Oroville Spillways Construction Update - September 26, 2018


Workers prepare four energy dissipator blocks for new concrete surfaces on the lower chute of the Lake Oroville main spillway.

Workers prepare four energy dissipator blocks for new concrete surfaces on the lower chute of the Lake Oroville main spillway. DWR/2018

SACRAMENTO – The Department of Water Resources (DWR) today provided an update on construction activities for the Oroville Spillways Emergency Recovery Project.

Main Spillway

  • November 1, 2018 is a public safety construction milestone to complete placement of all concrete on the main spillway. Dry finishing, concrete curing, joint sealing, completing sidewall backfill and site clean-up on the main spillway will continue after Nov. 1.
  • The upper chute is 76 percent complete. Crews have placed 108 of 150 erosion-resistant concrete (ERC) structural slabs and 14 of 50 ERC structural walls on the uppermost 730 feet of upper chute.
  • The middle chute is 95 percent complete. Crews continue to place ERC structural slabs and walls on the middle chute. To date, crews have placed 221 of 228 slabs and 76 of 76 walls.
  • Hot and high winds affected the surface of a slab during its placement on the middle chute earlier this month. DWR determined the slab surface did not meet specifications and plans to remove and replace it. This will not impact the schedule.
  • Repair work on the energy dissipaters, or dentates, at the base of the main spillway is 65 percent complete.


Emergency Spillway

  • Placement of roller-compacted concrete (RCC) on the southern half of the emergency spillway splashpad is 83 percent complete. RCC placement resumed on Monday, Sept. 10, after completion of scheduled maintenance on the RCC batch plant.
  • Construction of the RCC buttress at the base of the emergency spillway will begin in October.
  • Work at the emergency spillway site is not contingent on the public safety construction milestone and will continue past Nov. 1, 2018. 


Other Updates

  • Work continues on an underground transmission line project along Oro Dam Blvd. East between Glen Drive and Canyon Drive. One-way traffic controls are in place from 6 a.m. to 6 p.m. and will continue until the project is complete in mid-October.
  • The speed limit has been reduced to 25 mph on this stretch of Oro Dam Blvd. East and cars will not be allowed to stop on the road. There are several designated turn outs for cars to pull over to get a view of the Oroville spillways construction site.
  • The Lake Oroville State Recreation Area free access program is complete, with the final free access days taking place on Sept. 6-7.
  • DWR met with the independent Board of Consultants for the 20th time on Sept. 5-6.


To view photos and video of the Oroville Spillways construction, visit DWR’s Oroville Spillway photo gallery and YouTube channel.



For more information, follow us on Twitter or Facebook, read our news releases or visit our Oroville Spillway Incident webpage


Erin Mellon, Assistant Director, Public Affairs, Department of Water Resources

(916) 651-2440 | erin.mellon@water.ca.gov