Mitigation is the last resort of regulators to protect the nations and maintain the no-net-loss standard. Ideally, traditional mitigation means the enhancement, restoration, or creation of comparable wetlands. Other means of mitigation include merely preservation and monetary compensation or in-lieu-fee. The mitigation is carried out by the permitee, who is held responsible as a condition of the permit.

Assumptions of a Mitigation Policy in Theory and Practice

The possiblity of mitigation as an option (even as a last resort) assumes that, dependent on location, the private and social benefits of development supersede the private and social benefits of wetlands. Even though society has realized that wetland losses have reached a critical level, wetland losses must still persist to support mainly suburban development. Thus, the word "net" in no-net-loss becomes the pivotal concept in wetland regulation. No-NET-loss assumes that wetlands can be replaced. American wetland policy absolutely depends on the science of wetland ecology and art of wetland creation.

On the whole, wetland ecologists are not confident in their own ability to support this system, which relies on the mutual convertiblity of natural capital (wetlands) and man made capital (parking lots). Wetland consulting firms have sprung up in great numbers to respond to this task. However, the nature of their business is subcontracting. Subcontractors compete for the lowest bid for a project. A fact of the wetland mitigation industry is downward pressure on the capital inputs for constructed wetlands. While competing with each other, wetland construction firms are then required to compete with the natural formed wetlands. The result is that wetland construction under the traditional mitigation method has not held up the no-net-loss standard by any measurement.

Numerous studies have shown that mitigation does not offer replacement acre for acre. A basic understanding of wetland ecology strongly suggests that wetland functions in an unnatural created wetland will not mirror those of a wetland that has been established for centuries or millenia. Under the standing permit regulations, a temporal loss of acres and functions occurrs as the wetland creation effort follow the wetland destruction efforts. The no-net-loss standard is betrayed by an emphasis on rigorous permitting language and posturing and a de-emphasis on monitoring and compliance. The causes of this dilemna are looked into in greater detail in the regulatory perspective section.

Failure

Wetland mitigation failure has occurred for a variety of ecological reasons, not just because of bad faith and incompetence, which both have been significant.

Nutrient levels-Wetland soils are relatively nutrient rich compared to terrestrial ones. Failure to choose a site with necessary nutrient inputs cause the project not to develop as planned. The Sweetwater National Wildlike Refuge was a restoration mitigation project by the California Dept. of Transportation. Old dike were destroyed and the marsh regraded to establish a Spartina cordgrass marsh to attract the endangered ligth-footed clapper rail bird. The Sweetwater site is nutrient poor; the cordgrass will not grow to the necessary height; the clapper rail is absent from the landscape.

Soil hydrology-Incomplete knowledge of a mitigation site's hydrology results in inadequate calculation of the flow and presence of water when the site is filled. PLantings can be in the wrong place, or poor grading can result in baked soil or a muddy hole in the ground. More common than complete failure, mitigation sites are often smaller in practice than when they pass the section 404 permit process on paper. Overestimation of soil hydrology is forseeable, when environmental conculting firms try to underbid each other for corporate or government mitigation work.

Exotic invasion-In constructing the Greens Bayou Mitigation Bank in Harris County Texas, considerable resources had to be spent to combat the pervasive presence of chinese tallow trees. The efforts involved hacking and slashing and the permit and use of herbicide. In traditional mitigation projects it is unlikely that the sponsor will commit the resources upfront to eliminate or during maintenence to control exotic invasion. Without knowledge of ecology, many probably believe that all plants are equal. Unfortunately because of past mistakes, our wetland restoration and creation projects become even more difficult.

Catastrophic events-In the early stages of a project, catastophic events can destroy a wetland permanently. Creation projects are more risky than resoration projects in this regard. Extreme floods and their opposite, extended droughts, are natural risk factors that cannot be reduced beyond a certain point. If flooding succeeds in washing a maority of the soil and plat cover away, the site can become permanently degraded. If droughts remove the water from certain wetland soils that are high in clay to cause large cracks, the returned water flow will take years to restore the impermeability and retention capacity of the site.

Human impact-Best managemnet practices, especially with construction equipment, are essential. The misguided construction of an access road, or the inadvertent altering of a berm can drain a site. Wetlands are maintained by subtle gradations in elevation, which must be watched closely. The construction equipment, such as bulldozers and scrapers can be unwieldy for wetland construction purposes and find it hard to match the level of precision on the design specifications.

Lack of maintence-One of the signifiacant cost to mitiation is maintenence. Routine monitoring may find new construction is necessary to respond to a hydrologic or landscape alteration from external to the site. Without enforcement by regulatory authorities, "voluntary" additional expenditure is unreliable.