HomeMy WebLinkAboutEmail from Kasey Schimke, Assistant Director for DWR - Updated Information on California Dams Menchaca, Clarissa
From: Oroville@DWR <0rovi11e@water.ca.gov>
Sent: Friday, September 1, 2017 10:43 AM
Subject: Updated Information on California Dams
Good Morning,
Today the California Division of Safety of Dams is releasing updated information on 1,249 dams under its
jurisdiction, including downstream hazard classification, condition assessment, and reservoir restriction status
for each dam. Below we have included the press release that will go out later this morning announcing the
release of this information. The links within the press release will be active just after 11:00 a.m. Please contact
me with any questions at Kase y.Schimkepwater.ca.gov.
Sincerely,
Kasey Schimke, Assistant Director
California Department of Water Resources
Office of Legislative Affairs
(916) 653-0488, office
(916) 798-9816 cell
kasey.schimke@waiter.ca.glov
rr
September 1, 2017.
Contact:
Erin Mellon, Assistant Director, Department of Water Resources, Public Affairs
(916) 651-2440 V erin.mellon@water.ca.gov
Updated Information Released on California Cams
Data Will Further Guide Efforts to Strengthen Critical Infrastructure
SACRAMENTO — The California Division of Safety of Dams (DSOD) today released updated
information on 1,249 dams under its jurisdiction, including downstream hazard classification,
condition assessment, and reservoir restriction status for each dam.
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The information reflects the most recent physical inspections and comprehensive re-evaluations by
DSOD engineers and engineering geologists, as well as technical analyses performed by dam
owners.
"In light of lessons learned from the Lake Oroville spillways incident, we know there is work to do to
expand and strengthen our dam safety program," DSOD Chief Sharon Tapia said. "Aging
infrastructure is a serious concern, with half the dams in our jurisdiction at least 50 years old. This
information will help prioritize where investments in dam safety need to be made."
Today's action is part of the state's ongoing efforts as a dam safety leader and furthers Governor
Edmund G. Brown Jr.'s four-point plan to bolster dam safety by making information readily
accessible. It also helps carry out legislation signed by the governor earlier this year requiring dam
owners to update emergency action plans and inundation maps to incorporate new information.
DSOD works closely with dam owners to identify and correct potential issues on an ongoing basis.
Dam owners are responsible for the proper operation, maintenance, and repair of their dams, and for
any associated cost.
Downstream Hazard Classification
The downstream hazard classification identified for each dam is based solely on the size of the dam's
reservoir and population that would be impacted by a dam failure, it does not reflect the condition of
the dam or its structures.
The hazard classification is used in part to prioritize development of inundation maps and emergency
action plans. Dams are classified as high or extremely high hazard if at least one person is at risk
downstream in the event of a dam failure. By that definition, 670 dams (54 percent) of those under
DSOD's jurisdiction are classified as high or extremely high hazard.
Condition Assessments and Reservoir Restrictions
DSOD dam condition assessments are based on five condition ratings from the U.S. Army Corps of
Engineers National Inventory of Dams, with some minor modifications. The ratings include
satisfactory, fair, poor, unsatisfactory, and not rated. Dams rated as satisfactory have no identified
deficiencies. Dams rated as fair, poor or unsatisfactory have at least one identified deficiency.
• Currently 1,151 dams (92 percent) within DSOD's jurisdiction are rated satisfactory, meaning
they have no identified deficiencies. Ninety-seven dams (less than 8 percent) within DSOD's
jurisdiction have a deficiency with a current condition assessment of fair, poor, or
unsatisfactory. Forty-four of those dams have a seismic deficiency.
• Of the 97 dams with deficiencies, DSOD records show repairs are underway by the owners on
63 dams. Records show repairs are delayed or progress unsatisfactory on the remaining 34
dams.
• Dam condition assessments may change from year to year as repair work is completed or new
deficiencies are identified.
• DSOD may require that reservoir storage be reduced (restricted) to a specific level if unsafe
conditions exist.
Additional Dam Safety Information
In the wake of the Lake Oroville spillways incident, DSOD initially prioritized spillway re-evaluations
for 93 dams with spillways similar to Lake Oroville's. Owners of those 93 dams were notified this
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spring of requirements to submit a work plan to investigate the condition of their spillways. DSOD's
re-evaluations of those spillways are now underway.
Over the past 20 years, DSOD has focused its attention on conducting in-depth re-evaluations of
dams located near active faults and in densely populated areas. Re-evaluations are more
comprehensive than physical inspections and typically require many years and millions of dollars to
complete. DSOD re-evaluations in the last two decades have resulted in dam owners investing over
$1.5 billion in repairs to reduce the risk of dam failures due to earthquakes.
"Dam safety is a collective effort," Tapia said. "While owners are responsible for the safety of their
dams, we need public and policymaker support to advance strong dam safety regulations and secure
funding for this critical work."
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