Seeking Optima for Wetland Restoration and Mitigation: Ensuring We Get There.

For decades, scientists, managers, policy makers, and practitioners have sought to improve the design and performance of restored and mitigated wetlands. Progress has been made, but further improvements are desperately needed. Creating wetlands that function at a lower level, similar to those of disturbed natural wetlands, cannot be considered an optimal restoration or mitigation endpoint. The use of reference sites has become increasingly common as a comparative tool for assessing restoration and mitigation project performance against the inherent variability in natural aquatic systems. By designing projects with characteristics derived from reference wetlands of relevant hydrogeomorphic (HGM) subclasses, practitioners are more likely to place a project on a performance trajectory that adequately replaces functions and ecosystem services of natural systems. Emphasizing hydrologic and soil components of functional assessments, we show how restoration and mitigation projects are typically located in different landscape settings and score lower for site-level conditions than reference wetlands. We explore the utility of design hydrographs, each comprised of a set of graphs and accompanying metrics, to ensure adequate water is available to support the new wetland. Riparia at Penn State has developed an interactive database designed to provide practitioners with data for designing these projects (http://www.wetlands.psu.edu/products/default.asp). The initial database contains data from 222 natural reference wetlands from Pennsylvania with plans to add data from hundreds of reference wetlands from Mid-Atlantic states. Because of their particular geographic origin, these data should be used with caution for other areas, but many of these variables will have some relevance to wetlands of a particular HGM type in other physiographic regions. Using these approaches routinely will help ensure that “we get there”.