The U.S. Army Corps of Engineers opened the gates on the spillway at Oologah Lake.
At 4 p.m. on May 10, 2017, the lake's level was just under 656 feet, 18 feet above its normal level of 638 feet.
The Corps opened all seven of the spillway's gates on Sunday afternoon, releasing 9,198 cubic feet of water per second. The gates' settings remained unchained as of Wednesday afternoon and the lake's level has gone down by about a foot in that time.
Opening the gates at the spillway on Oologah Lake is a fairly rare event. The last time it happened was in October.
The gates in the dam at the lake remain closed.
The spillway is about three miles east of the dam, and the water it releases flows across a pasture before joining the Verdigris River.
The Corps built Oologah and the other lakes it operates in Oklahoma primarily for flood control.