SOURCES FOR MINERALIZATION IN KENTUCKY DAM: IMPLICATIONS FOR DAM STABILITY

Kentucky dam is a hydroelectric dam located on the Tennessee River between Livingston and Marshall Counties in southwestern Kentucky. The dam was built in the late 1930s to early 1940s to reduce flooding of the Mississippi and Ohio river. Kentucky dam is 206ft in height and 8,422ft in length. A 160,000-acre reservoir allows the dam to produce 223,100 kilowatts of power, and discharge 1,050,000 cubic feet of water per second. With proximity to the New Madrid fault zone, the dam was built to withstand a strong earthquake; however, degradation of the dam, for instance by calcium leaching would lower stability in such an event. Failure of the dam would disrupt power production, affecting many customers regionally. Perhaps more importantly, it would release the water from the Kentucky Lake reservoir, a popular area developed with many expensive lake homes, as well as, create catastrophic damage downstream. Inside the bottom corridor of the dam, we observed travertine stalactites, knobs, and solid matter formed not unlike in a cave setting. In this project, we examined the water content passing through the dam to test what the source of calcium is for these carbonate solids. Water samples were taken from the upstream and downstream areas, as well as, areas within the dam including the sump, and air cooler discharge. A PerkinElmer AAnalyst 400 with HGA 900 Graphite Furnace was used to determine relative concentrations of calcium and magnesium in collected samples. Calcium and magnesium concentrations above and below the dam are equal. An elevation in calcium and magnesium by 19 wt.% and 5 wt.% respectively, is observed in samples from the air cooler discharge, within the dam. Evaporation of water in the air coolers explains the elevated concentrations, and seepage of this concentrated water downward to the bottom corridor is the likely explanation for the travertine growth.