Between the town of Nags Head and Cape Hatteras lies a strategic location for a ferry terminal in a small community known as Rodanthe. The ferry serves the purpose of transporting citizens, construction personnel, equipment and supplies to and from Hatteras Island communities in the event of an emergency shut down of the Herbet C. Bonner Bridge or the closure of North Carolina Highway 12 connecting Hatteras to the mainland. There is a history of such events in this area, most recently Hurricane Irene in 2011 and again in 2012 with Hurricane Sandy. Weather is not always the culprit, in 2013 the Bonner Bridge was closed due to safety concerns. In these extreme instances, the NC Ferry Division, a subsidiary of the North Carolina Department of Transportation (NCDOT), runs ferries from Stumpy Point to and from Rodanthe crossing a shallow Pamlico Sound in the process.
The Pamlico Sound averages four feet in depth, which poses a problem when a ferry, heavily laden with vehicles and supplies, needs to cross these waters. To accommodate 220 foot, 700-800 ton vessels, the NC DOT dredges these channels to deepen and widen them. Due to the dynamic coastal processes that helped create the need for the ferry in the first place, additional dredging is essential once again. The ferries require channels eighty feet wide and eight feet deep to travel safely across the sound. The NC DOT knows that the procedure is necessary, but what it wants to also know is how to best deposit the exorbitant amount of material left over from the dredging process.
To answer this the NC DOT teamed up with researchers at the Coastal Studies Institute to better understand the effects dredging the channel and the resulting deposition of dredge material would have on three key components of the defined research area. These components include the estuarine environment of the Pamlico Sound, submerged cultural material, such as shipwrecks found in the path of the channel, and the geological implications of dredging and deposition of sediment.
Traditionally, the sediment material removed from the sound floor, called dredge spoil, was often deposited wherever it was convenient. With the Rodanthe project, the NC DOT and Coastal Studies Institute are considering the alternatives. Now, researchers believe the spoil can be put to good use and considered a resource rather than a waste bi-product. By looking at it in this way, the focus shifts to where the deposition of this material can provide maximum benefit to the local community and the environment they share. Before researchers decide what course of action to pursue in regards to the dredge material it is important to gain a sense of what is happening beneath the waves as well as along the shoreline in Rodanthe. To do this, each discipline relies on a set of tools and systematic methods that measure, record, and collect data that can be analyzed and interpreted. This baseline data allows the scientists to provide objective suggestions, backed by science, for the NC DOT on a plan of action for the project.
1. Create maps that define the ecological, geological, physical and maritime heritage attributes of the research area.
2. Evaluate the net impacts of potential material deposition site plans, including but not limited to negative and positive ecological, geological and anthropological impacts.
3. Inform the local and regional communities about the rationale and costs and benefits of dredging and depositing the material from the Rodanthe Emergency Ferry Channel.
4. Provide a site selection structured approach that favors the reduction of negative impacts to the local ecology and archaeological remains, while also taking into account geological complications.
The coastal processes component is concerned primarily with the sediments that comprise the dredge spoil. Geologists look to discover the composition of the material and what useful properties it may contain. For more information on sediment dynamics in the Pamlico Sound and the research area at Rodanthe click here: Coastal Processes.
The back barrier sound by Rodanthe is populated with an extensive amount of seagrass, a type of sub-aquatic vegetation known to provide a large variety, as well as quantity, of ecosystem services. These services are of value to the creatures that populate this estuarine environment including human beings. To learn more about sub-aquatic vegetation and ecosystem services click here: Estuarine Ecology.
The Outer Banks of North Carolina are home to thousands of shipwrecks found up and down the coast. For an area that depended on maritime transportation for much of its history, the presence of shipwrecks and other remnants of human habitation are not confined to just the sea side of the coast. As part of the Rodanthe project, archaeologists investigated the history and archaeology of the research area. To learn more about their survey and findings click here: Maritime Heritage.