On April 30, 1864, after being transferred to Arkansas to oppose Union Major General Frederick Steele's Camden Expedition, Brigadier General Waul was wounded in the left arm at the Battle of Jenkins' Ferry. He returned to service in September 1864 and until December 1864 commanded Brigade I, Division I, I Corps of the Trans-Mississippi Department. From January 1865 to May 26, 1865, he commanded Brigade I, Division I, of the District of Texas, New Mexico, and Arizona in the Trans-Mississippi Department. There is no record of his parole.