HomeMy WebLinkAboutLake Oroville Community Update - Spillways Construction Updates Menchaca, Clarissa
From: DDR Oroville Spillways <oroville@a water.ca.gov>
Seat: Thursday, September 7, 2017 8:19 AM
To: Menchaca, Clarissa
Subject: Lake Oroville Spillways Construction Updates
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Lake Orov'I'lle Community Update
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September 2017
Lake Oroville SpillwaysConstruction pdat
"yesterday the Department of Water Resources (DWR) provided an update on construction
work on the Lake Oroville Spillways Emergency Recovery Project.
Continued Construction on the Main Spillway
Construction efforts at the Lake Oroville spillways remain focused on repairing and
reconstructing the gated flood control spillway, also known as the main spillway, by
November 1.
There are 55 days left on the construction timeline to reconstruct the 2,270 feet of main
spillway that will be completed this year:
Placement of reinforced, structural concrete is 20 percent complete. By
November 1 there will be 1,220 feet of spillway chute with structural concrete --
370, feet on the upper chute of the spillway and 050 on the lower chute of the
spillway.
* The 1,050-foot middle section of the spillway chute, including the filling of the
two scour holes, is now 33 percent complete„ with approximately 100,000 cubic
yards of roller compacted concrete placed. This middle section will be
completed to final design with structural concrete in 2013.
* Crews have installed more than 5,000 feet of underdrains in the structural
concrete sections.
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The 730 feet of main spillway leading to the radial gates will be patched,
reinforced and left in place this year. It will be removed and reconstructed with
structural concrete in 2018.
Construction at the Emergency Spillway
a DWR continues to make progress at the emergency spillway, and is still on schedule to
complete construction of the secant pile wall, or cut-off wall, in late December 2.517 or
early January 2018.
a Crews have completed 15 percent of the secant pile wall.
Other Updates
a On Tuesday, the Independent Forensics Team released an interim memo summarizing
its current findings on the physical factors that caused the, Lake Oroville spillway
failure. A full report that will include human factors is expected later this fall, After
reviewing the memo,, DVVR released a statement reiterating that protecting public
safety is the state's top priority and expressing its commitment to apply lessons learned
from the Lake Oroviile spillways incident, DWR agrees with the Forensic Team's
conclusions that dam owners need to reassess current procedures as visual
inspections would not have caught what happened in February.
a Last week, DWR released the Assessment of the Vegetation Area on the Face of
Oroville Dam, which explains the cause of vegetation that occasionally grows on the
face of the dam. Based on five decades of data and observation, the Department has
concluded the vegetation area does not pose a threat to the integrity of the dam.
0 The independent Board of Consultants met for the eleventh tirne, with: DWR on August
24 and 25. DWR presented the findings and conclusions of the Assessment of the
Vegetation Area on the Face of Oroville Dam to the BOC members, who agreed the
cause of the vegetation area does not pose a threat to the integrity of the Oroville Dam.
The, BOC"s eleventh memo, which will contain this conclusion, will be posted soon after
it is transmitted to DWR.
To view photos and video of the, Lake, Oroville Spillways construction, visit DWR's Oroville
Spillway photo gallery and YouTube channel.
-- Orovil!le Outreach Team
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