120 YEARS OF SOIL DEVELOPMENT IN A FORMER LAKEBED

Lake Conemaugh was created by the construction of the South Fork Dam in St. Michael, Pennsylvania, located 10 miles west of the Allegheny Front. When the dam failed catastrophically in 1889, the former lakebed was largely left to natural processes of successional vegetation and soil development. The only modifications to the former lakebed were the construction of a single-track railroad and establishment of a small pine plantation from the 1930s to 1989. Portions of the former lakebed are protected by the National Park Service as part of the Johnstown Flood National Memorial. This former lakebed now provides a natural laboratory to conduct experiments. With the increased emphasis on dam removal throughout the U.S., this area allows researchers to investigate some of the long-term (120+ years) impacts of dam removal. For this study, soil transects were created to represent various locations on the former lakebed. Soil cores were taken along the transects to determine depth of soils and degree of soil development across the lakebed. Soil development in this area is influenced by the former lake sediments, local bedrock (interbedded shale, siltstone, sandstone, red beds, limestone, and localized coal of the Pennsylvanian Casselman Formation), and a hemiboreal climate. Preliminary results indicate that the average depth to refusal is approximately 27 cm. Distinct horizons are present in the soil cores and the soil color and textures vary based on horizon and depth.