Question, how much time elasped between the bridge being pulled up and the arrival of Wheeler?
Very little.
Look at Col Kerr's account:
As the XIV Corps prepared to cross Ebenezer Creek, Davis ordered that the refugees be held back, ostensibly 'for their own safety' because Wheeler's horsemen would contest the advance. 'On the pretense that there was likely to be fighting in front, the negroes were told not to go upon the pontoon bridge until all the troops and wagons were over,' explained Colonel Charles D. Kerr of the 126th Illinois Cavalry, which was at the rear of the XIV Corps.
'A guard was detailed to enforce the order, ' Kerr recalled. 'But, patient and docile as the negroes always were, the guard was really unnecessary.'
Though what happened once Davis's troops had all crossed remains in dispute, it seems fairly certain that Davis had the pontoon bridge dismantled immediately, leaving the refugees stranded on the creek's far bank. Kerr wrote that as soon as the Federals reached their destination, 'orders were given to the engineers to take up the pontoons and not let a negro cross.'
'The order was obeyed to the letter,' he continued. 'I sat upon my horse then and witnessed a scene the like of which I pray my eyes may never see again.'
How many women, children, and older men were stranded cannot be determined precisely, but 5,000 is a conservative estimate. 'The great number of refugees that followed us…could be counted almost by the tens of thousands,' Captain Hopkins of New Jersey guessed. Major General Oliver O. Howard, commander of the right wing of Sherman's army (which included Davis's corps), recalled seeing 'throngs of escaping slaves' of all types, 'from the baby in arms to the old negro hobbling painfully along the line of march; negroes of all sizes, in all sorts of patched costumes, with carts and broken-down horses and mules to match.' Because the able-bodied refugees were up front working in the pioneer corps, most of those stranded would have been women, children, and old men.
What happened next strongly suggests that Davis did not have the refugees' best interest in mind when he delayed their crossing of the creek, to say nothing of his apparently having ordered that the bridge promptly be dismantled. Davis's unabashed support of slavery definitely does not help his case, though Sherman insisted his brigadier bore no 'hostility to the negro.'
Painting by Dave Russell
Kerr saw Wheeler's cavalry 'closely pressing' the refugees from the rear. Unarmed and helpless, the former slaves 'raised their hands and implored from the corps commander the protection they had been promised,' Kerr wrote. '…[but] the prayer was in vain and, with cries of anguish and despair, men, women and children rushed by hundreds into the turbid stream and many were drowned before our eyes.'
Then there were the refugees who stood their ground. 'From what we learned afterwards of those who remained upon the land,' Kerr continued, 'their fate at the hands of Wheeler's troops was scarcely to be preferred.' The refugees not shot or slashed to death were most likely returned to their masters and slavery.
Kerr's descriptions of the atrocity apparently met widespread skepticism, and he was forced to defend his integrity. 'I speak of what I saw with my own eyes, not those of another,' he asserted, 'and no writer who was not upon the ground can gloss the matter over for me.' Still, he left it to another officer, Major James A. Connolly of Illinois, to blow the whistle on Davis. 'I wrote out a rough draft of a letter today relative to General Davis' treatment of the negroes at Ebenezer Creek,' Connolly wrote two weeks after the incident. 'I want the matter to get before the Military Committee of the Senate. It may give them some light in regard to the propriety of confirming him as Brevet Major General. I am not certain yet who I had better send it to.'