EVOLUTION OF A HEADWARD ERODING RIVER THAT IS EXTENDING THE PIEDMONT INTO THE BLUE RIDGE ESCARPMENT: MIDDLE SALUDA RIVER GORGE, JONES GAP STATE PARK

Jones Gap State Park is a dynamic landscape where the Middle Saluda River has cut a steep gorge into the Blue Ridge escarpment through the process of headward erosion. The shape of the gorge is the result of a constant state of disequilibrium as the over-steepened slopes fail in dramatic fashion as they attempt to reach a stable angle of repose.

The Middle Saluda River is the source of disequilibrium as it continually erodes and destabilizes the base of the slope at river level. This instability progresses in stages over the slope from river level to the rim. The most efficient mechanism to reduce the slope angle is the process of mass wasting which is a mixture of rock falls, landslides, and debris flows.

Detailed mapping using lidar analysis and ground truthing has identified a much larger extent of landslide deposits than previously mapped. These deposits have been connected to (a) conduit paths that conveyed the failed material from up high to the valley floor and (b) to the initiation zones where the failure originated.

Four areas of research will be presented: (1) an updated geologic map that shows the new extent of the landslide deposits, conduit paths, and initiation zones, (2) a fracture aperture measurement system developed here at Clemson University to identify potential initiation zones, (3) the results of a shallow P-wave geophysical study to examine buried channels under landslide deposits, and (4) the interpretation of interesting landforms that develop as the landscape adjusts to added material.