Part II: Wetland Mitigation & Functional Assessment Methods
- posted in: Knowledge Center
Methods that biological resource specialists’ use for assessing the functional quality of a wetland can vary from state to state. California employs the California Rapid Assessment Method (CRAM), whereas Florida’s state regulators first developed the Wetland Rapid Assessment Protocol (WRAP) and then developed a more detailed method known as the Uniform Mitigation Assessment Method (UMAM).
As we discussed in Part I of this series, Utah has the UDOT Wetland Functional Assessment method. On a federal level, the Environmental Protection Agency (EPA) has developed a rapid assessment method for assessing wetland condition. Typically, the state-developed methods are most applicable to the wetland types and communities found within that state.
The objective of Section 404 evaluations and the methods mentioned above is to provide a standard way to evaluate the health and function of a wetland by looking at factors unique to wetlands in general or particular wetland types. We then determine the level of existing impact on each of those factors.
The UDOT method looks at a number of variables, including level of disturbance; vegetation composition; federally listed or proposed species; animals ranked by the Utah Natural Heritage Program (UNHP); wildlife utilization; and hydrological factors. Within the UDOT method, each variable is given a functional score in its existing condition based on specific parameters. Once the evaluator has scored the wetland variables, the assessment must be provided to federal and state agencies for input regarding likely utilization of the wetlands by state and federal listed species. The resulting score reflects the existing function of the wetland.
Referring back to the restoration project from part I, the majority of wetlands received low functional scores due to existing impacts, such as grazing, dewatering, active farming, and heavy weed infestation. In order to determine the potential functional impacts to these wetlands, our biological resource specialists then scored the wetlands for what they anticipated the post-project condition of the wetlands to be. The proposed activities associated with this project are anticipated to improve the functionality of the wetlands by removing impacts, restoring hydrology, and providing an appropriate habitat for native species. This resulted in what we call a “functional lift” in the quality of the project wetlands.
In some cases, the anticipated post project condition may result in a functional loss for project wetlands, usually due to a loss of wetland acreage. However, the “degree” of impact can be determined by the functional assessment score. If project wetlands scored low in their existing condition, a loss of function due to project activities is determined to have a lesser impact than a loss of function to pristine, high-functioning wetlands. This distinction becomes important during the Section 404 permitting process when negotiating mitigation for proposed impacts.
Having biological resource specialists with experience using wetland functional assessments and incorporating the information during your wetland Section 404 permitting process can be a valuable asset when negotiating with the permitting agency.
Join us in our last examination of how to protect project wetlands during construction in part III of the series in the next coming weeks!