IS MITIGATION A MYTH OR MIRACLE?
Is mitigation a myth or miracle?
This week I wanted to research and discuss Mitigation as a tool for reducing the impact of development on water resources. Wetlands and streams are important parts of the watershed system. Yet, developmental needs can conflict with these resources, and when this occurs developers must find a way to meet their needs with the least impact to wetlands and streams.
WHAT IS WETLAND MITIGATION?
Summary:
Wetland mitigation/compensatory mitigation is the reducing or negating the impact or destruction of aquatic and wetland systems through the creation new systems, enrichment of current systems, or restoration of previously impacted systems.
Wetland Mitigation: Clean Water Act
Mitigation is encompassed under section 404 of the Clean Water Act (CWA) compensatory mitigation. The act is an important part of the United States's protection of Waters of the United States (WOUS). Like many environmental law the CWA is administrated by the Environmental Protection Agency to ensure the protection of humans, aquatic life and wildlife from contaminated waters. The Section 404 specifically deals with impacting of wetlands under the CWA. Ultimately, section 404 seeks to result in no net loss of wetlands nation wide. The enforcement of this policy is done through three primary ways:
- Avoidance: The primary way wetlands are not impacted is by simply not impacting them. Outlined in section 230.10(a), individuals/organizations seeking to develop must choose a development plan the allows for the desired impact with the least or complete avoidance of wetland impacting. More often then not development can't avoid impacts.
- Minimization: Once a plan is determined to impact wetlands, the plan with the least impact must be used and any wetlands that are lost or degraded must be compensated for.
- Compensatory Mitigation: Appropriate and practicable compensatory mitigation is required for unavoidable adverse impacts which remain after all appropriate and practicable minimization has been required. Compensatory actions (e.g., restoration of existing degraded wetlands or creation of man-made wetlands) should be undertaken when practicable, in areas adjacent or continuous to the discharge site (on-site compensatory mitigation). If on-site compensatory mitigation is not practicable, off-site compensatory mitigation should be undertaken in the same geographic area if practicable (i.e., in close proximity and, to the extent possible, the same watershed). In determining compensatory mitigation, the functional values lost by the resource to be impacted must be considered. Generally, in-kind compensatory mitigation is preferable to out-of-kind. There is continued uncertainty regarding the success of wetland creation or other habitat development. Therefore, in determining the nature and extent of habitat development of this type, careful consideration should be given to its likelihood of success. Because the likelihood of success is greater and the impacts to potentially valuable uplands are reduced, restoration should be the first option considered.
Wetlands play a significant roll in watershed systems helping to .....I want to use this post to take a much closer look at On and off site mitigation and a detailed look at wetland restoration and creation success to evaluate how effective they are at achieving the no net loss goal.
WETLAND CLASSIFICATION AND METHODS FOR MITIGATION
Identifying Wetlands:
Compensating for wetlands impacts starts with an identification. Potential developers should always have their project area searched for jurisdictional features (these are features that our under the jurisdiction of the Army Core of Engineers (COE) as spelled out under the CWA). Jurisdictional features generally include streams and adjacent wetlands. Once, identified wetlands are usual characterized as emergent, scrub-shrub, and forested. These wetlands require different amounts of compensation this is because not all wetlands are equal in there ecological services generally wetlands are compensated at a 1:1 ratio for emergent wetland, 1:1.5 for scrub-shrub wetlands, and 1:2 for forested wetlands, however this is not always the rule and wetlands can require higher rates depending on the wetland, location, and any other number of reasons not addressed here. Typically developers ether construct wetlands on site or perches credit from a banking system. Wetland banks create, restore, and enhance wetlands in order to received credit that can be sold to at a market price. for more on banking check out the links here: Wetland and Stream Mitigation Banking
Types of Mitigation:
Enhancement
Wetland enhancement is the improvement of an existing wetland habitat natural, restored, or created. Enhancement activities can include invasive specie removal, tree plantings, native vegetation seedings, habitat creation for resident and migratory wildlife, creation of riparian buffers, and anything that improves the ecological function of the wetland. Credits earned through enhancements can be banked like thoughts from earned from creation and restorations.
Restoration
Wetland restoration restores previously degraded or destroyed wetlands this could include reestablishing wetland hydrology, replanting native vegetation, or by any other means of restoring past undisturbed conditions.
Creation
Wetland creation is the building of wetlands in areas not previously considered wetlands though many wetlands enlarge existing wetlands. Wetland creation can be done in a number of ways, but most are conducted in clay soils with high water table or a year around or seasonal source of water such as an perennial/intermittent stream.
MITIGATION CHALLENGES
The success of wetland mitigation program is mixed in. In a study of compensatory wetland and stream mitigation in North Carolina conducted by Hill et. al. (2013) mitigation was successful (i.e. sites met regulatory standards) 75% these findings are similar to other studies such as Erwin (1991) that found that approximately half of the created wetland area failed to meet regulatory standards with 24 of the 40 sites monitored considered incomplete or failed. The lack of success in restoration and creation can ultimately result in a net loss of wetlands this was in observed by Kentula et. al. in Oregon and Washington states in 1992. However, this is not completely bad news. The discipline of wetland creation is extremely young for example first approved wetland bank of Virginia (Julie J Metz) mitigation bank created in Prince William County in 1995. Over these past 30 years the science of wetland restoration and creation is learning from its failures. Identifying and understanding the challenges of wetland creation will be important to understanding if mitigation works.
The Avoidance Issue
A major issue is that avoidance is rarely used to protect wetlands. Preservation and enhancements of natural and existing wetland systems has proven to be more successful then the creation of new wetlands or the restoration of a degraded system. Rarely, are wetland impacts avoided accept in cases in which the economic cost out weighs the benefit of development. A specific case in which avoidance and 404 fails to protect wetlands in the case of smaller features which are often destroyed completely and mitigated through bank credit. This leads to wetland consolidation. A few 100 small impacts may all perches from the same bank. In this case the wetlands have been mitigated bu the importance of small wetland to its specific location is hard to fully quantify.
The Success Issue
Success in habitat creation and restoration are controversial topics what is success? who decides success? Do we treat all creation and restorations to the same standard of success? What do we do when we fail? The federal government through delegation to the states has developed success criteria. This allows for the creation of state even county standards for creation and restoration of aquatic resources (includes wetlands and streams). For example Fairfax, Prince William, and Loudoun counties have there one wetland and stream banking system with specific monitoring and success requirements. This is because habitats can differ over a few square miles and because of local environmental issues (land use differences, topography, past/present/future development). The issue is that not all success standards are created equal. A created wetland (even years after construction) may not provide all of the ecological benefits provided by the destroyed wetland. Since most permits require 10 years of monitoring before the permit is released, meaning not required to be actively monitored it the data is spotty on the long term success of created wetlands.
The Habitat Issue
Possibly the biggest issue facing wetland restoration and creation is the desired target habitat. A emergent coastal salt marsh may be restored/created with a much grater chance of success then compared the restoration/creation of say a non tidal forested swamp. In Hill et. al. 2013 study in North Carolina over half the restorations and creations in the Piedmont (an area located between the Atlantic coast and the Appalachian Mountains) failed to meet regulatory standard. The same issues are experiences in the Piedmont regions of Virginia particularly with the creation of forested wetland systems.
FUTURE OF WETLANDS
Is mitigation a myth of miracle? Mitigation is certainly a mixed bag. On one hand it helps off set wetland and stream impacts, but on the other hand it creates a legal means for wetland destruction without a clear path for the successful creation or restoration. The "No Net Loss" policy certainly seems to be a myth. Created/restored wetlands may take decades to provide the same ecosystems services as those of natural wetlands if at all. Section 404 and mitigation practices must continually be adapted as technology and knowledge provide for a better means of reducing and mitigating wetland impacts. The future of wetlands and watersheds are closely linked, and both are likely to undergo
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