The Federal Highway Administration's
2003 Environmental Excellence Awards
Lengyel Mitigation Site in New Bern

In 1994 The North Carolina Department of Transportation (NCDOT) listed the roadway improvement project of US 17, in the eastern portion of the state, as a priority completion corridor. Portions of this project involved unavoidable wetland impacts. Although roadway corridors rarely provide suitable area for onsite compensatory mitigation for wetland impacts, NCDOT endeavored to establish such mitigation as compensation for the projected loss of tidal brackish marsh habitat. Therefore, NCDOT developed a mitigation plan to compensate for the loss of wetlands due to the construction of the US 17 bridge crossing at New Bern, North Carolina as part of the planning and environmental studies for the project. In the spring of 1996, NCDOT performed a preliminary ecological assessment of the Lengyel wetland mitigation site located in Craven County. This site, which is named for the original landowner, is located along the Neuse River in the southeastern quadrant of the US 17 bridge crossing at New Bern.

The Lengyel site was initially selected for ecological evaluation because of the onsite, in-kind mitigation potential for unavoidable wetland impacts and because it was an uneconomic remnant of the project. The type of wetlands that were potentially going to be impacted by the bridge construction are rare in the region and serve several important roles in the local watershed such as flood prevention, water quality, and wildlife habitat.

Because of its urban location and proximity to the traveling public, the NCDOT knew the Lengyel site would serve as a flagship for their mitigation program. NCDOT had previously located mitigation sites for wetland impacts directly adjacent to road construction projects, but they had never before created a wetland mitigation site that was such an integral part of a construction project. That is exactly the case for the Lengyel mitigation site. It is directly within one of the bridge’s looped ramps. Whereas NCDOT could have chosen to leave this site in the dilapidated condition in which they found it and simply mitigate wetland impacts offsite at some rural location, they chose instead to clean up the industrial wasteland and restore this highly visible property to its native condition.

Historical aerial photography provided by NCDOT (1961, 1970, 1989, and 1996) was used to identify recent alterations affecting the site and to evaluate land use trends during the last 35 years. The peninsula was originally developed in the late 1890’s to support a sawmill, lumber storage area, and lumber-shipping port. Several brick structures associated with the sawmill were constructed within the site. The sawmill ceased operation in the mid-1920s and fell into disrepair. Scattered bricks, other building debris, and sawdust marked locations of the milling operation within the site.

The Lengyel site originally served as a deposition area for dredged material collected from the barge docks and shipping ways. The peninsula landscape has been subject to excavations, deposition of fill material, construction impoundment, and grading activities that have occurred over the last century or more. The age of trees within the depression indicate that it was excavated in the mid-1970s in association with a dredging operation in the Neuse River.

In building the wetland project in such an urban setting, NCDOT essentially constructed a "wildlife park" very near downtown New Bern, providing habitat for reptiles, amphibians, and other types of marsh wildlife native to the area. Now fish, birds, and other wildlife have an urban oasis to safely live and reproduce. This mitigation site is an environmental beacon to the traveling public who pass over the bridge. Instead of entering New Bern and looking down and seeing an abandoned sawmill, they are able to see a pristine coastal marsh. NCDOT hopes this effort will raise people’s awareness toward the department’s role in environmental stewardship.

NCDOT was able to use the same contractor who was building the bridge to also construct the wetland preservation/restoration site. In doing so, NCDOT was able to lower project costs and construct the mitigation site simultaneous to the bridge construction. It takes up to five years or longer of monitoring a mitigation site after it has been constructed to ensure it is successful and functioning properly. Therefore, the sooner the construction of a mitigation site is completed, the sooner the monitoring for the site can begin and modifications made, if required. The Lengyel wetland mitigation site was actually completed prior to the completion of the bridge construction project. This was looked upon very positively by the environmental resource agencies involved with the project since it allowed monitoring to begin much earlier than what might have been the case otherwise. Earlier completion of the mitigation site also meant less impacts on the local ecosystem.

Upon completion of the implementation activities, the Lengyel Mitigation Site will provide approximately 13 acres of brackish marsh restoration / preservation. Mitigation goals for the site include approximately 6.5 acres of brackish marsh restoration, 5.2 acres of brackish marsh preservation, and 0.85 acre of upland buffer. By restoring this site back to its original condition, NCDOT will significantly improve the water quality in this region as well as greatly improve wildlife habitat. NCDOT has also erected an osprey nesting platform in the mitigation site since the habitat is suitable for this species. Additionally, a tidal swale was created onsite to enhance fish habitat.

In order to demonstrate successful mitigation, hydrologic and vegetative monitoring must be conducted for a minimum of five years. Vegetation success criteria are based on the National Marine Fisheries Service (NMFS) guidelines while hydrologic success criteria are based on federal guidelines for wetland mitigation. Construction of the mitigation site began in April of 1998 and was concluded in March of 1999. Three full years of monitoring data have been collected and analyzed and a fourth year of data is currently being collected.

Hydrology for the Lengyel mitigation site has met the success criteria for the third year in a row, even with normal or below normal rainfall over that period. Additionally, the site is establishing wetland vegetation and is on target to meet the success criteria in 2003.

Additional observations include the siting of ospreys on the nesting platform and the presence of crabs and other aquatic organisms in the constructed tidal swale.

Overall the benefits of this project are numerous. Not only did NCDOT cut costs related to mitigating for unavoidable impacts to wetlands due to the bridge project, but they were able to do so in a timely and environmentally conscious manner. In doing so, NCDOT was able to enhance the quality of the environment in the midst of a large transportation project. Such projects help build the trust between NCDOT and the regulatory community, leading to more effective partnering and long-term sustainability of the environment.