Monday, October 24, 2011

Holy Cow! It’s Cattle Fencing.

If you ever had the opportunity to drive along Calaveras Road in Alameda County, you may have noticed a number of cows and calves along the hillside. In preparation for work on the Calaveras Dam Replacement Project, the project included the installation of additional cattle fencing to harbor and protect the cattle, which was completed in September 2011. In addition to cattle, the fencing protects other wildlife species from entering the construction site.


The Calaveras Dam Replacement Project, as well as other Water System Improvement projects in Sunol Valley, work side by side with these animals. These lands have been grazed by cattle for over a century. The SFPUC is on the leading edge of research into the benefits of responsible cattle grazing to watershed lands.


Properly managed livestock grazing has many benefits: reduces fire hazards by controlling the amount and distribution of grasses, benefits plant life by controlling non-native species growth, benefits wildlife by diversifying various species’ habitats while providing natural vegetation management.


For more info, contact us at our 24 hour answer line at (866) 973-1476 or email mle@sfwater.org

Friday, October 21, 2011

The Modern Day Canary: A Handheld Gas Detector

When the existing Irvington Tunnel was constructed miners might have used canaries to warn them of dangerous gases.


Meet the modern day canary. Like its feathered forbearer it alerts miners to presence of dangerous gasses underground. However, instead of wings and a beak, today’s canary- a handheld gas detector is encased in rugged rubberized armor and has ultra-bright LED alarms.


Handheld gas detectors are operated by a certified gas tester that accompanies each tunnel crew underground. The modern canary tests for oxygen content, hydrogen sulfide, carbon monoxide, carbon dioxide, nitrogen dioxide and explosive gases like methane. If certain levels explosive or hazardous gases are detected then LED lights flash and an audible alarm is sounded.

Gas levels dictate the strict safety procedures the crews follow. If gas levels are detected at 10% LEL or Lower Explosive Limit, then steps are taken to increase ventilation in the tunnel. Work can continue but must be performed with extra care. If gas levels reach 20% LEL then electric power is shutdown and miners must evacuate the tunnel.

Safety comes first inside of the New Irvington Tunnel. Miners take great care to check their surroundings when operating hundreds of feet below ground. For the risks they can’t see with the naked eye, the modern canary- a handheld gas detector has their back.

Monday, October 17, 2011

Calaveras Critters: Nurturing Nature at the Calaveras Dam

Major construction is complicated in any setting, as well as in watershed lands that harbor rare and endangered species, it is doubly so. Members of the Calaveras Dam Replacement Project Environmental Team are on site every minute of every day to ensure that our construction activities do not harm these precious plants and animals. Case in point – last week monitors on site found a juvenile threatened Alameda Whipsnake. It took four specially-trained personnel a long time to carefully capture and move the animal to a safe pre-determined release location far away from construction.


The SFPUC owns and manages approximately 36,000 acres of the Alameda Creek Watershed. The Watershed contains grassland and oak woodland communities that support a wide range of animals including Special Status Species.

Environmental Compliance Manager Cullen Wilkerson, a U.S. Fish and Wildlife Service and California Dept. of Fish & Game approved Biologist, handled the Alameda Whipsnake and relocated it safely to a new habitat nearby.


Alameda Whipsnake (Masticophis lateralis euryxanthus)
Federal Status: Threatened
State Status: Threatened

Description: A slender, fast-moving snake 3 to 4 feet in length with a slender neck, broad head and large eyes. Back is colored sooty black with a distinct yellow-orange stripe down each side.

Habitat: An active daytime predator, adult snakes peak in surface activity during the spring mating season with a smaller peak during late summer and early fall. Rock outcrops are important for retreat opportunities. Generally retreats in November into a small mammal burrow or other shelter, and emerges in March.

For more info, contact us at our 24 hour answer line at (866) 973-1476 or email mle@sfwater.org

Friday, October 14, 2011

Grinding Forward


Tunnel crews are grinding their way forward on the New Irvington Tunnel Project. Miners excavate in four directions using road headers (tracked tunneling machines) and controlled detonations when necessary to dig out the 18,600-foot (3.5 mile) tunnel.

Over 2000 feet of tunnel has been excavated with approximately 16,600 feet remaining. Last Friday tunnel crews dug out a new daily record of 50 feet for the project. As the crews become more familiar with and how to deal with the variable ground conditions, the mining production has steadily improved each week. Tunnel excavation is estimated for completion in mid-2013 with project completion in mid-2014. Check out www.sfwater.org/nit for weekly updates of tunnel progress.

The New Irvington Tunnel will provide a seismically-designed connection between water supplies from the Sierra Nevada Mountains and the Alameda Watershed to Bay Area water distribution systems. The new tunnel will lay parallel to the existing tunnel between the Sunol Valley south of Highway I-680 and Fremont, California.

Monday, October 10, 2011

Calaveras Dam Replacement Project Update



Road Closure Update
We have received permission from Alameda County to temporarily close Calaveras Road south of Geary to the Alameda/ Santa Clara County Line for two separate periods
- The first two-month road closure, initially planned for fall 2011 is now planned for early 2012.
- The second road closure is expected in late 2012/early 2013 for a period of 18 months.
- Calaveras Road will remain open on weekends, but will be closed Monday-Friday during these periods.
- Access to the Sunol Wilderness will remain open
from the north at all times and from both the north and south on weekends.
- Emergency vehicles will have access to the road at all times.
- The roads will be swept clean of debris prior to weekend openings.

Calaveras Dam – Controlled Detonation
The contractor will be using controlled detonation to produce the hard rock required for construction of the dam. To excavate the foundation of the dam, we may encounter rock that is too hard for our machinery, in which case we may also use controlled detonation. You may hear the detonation or feel minor vibrations from the activity. If you would like to receive an email notification beforehand, please contact Maria Le at mle@sfwater.org.

If you have any additional questions or concerns, call our 24-hour answer line at (866) 973-1476.

Wednesday, October 5, 2011

Share the Road: One Road, Many Users


Construction activity is now underway for the Calaveras Dam Replacement Project. Safety is our #1 priority.

Please be cautious of the large trucks and increased traffic along Calaveras Road, specifically south of I-680. Due to the narrow road conditions, please remember to ride and drive safely through the blind curves. The speed limit is 25 mph in construction zones.

We understand this is a popular route for bicycling enthusiasts and we hope we can all share the road safely. Please note that Calaveras Road will be closed for 2 periods. The first closure has been postponed until early 2012. Please check back here for updated road closure info.

Feel free to contact us at any time at 24 hour answer line at (866) 973-1476, or mle@sfwater.org. Thank you for sharing the road!

Tuesday, October 4, 2011

Then and Now

The existing Irvington Tunnel was built in the early 20th century and can no longer be taken out of service for repairs or maintenance without impacting the water supply to customers. The New Irvington Tunnel is designed to provide a seismically-strengthened or reinforced connection between water supplies from the Alameda Watershed to Bay Area customers.



The Alameda West Portal in August of 1929. Miners excavated the existing Irvington Tunnel between 1928 and 1931 primarily using drill and blast techniques.


The Alameda West Portal in April of 2011. Miners are using road headers (conventional tunneling machines) and limited controlled detonations to excavate the tunnel. The project is expected to be completed by mid-2014.