DWR Releases Latest Oroville Spillways Emergency Recovery Project Construction Update

By on August 9, 2018
Department of Water Resources

With an eye on the November 1, 2018 public safety construction milestone to complete the placement of all concrete on the main spillway at the Oroville Dam, the Department of Water Resources (DWR) released an update on construction-related activities for the Oroville Spillways Emergency Recovery Project on Wednesday.

Although the November 1 milestone date relates to a public safety construction milestone and the completion of concrete placement on the main spillway, other activities on the main spillway will occur after that date.  Dry finishing, concrete curing, completing sidewall backfill, joint sealing and site clean-up on the main spillway will continue after November 1.

Construction on the main spillway now includes the placement of erosion-resistant concrete (ERC) structural slabs. This work on the uppermost 730 feet of upper chute began Monday and placement of ERC structural walls is anticipated to start later this month. Additionally, crews have placed 109 of 228 slabs of the ERC structural slabs and 21 of 76 walls on the middle chute to date. Workers are now applying a cure to the new concrete sidewall on the middle chute to prevent it from drying out and cracking during Phase 2 of the recovery effort.

Demolition is complete on the main spillway and crews anticipate beginning placement of reinforcing steel and the concrete framework on the energy dissipaters, or dentates, at the base of the main spillway in the coming weeks. Crews anticipate placement of structural concrete on the dentates to begin near the end of August.

The uppermost 730 feet of upper chute on the main spillway is now 45 percent complete. The middle chute is now 58 percent complete.

Although work at the emergency spillway site is not dependent on the public safety construction milestone of November 1, construction on this secondary spillway also shows progress. Crews are continuing the placement of roller-compacted concrete (RCC) on the southern half of the new emergency spillway splashpad, which is 58 percent complete. Drilling of steel dowels into the emergency spillway monolith structure that will support the buttress is 94 percent complete. The RCC buttress at the base of the emergency spillway weir will be built later this year. Construction on the emergency spillway will continue past November 1 as weather permits.

Work related to the Oroville Dam and spillways includes an underground transmission project along Oro Dam Blvd. East between Glen Drive and Canyon Drive which began on Wednesday. One-way traffic controls will be in place from 6 a.m. to 6 p.m. as work progresses through the end of the project in mid-October. Oro Dam Blvd. East was recently reopened to the public though the speed limit has been reduced to 25 mph on this stretch of the road. Cars are not be allowed to stop on the road except at designated turn outs where people can get a view of the spillways construction site.

Regarding recreation while construction continues at the Oroville Dam, the next free access dates at the Lake Oroville State Recreation Area will be Thursday and Friday, Sept. 6 and 7. The access dates are part of the DWR’s free access program. (This includes two free days a month during the summer months at Lake Oroville.) The free dates in September are the last two dates for the year.  You can read more about the access program at: https://water.ca.gov/News/News-Releases/All-News-Articles/Lake-Oroville-SRA.

As part of the oversight of the Oroville Spillways Emergency Recovery Project – and to better communicate with invested parties — DWR will meet with the independent Board of Consultants for the 19th time on Wednesday and Thursday, Sept. 5 and 6.