Hole In Oroville Dam Spillway Grows As Officials Plan Next Move

OROVILLE (CBS13) — Department of Water Resources officials, engineers, and contractors spent the day testing and assessing the gaping hole that stretches across the Oroville Dam spillway.

"What you see today may not be there tomorrow," said Bill Croyle the acting DWR Director.

"We wouldn't be surprised if by the end of this wet season, much of the lower portion of the spillway has been eroded away," Croyle continued.

The spillway, where reservoir water is released during rain events, is no longer a smooth track.

"Water is a very powerful force," said Chris Orrosk the DWR public information officer.

According to inspection reports, the spillway chute has been patched up in the past, but recently everything appeared normal. Only minor cracks were noted along the spillway walls.

On Tuesday, something went wrong as a giant hole opened up, prompting DWR to close the flood gates.

On Wednesday, DWR opened the gates for a test run and to ease pressure on the dam, and 20,000 cubic feet of water per second ripped the hole apart even more. Water blasted cement into the air. A portion of the spillway side wall is now gone.
Earth was torn away as the brown water crashed towards the river below.

When the gates closed after several hours, a larger hole was revealed.

"There is a sense of urgency," said Orrosk.

There were tense moments and concern above the dam, and below.

"Get in the truck and take off," said one woman.

People in Oroville are worried the erosion of the spillway could lead to a more serious situation with the dam itself.

"Mainly concern for my home itself and my pets and stuff like that," said another woman who lives a mile from the dam.

On Wednesday, officials quickly calmed fears.

"We do not believe there is an imminent danger to the dam," said Croyle.

The spillway problem persists and the water must go somewhere.

"We still have some room to absorb water coming in. Long-term, yeah, we're going to have to move water out of the lake," said Orrosk

Croyle says there is an emergency spillway, but it is unregulated and a last resort.

He says their goal is to keep water moving through the spillway, even if it causes some erosion, to avoid using the emergency spillway.

DWR plans to be back to normal operations by the fall. They anticipate the costs to fix the problem to be in the millions of dollars.