First Phase Of Oroville Dam Spillway Work Finished Ahead Of Wet Season

OROVILLE (CBS13) — It was an ambitious timeline: rebuild the collapsed Oroville Dam Spillway and emergency spillway in less than a year.

The undertaking is the largest active construction project in the country.

Shortly after the spillway collapsed and nearly 200,000 people were evacuated over fears the emergency spillway could fail, the demolition and reconstruction began.

The project involved more than 400,000 cubic yards of concrete and a cost expected to exceed $500 million, which is double the original estimate.

On Wednesday, the final load of concrete was laid, completing Phase 1 of the project.

Phase 2 will last until 2019. That work includes applying joint sealant and finishing drain lines.

The project manager from Kiewit Construction said that the spillway, in its current condition, would be able to withstand a release of 100,000 cubic feet of water per second. That was around the peak of the releases during the emergency in February.

"We have a very high level of confidence that the concrete and RCC will hold up very well to that kind of flow," said Jeff Petersen, the Kiewit project director.

The project is an engineering marvel, but there are still other issues that many worry haven't been addressed.

"There is a lot more work to be done," said Assemblyman James Gallagher of Yuba City.

He says while the construction is an amazing accomplishment, the impacts of last February's crisis are still being felt by many of his constituents.

"There was a lot of devastation downstream," said Gallagher.

Debris still clutters the fish hatchery, and sediment displacement has destroyed acres of farmland.

"That's one of the long-term things that we need to do too. We need to clear out the river and restore the riverbed," said Gallagher.

Gallagher says he hasn't seen a plan to remedy the destruction downstream nor ways to improve the oversight of the spillway and dam.

"So far just analysis. But what we're really looking to see is action," said Gallagher.

A forensic report by an independent firm detailing possible causes of the failure and recommendations is expected to be released in the mid-November.