Regional Guidebook for Applying the Hydrogeomorphic Approach to Assessing the Functions of Tidal Fringe Wetlands Along the Mississippi and Alabama Gulf Coast

摘要

The Hydrogeomorphic (HGM) Approach is a collection of concepts and methods for developing functional indices and subsequently using them to assess the capacity of a wetland to perform functions relative to similar wetlands in a region. The approach was initially designed to be used in the context of the Clean Water Act Section 404 Regulatory Program permit review sequence. During the Development Phase of the HGM Approach, four critical components are integrated in a Regional Guidebook for assessing the functions of a regional wetland subclass. Subsequently, during the Application Phase, end users, following the protocols outlined in the Guidebook, assess the functional capacity of selected wetlands. This Regional Guidebook (a) characterizes the tidal fringe wetlands of the Mississippi and Alabama Gulf Coast (north-central Gulf of Mexico) reference domain, (b) provides a rationale to select functions for the regional tidal fringe subclass, (c) provides a rationale to select model variables and metrics, (d) provides a rationale to develop assessment models, (e) provides data from reference wetlands and documents their use in calibrating model variables and assessment models, and (f) outlines protocols for applying the functional indices to the assessment of tidal fringe wetland functions in the north-central Gulf of Mexico.