Category Archives: Los Angeles County

Mt Wilson Observatory Geology Talk

Lectures

On Saturday, June 16, at 5:30 pm Mount Wilson Observatory will be hosting a talk by Dr. Tanya Atwater, professor emeritus of geology at UC Santa Barbara. Dr. Atwater played a major role in piecing together the plate tectonic history of our part of the planet. She will talk about how the motions of the Earth’s crust created the current topography of southern California (including the perfect site for astronomers to explore the Universe). The talk will be followed by a rare chance to look look through Mount Wilson Observatory’s 60-inch Telescope, which revolutionized telescope design and allowed astronomer Harlow Shapley to find our place in the Milky Way Galaxy. Tickets are only $20 and proceeds will all go to the maintain the Observatory.

Featured Image – March 12 and 13, 2018

St Francis Dam site in 2003.

This featured image covers two dates for a reason. The St. Francis Dam, a former dam in San Francisquito Canyon above Santa Clarita, California, collapsed at 11:57:30 pm on March 12, 1928. The ensuing flood caused a great deal of damage along the canyon and the Santa Clara River Valley. Over 500 lives were lost that night in, even in 2018, the second largest disaster by loss of life in California. The even had repercussions throughout the world. Following that event, dams, as well as other large projects, no longer were approved by engineers. Geologists had the final say, not engineers. Both geologists and engineers also had to be certified by their state government to work as professionals.

The head engineer on the project, William Mulholland, was a great engineer. He oversaw and helped design the Los Angeles Aqueduct, which was the largest and longest project of its time. It is still an engineering marvel today, more than 100 years later. The disaster ruined his career and during the investigation, he not only took full responsibility for the event, but also was said to have “envied the dead”. The collapse took a big toll on the “Chief” and he died a few years later.

This post is in memory of both those that died that fateful night in 1928 and to William Mulholland. A man that went from the “Savior of the City” to a pariah in just a few years.

Image of the Week – 8/27/2017

Looking toward Timber Mountain with Mt San Antonio and Cattle Canyon to the left.

US 6 – Santa Clara River Bridge – A Closer Look

US Highway 6, now known as Sierra Highway, crossed the Santa Clara River near Solemint, California. The bridge it originally used, constructed in 1938, is planned to be replaced in the near future. This bridge is one of the oldest remaining in the Santa Clarita area and is the longest span on former US 6 in California. The bridge has remained almost intact from its original construction. The only changes have been minor to the bridge itself. The highway, however, has changed quite a bit. In 1968, Sierra Highway, then State Route 14, was widened to four lanes. A second bridge for northbound traffic was added, with the original bridge being used for southbound traffic.

Presently, Sierra Highway is six lanes wide at the river crossing. As the bridges were built with a four-lane highway in mind, only a narrow shoulder along both directions exists. This condition is one of the reasons the bridges across the Santa Clara River are being replaced.

In March of 2017, I took a trip to inspect in more detail the bridge and the surrounding area. It was nice to see the bridge again, as it brought back a lot of memories. I used to live near the bridge and crossed it almost daily. It will be sad to see it go as it is one of the last remaining pieces of the old highway. So, please, check it out yourself while you still can. I’m not quite sure when the construction will begin, it may have already.

Main Structure:

Side view, from the northern end. Note the small arches along each span.
Southern abutment and wing wall.
Between the 1938 and 1968 spans. Quite a difference between the girders.
Deck view, looking northerly from the south end.
Side view showing the railing, arched spans, and wing wall.

Detailing:

Underside view of the bridge.
Closeup of the west side railing from the south end of the bridge.
View showing the railing at the expansion joint.
Expansion joint that may have moved during an earthquake or from settling.
Expansion joint along the bridge deck.
Deck drain detail.
Remaining section of railroad rail and wire fence embankment protection.

Los Angeles County Survey Records

Los Angeles County Department of Public Works has a wealth of information available on their website. With a bit of patience and some looking around, you can find quite a few treasures using their mapping application. I’ve so far found the original survey data for the “Bridge To Nowhere” roadway, plans for other roadways that were never built in the Sierra Pelona Mountains, as well as the forest service permit for the Shoemaker Canyon Road that was never completed.

http://dpw.lacounty.gov/sur/landrecords/index.cfm

Image of the Week – 4/2/2017

Hiking to the Bridge to Nowhere with my husband while in a wetsuit

Wigwags – Part 4

When you did deep enough and look hard enough, you’ll find there is far more history left in Southern California than you might think. I have found this to be true when it comes to finding wigwags in the region. This one, in Hawthorne, CA, is along a former Pacific Electric Railway line that headed to Manhattan Beach. Located at Eucalyptus Ave just north of El Segundo Blvd, it still presses on as a lasting tribute to the old railway, now a part of the Union Pacific Railroad.

General view along Eucalyptus Ave showing the crossing.
Closeup of the wigwag.

New Ridge Route Video, sort of

After finally resolving some software issues, I have finally been able to start editing and posting videos again. My most recent one was taken in November 2015 along the Ridge Route from near Liebre Summit. It shows some of the issues the road is facing presently regarding erosion and a lack of maintenance.

Ridge Route Online Petition

Tumble Inn arch on the Ridge Route
Tumble Inn arch on the Ridge Route

Hello all,

The Ridge Route in Southern California needs your help. The Ridge Route Preservation Organization has put together an online petition to help get the roadway back open and in working order. It has not been fully open to traffic since 2005 and is in need of your support. Please sign this petition to get the legislators and the Angeles National Forest to fix what they did wrong. More details are on the site for the petition.

Thank you for your time and efforts!

https://www.change.org/p/help-save-the-old-ridge-route-road?recruiter=558871232

Image of the Week – 10/18/2016

Looking south toward the south closure on Hwy 39.
Looking south toward the south closure on Hwy 39.