The Battle of Arizona Spillway was fought between the Caesar's Legion and the New California Republic which took place some time after the Battle of Willow Beach and was part of the attempt to force the NCR presence out of the eastern side of the Colorado River.
Background
After the fall of Willow Beach in the Colorado River, Caesar's Legion attacked the New California Republic military camp at Arizona Spillway. This refers to a tunnel which the Dam's builders had blasted through the eastern rock facing to allow overflow to pass around the dam, with the spillway itself being spanned by a two-lane concrete bridge. As a result of the battle, the camp was destroyed and the NCR lost its bridgehead across the Dam, giving the Legion complete control of all territory east of the Colorado River.[1]