SINKHOLE SEDIMENT EVALUATION OF VICTORY LAKE IN-FILL

Berry College campus consists of 26,000 acres in northwestern Georgia. The main campus contains limestone terrain which is susceptible to sinkhole formation due to adjacent open-pit mining and fluid withdrawal. In 1986, the formation of sinkholes located at the southern end of Victory Lake caused it to drain instantaneously. Attempts were made to restore the lake, but all were unsuccessful. The sinkholes located at the southern end of Victory Lake were finally filled and the lake was abandoned. Little information on the sinkhole problem such as size, scope, and sources of the sediment in-fill was documented or made available for public record.

Currently, plans for lake restoration have been revived by administration, faculty, and alumni of Berry College. This renewed interest brought with it the uncertainty of the lake system’s sustainability and water budget, along with the question of the content of the sinkhole in-fill sediment. The purpose of this study was to evaluate the inorganic content of the in-fill sediment in order to determine the safety and viability of the restoration of the lake system, along with providing basic background research on the history of the Victory Lake sinkhole management.

The study was implemented with the collection of eight core samples of Victory Lake in-fill sediment at shallow surface depths ranging from 0.15 meters to 0.58 meters. The sediment cores were then analyzed for grain size, color, and inorganic heavy metals: Al, Cd, Pb, Zn, Cu, Fe, and Ni content by means of Atomic Absorption Spectrometry. Grain size analysis was performed using USA standard test sieves and a RO-Tap sieve shaker. A Munsell Color Chart was used to assess the sediment grain colors.

The results of the study found grey and brown clay soils ranging from 300 mm to less than 0.500 mm in grain size at various percentages. Chemical testing of the core samples indicated trace to non-existent levels of each of the analyzed elements. The heavy metal content of the soil proved to be under the permissible limits of metals in soil published by the Environmental Protection Agency. Also, the source of the infill sediment remains inconclusive. With the assessment of Victory Lake sediment as it presently stands, plans for future restoration are able to continue.