STATE OF CALIFORNIA- CALIFORNIA NATURAL RESOURCES AGENCY

EDMUND G . BROWN JR., Governor

DEPARTMENT OF WATER RESOURCES
1416 NINTH STREET, P.O. BOX 942836
SACRAMENTO, CA 94236-0001
(916} 653-579 1

November 7, 2017

Mr. Frank L. Blackett, P.E.
Regional Engineer
Federal Energy Regulatory Commission
100 First Street, Suite 2300
San Francisco, California 94105-3084
FERC Project No. 2100 - Oroville Emergency Recovery- Spillways
Review of Flood Control Outlet Spillway Chute Concrete Slabs
Dear Mr. Blackett:
This letter is in response to your letter dated October 2, 2017, regarding the observation
of hairline cracks in some of the concrete slabs in Oroville Dam's Flood Control Outlet
spillway chute. The Department of Water Resources (DWR) has performed an
assessment of the concrete slabs and concludes the hairline cracks are a result of
some of the design elements included to restrain the slabs and produce a robust and
durable structure. These design elements include: anchoring the slabs to the
foundation ; placing the slabs on a layer of leveling concrete; and interlocking the slabs
with keyways and a continuous bottom layer of reinforcing steel. With the inclusion of
these design elements, the presence of hairline cracks was anticipated and is not
expected to affect the integrity of the slabs. Additional details regarding DWR's
assessment are included in the enclosed Technical Memorandum SRT-FCO-DOC-9.
If you have any questions or would like to discuss this further, please contact me at
(916) 502-2067.
Sincerely,

Ted Craddock, Project Manager
Oroville Emergency Recovery - Spillways
Executive Division
Enclosure

 20171108-5021 FERC PDF (Unofficial) 11/7/2017 5:16:34 PM

Document Content(s)
20171107_DWR-FERC_P2100_FCO_Slabs.PDF.................................1-1