Restored

Feature | San Clemente Dam Demolition
Above: In the dewatered reservoir, excavators and
trucks remove sediment in 2014 in preparation
for the Diversion Dike constructed later that year
to divert the Carmel River and retain reservoir
sediment.
Above: From July to August 2015, the 300-foot
long, 106-foot tall San Clemente Dam in Monterey
County was removed in four weeks using excavators
equipped with hydraulic hammers.
Left: DSOD's Engineer Kristen Martin inspects the
project.
“Our main objective was to confirm that
an obvious threat to the downstream population
would not exist after the dam was
removed.” said DSOD Engineer Kristen
Martin with the Design Engineering Branch.
“We independently evaluated designs to
ensure the safety of the project.”
DSOD and California American Water
(Cal Am), the dam owner, worked together
to reduce the risk of dam failure after DSOD
evaluated and determined that the thin concrete
arch dam was seismically unstable. The
final solution involved relocating and stabilizing
the sediment that had accumulated
behind the dam, re-routing the Carmel River,
demolishing the dam and providing habitat
restoration for the Carmel River channel.
“There have been a number of Department
engineers, environmental scientists and attorneys
from DSOD, South Central Region
Office and our legal office working on this
project for decades,” said David Gutierrez,
Chief of DSOD. “There were complex
engineering, financial and environmental
issues to resolve and sometimes competing
interests to overcome. All this hard work
8 DWR Magazine j
Winter 2015 | 2016
Our main objective was to confirm that
an obvious threat to the downstream
population would not exist after the
dam was removed.
—Kristen Martin, DSOD Engineer
Design Engineering Branch.
resulted in a unique project that met all goals
including eliminating a long-standing threat
to both people and the environment.”
Today, where the concrete dam once
impeded Carmel River flows, the water
is flowing freely again, providing habitat
for endangered South Central steelhead
trout, California red-legged frogs and other
native species.
“However, the build-up of sediments
behind the dam, which filled 95 percent
of the reservoir’s capacity and the rerouting
of the Carmel River flows through San
Clemente Creek on the upstream side of
the dam were not the only things that made
this project unique and complex,” said
Supervising Engineer Daniel Meyersohn of
DSOD’s Design Engineering Branch. “The
fact that this was a design-build project added
to its intricacy. Phases of the project were
constantly being designed, reviewed, concurred
with, and then built, which forced us
to adapt and expedite our process.”
Assessing Stability
“In order to divert the river into its new
reroute channel, a diversion dike was constructed
across the old course of the Carmel
River at the upstream end of the sediment
stockpile,” said DSOD Geologist Robert
Burns. “Located approximately one mile up
from where the dam sat, the dike also serves
as a sediment retention structure and is
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