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!

Alameda Whipsnake Sightings Near You

Here in the Sunol Valley we have a special species of snake that lives among us. It’s no other than the Alameda whipsnake or sometimes called the Alameda Striped Racer, (Masticophis lateralis euryxanthus), a subspecies of the California whipsnake (Masticophis lateralis). It has made the coastal scrub, chaparral, and grassland habitats in the hills east of the San Francisco Bay its habitat.

Known for its ability to move fast, the Alameda whipsnake has the following distinct features: broad head, large eyes and a long slender body with a distinct yellow-orange “racing stripe” down each side. Adults can grow to six feet long. They are diurnal which means that they are active mainly during the day. Surprisingly good climbers, these snakes seem to prefer to hunt for lizards, snakes, and frogs. They are not venomous and pose no threat to humans.

All of the workers on SFPUC-related construction projects in the Valley have been trained to be on the look out for these special snakes. If they see one, they stop what they're doing, and contact a trained biologist to rescue them to a safer location.



Here is an up and close picture of one rescued by our field biologist, Aaron.

November is the time of year when they look for a dry, safe burrow to hibernate during the winter. The springtime is when courtship and mating takes place, usually from late-March through mid-June.



Alameda whipsnakes are considered to be both a federally and state threatened species.









See you around the Valley!

Spraying it Green

Most of us don’t give hydroseeding much thought. As it turns out, we at the Calaveras Dam Replacement Project do.

Hydroseeding is, in essence, spreading seeds over an area after the ground has been disturbed by things like the construction of a large dam.  It is an important part of restoration and erosion control.  What is cool is the way we plant these seeds.  What we call hydroseeding was invented in the 1950's and involves mixing mulch, seed, and water together to form a slurry and then literally spraying it on the ground. This mixture increases the likelihood of germination of the plants and it holds firm to sloped areas.

One of the best times to hydroseed is the fall, which is why our teams are spending a lot of time hydroseeding now.  Our hydroseed is a mix of native annual and perennial grasses and forbs that grow quickly and easily from seed. The restoration goals for the project include establishing native plant communities. The vegetation provides habitat for threatened species and helps improve water quality.

Here is a beautiful picture of the recent hydroseeding of Borrow Area B (BAB). The green color is not green grass but a natural dye used so the contractor can track locations where they applied the hydroseed. The color will eventually disappear until the vegetation begins to grow. 






And, here is a picture of the newly hyroseeded dam. You can see the hydroseeder (truck) spraying the hydroseed onto the dam's face.  The thick lines are straw wattles used to prevent erosion on the slope.

Here is a closer picture of one of our workers spraying the hydroseed onto a steep slope.

Now we just need a nice winter's rain to help the hydroseed grow. 

See you around the Valley!

Loma Prieta Earthquake Anniversary Week - The New Irvington Tunnel

Happy Friday

This week marks the anniversary of the 1989 Loma Prieta Earthquake. 

We've been blogging about the San Francisco Public Utilities Commission's efforts to seismically upgrade our water system for many years now. The $4.8 billion Water System Improvement Program is more than 96% complete as of this writing. The water system that supplies water to 2.7 million customers in four Bay Area counties is much more earthquake ready today than it was 5 years ago. 

In honor of the Loma Prieta Anniversary week, we wanted to remember a post from October of 2013 when a crucial seismic project for the Water System Improvement Program achieved a huge milestone. Final hole through. 

Miners worked long hours in the New Irvington Tunnel .

The New Irvington Tunnel Project ,which went into service in February 2015, is a new 3.5 mile long seismically designed tunnel. We mined the tunnel from different directions, and the moment the two teams met underground to complete the digging is called Final Hole Through.

See the October 2013 Story here.

One of the three road headers that excavated the New Irvington Tunnel.

Have a great weekend, everyone.

See you around the Valley!

Calaveras Dam Embankment Celebration- Photo Friday

The replacement Calaveras Dam has reached its full height of 220 feet.

The month of September marked a huge milestone for the Calaveras Dam Replacement Project.  The new replacement earth and rock fill dam has finally reached its full height and is nearly ready to begin impounding water this winter. 

You might have read about it or seen it on the news.  We had many media outlets out at the dam on September, 21, 2018 to cover the occasion.  

Here are some photo highlights in honor of Photo Friday.

San Francisco Public Utilities Commission Vice President Vince Courtney addressing the crowd.

Sharon Tapia, DSOD, Division Chief addressing the crowd.  DSOD or California's Division of Safety of Dams regulate dams in California.  They were a key partner in the construction of Calaveras Dam. 

General Manager Harlan L. Kelly, Jr., was joined by SFPUC Commissioners, SFPUC Deputy General Managers, and representatives from the Bay Area Water Supply and Conservation Agency to make it official with a ribbon cutting. 

Here is the entire Calaveras Dam Replacement Project Team atop the new dam.








The project isn't completed, however. The crew will work on completing the approach channel, constructing access and roadways throughout the site, restoration and revegetation, placing instruments, and installing gates and security systems. 

The overall project is 94% complete and is scheduled to be completed in spring 2019.

See you around the valley!

Calaveras Road Closure Extended through November 2, 2018

The Closure of Calaveras Road to through traffic between Milpitas and Sunol has been extended from September 30, 2018 to Friday, November 2, 2018.

The road will reopen to all traffic, weekdays, weekends, and holidays starting Saturday, November 3, 2018.

Why:

The SFPUC has been working with the appropriate county agencies to secure final approval for renewed public access to the road after a portion of the road was built by the SFPUC to replace a portion undermined by a landslide.

Background:

We have been working since 2011 to replace the 93 year-old Calaveras Dam to increase the reliability of the Hetch Hetchy Regional Water System, which serves 2.7 million people in four Bay Area counties.

The closure of Calaveras Road began in July 2016 to protect public safety on the extremely narrow portions of Calaveras Road while large trucks utilized the road for construction.  

Road Closure Details:

Where: Calaveras Road just south of Geary Road (entrance to Sunol Regional Wilderness) to Oakridge Road near the Alameda /Santa Clara County line.

When: July, 2016 through November 2, 2018. The Road will be open on weekdays, weekends, and holidays starting Saturday, November 3, 2018.

For more information, visit sfwater.org/calaverasroad

Thank you for your continued patience. We apologize for the inconvenience.

Meet the CAT-773

Our work at the Calaveras Dam Replacement Project wouldn’t be possible without the help of heavy equipment. Heavy equipment helps our team complete big tasks like moving 12 million cubic yards of rock and earth. Because of the size and scope of our project, we have the privilege of working with some big and cool heavy equipment on our job site.

On any given day we could have approximately 20 pieces of heavy equipment operating. Today I would like to introduce you to the CAT-773

Here is a picture of some of our equipment.

With a full load it can carry 100 tons of dirt or 200,000 pounds of material. This machine can climb steep roads and is very comfortable for the operator. It has a 12-cylinder engine that can reach 42 miles an hour.

John Rocca, Field Operations Manager in front of a CAT-773.

It’s a real life Tonka truck. We have a total of 10 CAT-773’s on site hauling material and getting the job done.

 This equipment belongs to our Joint Venture (Dragados, Sukut and Flatiron), our partners on this project.

See you around the Valley!

Sikorsky 58-JT helicopter at Alameda Creek Diversion Dam

Our teams have used many different kinds of equipment to build a fish ladder and other appurtenances at our Fish Passage Facilities within the Alameda Creek Watershed Project.

This past Monday, July 9, 2018, however, was a first: crews used a Sikorsky 58-JT helicopter. Why? The project site is remote, and the item to be transported was large.

Specifically, the contractor needed to move a 600-pound electrical box to an abutment of the remote Alameda Creek Diversion Dam. The helicopter picked up the electrical box at the staging area, located at the cattle corral and then lifted it to the left abutment of the Diversion Dam, which is located on SFPUC-owned property adjacent to the East Bay Regional Park District's Sunol Regional Wilderness.

A Sikorsky 58-JT  Helicopter makes quick work of transporting a 600 pound electrical box to the Alameda Creek Diversion Dam

The operation took just 20 minutes.

The Fish Passage Project is located in Sunol. The goal of the project is to provide for safe passage of fish around the Alameda Creek Diversion Dam to support the restoration of the Steelhead Trout to the Alameda Creek Watershed. 

The Alameda Creek Diversion Dam is visible in the distance. The electrical control building is located to the left. The project is at 92% completion and is expected to be finished this fall. 

The project is part of the SFPUC’s $4.48 billion Water System Improvement Program.

See you around the Valley!

Attention Sunol Regional Park Users: Camp Ohlone Road will be closed to the pubic Monday, July 16th-Wednesday, July 18th.  Plan on using either Canyon View or Estes Trail  to get to Little Yosemite.

Meet Manny Yeboah

Meet Emmanuel (Manny) Yeboah. Manny has been an employee of the San Francisco Public Utilities Commission (SFPUC) for over 10 years. He started his career with the SFPUC's Bureau of Environmental Management preparing categorical exemptions and mitigation monitoring reports. Currently, Manny is an Office Engineer for the Fish Passage/ACDD project and a Project Construction Manager for the Sunol Nursery Project. As a Project Construction Manager, Manny ensures that the project is running on time, on budget and that the Contractor’s operations comply with the contract specifications, drawings and permits.

He and his team are responsible for constructing the first nursery project of its kind for SFPUC. The Sunol Nursery Project is a $2.2 million dollar project located within the Sunol Temple yard. The new Sunol Nursery encompasses 1-acre and includes construction of new water storage tanks, garage, office building, shade house and a state of the art greenhouse structure with a cooling pad system. The purpose of this project is to propagate plants for the Alameda Creek Watershed Center, Sunol Yard and other SFPUC projects. The project is scheduled to be completed by October 2018.

Manny enjoys his role as a Project Construction Manager. When asked about his role as a Project Construction Manager he stated, "It’s a huge accomplishment to be in this position, I’ve worked hard throughout the years and now my goals are coming into fruition with me running an innovative project for the SFPUC."

Manny is no stranger to construction projects. He has worked as an office engineer for over 6 years and has a degree in Urban Studies Regional Planning from Cal State Northridge. When he is not working, Manny enjoys going to new restaurants, working out, and spending time with family.

If you ever see him around the valley, don't hesitate to say hello.

What's the Big Deal about an Approach Channel?

We are building a new earth and rock fill Calaveras Dam right next to the existing 93 year-old dam (directly downstream of the existing dam as they say in the dam industry.)  As many of our previous blog posts have been tracking, we have been busy building the new dam, foot by foot, from the bottom up like a layer cake. A very large layer cake.

Our Calaveras cake is high enough now to allow us to begin to excavate out the approach channel to the new dam this week.

"What is an approach channel?" you ask. An approach channel is a breaching of an existing dam in order for its adjacent reservoir to come in contact with it. We will remove a portion of the existing dam (500,000 cubic yards of it to be exact) to allow reservoir water to eventually fill in the space between the old dam and the new dam. The old dam will look like a peninsula in the reservoir when the project is done. 

"Why not remove the old dam in its entirety?" We don't have to. Complete removal would be expensive, environmentally difficult, and not necessary to operate the reservoir. 

The start of excavation of the approach channel means that we have reached a high enough elevation with the new dam to safely begin carving out a huge chunk of the existing dam. It's a coming of age for the new dam, if you will. A significant milestone. 

Here is what the approach channel looked like at the beginning of last week.



And, here is what it looks like this week.




The channel will be lined with large rocks called rip rap to protect it from erosion so the channel will be ready when we start to refill the reservoir this fall.

Approach channels may not seem exciting at first glance, but we at the SFPUC are thrilled!

See you around the valley!

SFPUC Project Team Leads National Discussion about Dams and Ecosystems

In early April members of the Fish Passage Facilities project team went to Miami, Florida to present at the 38th United States Society of Dam’s (USSD) Annual Conference on behalf of SFPUC. This year's conferences theme was A Balancing Act: Dams, Levees and Ecosystems. It focused on the importance of environmentally sustainable water projects within diverse and sometimes fragile ecosystems.

Our Fish Passage Facilities team were selected to present their paper called "Fish Passage Facilities at the Alameda Creek Diversion Dam, Final Design and Construction Update."

The Fish Passage Project is located in Sunol.  The goal  project is to provide for safe passage of fish around the Alameda Creek Diversion Dam to support the restoration of Steelhead trout to the Alameda Creek Watershed.  The project is part of the SFPUC's $4.8 billion Water System Improvement Project (WSIP) to repair, and seismically upgrade portion of the Hetch Hetchy Regional Water Sytem. Construction is expected to be completed in fall 2018.

Below is a photo of our fabulous four presenters: Eric Gee, Project Manager, Yen Ng, Engineer and Karl Tingwald, (former AECOM) civil engineer and Dan Wade, Director of Water Infrastructure Capital Projects and Programs.

We want to congratulate the Fish Passage team members for a job well done.

See you around the valley!

Memorial Day 2018

In observance of Memorial Day, our construction teams at the Calaveras Dam Replacement Project, Fish Passage Facilities within the Alameda Creek Watershed (within EBRPD's Sunol Regional Wilderness) and the Sunol Valley Long Term Improvements (Water Temple) will not be working on Monday, May 30th.

Here is a photo of one of our D4 Dozer's working on the dam’s core at the Calaveras Dam Replacement Project.



We hope all of you have a safe and wonderful Memorial Day weekend.

See you around the valley!

Happy Infrastructure Week 2018

The Week of May 14 to May 21^st is national Infrastructure Week! This is the week where public agencies across the nation highlight the importance of our nation’s infrastructure, and the need to maintain it.

At the San Francisco Public Utilities Commission, our ratepayers had the foresight more than 10 years ago to allow us to pass the $4.8 billion Water System Improvement Program (WSIP). The program has 87 projects, spanning seven counties, to repair, replace, and seismically upgrade aging portions of the Hetch Hetchy Regional Water System. To date the program is more than 90% complete.

A tremendous amount of work was done in the Sunol Valley to ensure a seismically reliable water supply for our Bay Area customers.  The Calaveras Fault runs right through the Sunol Valley. The Calaveras Dam Replacement Project is the largest WSIP Project in construction, but there have been many others. Here are the highlights:  

Alameda Siphon #4. A high tech pipeline crossing of the Calaveras Fault designed to survive an earthquake. Completed 2013.

New Irvington Tunnel. A new seismically designed tunnel to connect the new Siphon with new pipelines in Fremont. Tunnel brought into service in 2015.

Upgrades to our Sunol Valley Water Treatment Plant to enable the plant to provide minimum demand to all of our 2.7 million customers on its own for up to 60 days. Completed 2015.

A complete new Bay Division Pipeline #5 to connect the New Irvington Tunnel to a new Bay Tunnel and the Peninsula. Completed 2016.

We've been posting videos on Facebook all week to highlight the SFPUC's efforts to upgrade your infrastructure. And at Twitter: #TimetoBuild. See the Facebook posts  here.  

See you around the Valley!

The Building Blocks of the Replacement Calaveras Dam

If you are new to the world of dam construction, you might wonder what types of materials are used in building one.  Today’s blog will focus on what types of materials we are using to construct the new Calaveras Dam. Calaveras Dam is an earth embankment dam.  Earth embankment dams tend to be constructed of all types of geologic materials.

Calaveras Dam, July 2017

The picture above was taken recently; from it you can visually see the different materials. Let’s start with the middle and the most important material used in our dam, the core. 

The Core of Calaveras Dam

Zone 1 & 1A—aka…the Core

The core is made up of clay.  Clay is very dense and less permeable than most materials.  Our new dam will have a large core, which will help ensure that the dam withstands a 7.2 magnitude earthquake.  The clay used in our dam has been ‘borrowed’ from the south end of Calaveras Reservoir.

The core is taking shape.

Zone 1A- Core’s foundation

At the bottom of the core, you will find Zone 1A material. This clay is plastic, pliable clay, or another words, clay that has a Play-dohtm like consistency.   Zone 1A material is placed on the foundation’s bedrock and acts as a seal against water flow beneath the dam.

The core is the most important element of the dam and therefore must be protected.  We protect our core by using filters in both the upstream (reservoir side) and the downstream (dry side) of the dam to control the seepage of water and remove it safely from the Dam.

Zone 2 and 2A- Sand

Upstream zones are made of sand  (Zone 2A) and large gravel (Zone 5A)The downstream filters or chimneys are made of sand (Zone 2) and pea gravel (Zone 3).

Zone 5-Rock Fill

Further protection for both the core and filters is provided by rockfill shells. The upstream shell consists of hard durable rock because it will be submerged in the reservoir, Zone 5 material.  This material consists of metamorphic rock known as blue schist.

The downstream shell (Zone 4) consists of onsite material from a geologic formation known as Temblor Sandstone.  While this is a sedimentary rock, it tends to degrade into a gravelly, sandy soil and is best suited for drier conditions than the upstream shell.

Zone 6- Rip Rap

Wave action in the reservoir due to wind can erode most earthen materials.  Large durable rocks are placed on the slopes of the dam at the waterline to prevent this erosion. This is Zone 6 also known as rip rap.

Image courtesy of www.fhwa.dot.gov

See you around the valley!

What is a desmostylus and what is it doing in the Sunol Valley?

Photo courtesy of www.alchetron.com

A Desmostylus was a hippo-like creature that lived about 20 million years ago. It happens to be the only order of marine mammal to have gone extinct. Some individuals lived along the shoreline of an ancient ocean that used to be located where the Sunol Valley is today.

If you stumbled upon this would you know it was a rib cage?  What it looked like prior to Excavation

During excavation of the Calaveras Dam Replacement Project, the project paleontologists found not only a few teeth belonging to these strange creatures, but recently found an entire rib cage. Removing the fossilized rib cage of an animal that likely weighed between 200 and 400 pounds in life is no small task.

First the bone had to be cleaned and separated as much as possible from the surrounding rock on the hillside.

Above is the picture after our fossil was cleaned and ready to be removed.

In order to physically remove it from the hillside, crews used a lift to grab the entire rib cage. Now that the rib cage has been safely removed from the construction site, it awaits further stabilization treatment by project paleontologists. 

See you around the Valley!

Blankets and Curtains for Calaveras Dam?

Here at the Calaveras Dam Replacement Project we are building what is called an earth and rock-fill dam. The replacement Calaveras Dam, like all so-called embankment dams, is made of mostly compacted earth (see a cross section of the future dam below). An important aspect of this type of dam is the management of water. All earthen dams leak, the important thing is to control where the water flows to protect the integrity of your dam.  In the case of the Calaveras Dam Replacement project, we accomplish this with blankets and curtains. 

No fooling! Here’s how it works.  For years, the crews onsite have been constructing an entire dam that extends more than 100 feet below the base of the future dam.  We call this a grout curtain. Grout for those of you not in the construction industry is a special mix of cement that can be injected or literally blown onto a surface to seal it.  

Grout Curtains

As you can see in the photo from 2015, crews drilled countless small diameter holes into the bedrock a hundred feet down below the future dam and injected the holes with pressurized grout. The grout effectively seals up cracks and fractures within the rock underneath the new dam.  We did this for years. Why is this grout curtain so important? It prevents water from seeping underneath the new dam and undermining it.  In essence we drilled an entire new dam underneath the future dam. 

Drainage Blanket

If you thought grout curtains alone were enough to protect the future Calaveras Dam, guess again! We need blankets, too. More specifically a drainage blanket. The drainage blanket prevents water from exiting to, and damaging, the down-stream face of the dam (the face of the dam away from the reservoir).  At the end of the drainage blanket we are constructing a ‘mini dam’ made out of the same clay material as the core to capture any water in the drainage blanket. You can see the drainage blanket being constructed here.  This ‘mini dam’ is also known as the seepage barrier.  This seepage water is then collected in an inspection well to monitor the condition of the dam.

The Calaveras Dam Replacement Project, along with its blankets and curtains, is more than 80% complete.

See you around the Valley!

Photo Friday at the Calaveras Dam Replacement Project

Did you ever look at a photo of yourself or a family member from a long time ago and compare it to a recent picture? For today’s Photo Friday, we decided to do just that for the Calaveras Dam and its replacement.

Calaveras Dam in 2011. The project groundbreaking was in 2011. 

Calaveras Dam in April 2017. The project is more than 80% complete. We have moved more than 8 million cubic yards of rock and soil to date. We have fully excavated and grouted the left and right abutments. And in the center of the picture, the core of the new Calaveras Dam begins to take shape.  The huge concrete spillway (as wide as a freeway) is visible at the lower right. Wow.

Construction on this project started in 2011 and is expected to be complete in April 2019.

To learn more about this project and see a time lapse video of all of this excavation, visit us here.  

See you around the Valley!

Spring Wildflower Festival Draws Crowds to Sunol Regional Wilderness

This past weekend, the San Francisco Public Utilities Commission (SFPUC) joined an estimated 1,000 attendees at the 2017 Spring Wildflower Festival, hosted by the East Bay Regional Park District.

The beautiful sunshine, wildflower blooms, nature hikes, and live music drew families from all over the Bay Area to Sunol Regional Wilderness. Over 300 kids stopped at the SFPUC resource booth to create their very own personal paw print necklaces while staff shared information to residents about our Sunol Valley projects underway including the Sunol Yard upgrade, construction of the Fish Passage Facilities Project within Alameda Creek Watershed and the Calaveras Dam Replacement Project.

We hope that you were able to experience this awesome event and enjoy the wildflower season as much as our staff did. See you around Sunol Valley!