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Every vehicle on the road sheds tiny particles from its rubber tires into the environment. Tire wear is one of the top sources of microplastic releases to the environment. Tire wear also disperses tire-related chemicals into the environment. SFEI studies supported by the Regional Monitoring Program for Water Quality in San Francisco Bay (RMP) and others have found tire wear particles and tire-related chemicals in San Francisco Bay and its small tributaries, which drain the Bay watershed’s local urban areas. The RMP has developed a short-term multi-year plan of potential special studies (“Tires Strategy”) that responds to recent data revealing the magnitude of tire particle and chemical emissions and their potential toxicity to aquatic organisms.

This article is available upon request. Please message [email protected] for the materials.

The Preparing for the Storm project, led by Zone 7 Water Agency (Zone 7) and funded by the US Environmental Protection Agency (EPA) Water Quality Improvement Fund, aims to develop science-based plans, strengthen existing and new partnerships, and pilot new methodologies for tackling these issues surrounding coarse sediment. As a task within this larger project, this report describes four projects in the East Bay that serve as case studies for beneficial reuse of sediment. Each example highlights a project with sediment that could be reused (in lieu of landfilling) or a project that needs additional sediment and could benefit from deliveries of sediment that normally would not have been beneficially reused.

While the antimicrobial ingredient triclosan has been widely monitored in the environment, much less is known about the occurrence and toxicity of its major transformation product, methyl triclosan. An improved method was developed and validated to effectively extract and quantify both contaminants in fish tissue and was used to characterize concentrations in small prey fish in areas of San Francisco Bay where exposure to triclosan via municipal wastewater discharges was expected to be highest. Concentrations of triclosan (0.44–57 ng/g ww, median 1.9 ng/g ww) and methyl triclosan (1.1–200 ng/g ww, median 36 ng/g ww) in fish tissue decreased linearly with concentrations of nitrate in site water, used as indicators of wastewater influence. The total concentrations of triclosan and methyl triclosan measured in prey fish were below available toxicity thresholds for triclosan, but there are few ecotoxicological studies to evaluate impacts of methyl triclosan. Methyl triclosan represented up to 96% of the total concentrations observed. These results emphasize the importance of monitoring contaminant transformation products, which can be present at higher levels than the parent compound.

Historic and current regional management of watersheds and channels for water supply and flood control across the San Francisco Bay Area has cut off much of the coarse sediment that was historically delivered to the Bay. Here we define coarse sediment as having grain sizes larger than 0.0625 mm, which includes sand, gravel and even cobble, as opposed to fine sediment that includes clay, mud and silt. Future projections indicate that sediment supply will not meet the demand from extant and restored tidal marshes to keep up with sea level rise.

The US EPA Water Quality Improvement Fund Preparing for the Storm grant has funded the Zone 7 Water Agency, the San Francisco Estuary Institute and the San Francisco Bay Joint Venture to support the future development of a successful regional coarse sediment reuse strategy. Development of such a strategy requires an understanding of logistical and regulatory hurdles and identification of key strategies for breaking down barriers. One potential solution for meeting the sediment demand along the Bay margin is to utilize coarse sediment that is removed from flood control channels by public agencies. To-date, very little of this sediment that is removed is beneficially reused for restoration along the Bay shoreline. The current economic and regulatory framework around sediment removal presents many challenges, barriers and lack of incentives for agencies to reuse their sediment.

This document represents a step forward towards beneficially reusing coarse flood control channel sediment by outlining reuse challenges, and identifying incentives for participation and potential solutions.

Effective implementation of urban greening strategies is needed to address legacies of landscape change and environmental degradation, ongoing development pressures, and the urgency of the climate crisis. With limited space and resources, these challenges will not be met through single-issue or individual-sector management and planning. Increasingly, local governments, regulatory agencies, and other urban planning organizations in the San Francisco Bay Area are expanding upon the holistic, portfolio-based, and multi-benefit approaches.

This effort, presented in the Trees and Hydrology in Urban Landscapes report, seeks to build links between stormwater management and urban ecological improvements by evaluating how complementary urban greening activities, including green stormwater infrastructure (GSI) and urban tree canopy, can be integrated and improved to reduce runoff and contaminant loads in stormwater systems. This work expands the capacity for evaluating engineered GSI and non-engineered urban greening within a modeling and analysis framework, with a primary focus on evaluating the hydrologic benefit of urban trees. Insights can inform stormwater management policy and planning. 

Microplastic contamination in the marine environment is a global issue. Across the world, policies at the national and international level are needed to facilitate the scale of change needed to tackle this significant problem. However, sources and patterns of plastic contamination vary around the world, and the most pressing actions differ from one location to another. Therefore, local policies are a critical part of the solution; recognizing local sources will enable mitigations with measurable impacts. Here, we highlight how investigating the contamination comprehensively in one location can inform relevant mitigation strategies that can be transferred globally. We examine the San Francisco Bay in California, USA—the largest estuary on the West Coast of the Americas, and home to over 7 million people. The local contamination of microplastics in surface water, sediments, and fish from this urban bay is reportedly higher than many places studied to date.(1) This example demonstrates the value of local monitoring in identifying sources, informing local mitigation strategies and developing an array of solutions to stem the multifaceted tide of plastic pollution entering our global oceans.

In a previous report titled “A Delta Renewed” we offered a collection of guidelines for science-based ecological restoration in the Sacramento-San Joaquin Delta that emphasized restoring or emulating natural processes, anticipating future changes associated with climate change, establishing appropriate configurations of habitat types at the landscape scale, and utilizing a variety multi-benefit management strategies. In this talk, we present on our recent work to support regional restoration planning efforts by developing a repeatable process for using these guidelines to identify spatially-explicit restoration opportunities. The process is largely GIS-based and utilizes spatial data on existing land cover and conservation status, habitat configuration (including patch sizes and distances), surface elevations (including depth of subsidence), and future changes in tidal elevations associated with sea-level rise.  By distilling generalized guidelines into spatially-explicit opportunities, we hope to provide a practical tool for incorporating science into planning. To that end, these new methods are currently being piloted through planning efforts focused on the Central Delta Corridor and the McCormack Williamson Tract, and are also being used to assist with the quantification of ecological restoration potential in the Delta Plan Ecosystem Amendment.

Presentation recording: available here.

The Tijuana River Valley Historical Ecology Investigation addresses a regional data gap by reconstructing the landscape and ecosystem characteristics of the river valley prior to the major modifications of the late 19th and 20th centuries. The research presented here, funded by the California State Coastal Conservancy, supplies foundational information at the regional and system scale about how the Tijuana Estuary, River, and valley looked and functioned in the recent past, as well as how they have changed over time. The ultimate goal of this study is to provide a new tool and framework that, in combination with contemporary research and future projections, can support and guide ongoing restoration design, planning, and management efforts in the valley.

Hot springs in the Tijuana River? Antelope by the beach? Zip-lines over the international border?
Come find out what the Tijuana River Valley looked like in the not-so-distant past and how the river, estuary, and surrounding areas have changed over the past two centuries. Hear how researchers “recreated” the historical landscape and how this information helps us to better plan for the future.