initiate construction no later than concurrent with the permitted activity; construct and monitor to meet performance requirements; and transfer the long-term responsibility for ownership, monitoring, and adaptive management of the site to a certified wetland management entity.
Permittees' development projects cannot be delayed until compensation sites meet performance standards. Therefore, for permittee-responsible mitigation there needs to be some practical compromise between the goals of securing functional compensatory wetlands and placing realistic requirements on permit recipients. Toward that end, the first obligation of the permittee should be to initiate the required compensatory project no later than concurrently with the permitted activity. If there is a lag, a financial assurance that would be adequate to initiate, complete, and manage a comparable project at another location should be secured. Such an expectation would assure that permittee-responsible mitigation proceeds in the same expeditious time frame that is comparable to third-party mitigation systems.
Linking designs to ecological performance can be extremely difficult, because wetland science and restoration and creation efforts are still developing and must be tailored to individual sites. Therefore, while site designs should reflect current mitigation science and emerging scientific understanding, the initial designs may not always result in the exact wetland properties that were the original intent of the design. However, much can be accomplished within the limits of the current science. The committee believes that enough is understood about wetland hydrology, place in the landscape, soils, and other determinants of wetland structure to specify design requirements that will result in a site that will develop into a wetland and provide for a number of wetland functions. However, as was noted in Chapter 2, some wetland types are more difficult to create or restore than others. In short, we can design sites with a high probability of becoming functional wetlands, but whether particular sites will always result in particular functional outcomes is less certain. Based on the difficulty of restoring or creating wetland type, the permit could require more than an acre of replacement for each acre permitted —a mitigation ratio greater than 1:1. This use of mitigation ratios is already common in setting regulatory requirements.
Permit conditions for legal compliance with the mitigation obligation should recognize this reality. First, the permittee and regulators would