The corps had previously said only that the work would take 24 to 80 days.
The corps said last week that the project was being placed on hold until the questions could be answered.
The corps said it would favor a series of less contentious alternatives.
The corps says it intends to complete 3,700 rebuilding projects.
Despite that effort, the corps says, the federal government stands to lose some $3 million in forgone energy.
Currently, the corps says 758 acres of wetlands will be destroyed.
The Marine Corps, though, says it is learning from the accident.
The corps says the surfers' proposal to move the lighthouse back 800 feet instead would cost $27 million.
With the delays in completing the hospitals, the corps says, those costs have risen too far.
The entire corps of candidates say they would have opposed all the 2008-2009 financial bail outs.