Hydrogeomorphic (HGM) Classification, Inventory, and Reference Wetlands

Classifying wetlands is useful for describing and managing their natural variability. The hydrogeomorphic (HGM) approach, which covers classification, reference, and functional assessment aspects, has proven to be helpful in classifying wetlands as to their position in the landscape, their source of water, and the flow of that water. In this chapter, we review the origins and characteristics of freshwater wetlands for ecoregions of the Mid-Atlantic region (MAR), which are dominated by riverine types. Inventories of wetlands in the MAR are dated, so we discuss what is known with regard to status and trends, and potential solutions. We discuss the value of establishing a reference set to assist with classification, assessment, and mitigation of wetlands, and describe the set of reference wetlands compiled for Pennsylvania by Riparia. Preliminary results from a regional condition assessment of wetlands in the MAR are provided.