The Federal Highway Administration's
2003 Environmental Excellence Awards
Tulula Creek Wetland Mitigation Site

The Tulula Creek Wetlands Mitigation Site is a 235-acre site in Graham County, North Carolina that was purchased by the North Carolina Department of Transportation (NCDOT) to mitigate wetland and stream impacts from transportation projects in western North Carolina. The site is nestled between Cheoah Bald and the Snowbird Mountains near the headwaters of Tulula Creek at an elevation of 2620 feet. This mitigation site, rather unique for its large size and mountain location, is mostly surrounded by the Nantahala National Forest. Historically, it contained a mountain floodplain forest-fen complex that included a variety of wetland habitats such as woodland seepages, vernal ponds, and boggy openings (fens). Mountain fens, vernal ponds, and floodplain forests provide critical habitats for many native plants and animals in the southern Appalachians; however, most of these habitats have been destroyed due to human activities. The Tulula Wetlands is the last remaining sizeable swamp forest-fen complex in Graham County, and fewer than 250 acres of this rare community type are known in North Carolina. The site remained in a natural state until the mid-1980’s when developers began constructing a golf course on the site. The construction process violated Section 404 of the Clean Water Act and ultimately the project was abandoned.

The swamp forest-fen complex was severely impacted during the attempted golf course construction. The natural channel of Tulula Creek was channelized throughout the site and a network of ditches was developed joining into it in an attempt to drain the site. This detrimentally affected both the wetland and stream habitat of the site. Fairways were completely cleared and graded, with much of this work occurring in the wetland areas. Golf course ponds were also excavated, some of them in wetlands, and the spoil also deposited in wetlands.

NCDOT gave the restoration of this site a high priority by purchasing it in 1994 for use as mitigation. Since the initial purchase, NCDOT has formed intricate partnerships with the University of North Carolina at Asheville (UNC-A), Center for Transportation and the Environment (CTE), U.S Army Corps of Engineers, U.S Fish and Wildlife Service, N.C. Department of Environment and Natural Resources, N.C. Wildlife Resources Commission, and environmental consultants to develop and implement a plan to restore the Tulula site.

NCDOT and its partners collected baseline data on all environmental facets of the Tulula project. This included an assessment of the plant communities, hydrology, and soils and an inventory of the plants, amphibians, reptiles, mammals, birds, fish and benthic macroinvertebrates. In addition, there has been continuous monitoring and evaluation of changing ecological conditions at the site as restoration activities are implemented. A key educational component of the project has been the use of innovative approaches to better understand species interactions and natural community organization and the development of a GIS database to enhance the ecological assessment of the entire site. This research has and will provide important information on the ecology of southern Appalachian floodplain forests and associated wetland complexes, as well as information that will be useful for designing and restoring other mountain wetlands. To date, researchers from UNC-A have published over eleven technical reports in peer-reviewed publications to disseminate their findings.

The Tulula site has also been utilized for a variety of educational purposes related to wetland restoration and wildlife conservation. Examples include university class trips to study hydrology and soils, birding trips by local ornithology groups, and Upward Bound classes to learn basic principles of ecology and conservation biology. Over forty undergraduate students have participated in all aspects of the field research efforts at the site, greatly enhancing their undergraduate experience. Undergraduates have also had the opportunity to pursue semi-independent research projects. Their projects have included studies of plant seed banks, box turtle microhabitat use, carnivorous plants, amphibian species interaction, distribution of insects and bacteria, among others.

Some of the primary components of restoring the Tulula site have involved restoring the Tulula Creek channel, eliminating side ditches, removing fill from areas to expose the original wetland soils, revegetating the site, and creating vernal pond habitats for aquatic organisms. Vernal ponds were created on the site in 1995-1996 as amphibian breeding sites and are currently being monitored to determine if they are functioning adequately. Test plantings of nursery stock that could be used for revegetating the site are currently underway to determine the ability of nursery stock to tolerate saturated soils. UNC-A and CTE are also gathering data on movements of resident animals such as the box turtle to determine the extent to which resident species use adjoining uplands. Additionally, researchers are intensively studying the golden-winged warbler, one of the most abundant breeding birds at the site, to examine this species’ association with water.

Many of the former golf course fairways have shown rapid successional change since disturbance ended. An evaluation of the natural succession has been conducted in areas that are planted with a variety of canopy species such as red maple, black gum, and several oaks. It was determined that many of the fairways at Tulula will not require revegetation of canopy species due to the rapid recolonization of the site by these species since the initial project stages.

The primary focus of restoration at Tulula has been to restore the historic hydrology that was severely altered when the channel of Tulula Creek was dredged. NCDOT constructed a meandering channel (1.2 miles in length) across the floodplain to recreate the pre-disturbance condition of stream flow. A consultant developed the design of the new channel partially based on the physical characteristics of a relic channel found mainly at the lower end of the site. Wherever practical, these relic channel fragments were incorporated as part of the new meandering channel. The existing dredged channel was completely backfilled. The stream flow of the new channel was constructed and diverted in stages in 2001 and 2002. The final channel tie-in and flow diversion was completed in July 2002.

The construction work on the site was primarily performed by NCDOT staff from the local division office. This provided an invaluable training opportunity for staff in a part of the state where routine road improvement projects often require relocating streams that support trout and other sensistive species.

The banks of the new channel are being protected from stream bank erosion with a natural fiber matting that covers the sides of the channel banks and a half meter of the adjacent floodplain. To increase the protection of stream banks, NCDOT installed coir fiber rolls along the bottom of the outside banks of constructed meanders and planted live stakes of willow or silky dogwood on the sides of banks and on the adjacent floodplain. Root wads were also installed in the channel banks to improve fish habitat. Rock weirs were utilized to control the stream grade at critical points and as habitat features. The exposed soils in the disturbed corridor of the new channel were seeded with a mixture of annual grasses, including winter rye and switchgrass. The seeded grasses survived in drier (higher) portions of the floodplain, but wetter (lower) areas of exposed soils were quickly colonized by wetland species. The corridor of the new channel will eventually be planted with canopy tree species.

Concurrent with construction of the new channel, NCDOT blocked the outlets of drainage ditches and partially refilled the ditches with adjacent soil. The project intentionally left segments of these drainage ditches to collect water to serve as amphibian habitat. Recreating the meandering channel should decrease water velocity, which, coupled with the backfilling of drainage ditches, should raise the level of the water table across the floodplain and allow for more frequent overbank flooding. NCDOT also partially backfilled ten of the eleven golf course ponds with soil removed during their construction to create vernal pond conditions.

Freshwater wetlands in the eastern United States provide critical habitats for a variety of rare or uncommon plants and animals. While these habitats are biologically rich and harbor many unique life forms, they have been destroyed at an alarming rate during the last century. Although precise information on the percent of wetlands that have been lost in western North Carolina is not available, estimates based on the amount of floodplain habitats that have been converted into agricultural lands or urban areas suggest that >95% of the original wetlands are now gone. Without the restoration performed by NCDOT and its partners, Tulula probably would have lost most of its wetland qualities, dramatically changing the surrounding ecosystem.

Tulula is the most significant wetland mitigation effort in the Blue Ridge Province of North Carolina. It has provided an important and unique opportunity for NCDOT to restore and enhance a mountain wetland and stream complex that was previously and severely degraded. Further, it has provided not only mitigation, but also a valuable learning experience for students and educators interested in biology and environmental subjects. The research efforts have yielded a comprehensive set of data about this site, an important contribution to the limited body of knowledge about southern Appalachian wetlands. It has also provided a vital training experience for NCDOT staff on using natural channel design concepts in construction of stream relocations. The Tulula Creek Wetlands Mitigation Site has been an exemplary project for NCDOT and its partners and will continue to provide valuable information for incorporation into future wetlands and water quality projects nation wide.