Update on Silicon Valley Clean Water (SVCW) Pipeline Project Alternatives Involving Redwood Shores

As a result of public input on alternatives for Silicon Valley Clean Water’s (SVCW) proposed pipeline improvement project through Redwood Shores, coupled with lessons learned from the successful Bay Tunnel project from Menlo Park/East Palo Alto to Newark, SVCW is studying alternatives to improve the system and that could avoid most of the earlier identified disruption to the community.

The earlier alternatives assume the pipeline replacement would be from the San Carlos Pump Station near the San Carlos Airport and would require significant disruption to the surface along the route due to excavation. They include an in-street alignment up Redwood Shores Parkway, an in-levee alignment, an in-lagoon alignment, and an in-slough alignment.  The in-slough and

in-lagoon alignments have been determined to be impractical due to environmental impacts of the excavation in waterways.

SVCW Manager  Dan Child said that after listening to the community and meetings with the Army Corp of Engineers, Environmental Protection Agency, California Department of Fish & Wildlife, and the San Francisco Regional Water Quality Control Board, SVCW staff and consultants were directed to eliminate the in- slough and in-lagoon alternatives.  Child then requested a review of the alignments and other alternatives that had been previously eliminated or not considered in the earlier evaluation.

One alternative that has come to light is the potential of tunneling the line directly to the treatment plant.  Micro-tunneling had been considered earlier, but due to limitations on depth and the required intermediate shafts, may not be feasible.  The tunneling process is deeper and does not require the intermediate shafts.  This technology was eliminated in the very early stages of the process (prior to 2009) as there was little experience with this technology in similar soils in the Bay Area and previous high costs did not support its selection. 

Since that time, a successful tunneling project has occurred in the area. The Bay Tunnel project is a $286 million, earthquake-resistant water pipeline and the first tunnel to be built beneath the floor of the San Francisco Bay. The tunnel runs from Newark at a depth of up to 125 feet under the floor of the bay to the eastern edge of Menlo Park. Scheduled to be completed this fall, it is the first tunnel constructed under the bottom of the bay. BART's Transbay Tube was built on top of the bay's floor. The Bay Tunnel, which is about 90 percent complete, is to be part of the 176-mile Hetch Hetchy Regional Water System that pipes fresh water from reservoirs outside Yosemite National Park to San Francisco, serving 2.5 million people.

“We want to be careful about raising the profile of this alternative, but it is on the table,” Child said. “Initially consultants thought the tunneling alternative would be both technically and cost prohibitive, but lessons learned from the Bay Tunnel project make it an option we can now consider and evaluate.”

He emphasized that feasibility studies and environmental assessment are crucial in helping determine which of the alternatives is the most practical.  Feasibility studies on the alternatives are expected to take two to three months, followed by a California Environmental Quality (CEQA) environmental process, which could take from nine to 12 months to complete.  The CEQA process provides ample opportunity for public review and input

The replacement pipeline is part of SVCW’s overall Capital Improvement Program (CIP), adopted in 2008, to replace and upgrade aging infrastructure in order to ensure the reliable operation of the overall sanitary sewer system. The pipelines and pump stations will be designed to reliably convey wastewater to the treatment plant. Whichever construction technique and alignment is ultimately chosen, construction of the Redwood Shores portion of the pipeline is not likely to begin until early 2016 at the earliest.

For future updates, visit our website at http://www.svcw.org/  If you would like to receive updates, please send us your email to siliconvalleycleanwater@svcwnews.com or duanesandul@gmail.com