INVESTIGATING LANDSCAPE CHANGE DURING THE EIGHTEENTH CENTURY ALONG THE OLD BURKE WAGON ROAD WITHIN THE YADKIN RIVER VALLEY IN WESTERN NORTH CAROLINA

The Great Wagon Road provided a conduit for European settlers travelling south from Philadelphia into North Carolina from 1740-1780. Colonial settlers then migrated from settlements established on the Piedmont westward into the mountain region using the Yadkin River corridor. Located on a tributary to Moravian Creek, the Benjamin Hubbard House, part of a small family farmstead, is listed on the National Register of Historic Places as a two-story log house built in 1778. The front of the house is within 16 m of the Old Burke Road. This wagon road extended ~60 km from Moravian Falls to Morganton, NC and provided a route for settlers and trade in the region. We have identified the trace of this road along a 10 km stretch using LiDAR imaging (NC Floodplain Mapping Program). At Hubbard Farm the roadbed was identified and surveyed using a total station. It averaged 4 m in width, large enough to accommodate Conestoga wagons, and was incised from 0.5 to > 6 m below the land surface. The amount of downcutting measured on the roadbed at Hubbard Farm was used to estimate the volume of sediment removed from the road on the LiDAR image.

Five categories of downcutting were mapped on the LiDAR image along the Old Burke Road. Category 0 had no visible incision, category 1 had 0.5-1 m of incision, 2 had 1 m-2 m of incision, 3 had 2 m-3.5 m of incision, and 4 had greater than 3.5 m of incision. Segments with no visible incision could be the result of sheet wash without focused erosion. 54 segments with incision totaled a length of 5872 m with category 3, 1754 m, and category 2, 1688 m, being the longest. The total volume of soil erosion was calculated for each segment using a midpoint depth and totaled 40,824 m³. The 60 km road could account for up to 250,000 m³ of sediment entering tributary channels. Categories 4 and 3 accounted for 43% and 34% of the sediment volume, respectively.

Erosion along the Old Burke Road occurred when it was in use in the late 18^th and early 19^th centuries. The highest incision rates (categories 3 and 4) are associated with the steeper slopes from the interfluves into the tributary valleys. The incised roadbeds likely became conduits for sediment transport from the recently cleared farm fields into tributary streams. This study suggests that early transportation routes may have contributed a significant volume of anthropogenic sediment into river valleys.