Restoration vs. Enhancement in Wetland Mitigation Banks

Wetland mitigation banks are often sited in areas that have been historically altered by significant anthropogenic activities. These areas, prior to man’s disturbances, were often natural wetland areas with significant ecological value and habitat for what are now threatened and/or endangered species. While some natural aspects may return to these sites once disturbances cease, more often than not, these sites never regain natural plant assemblages and habitat features. i.e., normal wetland functions and values. Mitigation banking, using state-of-the–art wetland restoration techniques, can bring about the necessary site improvements that allow for natural wetland attributes to return.

Federal regulations and some state (notably Maryland) regulations provide wetland banking credits as restoration credits, rather than merely enhancement credits. These governmental entities recognize that bringing back wetlands in disturbed areas (in particular, formerly farmed areas) is a true restoration activity that warrants restoration credits at a 2:1 ratio rather than merely enhancement credits, at a higher 3:1 ratio. Unfortunately, the State of New Jersey regulations are vague, leaving the agency to follow their own policy that does not recognize the significance of restoration and discourages mitigation banking. In the case of the Oxford Western Wetland Mitigation Bank, the state needs to recognize that the project is a wetland restoration, not merely enhancement, as federal agencies and other states would.

In 2003, federal agencies put together a user’s guide for wetland restoration, creation and enhancement.* These agencies use commonly-accepted definitions of these terms as follows:


Restoration – Returning a degraded wetland or former wetland to a pre-existing condition or as close to that condition as is possible.

Creation – Converting a non-wetland (either dry land or un-vegetated water) to a wetland.

Enhancement – Increasing one or more of the functions performed by an existing wetland beyond what currently or previously existed in the wetland. There is often an accompanying decrease in other functions.

Since that time, most agencies and states have allowed former farmland to be considered restoration for mitigation banking purposes. According to the definitions above, restoration entails returning a wetland to a natural former state, while enhancement means changing the wetland so that one or more functions are increased beyond their original state. Enhancing a wetland in one way can degrades it in another way.

Since restoration and enhancement projects may be difficult to distinguish from each other – because both can encompass activities in existing degraded wetland – NJDEP can place reliance on the expertise of other agency personnel, university researchers and wetland professionals to make that determination.

In the case of the Oxford Western Wetland Mitigation Bank, restoration is achieved by returning a farmed area to its pre-existing wetland state by creating a natural meander to the channelized brook and ditched farmland. The project restores wetland functions beyond the farmland condition and in no way degrades any other functions.

Unfortunately for many sites, the State of New Jersey has considered passive methods (leaving sites alone) as proof that the sites may become wetlands again, disregarding true functions and values. However, other states and the federal government have noted that passive methods are not enough to restore the natural system and an active approach (as in Oxford) is necessary. Active approaches involve physical intervention in which humans directly control site processes to restore, create, or enhance wetland systems. The active approach is most appropriate when a wetland is severely degraded. Active methods that will be employed in Oxford include re-contouring a site to the desired topography and micro-topography; intensive planting and seeding, intensive non-native species control, and ensuring that soils provide the proper substrate for native species. The design, engineering, construction, and costs for such work can be significant. In the case of the Oxford Mitigation Bank, the cost will be close to $1 million.

It is our hope that NJDEP will review their policies and use the current flexibility in their regulations to view this Oxford project correctly as a restoration effort. What are your thoughts?

* 2003. Interagency Workgroup on Wetland Restoration: National Oceanic and Atmospheric Administration, Environmental Protection Agency, Army Corps of Engineers, Fish and Wildlife Service, and Natural Resources Conservation Service. An Introduction and User’s Guide to Wetland Restoration, Creation, and Enhancement.

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