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Watershed Sciences' analysis and comments on the Sausalito GP Update and DEIR

As the result of lengthy discussions with residents, business owners, and community members who live and work in Saualito’s Marinship, Community Venture Partners, Inc. retained Watershed Sciences’ principal, Laurel Collins, to undertake a review of Sausalito Draft Environmental Impact Report (DEIR) of the 2040 General Plan Draft Update (2040 GP).

Ms. Collin’s meticulous, technical review focuses on environmental impacts that presently put people, buildings and infrastructure at risk with increasing probability of future risk and adverse environmental impacts of proposed, future development when the type, feasibility, and impact of necessary mitigation actions are not sufficiently identified in a city’s DEIR. Ms. Collins is an acknowledged expert in her field.

Based on her review, she has identified salient issues of concern, regarding the DEIR. Her conclusions are that the analysis of impacts of the proposed increased development in Marinship have not been adequately evaluated in the DEIR. As a result, potential adverse significant impacts are likely, because

1) Future conditions within the planning horizon and beyond and how geomorphic processes of the altered environment will affect infrastructure, buildings, and safety of people in Marinship has not been addressed;

2) Evaluation of certain critical impacts is missing;

3) Assessment of the mitigation strategies that will be necessary to reduce potential hazards, such as sea level rise (SLR), creek and storm drainage, and subsidence, is missing or inadequate;

4) Assessment of the environmental impacts of the potential mitigation actions is missing for the increased development; and

5) An adequate and sustainable SLR adaptation vision for Marinship is missing, about what is environmentally practicable, economically feasible, and reasonably safe for continuing to maintain the existing artificial landscape that is facing mounting geologic, hydrologic, environmental, public safety, and structural hazards.

Her review is broken down into key topics that address major issues itemized below:

A. Under 2020 conditions, Marinship is an artificial landscape that has significant and numerous environmental risks and hazards. Their potential adverse impacts and interactions need to be fully characterized and envisioned to plan for the scope of actions needed to maintain the existing development to make it safe for people to live and work before increased development can be accommodated as proposed in the DIER. Key environmental conditions, potential hazards, and necessary mitigation impacts for existing and future conditions are incomplete or missing in the DEIR.

B. Combined SLR, subsidence, and elevated groundwater conditions in Marinship and elsewhere are plainly foreseeable between now and 2040. These components need to be merged with projections of future stream flooding maps to realistically evaluate environmental impacts of future developments along Richardson Bay shoreline. This can and should be documented in the DEIR.

C. Future increased development will require continued and increased large-scale mitigation to make it a viable environment for existing and proposed development. SLR accommodation, subsidence remediation, and other necessary infrastructure repair/relocation projects are therefore also plainly foreseeable but have not been evaluated in the DEIR.

D. Even if the precise details of necessary accommodation projects may not be known at this point, certainly the DEIR can identify the category or types of projects that will likely be required (sea walls, levees, dredge/fill etc.), and also the most likely locations of the projects based on projected flood areas. The DEIR does not adequately assess which mitigations will be used to minimize negative impacts in Marinship.

E. Since this is a plan level EIR that defers project-level impact analysis to the future as specific development proposals are brought forward, the same plan level approach should be taken with regard to future SLR / subsidence accommodation projects, which again are necessary and foreseeable.

F. Whether projects that will be required to protect the City under 2040 buildout scenario are financially feasible, whether they will be effective, and whether their own direct or indirect environmental impacts will be significant (e.g., sea wall displaces tides to other locations in the San Francisco Estuary).

G. In addition, the DEIR has inconsistencies and incompatibilities between different 2040 GP policies with environmental purposes/impacts (e.g. one policy calls for maintaining natural stream channels, which could undermine other policies of minimizing flood risks).

Each of these major topics are further broken down into subsections that provide supporting discussion, examples, and citations from the DEIR or other reports listed in the review and comment letter.

The Watershed Sciences' analysis and comment letter is quite lengthy and based on complex science. However, it is well worth reading for anyone who has a serious interest in the future of the Marinship and in understanding the geological, hydrological, flooding, earthquake, toxicity, sea level rise, and other such challenges that presently exist and must be carefully considered by the City of Sausalito, prior to adopting the proposed Sausalito General Plan Update and DEIR.


Ms. Collins has been a geomorphologist since 1981, specializing in riverine (fluvial), tidal wetland and hillslope geomorphic processes, hydrology, landslide analysis, sediment budgeting, geomorphic effects of wildfire, and anthropogenic influences on geomorphic landscape change. Her opinion on environmental issues is based on decades of experience and scientific analyses of projects concerning geomorphic processes and land use impacts throughout Marin County, other counties throughout the Bay Area and California, and various western states in the US.

During her 40 year career, she had worked on stream and geomorphology related projects for Marin County Public Works, Flood Control and Water Conservation District, and Open Space District, Alameda County Flood Control and Water Conservation, East Bay Regional Park District, Contra Costa Clean Water Program, US Geological Survey, US Forest Service, California Department of Forestry, US National Park Service at Point Reyes National Seashore, Pacific Northwest Forest and USDA Range Experiment Station,San Francisco Bay Regional Water Quality Control Board, University of California at Berkeley, Lawrence Berkeley Laboratory, San Francisco Estuary Institute, and the US Department of Justice.


Bob Silvestri is a Mill Valley resident and the founder and president of Community Venture Partners, a 501(c)(3) nonprofit community organization funded only by individuals in Marin and the San Francisco Bay Area. Please consider DONATING TO CVP to enable us to continue to work on behalf of Marin residents.