Mount Morris, N.Y. (WHAM) — The Mount Morris Dam on the Genesee River is actively managing water levels following the recent heavy rainfall across the region.

The dam is storing excess water to reduce any downstream flood risks, barricading the water in a river “lake” now about 86 feet deep at the northern end of the Letchworth canyon.

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“When this kind of thing happens, that’s when we come into action and close gates here at the Mount Morris Dam,” said Steve Winslow, the dam’s manager for the U.S. Army Corps of Engineers.

Winslow said the Corps is restricting the flow of water — to avoid any creeks, streams or outlets from rising — by closing the gates on the dam.

If the structure wasn’t in place earlier this week, “This would have been another catastrophic flood event in downstream areas had the dam not been available to do its job,” Winslow said.

The dam, which opened in 1952, is the largest concrete gravity dam east of the Mississippi River, standing 250 feet and spanning 1,028 feet, with the ability to store 302,000 acre feet of water behind it.

“We have nine giant conduits,” Winslow said. “They’re five feet across, seven feet tall. Each one is operating. We have a big steel vertical lift gate on each one of those conduits.”

Winslow said the Corps opened those halfway Thursday night, letting off 800 cubic feet per second of water downstream.

“We just kind of cracked things open a little bit,” he said. “Today, we were up over 3,600 cubic feet per second. We just opened another gate.”

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Levels are slowly returning to normal, but Winslow said it’s a constant hour-by-hour monitoring.

“We’re looking ahead to the next storm,” he said. “We want to lower this as quickly as we can, because we can only look ahead so many days and try to guess on what the weather’s going to be.”

The Mount Morris Dam has an outdoor recreation area is open year-round from 6 a.m.-11 p.m., with a visitor center Wednesdays through Mondays from 10 a.m.-4:30 p.m.