Matilija Dam: Sediment Management

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National Marine Fisheries Service
Matilija Dam Removal

• Matilija Dam Sediment Management
• Mark H. Capelli
• Area Recovery Coordinator
• Southern California
• National Marine Fisheries Service

American Society of Civil Engineers, EWRI August
16-17, 2004 U.C Berkeley
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National Marine Fisheries Service
Matilija Dam Removal
Ventura River Watershed
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National Marine Fisheries Service
Matilija Dam Removal
Ventura River Delta 1997
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National Marine Fisheries Service
Matilija Dam Removal
Ventura River Mainstem 1998
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National Marine Fisheries Service
Matilija Dam Removal
Matilija Canyon
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Matilija Dam Removal
Matilija Creek above Matilija Dam 2003
Provided half of the steelhead spawning and
rearing habitat in the Ventura River
Retains land-locked remnants of residualized
historic steelhead run
Matilija Creek below Matilija Dam 1995
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National Marine Fisheries Service
Matilija Dam Removal
Matilija Dam 1949
Matilija Dam Site 1880
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National Marine Fisheries Service
Matilija Dam Removal
Completion of Matilija Dam in 1948 cut off 50 of
the steelhead spawning and rearing habitat in
the Ventura River.
Matilija Canyon Angler 1900
Ventura River Steelhead 1946
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National Marine Fisheries Service
Matilija Dam Removal
Status of Steelhead in the Ventura River
Prior to construction of the Matilija, Casitas
and Robles Dams in the 1940 and 1950, adult
steelhead runs in the Ventura River numbered
5,000 -6,000 annually.
Ventura River Steelhead 1918
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National Marine Fisheries Service
Matilija Dam Removal
Ventura River Steelhead 1906
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Status of Steelhead in Ventura River
National Marine Fisheries Service

Matilija Dam Removal

• Steelhead in the southern California ESU were
  listed by NOAA Fisheries as Federally endangered
  in August 1997.

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Status of Steelhead in the Ventura River
National Marine Fisheries Service
Matilija Dam Removal

• The current size of the steelhead run is
  estimated by NOAA Fisheries to be less than 100
  adults per year, on average, with considerable
  fluctuation from year to year.

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National Marine Fisheries Service
Matilija Dam Removal
A fish ladder was added to Matilija Dam as an
after thought at the request of the Department of
Fish and Game.
Matilija Dam Fish Ladder
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National Marine Fisheries Service
Matilija Dam Removal
Matilija Dam 1958
Matilija Dam 1958
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Matilija Dam Removal
Matilija Dam 1985
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Matilija Dam Removal
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Matilija Dam Removal
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Matilija Dam Removal
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National Marine Fisheries Service
Matilija Dam Removal
Sedimentation and notching of the dam has
reduced storage capacity to approximately 500
acre feet
Matilija Lake 2001
Original storage capacity of Matilija Reservoir
was 7000 acre feet
Matilija Delta 2001
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National Marine Fisheries Service
Matilija Dam Removal
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National Marine Fisheries Service
Matilija Dam Removal
U.S. Bureau of Reclamation completed Appraisal
Study in 2000 Sediment storage estimated at 6
million cubic yards Estimated cost of removal
projected 69 - 179 million Outlined future
sediment studies
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National Marine Fisheries Service
Matilija Dam Removal
Detailed pre- and post-dam topographic profile of
Matilija Canyon Dam and Reservoir site
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Matilija Dam Removal
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Matilija Dam Removal
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National Marine Fisheries Service
Matilija Dam Removal
Dam would be removed, but a majority of the
sediments would be stabilized in place. Grade
stabilization of the channel would be necessary
to provide fish passage.
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Matilija Dam Removal
Dam would be removed incrementally. Sediment
would be removed incrementally (or
catastrophically) depending upon rainfall and
runoff.
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Matilija Dam Removal
Active removal could include Dredge and
slurry Excavation and trucking Mining on
site Combination (including natural erosion)
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National Marine Fisheries Service
Matilija Dam Removal
Spillway Sections Removed 2000
Matilija Spillway Crest 2000
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National Marine Fisheries Service
Matilija Dam Removal
Robles Diversion, 2003
Potential High Flow Sediment Bypass
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National Marine Fisheries Service
Matilija Dam Removal
Sediment impacts to the estuary could effect sand
bar breaching patterns
Lower Ventura River, 1995
Released sediment from Matilija Dam has potential
to degrade significant downstream steelhead
habitat
Ventura River Estuary, 1985
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National Marine Fisheries Service
Matilija Dam Removal
Potential flooding of downstream residents is a
major consideration in moving sediment stored
behind Matilija Dam by natural erosion.
Ventura River Flood, 1998
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National Marine Fisheries Service
Matilija Dam Removal
The U.S. Army Corps of Engineers (along with the
Ventura County Watershed Protection District and
the U.S. Bureau of Reclamation) prepared a
Feasibility Study to evaluate dam removal
alternatives.
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National Marine Fisheries Service
Matilija Dam Removal
Testing for sediment contamination revealed no
pollutants but small amounts of methane
Taking Reservoir Sediments, 2000

Launching Sediment Drill Barge, 2000
Coring is necessary to fully characterize grain
size and distribution of sediments
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Matilija Dam Removal
Sediments were characterized for
Composition Grain size Distribution
Toxicity
Archiving Sediments, 2000
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Matilija Dam Removal
Sediment Distribution Zones
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Matilija Dam Removal
Sediment Distribution in Matilija Reservoir
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Matilija Dam Removal
Sediment Deprivation
Coastal Erosion
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Matilija Dam Removal
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National Marine Fisheries Service
Matilija Dam Removal
U. S. Army Corps of Engineers and the Ventura
County Watershed Protection District have
identified a Preferred Alternative.
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Matilija Dam Removal
Temporary Sediment Storage in Matilija Reservoir
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National Marine Fisheries Service
Matilija Dam Removal
Sediment and Flood Control Measures along the
Ventura River
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Matilija Dam Removal
New or raised river levees and enlarged bridges,
Robles Diversion high-flow sediment by pass, and
de-silting basin
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Matilija Dam Removal
Recreational Plan includes trails connecting the
Matilija Dam site with existing trails, and
interpretive facilities.
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Matilija Dam Removal
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Matilija Dam Removal
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National Marine Fisheries Service
Matilija Dam Removal
Before
After
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National Marine Fisheries Service
Matilija Dam Removal
Matilija Dam Sediment Management
2006 ?