Happy Holidays from the SFPUC

We hope you are having a joyful and restful holiday season!

It doesn't snow very often in the Alameda Watershed, so we had to go way back into the photo archives to find this one from the Calaveras Dam construction site, dated January 9, 1913. The site was so remote at the time that onsite camps housed construction workers.

Calaveras Dam was constructed three times in total. 

• The first dam, started in 1913 and completed in 1918 collapsed under its own weight because of the dam construction method builders used.
• The second dam, which served us for over 90 years, was completed in 1925. 
• The third replacement Calaveras Dam reached its full height in September 2018.

Happy Holidays to you and yours!

See you around the Valley!

Calaveras Dam - The Real 'Shark Tank'

Crews constructing the SFPUC’s new Calaveras Dam in the East Bay uncovered a geologic layer that happened to contain thousands of fossils. Through a cooperative agreement with the University of California Museum of Paleontology (UCMP; Berkeley, CA), those fossils are now being cleaned, analyzed, and catalogued.

“We transferred all of the fossil specimens to UCMP this year,” said JT Mates-Muchin, the SFPUC’s Environmental Compliance Manager who helped broker the agreement. “Fossils are a non-renewable resource. It is important that they are carefully catalogued and preserved for scientific research.”  

 A Megalodon Shark Tooth Being Scanned in the Lab.

The lead researcher and lab manager at UCMP, Cristina Robins, and her team are beginning to tease information out of the fossils.   Fifteen million years ago, the site of Calaveras Reservoir was located at the mouth of a vast inland sea that stretched into the Central Valley.  Just like in the seas of today, there was a lot of plant and animal life throughout. When they died, they left a fossil record.

This included sharks, lots of sharks. More than 2,000 shark teeth have been found from 35 species. These include many from requiem and mako sharks. Some teeth from the 35-foot megalodon shark have turned up as well. What do these shark teeth tell us?

1. The area around Calaveras Dam was once completely submerged by water.
2. The depth of the ocean could have been as deep as 700 to 1,000 meters.
3. The distribution of species is similar to fossil locations as far as way at Gatun, Panama.
4. Calaveras has a higher diversity of sharks than other sites.

At this point the paleontologists have only begun to scratch the surface of the Calaveras fossils, no pun intended.

The teeth from 35 different species of shark have been found at the Calaveras Dam Replacement Project.

We look forward to learning more secrets about the Bay Area’s past through these amazing fossils.

Keep up to date on the Calaveras fossils through the UCMPFacebook Page.

A 30 foot long predator left its tooth at Calaveras Dam. The Megaladon tooth is being analyzed at UCMP.

 See you around the Valley!

Floating Yellow Curtains

If you've seen one of our aerial photos of the Calaveras Dam Replacement Project, you might have noticed what look like yellow lines in the reservoir. Those are turbidity curtains. What's that?

We're glad you asked.  A turbidity curtain, also known as a silt curtain, is a floating barrier that collects suspended solids that are present in the water and allows them to settle in a contained area.

Calaveras Reservoir, and our turbidity curtains, are visible below.



Turbidity curtains are usually placed near areas were we have disturbed soil in or near the reservoir. The turbidity curtains act as a floating filter to protect the water around the outlet tower where we take water out of the reservoir. Although we filter this water at the nearby Sunol Valley Water Treatment Plant before we serve it to our customers, these curtains add an additional layer of protection to our water supply from any particulates or sediment from the Calaveras Dam Replacement Project.

The top of the curtain is made from a float from which a skirt hangs down. There are generally two types of turbidity curtains: hanging and standing silt curtains. At the Calaveras Dam Replacement Project we use hanging silt curtains.





Image curiosity of : https://www.landmsupplyco.com/

A close up of our turbidity curtains.

Turbidity curtains are an important part of the Calaveras Dam Replacement Project to continue to protect our our water sources during construction.

See you around the Valley!