Building Bridge #2 Removal


A key part of the project is the removal of the concrete bridge platform, known as Building Bridge 2 (BB2). BB2 is considered a historical obstruction of creek water flow, and its removal will lower the Base Flood Elevation to approximately 480 homes and reduce the amount of water leaving the creek channel that typically flows through San Anselmo Avenue causing damage to downtown commercial buildings. The project has generated considerable discussion in the Towns of San Anselmo and Ross, and the District has been working diligently with its regional partners and affected property owners to make the flood control improvements in a strategic and proven manner. Final analyses, review, and permitting for BB2 removal is currently underway.

Purpose and need

  • Building Bridge 2 (BB2) is a major creek obstruction and contributes to flooding.
  • 480 parcels will see a flood risk reduction benefit once it is removed.
  • Removal of BB2 will facilitate construction of San Anselmo’s Creekside Park.
  • The work will enhance creek channel capacity and improve fish habitat.
  • Mitigation measures will be implemented for affected parcels in conformance with FEMA, local Floodplain Ordinance and the Environmental Impact Report.

Timeline and status

  • Environmental Impact Report (EIR) Approved 2018
  • EIR Addendum  #1 completed Spring 2023 (FDS changes addressed)
  • EIR Addendum #2 completed late 2023* (BB2 changes addressed)
  • Meet with downstream property owners to discuss the findings of creek modeling and property surveys in December 2023
  • Provide a project update at a community meeting in San Anselmo in January 2024
  • Upcoming: Finalize plans, permits and bid package and select contractor
  • Upcoming: Remove Building Bridge 2 and conduct of creek improvements

An Environmental Impact Report (EIR) under CEQA was approved in 2018. An addendum was finalized in late 2023. This EIR addendum #2 will be presented to the Board of Supervisors on January 23, 2024. The final design, right-of-way and permitting phase is currently underway.

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