Downstream Flood Mitigation Measures
Description
The Marin County Flood Control and Water Conservation District has performed computer modeling to help predict the behavior of the creek waters during serious storm events. The District’s technical analysis identifies the following associated with the potential removal of Building Bridge 2:
- Properties with a modeled rise in Base Flood Elevation
- Affected structures (e.g., buildings)
- Appropriate mitigation
The District has notified property owners with a modeled rise in Base Flood Elevation due to potential removal of BB2. This FEMA-required notice was sent as part of the process for submitting an application for a Conditional Letter of Map Revision (CLOMR), to be submitted in July 2025. The towns of Ross and San Anselmo have provided formal comments about a draft of the CLOMR application and the impact of the removal of BB2 and those comments were incorporated into the CLOMR application. The CLOMR application will be available on the District’s website once it is submitted.
The FEMA review of the application is expected to take a minimum of six months. During this time, District staff will conduct public outreach efforts to help the community understand how the CLOMR application was developed and provide additional information.
FEMA’s review will affect whether the project proceeds or not. It will include a review of proposed mitigation for structures identified as potentially impacted by an increase in modeled Base Flood Elevation. The District will notify property owners of potential impacts, as defined by FEMA, to building structures and necessary mitigation.
The response from FEMA is currently anticipated by the end of 2025; however, timelines may change due to the complex nature of the project.
Definitions of these various terms can be found in the project glossary.