Lake Oroville Spillways Construction Updates February 21


Lake Oroville construction image

Crews construct forms for concrete beam to be anchored to the top of the underground secant pile, or cut-off wall, at the Lake Oroville emergency spillway. DWR/2018

Today the Department of Water Resources (DWR) provided an update on construction activities for the Lake Oroville Spillways Emergency Recovery Project.

Construction at the Emergency Spillway

  • The underground secant pile wall is 95 percent complete and is targeted for completion in March of 2018. The secant pile wall is being constructed 730 feet downhill of the emergency spillway at depths of 35 to 65 feet.


  • Foundation preparation continues for the roller-compacted concrete (RCC) splashpad. Crews are expected to begin placing RCC next week. The RCC splashpad, in conjunction with the secant pile wall, will armor the existing terrain to significantly reduce the type of uphill erosion that occurred during February 2017 if the emergency spillway is ever used again.
  • Work at the emergency spillway also include construction of an RCC buttress at the base of the emergency spillway, which will begin later in 2018.


Construction on the Main Spillway

Phase Two of construction on the main spillway is expected to begin in May, but exact timing depends on weather. This year’s work includes:

  • Removal of the original 730 feet of the upper chute leading to the radial gates and replacement with steel-reinforced structural concrete.
  • Placement of a 2.5-foot layer of steel-reinforced structural concrete over the RCC middle chute.
  • Removal of the RCC walls in the middle chute and replacement with structural concrete walls.
  • Hydro-blasting and resurfacing of the energy dissipaters at the base of the main spillway.


Oversight Update

  • DWR will meet with the Independent Board of Consultants (BOC) for the 15th time tomorrow and Friday, Feb. 22 and 23. The BOC is also reviewing the Independent Forensic Team’s final report released last month.


To view photos and video of the Lake 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 |