For more than seventy years, Lake Murray has provided electricity for residents of the South Carolina midlands. Learn more about the dam's history and future.
Changes to the dam started in 1943, about 13 years after the companion Saluda Hydroelectric Plant began producing electricity. They wouldn't be the last.
Initial design and construction of the dam were done to the standards generally accepted at the time of construction. However, during the first few year's of the dam's existence, standards changed. The 'science' of rainfall and flood studies was still in its infancy, and design and construction standards for dams were changing. So in order to enhance the stability of the dam and protect it from larger floods than those initially designed for, the dam was raised three feet, two additional spillway gates were added, and large rocks from the enlarged spillway channel were placed on the downstream face of the dam.
No additional changes were needed for a number of years until standards began evolving again during the 1970s and '80s. In the late 1970s, SCE&G was required to perform a dynamic stability analysis of the dam to see if the structure met a new standard for earthquakes. Analysis showed that the dam would meet the standard for safety during a re-occurrence of the Charleston earthquake of 1886, which is the design basis earthquake for the original Saluda Dam.
Then in the late 1980s, the Federal Energy Regulatory Commission, which has oversight authority for all federally licensed hydroelectric facilities in the country, came out with a new standard for dealing with a Probable Maximum Flood. As a result of that study, SCE&G added a sheet piling wall on the lake side of the road on top of the dam in order to raise it once again to accommodate the new worst-case flood requirements.
The latest modification – the backup dam -- is the result of a new set of earthquake design standards and an increase in the magnitude factor used for calculating the Charleston earthquake.
The backup dam is made up of millions of tons of rock and concrete placed strategically so that the mass and weight of the wall will prevent the release of water should an earthquake damage the existing dam. The rock section will attach to the existing dam at both ends and to a 2,300-foot center section of roller-compacted concrete. The new structure extends along the length of the original dam with a slight valley in between.
Work began in the spring of 2002 was completed in the summer of 2005.
Lake Murray Backup Dam Video
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Learn more about the history of the Lake Murray...