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Central Bayside System Improvement Project (CBSIP)

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Upcoming Presentations

The CBSIP project team is going to be out and about in the community this summer presenting at local neighborhood associations and community groups. Check our calendar for days and locations.

CBSIP at a Glance


The Project Seeks to:

  • Improve seismic reliability by adding needed redundancy to the Channel Force Main and the overall Bayside Collections System

  • Improve water quality along the shores of the Bay by reducing the frequency and volume of combined sewer discharges

  • Improve stormwater management in the Channel and Islais Creek Watersheds

Proposed Features:

This project will develop potential options that include improvements to important infrastructure such as:

  • Gravity tunnels to convey sewage more reliably for treatment

  • Storage capacity to reduce the frequency of sewage discharges during wet weather

  • Refurbished Channel Pump Station to provide greater reliability

  • New lift station near the Southeast Plant to efficiently deliver the sewage to be treated
Image of Channel Pump Station

Channel Pump Station

The Central Bayside System Improvement Project (CBSIP) is a part of the Sewer System Improvement Program (SSIP), and is a critical element of the City’s efforts to upgrade the aging and seismically vulnerable combined sewer system on the Bayside.

As part of the Bayside Collections System, the Channel Force Main transports 64% of wastewater from homes and businesses on the Bayside to the Southeast Treatment Plant. This important piece of infrastructure is a weak link on the Bayside as it is vulnerable to seismic damage, and has suffered several failures since the 1989 Loma Prieta earthquake.

To address this need, the design team is investigating a potential tunnel to provide reliable and redundant gravity conveyance and storage of wastewater flows from the Channel Pump Station (located near AT&T Park) to the Southeast Treatment Plant. Channel Pump Station improvements and a new pump station near Islais Creek are also under consideration.

CBSIP Schedule 3.14.2017

Proposed Alignment Map 4.27.2017
Benefits of a Tunnel
  • Less disruption to vehicle and pedestrian traffic. 
  • Less noise along the alignment of the tunnel. Construction noise is reduced because it’s deep underground.
  • Less construction vibration. The excavation work is far underground and expected to be undetectable at the ground surface. It will be considerably less disruptive than work in a trench at street level.
  • Less seismic risk. During seismic activities soft soils move more than harder, soils or rock. These movements have the potential to damage or break infrastructure. At the depth of the tunnel the ground conditions are harder and the majority of the tunnel is in rock. This reduces the likelihood and/or magnitude of damage to the tunnel compared to a shallow pipe.

Get Involved

Want to learn more about the CBSIP? If you would like to request a presentation for your group, please email to request a presentation.

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Last updated: 5/2/2017 9:07:52 AM