Photo Friday: Beyond the New Calaveras Dam

Happy Photo Friday!

Here are some beautiful aerial photos of the New Calaveras Dam and Calaveras Reservoir.  Photos are courtesy of SkyHawk Photography.  

Here is a stunning photo of the Calaveras Reservoir from the south looking north towards the New Calaveras Dam. Calaveras Reservoir helps supply drinking water to 2.7 million Bay Area residents. 

Workers completed the road that leads to the dam.

















We couldn't resist adding a picture of the new intake tower.  
  

The seismically robust New Calaveras Dam is in full operation. It can now hold its historic storage capacity of 96,850 acre feet of water (31 billion gallons).  

The dam was completed in May 2019. The team is finishing up a few minor items at the Dam, but the majority of construction activities are now complete. 

See you around the valley! 

Photo Friday: Calaveras Reservoir

Mother Nature has given the Bay Area a serious drenching during the last couple of weeks.

So much in fact that Calaveras Reservoir has started to fill. The SFPUC lowered the water level in Calaveras Reservoir because of seismic concerns about the old Calaveras Dam.

The SFPUC built a new dam, which reached its full height in September. This means we are ready to allow the reservoir to start filling with local Alameda Creek Watershed runoff.

And fill it did.


This photo was taken in January 2019. The remnants of the old dam are seen on the right, where the reservoir begins to fill. The new dam is on the left.



This photo was taken last week. The reservoir has filled the entire space between the old and new dams.

Calaveras Reservoir helps supply drinking water to 2.7 million residents in four Bay Area counties.

The Calaveras Dam Replacement Project is 98 percent and is scheduled to be completed in spring 2019.

See you around the Valley!

The Rainbow Trout Count

It is that time again. Time for the Trout Count. Biologists with the San Francisco Public Utilities Commission have been working to estimate the total number of adult rainbow trout living in Calaveras Reservoir.



Sunol biologist Randy Renn trolling for fish on the reservoir.

Rainbow trout (Oncorhynchus mykiss) are a cold water species native to the rivers and lakes of North America. Like all native fishes, it’s important to preserve them and our ecological systems. Monitoring fish populations is an important part of protecting trout in Calaveras Reservoir.



Here is a good specimen from Calaveras Reservoir.

How do the biologists estimate the rainbow trout population size?

They use a technique known as mark and recapture. During spring, when adult rainbow trout migrate from the reservoir upstream to Arroyo Hondo to spawn, the biologists capture and mark as they can. During summer, after the adult fish move back down into the reservoir, the biologists fish for them and check for tags. Knowing how many trout were originally tagged in Arroyo Hondo, they can use the ratio of tagged to untagged fish caught in the reservoir to estimate the total number that are there.

Pictured here is Scott Chenu SFPUC Sunol biologist, with one of his catches.

Our dedicated biologists will continue track the fish through the end of September. After Calaveras Reservoir is refilled, they will check the population size again to see if there is a difference. 

Periodically tracking the rainbow trout population size is also important because it helps our biologists determine whether they are healthy and thriving or being negatively impacted by reservoir operations.

See you around the valley!

Photo Friday at the Arroyo Hondo

Happy Photo Friday!

Today's post comes courtesy of watershed keeper Pat Jones.

Recently cloudy skies helped produce some stunning photos. This one shows Calaveras Reservoir and a major tributary into it - the Arroyo Hondo.

Have a great weekend, and we'll see you around the Valley!

What is this Building and What Does it Have to do with Fish?

Despite the recent heavy rains, the crews at the Calaveras Dam Replacement Project have been pouring concrete for an important feature of the future Dam – the stream maintenance building, pictured below.  The new building stands 25 feet tall and is located downstream at the toe of the future replacement dam.

We at the SFPUC will be releasing water from the future Calaveras Dam to support fish in the Southern Alameda Creek Watershed.  What’s that have to do with this building?  A lot, actually.  The stream maintenance structure provides a place for water discharged out of the future Dam to be collected and then discharged in a controlled manner to the nearby Creeks to support fish habitat. Water will flow from the reservoir to the structure via two 30 inch diameter pipes. Water will exit the structure over grouted rip rap to prevent erosion.

The Calaveras Dam Replacement project is more than 80% complete and expected to be completed in mid-2019.

Calaveras Dam Celebrates another Safety Milestone

According to the U.S. Department of Labor Occupational Safety and Health Administration (OSHA), nearly 6.5 million people work at construction sites across the nation on any given day. The rate of injuries for construction workers is higher than those workers in other job categories in the United States. On average, we could have 150 workers on site at the Calaveras Dam Replacement Project.

The construction crews at the Calaveras Dam Replacement Project work multiple shifts – both day and night – working with huge machinery on a very complicated job site in challenging conditions. And yet the construction crews, who work for the joint venture of Dragados USA, Flatiron Construction and Sukut Construction, celebrated a huge safety milestone this week. Our crews have worked 75,000 safe working hours for the last quarter (from September 24, 2015 through December 31, 2015) without any recordable safety incidents. In fact, to date, they have a total of 304,146 work hours without recordable safety incidents as of December 2015. The last lost time incident was recorded in 2012. The teams celebrated with a well-deserved barbeque lunch on site to celebrate their success, and remind each other of the need to continue with their best practices to keep everyone safe.

As we continue the critical work to complete the project, we applaud our teams for continuing to make safety a priority here at Calaveras Dam.



Construction team who perform major structural work at the dam
(Pictured in no particular order: Jose Rodriguez, Dewayne Grayer, Ben Simbra, Benny Jasper, Alfredo Simao, Miles Cheek, Tomas Orantes, Eddie Fuentes, Garrett Colvin, Mike Morrison



Construction work on the new spillway chute

A New Bridge for the New Year

We at the Calaveras Dam Replacement Project have been talking a lot about the new spillway under construction at the dam. And why not? It is as wide as a six lane freeway, with walls that are 40 feet tall, and it is 1500 feet long. We placed over 50,000 cubic yards of concrete into the structure to date, and it has been the major focus of activity at the dam for over a year.  Spillways allow dams to safely discharge water without overtopping. This is a key safety feature of any dam, particularly Calaveras Dam as it is an earth and rock fill dam.

Last week we sent out a traffic notice for users of Calaveras Road to be aware that three large trucks would be making a very special delivery for our favorite spillway – its bridge. So special that it had to be trucked in six sections all the way from Ohio.

The spillway bridge will allow future personnel to drive across the top of the spillway safely and access the top of the new dam and outlet works at the toe of the dam. Crews used special cranes to begin installation of the bridge this week. We will be completely done with the spillway this spring.

 

Photos courtesy of Lead QA Inspector Glen Gorski and QC Engineer Shary Truong

Great Cat of Many Names

Out here at the Calaveras Dam Replacement Project, we're privileged to share this beautiful land with many amazing species that call this part of the country home - in this particular case, the mountain lion. 

Lucky for us, our cameras are set up to catch glimpses of wildlife.  This camera did just that:  it caught this mountain lion momma and her cubs out for a nighttime stroll.

These big cats have many names:  puma, cougar, catamount.  Catamount means cat of the mountains.  How fitting is that here in Sunol Valley?

These animals like to hunt during the night and at dawn and dusk -- likely why we have this moment captured on nighttime video. 

In fact, a couple of folks who work at Calaveras have seen the mountain lions if they work the night shift or come in very early in the morning. 

Sometimes they see a pair of gleaming eyes and other times, just a pair of sneaky paw prints across their dusty car hood!

Mountain lions' favorite prey is deer, but they also eat raccoons, porcupines and coyotes.   Their sheer power and incredible ability to hunt in super stealth mode makes them particularly adept at finding food sources.

Because mountain lions are solitary and tend to shy away from people, they are seldom seen.

See you around the Valley! 

One huge pipe at Calaveras Dam

As we busily work towards construction of a replacement Calaveras Dam, there are many fundamental issues we have to address. For example, given that the existing Calaveras Dam will be left in place when we are done, how will we be able to transport water out of the reservoir when the new dam is built?

Answer: We are building a large pipe (more than 7 feet in diameter) that will be completely buried in the new dam that connects directly to the outlet structure already in place in the existing dam.

This pipe will transport our drinking water supply from the Calaveras Reservoir to the Sunol Valley Water Treatment Plant and then on to our 2.6 million Bay Area customers when supplies are needed.

To date, our crews have installed 500 feet of the new steel pipe, welded  the joints, and started building the formwork for reinforced concrete encasement  around the entire pipeline to protect it. The pipeline and encasement  has been designed to withstand the force of being buried under 180 feet of earth embankment as well as the force of any seismic activity from the nearby Calaveras Fault. The team plans to connect the new 78 inch pipe to the existing pipes within the existing dam in Fall 2016. 

Seems a shame to put all this work into something that will be completely buried under more than 3.5 million cubic yards of earth and rock. But, thanks to these careful efforts, customers will be able to drink Calaveras Reservoir water, even after an earthquake.

The new pipe is shown here in orange on the layout, connecting to existing pipes in green.  The old pipeline in black is being abandoned to excavate the foundation for the new dam.

A Snapshot of our Spillway Chute and Stilling Basin Today

Spillways are important safety features on any dam. They allow for the safe discharge of high water in a reservoir around a dam.  And the new spillway at the Calaveras Dam Replacement Project is no different.

Work began on our spillway in March 2014. A total of 40,000 cubic yards of concrete, equivalent to one football field filled six feet deep, will be used to build the structure. All of the concrete is being supplied by our on-site concrete batch plant. The concrete is placed into the spillway in sections, or slabs. This spillway requires a total of 170 slabs, and we only have 18 more to go.

The spillway chute is 60 feet wide, equivalent to a five lanes of a highway. The slabs are strengthened with reinforcing steel bars and the entire structure is anchored to the bedrock to resist movement during an earthquake. 

The quality of the concrete used in the structure is key. It has to be kept at a cool temperature while it cures in order to prevent cracking. Sunol Valley in summer is anything but cool. That means our crews often begin cement pours at 2 o'clock in the early morning, the coolest time of the day.

The spillway is expected to be completed later this year. This will be a major milestone for the project to complete this important feature of the dam.

National Dam Safety Awareness Day

As construction continues at the Calaveras Dam Replacement Project, we take a moment to recognize May 31^st as National Dam Safety Awareness Day. Each year on May 31st, the nation remembers teh devastation that occurred on May 31, 1889 in Johnston, Pennyslvania when the South Fork Dam failed. This tragic event resulted in thousands of deaths and left many homeless. The Johnston disaster was the worst dam failure in the history of the U.S.

National Dam Safety Awareness Day reminds us of the importance of dam safety and preventing future failures. Dams provide many befefits such as water supply and storage, hydropower, recreation, flood prevention and improve wildflife habitats.

 

This also reminds us how critical and important our work is here in Sunol Valley to rebuild the Calaveras Dam. We are currently 66% complete and anticipate final completion of the dam in end of 2018.

The Calaveras Replacement Dam when complete will provide us:

·         The largest drinking water reservoir in the local Bay Area storing 31 billion gallons (96,850 acre ft) of water, providing more than half of the storage capacity for 2.6 million customers

·         A new seismically upgraded dam with a structural height of 220 feet, a crest length of 1210 feet and width of 80 feet at the crest and 1180 feet at the base

·         A new 1550 ft spillway and a new intake/outlet shaft tower which will convey water to and from the reservoir through a pipeline downstream and to our Bay Area customers

 

Aerial Photo of the Calaveras Dam Replacement Project
taken on May 21, 2015

 

 

Heroes in a Half Shell at Calaveras Dam

We at the Calaveras Dam Replacement Project are constantly reminded that our construction area is someone else’s home. Case in point: the Western pond turtles (Actinemys marmorata). Our little heroes in the half shell are coming out of hibernation. A species of special concern in California, Western pond turtles prefer calm water with lots of things to bask on and plants to hide under.  They are opportunistic feeders and will eat pretty much anything they can reach and overpower, including aquatic plants, fishes, aquatic invertebrates and carrion if they can find it. They hibernate nearby in burrows or in upland areas until the temperature is nice, then they come out and head to the water to find food and mates.

Our construction workers spotted the first Western pond turtle of the season roaming on one of our haul roads. Given there are large vehicles (think trucks with wheels that are 9 feet tall), it was important to sweep this girl up and put her in a safe place away from the site. Our biological inspector Aaron Sunshine did just that at a pre-designated release site. On a daily basis, our environmental inspectors work closely with construction staff to identify any wildlife that enter the construction area. Our team works to protect the wildlife in the Watershed ensuring we keep these protected native species safe from harm while we build this important project.  

Maybe it was the luck of the Irish? Or just a good day for our Western pond turtle to be returned to a safe habitat. Aaron and his team will be keeping a sharp eye out! Happy St. Patrick's Day!

Peek-a-boo: Western pond turtle (measured at 16 cm carapace length) safely relocated at the Calaveras Dam Replacement Project by our project Environmental Monitor

Here is our Western pond turtle being released
safely back into the reservoir shoreline

Sunrise at Calaveras Reservoir

I hope this blog post finds you safe, warm, and dry during this storm!

We thought you might like to take your mind of the rains and wind outside. 

So, for your viewing pleasure, we are happy to present, Calaveras Reservoir at Sunrise, November 2014, courtesy of watershed keeper Pat Jones.

Our Watershed Keepers patrol the 36,000 acres of land the SFPUC owns in the Southern Alameda Creek Watershed in every kind of weather.

They also fight fires, respond to all sorts of calls, help maintain the watershed, and when we are lucky, share the photos they take while going about their duties. We will be posting more of Pat's photos, so keep an eye out!

See you around Sunol Valley!

California red-legged frog: Our Newly Famous Sunol Valley Resident

Just a few weeks ago, Governor Jerry Brown signed legislation designating one of our local Sunol Valley animals -- the California red-legged frog -- as the official State Amphibian! Since getting an autograph is out of the question, we thought we’d offer you a reintroduction to our famous resident instead.

The California red-legged frog is the largest native frog in the state and was first made famous in Mark Twain’s The Celebrated Jumping Frog of Calaveras County. According to the National Wildlife Federation, true to its name, they have reddish coloring on the underside of their legs and belly. They dine on anything they can catch and fit into their mouths. Mostly insects, but the occasional amphibian or small mammal might also become dinner. Speaking of dinner, California red-legged frogs were once a popular dinner cuisine during the Gold Rush era.

Contra Costa and Alameda Counties contain the majority of known observations of California red-legged frogs in the San Francisco Bay Area (U.S. Fish and Wildlife Service 2002). Today, their existence is threatened due to loss of habitat, particularly near urban communities and development. Thankfully, the 36,000 acres of Southern Alameda Creek Watershed lands owned by the San Francisco Public Utilities Commission has been protected and is a haven for our famous residents.

Our primary goal as watershed stewards is to protect existing populations, control non-native predators, and protect habitat for the red-legged frogs. As we make progress on our Water System Improvement Program in Sunol Valley, our Environmental Compliance teams work side by side with construction contractors to ensure our newly-designated Official State Amphibian is safe from harm.

Photos courtesy of Bill Stagnaro, Environmental Inspector
with the Calaveras Dam Replacement Project

We are halfway there!

The Calaveras Dam Replacement Project team reached an important milestone for the project this week. Crews have excavated more than 5.4 million cubic yards of earth and rock material at the project site. This material would fill approximately 1,656 Olympic-sized swimming pools. A total of 10 million cubic yards of material is required to be moved for the entire project--- 6.5 million cubic yards to be excavated and 3.5 million cubic yards which will go into the construction of the new dam.  In addition, 10,000 cubic yards of concrete to date has been poured and placed in the new intake tower and the new spillway structure. Much work still lies ahead, but definitely something to celebrate for our hard working crews from Dragados USA /Flatiron/Sukut Construction Joint Venture.

Crews gather to celebrate reaching over 5 million cubic yards of earthen materials excavated

Concete work at the new spillway underway

Sunol Glen School Students Celebrate Earth Week with Us!

What do ancient shark teeth, wasps nests, and owl pellets have in common? All were on display last week at the Sunol Glen School’s Earth Day Science celebration last week.  We were lucky enough to have been invited to participate, along with other local groups and leaders.  The kids, grades Kindergarten through eighth grade, learned about the importance of building a seismically upgraded replacement dam at the Calaveras Reservoir. Our project Geologist Bradley Erskine showed some fascinating fossils found at the Calaveras site during construction. The biggest hit with the students by far was a prehistoric shark tooth possibly from a Megladon, dating at approximately 20 million years old.  We had a great time answering questions about how water gets to your tap and the importance of the Water System Improvement Program to future generations.

Having met the leaders of tomorrow at Sunol Glen School, we know the future is in good hands! Sunol Glen Schools students proved themselves to be inquisitive and curious scientists at Earth Day on May 2^nd. 

Geologist Bradley Erskine and Natural Resources staffer Amy Dawson share fossil finds from Calaveras Dam to the Sunol Glen School students

Sample fossils of prehistoric shark teeth dating over 20 million years old

Whales in the Sunol Valley?

Since construction began at the Calaveras Dam, team paleontologists have had some remarkable finds from ancient shark teeth to marine mammal vertebrae all collected during the excavation of over 4 million cubic yards of earth over the sediments that were once an ancient sea floor.  

Just this week, project paleontologists found a portion of an ancient whale skull in the slope above the spillway excavation of the new dam. The skull is almost a yard long and relatively intact, except for a small portion of the right rear section which is missing. Our paleontologists are still researching the find but initially assess the fossil to belong to a Mysticete (or baleen) whale, from the family of Humpback, Grey or Blue whales that live in the oceans today and forage on plankton. This fossil was discovered in the temblor sandstone formation which makes it over 20 million years old.

The project takes important steps to salvage these paleontological finds for educational purposes. The critical construction work to build a replacement dam has not been affected and continues, while we discover amazing fossils to add to the rich history of this valley.

Paleontologists Bruce Hanson and Jim Walker work on uncovering fossils at Calaveras Dam. Photo credit: Robin Scheswohl

In November 2013, a collection of bones including vertebra from a marine mammal were discovered on the lower portion of the Spillway.  It appears to show a complete cross section of the body, neural arch and measures 15 x 7 centimeters. Some of the other bones appear to be ribs. None of the specimens found interfered with construction activities and the specimen still remains in the rock.

Calaveras Dam Project Continues to Dig Away

Today the Calaveras Dam workers celebrated yet another milestone since construction began in August 2011.  Over 3 million cubic yards of soils and rock have been excavated to make room for the replacement dam.  The team enjoyed lunch on top of one of the disposal sites, where they have moved and compacted nearly 20% of the 3 million cubic yards of materials. 

Imagine the weight of 96 fully loaded Titanic ships--- this is the approximate equivalent weight of the 3 million cubic yards of soils and rock that have been excavated and moved to disposal sites around the project. 

By the end of the project, the Calaveras Dam Replacement Project will have moved more than 9 million cubic yards of soils and rock.  About 3.5 million cubic yards of the materials will be used in the construction of the new dam, while the remainder will be disposed of onsite.  As we celebrate today, we still have a lot of heavy moving to look forward to!

Calaveras Dam workers are acknowledged by Earthwork Superintendent Sam Aiello for moving over 3 Million Cubic Yards

View of the Calaveras Dam foundation today
where major excavation has taken place to make room
for the future replacement dam

Series #2 Do you Know Your Tap Water? – Local Waters

Second in our series of ‘Do you know your tap water’, begs the question, OK, 85% from Hetch Hetchy, straight through the Sunol Valley to our customers… but what about the rest?

 
The rest of the water supply comes from local reservoirs. In the Sunol Valley that includes two: Calaveras and San Antonio Reservoirs. Calaveras, when full, is our system’s second largest drinking water reservoir, second only to Hetch Hetchy Reservoir. It also stores only local watershed waters from the Arroyo Hondo and Alameda Creek. San Antonio Reservoir, on the other hand, stores water from San Antonio Creek, and we can also store Hetch Hetchy water there as well.
 

Calaveras Reservoir, shown here prior to the start of construction of the Replacement Calaveras Dam, stores local water only.

 San Antonio Reservoir Stores both Local Watershed Waters and Hetch Hetch Hetchy Water

We must filter the water from these local reservoirs at our Sunol Valley Water Treatment Plant before we send it to our customers.

Some facts about local dams and reservoirs that you may not know:

• The dam at San Antonio Reservoir is called Turner Dam, after former SFPUC General Manager, James H. Turner.

Turner Dam

• When originally constructed in 1925, Calaveras Dam was the largest earth-fill dam in the world.

Existing Calaveras Dam. The New dam is being constructed directly downstream of the existing one. The site looks very different today!

 

• Both reservoirs support habitat for many rare and endangered species. Each reservoir also has a nesting pair of bald eagles. Learn more about them here.

Catch up on the Do you know your Tap Water series.

See you around Sunol Valley!