Matilija Dam

Matilija Dam

View of Matilija Dam from the air
Country United States
Location Ventura County, California
Status 90% silted
Opening date 1947[1]
Construction cost about $4M
Owner(s) Ventura County Watershed Protection District
Dam and spillways
Type of dam Concrete arch dam
Height 198 ft (60 m) (original)
Length 620 ft (190 m)
Reservoir
Creates Matilija Reservoir
Total capacity 7,018 acre·ft (0.008657 km3) (original)

Matilija Dam is a concrete arch dam completed in 1947. Designed for water storage and flood control, it impounds Matilija Creek to create the Matilija Reservoir in the Los Padres National Forest, south of the Matilija Wilderness and north of Ojai, California.

The drainage area above the damsite is 55 square miles, and the reservoir had an original capacity of 7,018 acre·ft (0.008657 km3).[2] Matilija Creek flows on to become the main tributary of the Ventura River.

Matilija was one of the Chumash rancherias under the jurisdiction of Mission San Buenaventura. The meaning of the Chumash name is unknown.[3][4]

Silting and notching

Modern officials describe the dam design as "flawed from the outset".[5] Many experts including the U.S. Army Corps of Engineers and the California Department of Fish and Game aligned themselves against the project, and before construction an architect advised that the proposed materials would react together badly. An engineering survey twenty years later proved him right, finding "internal swelling, external cracking, disintegration of the wall and movement of the abutments".[6] Absolutely no provision was made for fish passage, causing spawning habitat loss for steelhead trout. The year after the dam opened, there was a major upstream fish kill caused by heated and/or stagnant water.[7]

The dam also began silting up, which had the side effect of depriving ocean beaches 17 miles downstream of replenishing sand.[8] The dam was notched (level of the dam face reduced in height) after being condemned in 1965 and notched again in 1977. Taking into account the reservoir's reduced capacity and losses to sedimentation, the reservoir is projected to be completely silted up by the year 2020.

Proposed removal

Ventura County official set the course for removal of the dam as early as 1998. In October 2000 United States Secretary of the Interior Bruce Babbitt visited the site, operated a crane to remove a ceremonial concrete slab from the dam face, and brought national attention to the then-novel concept of dam removal.[9]

The dam has been a candidate for removal ever since, along with the 1924 Rindge Dam near Malibu, completely silted up since 1950, and also built blocking steelhead trout spawning grounds.[10]

A bill allowing funding for the Matilija Dam Ecosystem Restoration Project reached Congress and survived President Bush's veto in November 2007, but the actual funding stalled. As of 2013 stakeholders including government agencies, non-profits and individuals seemed to concur that complete removal is the best option.[11]

The watershed is also challenged by invasive, non-native species, such as Giant Cane (Arundo donax).

References

  1. ↑ "Matilija Dam Facts and History". Matilija Dam Ecosystem Restoration Project. Retrieved 11 April 2016.
  2. ↑ "Matilija Dam Facts and History". Matilija Dam Ecosystem Restoration Project. Retrieved 11 April 2016.
  3. ↑ Erwin G. Gudde, William Bright (2004). California Place Names: The Origin and Etymology of Current Geographical Names. University of California Press. p. 231. ISBN 978-0-520-24217-3. Retrieved 2011-01-29.
  4. ↑ Durham, David L. (1998). California's Geographic Names: A Gazetteer of Historic and Modern Names of the State. Quill Driver Books. ISBN 978-1-884995-14-9.
  5. ↑ Chawkens, Steve (19 September 2011). "On a divisive barrier, a snippy bit of graffiti". Los Angeles Times. Retrieved 11 April 2016.
  6. ↑ Stolz, Kit (15 April 2001). "It's Time to End the Sad Saga of Silt-Clogged Matilija Dam". Los Angeles Times. Retrieved 11 April 2016.
  7. ↑ "Matilija Dam Facts and History". Matilija Dam Ecosystem Restoration Project. Retrieved 11 April 2016.
  8. ↑ Chawkens, Steve (19 September 2011). "On a divisive barrier, a snippy bit of graffiti". Los Angeles Times. Retrieved 11 April 2016.
  9. ↑ Booth, William (21 January 2001). "Dam-removal Sentiment Flows More Freely Now". Washington Post (syndicated). Retrieved 11 April 2016.
  10. ↑ Malibutimes.com
  11. ↑ Carlson, Cheri (3 March 2013). "Delayed plan to remove Matilija Dam near Ojai will get new studies". Ventura County Star. Retrieved 11 April 2016.

Coordinates: 34°29′06″N 119°18′30″W / 34.485007°N 119.308226°W / 34.485007; -119.308226

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