OROVILLE (CBS13) — Engineers with the Department of Water Resources are entering uncharted waters.

Oroville Dam was built in the 1960’s and at 770 feet tall, it is the highest dam in the country.

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“I’d hate to have to see them use that emergency spillway,” said Greg Mahon.

He’s lived below the dam since he was born.

“Just scared and weird [feeling],” said Mahon, “wondering what they’re going to do about it.”

He and thousands of others will be on edge the next few days as concerns over the broken and battered spillway continue.

“I hope this weather lets up for a few days so they can get a handle on it,” said Mahon.

On Tuesday, it was discovered that a giant hole was in the spillway about two-thirds of the way down the chute. The hole has now doubled in size.

Engineers with the Department of Water Resources are watching with a close eye.

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The lake levels continue to rise, nearing 10 feet from the crest. Authorities say they must do something to ease pressure on the dam, so they’re releasing water despite the fact that the water is eroding away the banks of the spillway.

Eric See with the Department of Water Resources says the water will eventually hit bedrock.

“The erosion will essentially stop or slow down greatly at that point,” explained See, “if that’s the case we could have use of the existing spillway which is what we’re hoping for.”

All effort is aimed at avoiding an unprecedented move; opening the uncontrolled emergency spillway.

“Unless conditions change, we anticipate there may be a release of water over the emergency spillway,” said Bill Croyle, the acting DWR Director, “maybe some time on Saturday.”

Workers spent the day clearing debris and trees from beneath the emergency spillway just in case.

“If we can push up to 50,000 to 55,000 cubic feet per second during the next 24 hours we think we can reduce or eliminate the need to use the emergency spillway,” said Croyle.

In the history of the dam, water has never gone over the emergency spillway. Now, it’s only feet away.

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“In all my years living here, I would have never imagined it,” said Mahon.