Extremely heavy rains hit the Arkansas River upstream of Keystone Dam during late May and early June 2019. So much water poured into the Keystone Reservoir in a short time, that it quickly became evident that a major release of water would be needed to prevent overtopping the dam, causing devastating floods downstream. Even so, water rushed downstream toward MKARNS at such a high rate that officials at the Corps of Engineers halted barge traffic to avoid calamities such as collisions or hitting trees and debris afloat in the river.