Acid Mine Drainage Abatement in the Lower Rock Creek Watershed – McCreary County, Kentucky

Carew, Mark

ABSTRACT: Rock Creek above White Oak Junction is a beautiful boulder strewn stream designated as a Kentucky Wild River and is the premier mountain trout stream in Kentucky. Below White Oak Junction acid mine drainage (AMD) from over 40 coal mine portals and eight pyrite-rich refuse dumps has decimated aquatic life and rendered the stream virtually lifeless. The Rock Creek Task Force, a group of 12 state and federal agencies and conservation organizations, was formed to find solutions to the degraded water quality in the lower Rock Creek Watershed. Funding was provided by several of the Task Force partners including an EPA 319 Clean Water Action Plan grant, an Appalachian Clean Streams Initiative grant, a PRIDE grant from NOAA, KYAML’s annual grant, and a USGS cost share agreement. In 1998 a biological and water-monitoring program began in the lower Rock Creek watershed. Acid loading was calculated and in spring of 2000 dosing of selected tributaries with sand-sized limestone particles began. Within two months the flow out of Rock Creek into the Big South Fork of the Cumberland River changed from net acidic to net alkaline. After four months similar results were obtained in White Oak Creek, a major source of AMD to Rock Creek. In the fall of 2000 construction began on a reclamation project targeting several of the worst AMD sites in the lower Rock Creek watershed. Pyrite-rich refuse was removed from the banks of Rock Creek. Open limestone channels were installed routing AMD through the limestone before discharging into the stream, and a modified vertical flow wetland was installed at a site with limited distance between the AMD source and the receiving stream. Dosing with limestone sand continued monthly with permanent dosing stations being established farther upstream in the impacted tributaries. Water monitoring results continue to be encouraging with reductions in acidity and dissolved metals in the affected streams. Fish sampling has revealed that fish populations are already being re-established in once lifeless sections of White Oak Creek and lower Rock Creek. Macro-invertebrate sampling indicates that species diversity and numbers are also improving.