HOW WILL MASSIVE ANTHROPOGENIC VALLEY-FILL DEPOSITS IN APPALACHIAN HEADWATERS ERODE?

Mountaintop removal/valley-fill mining practiced in the headwaters of the Central Appalachia has led to the construction of valley-fills, voluminous multimodal deposits in the headwaters of stream networks. There are over 7000 of these anthropogenic deposits in headwater valleys with volumes up to 200 million m³ and thicknesses of 120 m or more. Little field-based research on valley-fill erosional processes and landforms has been published to date, and government guidance on the long-term future trajectory of the deposits is lacking. Similar heavily compacted, geometrically designed post-mining landscapes around the world have exhibited a susceptibility to accelerated erosion. A combination of fieldwork, LiDAR analyses, and landscape evolution modeling will be used to investigate on-going processes and future possibilities. Authorization has been granted by the West Virginia Department of Natural Resources to conduct fieldwork on newly acquired lands intended for elk restoration in the headwaters of the Guyandotte River in Mingo and Logan Counties, West Virginia. Fifty-four valley-fills of varying dimensions and known ages are contained within the study areas. Preliminary visual inspection and digital terrain analysis of high-resolution LiDAR indicate the toe of valley-fill deposits may be particularly vulnerable to erosion. Erosional landforms such as gullies will be mapped and entered into a GIS for analysis. CAESAR-Lisflood landscape evolution modeling will attempt to show the trajectory of these massive anthropogenic deposits on a millennial timescale. Remotely sensed gully erosion on valley-fill faces and side slopes and early landscape evolution modeling results will be presented.