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.

Construction Advisory: New Irvington Tunnel

To our Irvington Portal neighbors:
We wanted to inform you of some very important construction activity affecting your neighborhood.

Project Update
The New Irvington Tunnel is now in service delivering water to our 2.6 million Bay Area customers.  With the new tunnel in service, we were able to take the old Irvington tunnel out of service for inspection and repairs. Both tunnels will remain in service during normal operations. The construction team has begun restoration of the above ground facilities. The contractor has demobilized and restored the southern portion of the property. The contractor has removed the sound barriers (shown in yellow) on the south section of the site.  (See map)

Starting as early as June 15, 2015, the contractor will begin the process of removing the remainder of the sound barriers at the Irvington Portal project site.  The sound barriers will be removed at the locations shown on the map in blue. The sound wall removal work is estimated to be completed by early July 2015.

Map of sound walls to be removed

What to Expect:

-       The work involves removal of the panels and digging around the concrete foundation. Workers then remove the foundation and cut or pull the steel beams out. The excavated area would then be backfilled.

-       Noise associated with sound barrier removal will include the operation of heavy equipment, back up alarms, and concrete breakup. The soil backfill will also require compaction where the steel beams and foundations have been removed.

 

Removal Hours:
Sound barrier removal will only take place Monday through Friday from 7:00 AM to 7:00 PM.  We will continue to monitor noise and vibration in this area to ensure full compliance with strict noise and vibration standards set forth in the project’s Environmental Impact Report.

What’s Next

-      Installation and burial of permanent portal facilities and security improvements will be completed by the end of June 2015.

-      Once the sound walls are removed, topsoil will be trucked in and spread throughout the disturbed areas of the site.

-      Site restoration for the remainder of the site will be throughout the summer and be completed by early Fall 2015.  This includes paving, fencing and hydro-mulching of the disturbed areas. 

-      An iron wrought fence will be installed at the Mission Road entrance sometime in Fall 2015.

-      Full project completion for the New Irvington Tunnel is currently scheduled for Fall 2015.

Questions?
We sincerely appreciate your patience and cooperation.  Please call our 24-Hour Answer Line at 866-973-1476 if you have questions or comments or email mle@sfwater.org

 

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

 

 

It’s National Safety Week!

Every year, more than 80,000 workers suffer an injury on construction job sites across the U.S.  Any one incident is one too many. Life is too precious to not make safety the number one focus in the U.S. construction industry. This week from May 3^rd through May 9^th, construction firms nationwide have joined forces to inspire everyone in the industry to be leaders in safety.

Here at the Calaveras Dam Replacement Project, the project team had a lot to celebrate. Over 150,000 work hours have been reached with zero safety recordable incidents since October 2014. Given the size of the machinery we are using on the site, the complexity of the work, and the sheer number of activities on site each day, this is truly remarkable. Safety is important to our teams as we build the replacement Calaveras Dam. Every morning this week, the teams had a special safety topic to remind workers the importance of construction safety. The workers got together for a celebratory barbecue to pat ourselves on the back for being vigilant, reminding us to take care of ourselves and each other as we continue with construction.

We are proud of our team and they are on to their next goal to reach another safety milestone!

Calaveras Dam workers listen to the safety milestones reached at the project
at a celebratory lunch provided by the contractor

 

Dragados/Flatiron/Sukut Construction Manager Mike Mullich
congratulates heavy equipment Operator Gary Gatehouse on our safety milestone

 

What do water pipes, water conservation, fossils and dams have in common?

They were all part of the cool topics shared with the Sunol Glen School students last week at their annual Earth/Science Day festivities.  We at the San Francisco Public Utilities Commission were honored to be a guest again this year to share information about the Hetch Hetchy Regional Water System.

We are always surprised and amazed at the enthusiasm and smarts of these first through eighth graders. Did you know that the California State Flower is the Golden Poppy? They did. Did you know that you could save your shower water in a bucket and water your plants with it? They did. Did you know the Sunol Valley was once a coastline? Many of them knew that, too. They enjoyed looking at the 20 million year old fossils unearthed during the construction of the Calaveras Dam Replacement Project, including a prehistoric shark tooth, seashells and rocks from the site.

We had a blast at Sunol Glen School and can’t wait to be back!

Now, for bonus points, what is the California State Fish? (Sunol Glen students, no telling!)

Water Heroes Unite at the East Bay Regional Park District’s Wildflower Festival

The crew at the San Francisco Public Utilities Commission (SFPUC) had a blast last Saturday at the East Bay Regional Park District’s Sunol Wildflower Festival at the Sunol Regional Wilderness.  New friends and old dropped by our booth to catch up on the ongoing efforts to upgrade the Hetch Hetchy Regional Water System in the Sunol Valley, such as the Calaveras Dam Replacement Project and the New Irvington Tunnel.

Water conservation and the drought were top of mind to all who stopped by. The booth’s youngest visitors also made super hero masks to become Water Saving Superheroes. We were blown away by how much these little guys and their parents knew about how to save water. Check out our event photos, below!

Our WSIP trivia prize wheel

Our water conservation crafts table

Check out this water-saving superhero!

Keep up the good work, water heroes! We are all in this drought together. Learn more about Sunol Valley Water System Improvement Progam projects at sfwater.org/sunolvalley.

See you around the Valley!