404 permit have been successfully fulfilled. Performance standards should generally reflect Corps of Engineers guidelines calling for a minimum of “one for one functional replacement”1 of wetlands unavoidably impacted by permitted activities. Performance standards also facilitate enforcement actions for projects that fail to comply with Section 404 permit conditions.
PERFORMANCE STANDARDS AND FUNCTIONAL REPLACEMENT: In recent years, a large literature has developed that offers post hoc assessment of compensatory mitigation wetlands. Most post hoc studies compare created or restored wetlands to nearby natural reference wetlands on the basis of a number of attributes, such as vegetation community composition, benthic invertebrate community composition, and water quality. This literature suggests that many wetlands created and restored as compensatory mitigation do not replace the structure and functions of lost natural wetlands. Although many authors have offered opinions regarding the cause of poor structural and functional replacement, few authors have attempted to relate performance standards required by permits with results of post hoc studies comparing compensatory mitigation wetlands and natural reference wetlands. There is a clear need for studies designed to link performance standards required by permits with the ability of created or restored wetlands to replace lost wetland structure and functions.
EXAMPLES FROM PERMITS: Table 1 summarizes performance standards from Section 404 permits and mitigation plans referenced by permits. Examples were compiled by reviewing permit files available at Corps of Engineers District offices and requesting copies of permit files from District offices. Over 300 permits were reviewed to compile examples for Table 1; however, the table represents selected examples rather than a comprehensive summary of Section 404 permit performance standards.
Many permits that required compensatory mitigation did not include performance standards. In some permits, items designated as “performance standards” or “success criteria” did not meet the definition of performance standards used in this technical note; for example, instructions regarding planting techniques were frequently called performance standards. No attempt was made to comprehensively review or representatively sample all Section 404 permits, so no conclusions can be drawn regarding the number of permits issued without performance standards.
Table 1 shows that there are no universally used performance standards for compensatory mitigation. Even within Districts, performance standards may vary from permit to permit. The absence of universal performance standards probably reflects the ongoing evolution of the Section 404 regulatory process as well as differences in regional or site-specific ecological conditions and regional needs.
At least seven distinct approaches can be identified from the examples in Table 1. Most examples combine two or more of these approaches. These approaches include:
As per the Memorandum of Agreement between the Environmental Protection Agency and the Department of the Army Concerning the Determination of Mitigation Under the Clean Water Act, Section 404(b)(1) Guidelines, 1990.