Location: Fayetteville, North Carolina
Michael Baker International restored 427.5 acres of previously converted wetlands and 34,005 linear feet of Harrison Creek in the North Carolina Coastal Plain. This full-delivery project required negotiating with the landowner to secure a conservation easement, developing the stream and wetland mitigation plan, gaining regulatory agency approval, designing the project, monitoring wetland hydrology and vegetation for seven years, and submitting annual monitoring reports.
The agricultural fields across the site had been drained by a series of lateral ditches and channelized streams. To restore wetland hydrology to the site, Michael Baker International’s design raised the streambed elevation of Harrison Creek to promote more natural flooding of the riparian wetland areas to be restored. The design partially to completely filled lateral field ditches, depending on the amount of fill material that was produced from minor land grading and excavation of the new stream channel. Grading activities focused on removing any field crowns, surface drains, or swales that had been imposed during conversion of the land for agriculture.
Michael Baker patterned the topography of the restored site after natural floodplain wetland reference sites. The design included the restoration of minor depressions and tip mounds that promote diversity of hydrologic conditions and habitats. These techniques were instrumental to the restoration of site hydrology by promoting surface ponding and infiltration, decreasing drainage capacity, and imposing higher water table conditions across the restoration site.
The design allowed stream flows greater than bankfull to spread onto the floodplain, dissipating flow energies and reducing stress on stream banks. Michael Baker International used in-stream structures to control streambed grade, reduce stresses on stream banks, and promote bedform sequences. The in-stream structures consisted of root-wads, log vanes, log weirs, and other wood structures that will promote a diversity of aquatic habitat features in the restored channel. Vegetation plans included planting a 200-foot-wide buffer corridor with a variety of native trees for bottomland and upland forest ecosystems. The buffer extended the full length of the project and connected to a pristine headwater system at the upstream end and a high-quality swamp at the downstream end. This provided a continuous wildlife corridor from the headwaters downstream to the swamp system.