Evolving Shorelines

As the potential future re-route for the pathway is studied in more detail, One Tam partners – Marin County Parks and Golden Gate National Parks Conservancy – are seeking community feedback on design options for the Tam Junction connection. In addition to other community outreach, project partners will be on the pathway Monday, October 31, Tuesday, November 15, and Wednesday, November 16 from  10 a.m. to 1 p.m.  They will share the latest project materials, including renderings of potential trail connector concepts, and answer your questions. During this time, geotechnical consultants will also be at Bothin to explore subsurface conditions along the pathway and in other areas of the marsh. To date, community feedback indicates:

• restoration of native plant habitat is a top priority
• a safer, wider, more accessible, and better-connected pathway is critical
• any potential trail connections or trailhead should not contribute to traffic congestion
• a trailhead with restrooms, drinking fountain, and simple features would be a welcome addition

The Bothin Marsh Open Space Preserve faces unprecedented challenges related to flooding and sea level rise over the next century. One Tam partners, Marin County Parks and Golden Gate National Parks Conservancy, in collaboration through the Evolving Shorelines Project have developed adaptation plans for the Preserve to ensure that the rich habitats and public access trails throughout the site are resilient to future sea level rise using nature-based solutions that enhance the ecosystem and benefit the broader community. This report documents the adaptation planning and design process that would serve as the foundation for more detailed design development.

• Evolving Shorelines Adaptation Concept Report pdf

Project partners presented three draft concepts, and recommended "Ringing the Marsh" as the favored approach for preserving the marsh and protecting the pathway. Based on community feedback received via emails, virtual events, and an online survey, an overwhelming majority supported the concept Ring the South Marsh. Removing the trail from the marsh and re-aligning it to the perimeter of the Preserve will afford the greatest opportunity for enhancing the tidal marsh, and provides design elements that include physical separation from roads and the trail, maintaining an inviting visual experience of the marsh.View a short video explaining each concept: 

• Ring the Marsh recommended concept video
• Span the Marsh alternative concept video
• Raise Trail in Place alternative concept video

In 2021, One Tam received about 850 responses to an online community survey soliciting feedback about conceptual approaches to elevating the Mill Valley-Sausalito Multiuse Pathway and enhancing the resiliency of Bothin Marsh. Results were included in the Adaptation Concepts Report as Appendix 3.  

• Community Survey Results

The One Tam team released an online interactive story experience about Evolving Shorelines. It provides a fast track and engaging way to learn about the history of the marsh, how rising tides are affecting recreation and wildlife habitat, and the community collaboration to find solutions.

• Evolving Shorelines Interactive Story Experience

• Bothin Marsh Initial Planning Memo pdf

To celebrate these milestones with the community, the Evolving Shorelines team hosted a Zoom virtual happy hour on Thursday, July 16, at 5:00 p.m. 

The County of Marin Board of Supervisors approved moving forward with development of conceptual designs for the Bothin Marsh Sea Level Rise Adaptation Project, based on shared community vision and research to date. The Golden Gate National Parks Conservancy will collaborate with the Marin County Open Space District on developing and completing conceptual designs, as well as continuing community outreach.

• Recommendation to the Board pdf

This shared vision report for Bothin Marsh reflects community feedback from hundreds of people who turned out to kayak, hike, play, and learn about the impact of climate change and sea level rise on Bothin Marsh. It is the collaborative effort of a broad coalition working to envision the future of the marsh and this section of the Mill Valley/Sausalito Multiuse Pathway.

• Evolving Shorelines: Vision For the Future pdf

One Tam partners will be on the Mill Valley/Sausalito Pathway in Bothin Marsh, Monday 10/31 through Wednesday 11/2/2022, 10 a.m. to 1 p.m., to answer questions as geotechnical consultants conduct subsurface investigations that will help inform efforts to preserve the marsh and protect the pathway from the impact of sea level rise.

An on-site community workshop took place at Tam Junction, to gather feedback on future design options for a trail connection where a proposed realigned Mill Valley/Sausalito Multiuse Pathway and Bothin Marsh Preserve could meet the junction of Shoreline Highway and Almonte Boulevard.

The online Adaptation Concepts Survey solicited broad community input on the Conceptual Design Concepts developed for the Evolving Shorelines Project at Bothin Marsh. The survey was designed to be completed by a general audience, even those who were not familiar with the project. It included graphic representations of the project concepts with simplified descriptions of the key differences.  

At this online community gathering, One Tam partners – Marin County Parks and the Golden Gate National Parks Conservancy – presented three draft concepts for preserving Bothin Marsh and protecting the Mill Valley/Sausalito Multiuse Pathway. The draft concepts were informed by an evaluation of ecological and public access benefits, as well as community feedback. 

During a Zoom session on October 15, One Tam partners – Marin County Parks and the Golden Gate National Parks Conservancy – presented draft concepts for the enhancement of Bothin Marsh Preserve’s tidal marsh and possible options for re-routing the Mill Valley-Sausalito Pathway. Members of the public shared comments on the design options for adapting to sea level rise. Watch a video of the Zoom session.

At this informal virtual gathering, One Tam partners – Marin County Parks and the Golden Gate National Parks Conservancy –  shared key findings and important considerations with the Marin community for conceptual designs that took shape in summer 2020.

Members of the community took part in a guided kayak tour during an exceptionally high king tide, to preview the new normal for the rising sea level at Bothin Marsh, and to explore ideas for sea level rise adaptation.

Proof Lab Beer Garden in Mill Valley hosted a family-friendly, happy hour social for the community to share a drink, have a bite to eat, and learn about innovative adaptive approaches being explored to address the impact of sea level rise on Bothin Marsh and the Mill Valley/Sausalito Multiuse Pathway.

Visitors of all ages enjoyed a series of reading panels installed along the Mill Valley/Sausalito Multiuse Pathway, featuring A Stone Sat Still, a book by award-winning author and illustrator Brendan Wenzel. One Tam partners - Marin County Parks and the Golden Gate National Parks Conservancy - collaborated on the StoryWalk with local libraries and Chronicle Books. A series of events along the pathway and in local libraries took place to celebrate the StoryWalk installation.

• StoryWalk Reading, Mill Valley Library, October 3
• StoryWalk Reading, Marin City Library, October 5
• StoryWalk Reading, Bothin Marsh, October 5
• Story Walk Reading, Bothin Marsh, October 19

Visitors joined a guided kayak tour from Bayfront Park to Coyote Creek and back, to learn about the evolution and ecology of marshes in Richardson Bay. One Tam partners – Marin County Parks and the Golden Gate National Parks Conservancy –  discussed the challenges Bothin Marsh Preserve faces dues to climate change and sea level rise.

The much loved stretch of shoreline along Bothin Marsh Preserve provides recreation and natural beauty for visitors and residents in southern Marin. The marsh also provides habitat for unique plants and animals. The marsh is surrounded by residential and commercial development. With current sea level rise projections, this preserve will lose a significant amount of vital wetland habitat by 2030. The Mill Valley-Sausalito Multiuse Pathway will also be greatly affected by increased frequency and severity of flooding.

As One Tam partners, the Marin County Open Space District and the Golden Gate National Parks Conservancy are working with scientists to assess existing conditions and the potential future impacts from sea level rise caused by climate change. In collaboration with the Marin community, they are reviewing and developing sea-level rise adaptation designs to preserve the marsh and protect the pathway. 

• Foster ongoing an ongoing community conversation about how to preserve the marsh and protect the pathway.
• Share scientific observations about the threats of sea level rise to tidal marsh conservation.
• Develop a shared vision and collaborative designs for sea level rise adaptation.

• One Tam

To date, the Evolving Shorelines project has been funded primarily by Marin County Parks Measure A. The California State Coastal Conservancy, the Marin Community Foundation, and members of One Tam have also generously provided financial support.

• Watershed sciences report.
• Bothin Marsh Geomorphology, Ecology, And Conservation Options

• 2016–17: Project need identified.
• January 2018: Bothin Marsh Geomorphology, Ecology, and Conservation Options research report.
• Fall 2018: Evolving Shorelines events series.
• Winter 2018: Public visioning process begins.
• Summer 2019: Bothin Marsh vision document.
• 2021:Conceptual adaptation design and recommendations.
• 2022: Tam junction connection design concepts and recommendations.