The $3.9 million rehabilitation project involves replacing welds and other components of the dam's spillway gates. Similar work will be under way at Lake Russell.
The contractors, Atlantic Marine Construction Co. and Hartman Walsh, hope to begin work next week, said Hartman Walsh spokesman Matt Tonnies.
"Unfortunately we will need to close one lane on the dam for operations," he said. "It will remain closed for about a year."
The renovations are being financed with stimulus money from the American Recovery & Reinvestment Act.