Friday, June 20, 2014

The WSIP Turns 10!

This year the Water System Improvement Program (WSIP) turns 10! One of the largest infrastructure projects in the nation, the WSIP is repairing, replacing and upgrading our aging water infrastructure to ensure we can deliver water to customers following an earthquake. We’ve gotten a little nostalgic about how far we’ve come in the last 10 years, and we would like to share this video with you.

Now 80 percent complete, the WSIP has already provided increased reliability to the water supply for customers as a result of the completion of some of the program’s major projects. The program has created over 6 million construction craft hours to date, employing more than 11,000 workers since 2007. Nearly half of those workers live in our four-county service area.

An Ode to the Calaveras Spillways, old and new

Workers repair original Calaveras Dam spillway in 1939

What is a spillway?
A spillway is an important safety feature on a dam that impounds water behind it to prevent the dam from overtopping and suffering damage during a flood. The spillway is often an open chute or channel that allows water when it reaches a high level in the reservoir to safely bypass the dam and flow downstream without causing any damage to the dam.

History of the Calaveras Dam Spillway

The original spillway on Calaveras Dam was completed in 1925. In 1939, workers had to repair the original spillway after damage was caused by a flood occurred in the Winter of 1937-1938.

Spillway Work Today

Back in March work began on the new spillway. We have made much progress since then to construct the spillway, which will be 1550 feet long. Approximately 40,000 cubic yards of concrete, equivalent to one football field filled six feet deep, is being used to build the structure. All of the concrete is being supplied by our on-site concrete batch plant.
Because of its crucial function in dam safety, it’s important to make sure that the spillway structure stays intact during an earthquake on the nearby Calaveras Fault. So we are drilling anchors, a solid steel rod, about 25 feet into the rock around the spillway to provide support and prevent damage to the structure during any seismic activity.  We are installing 1,825 anchors, that’s a lot of anchors!  The spillway is expected to be completed in mid-2015.

View of the left wall of the new Calaveras Dam spillway. The purple anchor in the foreground will be encased in the concrete slab (foundation) being formed here. The exposed ends of the wall anchors will be encased in a block of concrete as part of the spillway wall.

Aerial view of new spillway taking shape at the left abutment.
Red arrows indicate the top of the spillway.

Tuesday, June 10, 2014

Neighbors Catch up on the New Irvington Tunnel

Thank you to all of the community members who dropped by the New Irvington Tunnel Open House at the Mission Coffee House last week!  It was really great to see you.  For those of you who weren’t able to attend, here are the highlights as shared by the project team.
  • The New Irvington Tunnel Project is currently 95% complete.
  • The steel liner of the tunnel has been installed. We are welding and grouting the space between the tunnel lining and the outside of the tunnel to seal the tunnel off from groundwater intrusion.
  • The 3.5 mile New Irvington Tunnel will be brought into service sometime this fall 2014, allowing us to take the old tunnel out of service for inspection and possible repairs.
  •  Overall project completion is anticipated in fall 2015, soon after we complete site restoration of all of the above ground work.
  • The New Irvington Tunnel runs parallel to the existing tunnel (which was built in 1932)  between the Sunol Valley south of Highway I-680 and Fremont, California. It provides a seismically designed connection between Sierra Nevada and Alameda Watershed water supplies and 2.6 million Bay Area customers.
We will be back out with another open house in a about three months, so we hope you can make the next one. 
Neighbors have some tunnel talk at the New Irvington Tunnel Open House