Vicksburg: The First Assaults
On the night of 16 May, Pemberton withdrew his shattered army to a position he had previously prepared in front of the Vicksburg and Jackson railroad bridge over the Big Black River. Here he placed Bowen's division in the forward trenches and allowed Stevenson's crippled division to go into reserve. He stayed up all night waiting for Loring's division to arrive to strengthen the line. Loring, though, did not come, since he had retreated south after Champion Hill and was now cut off by Grant's army. Loring's absence left Pemberton's bridgehead position seriously undermanned, and Bowen's soldiers knew it. When they saw several Union divisions move up to attack them at 0800 on the 17th, the tired Confederates fired a few rounds and then began to bolt to the rear. Their retreat soon became a stampede. When it was over an hour later, the Confederates had lost 18 cannons and 1,800 prisoners; Union losses were less than 300.
It was fortunate for Pemberton's army that someone during the hasty retreat on the 17th remembered to set fire to the railroad bridge over the Big Black River. This act gave the Confederates the rest of the day to make their retreat to Vicksburg unmolested while Grant's advance was stalled at the river. Grant began building two improvised bridges as soon as he reached the river, but they took until midnight to finish. There was only one pontoon bridge traveling with the army. It reached the scene in the early afternoon and was not ready for use until after dark.