Weirs rebuilt; trial before the court of appeal – Chico Enterprise-Record

OROVILLE – Five years after the Oroville Dam spillway crisis, DWR has completed the structural reconstruction of the main and emergency spillways and says it supports spillway safety.

The rebuilt main spillway was first used on April 2, 2019 and successfully maintained a flow rate of 25,000 cubic feet per second.

John Yarbrough, Deputy Deputy Director of the DWR State Water Project, said the new weir is fully up to modern standards and has been subject to considerable oversight throughout the construction process.

The reconstructed spillways of the Oroville Dam are seen from an airplane Tuesday, Feb. 8, 2022 over Oroville, Calif. (Justin Couchot/Mercury-Register)

“Under the supervision of the Federal Energy Regulatory Commission, the California Division of Safety of Dams and an independent board of consultants, the main and emergency spillways were completely rebuilt to modern engineering standards to handle the flows needed to protect downstream communities from flooding,” said Yarbrough. “The main spillway is equipped with more than 100 sensors producing automated data that is collected daily to inform DWR engineers about the performance of the Additional sensor equipment has been installed in the dam, with additional installations planned for this summer.

In 2020, the American Society of Civil Engineers gave a nod to the reconstruction of Oroville Dam and called it an outstanding civil engineering project.

Yarbrough provided some of the numbers behind the main spillway which consists of a chute with 612 slabs and 204 wall pitches, 13 million pounds of reinforcing steel and over half a million cubic yards of concrete. The main spillway can handle up to 270,000 cubic feet of flow per second.

The emergency spillway, an accessory to the main spillway, has a splash pad, also called an “apron,” which Yarbrough says is intended to reduce the impact of water released from the structure.

Other projects around this dam that have been implemented since the disaster include a seismic retrofit study, gate structure assessments and the installation of piezometers that collect data from the spillway.

While questions about the spillway infrastructure have been answered, at least by the DWR, other findings remain up in the air as the litigation process between Butte County and the DWR continues.

Shortly after the spillway ruptured, the county filed a lawsuit against the department, claiming the spillway infrastructure had been neglected, resulting in severe damage to the river which received a sudden and powerful outflow of water. and debris.

Butte County District Attorney Mike Ramsey said the lawsuit centers on the Feather River, which suffered damage up to the Marysville area, adding that about two million cubic yards of dirt and harmful materials, consisting of materials deemed unsuitable for project use, had been released. in the Feather River south of the dam.

The case became more complicated as DWR sought to move hearings to Sacramento where a judge dismissed the lawsuit on the grounds that DWR was not considered an individual person based on legal terminology, Ramsey said.

This prompted Ramsey and the county to take the case to the Third District Court of Appeals, where she currently sits.

“Basically we’re exchanging briefs and the Third District court asked if we could negotiate a disposition,” Ramsey said. “We felt like we were trying to negotiate in good faith, but DWR was not – of course DWR may have felt that about us. Now all that’s left to do is exchange briefs and prepare for a panel hearing.

Ramsey said he believed the incident was due to 50 years of neglect by the department, leading to the rupture and subsequent flooding of the Feather River.

“We continue to seek justice for the damage done to the river and the environment,” Ramsey said.

Regarding the incident, Yarbrough spoke about the issues surrounding the crisis.

“The Oroville Spillway Incident had a lasting impact on dam safety in California and across the country,” Yarbrough said. “The reconstruction of the Oroville spillways is just one of many critical changes DWR has implemented since the incident to enhance dam safety.”

While litigation between the county and DWR over river pollution is ongoing, a settlement was reached in 2019 that led to a payout of approximately $11 million from DWR to help pay for road damage that occurred. as miles of traffic filled the roads and Highway 70. when residents attempted to flee Oroville due to the threat of flooding.

The total payment was $12 million, with the remaining funds going to the county’s general fund, a fund for future road projects, and other resources.