HomeMy WebLinkAboutLake Oroville Community Update - Lake Oroville Spillways Contruction Update Menchaca, Clarissa
From: DWR Oroville Spillways <oroville@water.ca.gov>
Sent: Wednesday, May 9, 2018 1:43 PM
To: Menchaca, Clarissa
Subject: Labe Oroville Spillways Construction Update
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Oroville
Community
Lake
May 9, 201
Lake Oroville Spillways Construction Update
Today the Department of Water Resources (DWR) provided an update on construction-related
activities for the Lake Oroville Spillways Emergency Recovery Project.
Construction Resumes on the Main Spillway
D'�R received approval from the Federal Energy Regulatory Commission (FERC) and the
California Divisiion of Safety of Dams (DSOD) to resume work on Lake Oroville's main spillway
on May 8. Crews started work promptly at 12;011 a.m, on Tuesday, May 8.
Overview of 2018 Construction on the Main Spillway
DWR is again using November 1 as a milestone to complete major construction work and
placement of all concrete on the main spillway. Additional work, including dry finishing and
curing of concrete, sealing joints, connecting drainage systems, backfilling side walls, and site
clean-up, will continue after November 1.
Upper chute
C Crews are using a combination of mechanical demolition and controlled blasting
to demolish the original 730 feet of the upper chute leading to the radial gates.
Foundation clean-up and preparation its anticipated to start in June.
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Placement of leveling concrete, uinder drains and'! slab anchors on this section of
upper chute will also start in June.
Placement of structural concrete slabs and walls will begin in July and will be
complete by November 1.
• Middle chute
* Crews have completed milling down the roller-compacted concrete (RCC) chute
to create a uniform surface for the placement of three-foot-thio structural
concrete slabs later this year.
* Crews are currently removing the temporary RCC walls to prepare for the
placement of permanent structural concrete walls.
* Placement of under drains and slab anchors on the middle chute willl begin in
June.
* Placement of steel-reinforced structural concrete slabs and permanent
structural concrete walls will begin in early July and will be complete by
November 1.
• Energy dissipaters
c, Work continues at the energy dissipaters, or dentates, at the bottom of the main
spillway chute and is expected to wrap up later this fall. Repair work includes
hydro-blast demolition of about 16 inches of the existing concrete surface,
adding reinforced-steel and epoxy-coated steel dowels and then placing new
erosion resistant concrete for the finished product.
Continued Construction, on the Emergency Spillway
* Secant Pile Cutoff Wall
0 Crews continue the placement of a concrete cap, or grade beam, on the
underground secant pile cutoff wall to reinforce the structural concrete piles and
secure the wall to the RCC splashp,ad,
The secant pile wall is 1,450 feet long and located 750 feet downhill of the
emergency spillway with concrete piles at depths of 35 to 65 feet.
* RCC Splashpad
* The RCC splashpad construction has been divided in two areas -a northern
section and southern section — on the hillside below the emergency spillway.
* Work has been underway since early 2.616 in the northern section and is 65
percent complete.
*
In the southern section of the splashpad site, DR received approval from
FERC and DSOD to begin removal of the remaining surface layer of grouted rip
rap, which was placed during emergency response effort in February 2017,
* RCC placement in southern section of the sp,lashpad site will begin in July.
* RCC Buttress
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o Later this year, an RCC buttress will be constructed at the base of the
emergency spillway after completion of the splashpad. Combined, the
splashpad, buttress and secant pile cutoff wall will help prevent the type of uphill
erosion that occurred during the 2017 incident.
Spring 2018 Oroville Operations Update
Watch the Spring 2018 Oroville SpiHways,operations update from John Leahigih, Water
Operations Executive Manager—the video explains how the Gate Closure Plan will
allow major construction to restart on the main spillway and shares forecasted lake
elevations for this year's recreation season.
Additional Updates
* Next week, crews will resurface a slab that did not meet DWR's quality control
standards on the main spillway last year. The slab has a poor surface finish and the top
layer will be removed and replaced with structural concrete.
*
CWP will meet with the independent Board of Consultants for the 18th time on May 29
and 30.
The BOC's 1791 memo will be posted on, the Lake Oroville Spillways webpage when it
is available.
To view photos and video of the Lake Oroville Spillways construction, visit BW 's Oroville
Spillway photo gallery and YouTube channel
For more information, follow us on Twitter or Facebook, read our news
releases or visit our Orovilla Spillway Incident webpgg
Coinnect With Us!
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