What is Plug Day? Our very own boating holiday that signals the start of boating season on Alabama’s largest body of water! Every year in the fall, Lake Martin is lowered 7 feet for the winter. On March 1st the water will start to rise back to full pool levels! A day of celebration that Alabama Power, operating under its license with the Federal Energy Regulatory Commission (FERC), begins the process of filling the lake back up to 491′. Full pool is reached around the end of April each year.