Lower Rock Creek is a beautiful stream that flows through southwestern McCreary County. As its name implies it is strewn with magnificent boulders, riffles and races, which led to its designation as a Kentucky Wild River. The stream offers anglers a real treat with a blue ribbon trout fishery. Lower Rock Creek flows out of Pickett and Scott counties in Tennessee and then into Kentucky. At its confluence with White Oak Creek the Kentucky Wild River status ends, but not because it isn't just as magnificent as it is upstream.
Acid mine drainage (AMD) from deep mines and refuse piles in the watershed pollute Lower Rock Creek from White Oak Junction to the Big South Fork of the Cumberland River. This AMD is sulfuric acid generated by pyrite in the strata associated with the mined coal seams and, as such, allows metals to be dissolved in the drainage. The combination of low pH and dissolved metals has made it difficult for anything to live in this stretch of Lower Rock Creek. However, that is all changing thanks to the cooperation of several government agencies and one private group. The Rock Creek Task Force was formed to find solutions to the degraded water quality in the Lower Rock Creek watershed. Members include:
- Kentucky Division of Water (DOW)
- Kentucky Department of Fish and Wildlife Resources (KDFWR)
- Kentucky Division of Abandoned Mine Lands (DAML)
- Kentucky Division of Mine Reclamation and Enforcement (DMRE)
- U.S. Forest Service (USFS)
- U.S. Geological Survey (USGS)
- U.S. Fish and Wildlife Service
- U.S. Natural Resources Conservation Service
- U.S. Army Corps of Engineers
- U.S. Office of Surface Mining (OSM)
- National Park Service
- Trout Unlimited
In 1995, initial water sampling of more than 40 mine portals identified the mine sites that were major contributors to the AMD entering the Lower Rock Creek watershed. In 1998, a biological and water monitoring program began in the White Oak Creek and Lower Rock Creek watersheds. Sampling is performed twice a year for macroinvertebrates. Samples are taken annually for fish species and monthly to measure the progress and success of the reclamation project.
In 2000, a pilot project was started to add alkalinity into the watershed. Alkalinity neutralizes the acid being produced by the abandoned mines. Sand-sized limestone was introduced into selected tributaries within the watershed. These small limestone particles slowly dissolve into the water building up alkalinity. The stream is buffered, and the acid load is reduced in the stream. After only two months of dosing with the limestone sand, the flow out of Lower Rock Creek into the Big South Fork changed from being acid to alkaline. After five months, similar results were obtained in White Oak Creek.
Later, in the fall of 2000, AML began reclamation and water treatment work under the Lower Rock Creek Phase I Abatement Project. This work involved excavating acidic refuse from the banks of Lower Rock Creek, reclaiming two coal load-out areas, establishing limestone treatment ditches, reclaiming a coal refuse fill and continuing limestone sand dosing. Testing of the coal mine refuse along the banks of Lower Rock Creek and elsewhere revealed that the mine waste was some of the most acidic material in Kentucky. In an effort to neutralize the material, ag-lime was mixed with the refuse as it was being placed into a compacted fill. The fill was then capped with soil material and revegetated.
A modified anaerobic vertical wetland designed by AML was installed at a portion of the project known as Paint Cliff. Extremely acid water was discharging from both a coal refuse pile and an abandoned deep mine at this site. To date, the wetland has reduced the acid and metal loading flowing into Lower Rock Creek from the Paint Cliff site by more than 90 percent. Monitoring results of the water quality and the aquatic life in White Oak Creek and on Lower Rock Creek have been very encouraging. In White Oak Creek before the limestone sand introduction, fish surveys found no fish. In the summer of 2000, after five months of limestone sand treatment, there were 91 creek chubs found in the fish survey. In July 2001, four species were found, including creek chub, green darter, stoneroller and black side dace, a federally protected species listed as threatened. The Lower Rock Creek fish surveys have yielded multiple species in good and improving numbers. The July 2001 survey collected a brown trout and a black side dace in the AMD-impacted section of Lower Rock Creek. In Phase II of the project during 2002, more alkaline-producing features were installed in the watershed to ensure long-term results in Lower Rock Creek. This will reduce the need for limestone dosing of the tributaries.
In 2010, Phase III of the project was completed. The Paint Cliff site included several mine portals and acid producing coal processing refuse. This was the first of the division’s AMD projects to utilize a self-flushing limestone pond (SFLP) as part of one of its abatement projects. The SFLP was constructed to treat AMD discharge from a mine portal. The SFLP is a buried basin of limestone that uses the water that discharges directly from the deep mine. Mine water flows into the system, dissolves the limestone, and then leaves the system, degassing the carbon dioxide and raising the pH of the water. Prior to work beginning on the project, Paint Cliff had a median pH level of 3.0. Post construction of the SFLP, the water at Paint Cliff now has a median pH of 5.5 after exiting the SFLP and the acidity was reduced by 12 percent.
As Lower Rock Creek continues to be restored, the local watershed is once again an environment conducive for several kinds of small fish to thrive and for recreational fishing, wading and swimming by local residents.