| Within the Appalachian hills of eastern Kentucky, large-scale coal mining operations are directly altering the headwater landscape through the construction of hollow fills. These man-made landforms and their associated in-stream structures alter a long-term, continuous morphologic evolution driven by the natural interaction of erosive forces and material of the earth's surface. Post-mining channel morphology, hillslopes, and hollow fills continue to actively evolve in response to erosive forces. Aquatic ecosystem functionality and hollow fill stability may be jeopardized by this condition, yet they may be preserved through efforts to restore or re-create channel morphology more representative of the natural headwater stream. The success of such stream restoration efforts depends largely on the incorporation of geomorphic considerations. A field investigation of select headwaters impacted by hollow fill construction revealed active post-mining morphologic evolution of streams and the interrelated hillslopes driven by discernable geomorphic processes. Through an analysis of longitudinal stream profiles, the current study presents practical geomorphic considerations regarding discrepancies between permitted hollow fill plans and as-built hollow fills. Additionally, pre- and post-mining longitudinal profiles are compared to investigate the physical differences that may instigate morphologic evolution. The examined hollow fills were constructed under regulations which pre-date those currently in place; the observations and considerations derived from them, however, will be useful in the development of stream restoration practices in mined areas. |
