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McKnight, K.; Braud, A.; Dusterhoff, S.; Grenier, L.; Shaw, S.; Lowe, J.; Foley, M.; McKee, L. 2023. Conceptual Understanding of Fine Sediment Transport in San Francisco Bay. SFEI Contribution No. 1114. San Francisco Estuary Institute: Richmond, CA.

Sediment is a lifeblood of San Francisco Bay (Bay). It serves three key functions: (1) create and maintain tidal marshes and mudflats, (2) transport nutrients and contaminants, and (3) reduce impacts from excessive human-derived nutrients in the Bay. Because of these important roles, we need a detailed understanding of sediment processes in the Bay.


This report offers a conceptual understanding of how fine-grained sediment (i.e. silt and finer, henceforth called fine sediment) moves around at different scales within the Bay, now and into the future, to synthesize current knowledge and identify critical knowledge gaps. This information can be used to support Bay sediment management efforts and help prioritize funding for research and monitoring. In particular, this conceptual understanding is designed to inform future San Francisco Bay Regional Monitoring Program (RMP) work under the guidance of the Sediment Workgroup of the RMP for Water Quality in San Francisco Bay, which brings together experts who have worked on many different components of the landscape, including watersheds and tributaries, marshes and mudflats, beaches, and the open Bay. This report describes sediment at two scales: a conceptual understanding of open-Bay sediment processes at the Bay and subembayment scale (Chapter 2); and a conceptual understanding of sediment processes at the baylands scale (Chapter 3). Chapter 4 summarizes the key knowledge gaps and provides recommendations for future studies.

 (46.2 MB)
S
McKee, L.; Peterson, D.; Braud, A.; Foley, M.; Dusterhoff, S.; Lowe, J.; King, A.; Davis, J. 2023. San Francisco Bay Sediment Modeling and Monitoring Workplan. SFEI Contribution No. 1100. San Francisco Estuary Institute: Richmond, CA.

This document was prepared with guidance gained through two RMP Sediment Workgroup workshops held in late 2022 and early 2023. Given the variety of participants involved, this Workplan encompasses interests beyond San Francisco Bay RMP funders. We thank the attendees for their contributions. 

In 2020, the Sediment Workgroup (SedWG) of the Regional Monitoring Program for Water Quality in San Francisco Bay (RMP) completed a Sediment Monitoring and Modeling Strategy (SMMS) which laid out a conceptual level series of data and information gaps and generally recommended the use of both empirical data collection and modeling tools to answer initial high priority management questions (McKee et al., 2020). At the time, the SMMS promoted the use of surrogates such as time-continuous turbidity measurements for cross-section flux modeling within the Bay without an understanding of existing Bay hydrodynamic models, their strengths, weaknesses, and potential uses for understanding coupled Bay-mudflat-marsh processes. Since then, the Wetland Regional Monitoring Program (WRMP, www.wrmp.org) has generally promoted the use of coupling monitoring and modeling techniques to inform wetlands sediment management decisions. In addition, he completion of the Sediment for Survival report (a RMPEPA funded collaboration) and the further development of sediment conceptual models has also advanced the need for a coupled dynamic modeling and monitoring program that has the capacity to explore more complex management questions (Dusterhoff et al., 2021; SFEI, 2023). Such a program will take time to develop, but will be more cost-efficient and adaptable and allow for more timely answers to pressing questions. 

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Plane, E.; Lowe, J. 2022. Adaptation Pathways: San Leandro Operational Landscape Unit. SFEI Contribution No. 1077. San Francisco Estuary Institute: Richmond, CA.
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Lowe, J.; Plane, E.; Gonzalez, J.; Salomon, M. 2021. Guidance for Restoration of Natural and Nature-Based Features in the Wetland-Upland Transition Zone. San Francisco Estuary Institute, California State Coastal Conservancy: Richmond, CA.
 (8.57 MB)
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Mckee, L.; Lowe, J.; Dusterhoff, S.; Foley, M.; Shaw, S. 2020. Sediment Monitoring and Modeling Strategy. Sediment Monitoring and Modeling Strategy. SFEI Contribution No. 1016. San Francisco Estuary Institute: Richmond, CA.
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McKnight, K.; Lowe, J.; Plane, E. 2020. Special Study on Bulk Density. SFEI Contribution No. 975. San Francisco Estuary Institute: Richmond, CA. p 43.

Sediment bulk density is the total mass of mineral and organic sediment within a defined volume. It is a key variable in many research questions pertaining to Bay sediment studies but one that is often poorly quantified and can be misinterpreted. The motivation for this report comes from a recommendation by Schoellhamer et al. (2018) to compile more accurate estimates of bulk density of Bay sediments to convert between volume and mass with a higher level of certainty. Through funding and guidance from the Bay Regional Monitoring Program Sediment Work Group, this report is a first step towards compiling the available data on sediment bulk densities across Bay habitats and along salinity gradients to provide better information for resource managers and others working on sediment-related issues. This report discusses the need to know the bulk density of Bay soils to convert between sediment mass and soil volume; clarifies general definitions and common points of confusion related to sediment bulk density; compiles primary sources of bulk density measurements, secondary sources of bulk density estimates, and standard engineering estimates of bulk density for different habitats in San Francisco Bay; and, provides a database where practitioners can track, analyze, and share bulk density measurements.
 

 (4.06 MB)
Beagle, J.; Lowe, J.; McKnight, K.; Safran, S. M.; Tam, L.; Szambelan, S. Jo. 2019. San Francisco Bay Shoreline Adaptation Atlas: Working with Nature to Plan for Sea Level Rise Using Operational Landscape Units. SFEI Contribution No. 915. SFEI & SPUR: Richmond, CA. p 255.

As the climate continues to change, San Francisco Bay shoreline communities will need to adapt in order to build social and ecological resilience to rising sea levels. Given the complex and varied nature of the Bay shore, a science-based framework is essential to identify effective adaptation strategies that are appropriate for their particular settings and that take advantage of natural processes. This report proposes such a framework—Operational Landscape Units for San Francisco Bay.

Printed copies available for purchase from Amazon.

 (259.64 MB) (84.6 MB) (20.93 MB)
S
Doehring, C.; Beagle, J.; Lowe, J.; Grossinger, R. M.; Salomon, M.; Kauhanen, P.; Nakata, S.; Askevold, R. A.; Bezalel, S. N. 2016. San Francisco Bay Shore Inventory: Mapping for Sea Level Rise Planning. SFEI Contribution No. 779. San Francisco Estuary Institute: Richmond, CA.

With rising sea levels and the increased likelihood of extreme weather events, it is important for regional agencies and local municipalities in the San Francisco Bay Area to have a clear understanding of the status, composition, condition, and elevation of our current Bay shore, including both natural features and built infrastructure.


The purpose of this Bay shore inventory is to create a comprehensive and consistent picture of today’s Bay shore features to inform regional planning. This dataset includes both structures engineered expressly for flood risk management (such as accredited levees) and features that affect flooding at the shore but are not designed or maintained for this purpose (such as berms, road embankments, and marshes). This mapping covers as much of the ‘real world’ influence on flooding and flood routing as possible, including the large number of non-accredited structures.
This information is needed to:

  1. identify areas vulnerable to flooding.
  2. identify adaptation constraints due to present Bay shore alignments; and
  3. suggest opportunities where beaches, wetlands, and floodplains can be maintained or restored and integrated into flood risk management strategies.

The primary focus of the project is therefore to inform regional planners and managers of Bay shore characteristics and vulnerabilities. The mapping presented here is neither to inform FEMA flood designation nor is it a replacement for site-specific analysis and design.


The mapping consists of two main elements:

  1. Mapping of Bay shore features (levees, berms, roads, railroads, embankments, etc.) which could affect flooding and flood routing.
  2. Attributing Bay shore features with additional information including elevations, armoring, ownership (when known), among others.

SFEI delineated and characterized the Bay shore inland to 3 meters (10ft) above mean higher high water (MHHW) to accommodate observed extreme water levels and the commonly used range of future sea level rise (SLR) scenarios. Elevated Bay shore features were mapped and classified as engineered levees, berms, embankments, transportation structures, wetlands, natural shoreline, channel openings, or water control structures. Mapped features were also attributed with elevation (vertical accuracy of <5cm reported in 30 meter (100ft) segments from LiDAR derived digital elevation models (DEMs), FEMA accreditation status, fortification (e.g., riprap, buttressing), frontage (e.g., whether a feature was fronted by a wetland or beach), ownership, and entity responsible for maintenance. Water control structures, ownership, and maintenance attributes were captured where data was available (not complete for entire dataset). The dataset was extensively reviewed and corrected by city, county, and natural resource agency staff in each county around the Bay. This report provides further description of the Bay shore inventory and methods used for developing the dataset. The result is a publicly accessible GIS spatial database.

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