Porter saw that it would not do for him to delay an hour.

He had had great difficulty in getting his fifty vessels up the narrow stream, whose current was falling so rapidly that it already appeared impossible to get the fleet past the snags and shoals to the point of safety two hundred miles below.
Improving every moment and under a continual fire from the shore, Porter managed to descend something more than half way down the river to Grand Ecore, where he found Banks and his demoralized army.

Porter advised the commander to remain where he was until the spring rains would enable the fleet to ascend the river again, but Banks was too frightened to do anything but retreat, and he kept it up until he arrived at New Orleans.
The river fell so rapidly that all the fleet would have been stranded above the falls but for the genius of Lieutenant-Colonel Joseph Bailey, of Wisconsin, a military engineer who accompanied Banks's expedition.
Under his direction several thousand men were set to work, and, at the end of twelve days, they had constructed a series of wing dams, through which the vessels were safely floated into the deeper water below the falls.

This accomplished their deliverance from what otherwise would have been certain destruction.

Porter pronounced the exploit of Bailey the greatest engineering feat of the whole war.