The necessary surgery was done so hastily that later a second operation was imperative, which left him with a mere stump below the elbow-joint.
Never for long at a time afterward was he free from pain and only a few years ago a third operation was performed which brought relief.
As soon as the original wound was healed he went back to his command, assisting as Division Chief of Artillery in the siege of Vicksburg.
After the fall of this place he took part in the Meridian Raid.

Then he served on detached operations at Vicksburg, Natchez, and New Orleans until the summer of 1864, when he was re-assigned to the former command in the Army of the Tennessee.

In all the operations after the fall of Atlanta he bore an active part, and when Sherman commenced the march to the sea, Powell was sent back to General Thomas at Nashville, in command of twenty batteries of artillery.

At the battle of Nashville he served on the staff of Thomas and continued with this command till mustered out in the early summer of 1865.

As a soldier his career was marked by a thorough study and mastery not only of the details of military life, but of military science.