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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.

Ethoxylated surfactants are ubiquitous organic environmental contaminants that have received continued attention over the past several decades, particularly as manufacturing rates increase worldwide and as toxicity concerns grow regarding alcohol ethoxylates. Presence of these compounds in surface water has been considered primarily the result of contaminated wastewater effluent by ethoxylated surfactant degradates; as a result, monitoring has focused on the small subset of short-chain ethoxylates in wastewater effluent and receiving waters. This study quantified long-chain alcohol and alkylphenol ethoxylated surfactants in San Francisco Bay area stormwater runoff, wastewater effluent, and ambient Bay water to determine concentrations and inform potential pathways of contamination. We employed high-performance liquid chromatography coupled to high-resolution mass spectrometry to quantitate long-chain polyethoxylates, which are rarely monitored in ethoxylated surfactant studies. Similar total ethoxylated surfactant concentrations were observed in stormwater runoff (0.004–4.7 μg/L) and wastewater effluent (0.003–4.8 μg/L, outlier of 45 μg/L). Ambient Bay water contamination (0.0001–0.71 μg/L) was likely the result of both stormwater and wastewater inputs to San Francisco Bay. These results suggest that a broader focus including long-chain compounds and stormwater pathways may be needed to fully characterize the occurrence and impacts of ethoxylated surfactants in urban surface waters.

In this study, we investigate how changes in the vertical distribution of suspended sediment affect continuous suspended sediment flux measurements at a location in the San Francisco Estuary. Current methods for measuring continuous suspended sediment flux estimates relate continuous estimates of suspended-sediment concentration (SSC) measured at-a-point (SSCpt) to discrete cross-section measurements of depth-averaged, velocity-weighted SSC (SSCxs). Regressions that compute SSCxs from continuous estimates of SSCpt require that the slope between SSCpt and SSCxs, controlled by the vertical distribution of SSC, is fixed. However, in tidal systems with suspended cohesive sediment, factors that control the vertical SSC profile—vertical turbulent mixing and downward settling of suspended sediment mediated by flocculation of cohesive sediment—constantly vary through each tide and may exhibit systematic differences between flood and ebb tides (tidal asymmetries in water velocity or particle size). We account for changes in the vertical SSC profile on estimates of SSCxs using time series of the Rouse number of the Rouse-Vanoni-Ippen equation combined with optical turbidity measurements, a surrogate for SSCpt, to predict SSCxs from 2009 to 2011 and 2013. Time series of the Rouse number were estimated by fitting the Rouse-Vanoni-Ippen equation to SSC estimated from optical-turbidity measurements taken at two elevations in the water column. When accounting for changes in the vertical SSC profile, changes in not only the magnitude but also the direction of cumulative sediment-flux measurements were observed. For example, at a mid-depth sensor, sediment flux estimates changed from − 319 kt (± 65 kt, negative indicating net seaward transport) to 482 kt (± 140 kt, positive indicating net landward transport) for 2009–2011 and from − 388 kt (± 140 kt) to 1869 kt (± 406 kt) for 2013–2016. At the study location, estimation of SSCxs solely from SSCpt resulted in sediment flux values that were underestimates on flood tides and overestimates on ebb tides. This asymmetry is driven by covariance between water velocity and particle settling velocity (Ws) with larger Ws on flood compared to ebb tides. Results of this study indicate that suspended-sediment-flux measurements estimated from point estimates of SSC may be biased if systematic changes in the vertical distribution of SSC are unaccounted for.

Recent modeling has demonstrated that sediment supply is one of the primary environmental variables that will determine the sustainability of San Francisco Estuary tidal marshes over the next century as sea level rises. Therefore, understanding the environmental controls on sediment flux within the San Francisco Estuary is crucial for optimal planning and management of tidal marsh restoration. Herein, we present suspended-sediment flux estimates from water year (WY) 2009–2016 from the San Francisco Estuary to investigate the environmental controls and impact of the record 2013–2016 California drought. During the recent drought, sediment flux into Lower South Bay, the southernmost subembayment of the San Francisco Estuary, increased by 345% from 114 kt/year from WY 2009 to 2011 to 508 kt/year from WY 2014 to 2016, while local tributary sediment flux declined from 209 to 51 kt/year. Total annual sediment flux from WY 2009 to 2011 and 2014 to 2016 can be predicted by total annual freshwater inflow from the Sacramento-San Joaquin Delta (R2 = 0.83, p < 0.01), the primary source of freshwater input into the San Francisco Estuary. The volume of freshwater inflow from the Sacramento-San Joaquin Delta is hypothesized to affect shoal-to-channel density gradients that affect sediment flux from broad, typically more saline and turbid shoals, to the main tidal-channel seaward of Lower South Bay. During the drought, freshwater inflow from the Sacramento-San Joaquin Delta decreased, and replacement of typically more saline shoal water was reduced. As a result, landward-increasing cross-channel density gradients enhanced shoal-to-channel advective flux that increased sediment available for tidal dispersion and drove an increase in net-landward sediment flux into Lower South Bay.

This data release presents digital surface models (DSMs) and orthomosaic images of the Whale's Tail Marsh region of South San Francisco Bay, CA. The data were created using structure-from-motion (SfM) processing of repeat aerial imagery collected from fixed-wing aircraft. The raw images were acquired from an approximate altitude of 427 meters (1,400 feet) above ground level (AGL), using a Hasselblad A6D-100c camera fitted with an HC 80 lens, resulting in a nominal ground-sample-distance (GSD) of 2.5 centimeters per pixel. The acquisition flight lines were designed to provide approximately 50 percent overlap between adjacent flight lines (sidelap), with approximately 70 percent overlap between sequential images along the flight line (forelap). Survey control was established using an onboard camera-synchronized dual-frequency GPS system as well as ground control points (GCPs) distributed throughout the survey area and measured using survey-grade post-processed kinematic (PPK) GPS. Both the data from the onboard GPS and from the GPS used to measure the GCPs were post-processed using a nearby Continuously Operating Reference Station (CORS) operated by the National Geodetic Survey (NGS). Structure-from-motion processing of these data was conducted using a "4D" processing workflow in which imagery from each of the different acquisition dates were co-aligned to increase relative spatial precision between the final data products.

This report describes the amount and distribution of aquatic resources in the Coyote Creek watershed, Santa Clara County, California, and presents the first reassessment of stream ecosystem conditions using a watershed approach and the California Rapid Assessment Method (CRAM). Field work was conducted in 2020, ten years after the baseline watershed assessment completed in 2010.

This memo summarizes the Sonoma County Water Agency's  2009 receiving water monthly monitoring results for the North Coast Regional Water Quality Control Board's NPDES Permit No. R1-2009-0050.  The data were compiled, formatted and uploaded to SFEI’s Regional Data Center and are availble through CEDEN (https://ceden.waterboards.ca.gov/AdvancedQueryTool) under the Program Name "Russian River MS4 Program" and Project Names "2009 5 year Permit for RR_MS4 Program SCWA" and "2009 5 year Permit for RR_MS4 Program CSR".  The memo summarizes field measures and water chemistry, bacteria, and toxiciity results from two receving waters sites in Santa Rosa Creek downstream (C1-SRC-D) and upstream of the City of Santa Rosa.  

This memo was funded by a Suplemental Environmental Project (SEP) settlement of an enforcement action by the North Coast Regional Water Quality Control Board against the County of Sonoma.  2016.

In 2016 The Santa Clara Valley Water District and its consultants conducted a watershed wide survey to characterize the distribution and abundance of the aquatic resources within the Lower Peninsula watershed wtihin Santa Clara County, CA based on available GIS data, and to assess the overall ecological condition of streams within the watershed based on a statistically based, random sample design and the California Rapid Assessment Method for streams (CRAM).

This 20-year water quality monitoring status and trends report for the Lahontan Water Board’s Surface Water Ambient Monitoring Program (Regional SWAMP) provides an overview of the environmental settings across the Region to give the reader a sense of the diverse ecological landscape, land uses, distribution and abundance of aquatic resources, and fire history. It includes a retrospective analysis of the Regional SWAMP’s ongoing, targeted water quality monitoring results (2000 - 2021), and concludes by presenting an adaptive monitoring and assessment framework (adapted from the California Wetlands Monitoring Workgroup's Wetland and Riparian Monitoring Plan, known as "WRAMP").  The framework was used to review the program and recommend future monitoring changes to improve efficiencies and address some of the recommendations listed in the Regional SWAMP's 2019 Core Program Review. 

This technical report describes the ten-year ambient stream condition reassessment survey design and monitoring plan (or strategy) for the Coyote Creek watershed. Because the reassessment employed (and modified) the 2010 sample draw, essential background information about the original 2010 probability-based survey design, sample draw, and field assessment outcomes were provided.

This report synthesizes the baseline assessments for Santa Clara County’s five watersheds to present similarities, differences, and compare ecological condition in streams across watersheds and their subregions, San Francisco Bay-Delta ecoregion, and statewide based on CRAM. It also interprets the assessment results and comparisons to identify risks to stream conditions, and opportunities for stream stewardship. Project D5’s baseline assessments establish a monitoring and assessment framework for evaluating the performance of Valley Water’s programs, projects, maintenance activities, and on-the-ground stewardship actions.

This report describes the application of GreenPlan-IT’s Site Locator Tool to identify and rank candidate GI installation sites within the City of Ukiah.  The Site Locator Tool is the first (foundational) tool of the GreenPlan-IT toolkit, meaning that the outputs are required inputs for both the Hydrologic Modeling and Optimization tools.   The Site Locator Tool addresses the question: where are the best locations for GI implementation based on local planning priorities? 

In 2015 The Santa Clara Valley Water District and it's consultants conducted a watershed wide survey to characterize the distribution and abundance of the aquatic resources within the upper Pajaro River watershed wtihin Santa Clara County, CA based on available GIS datasets, and to assess the overall ecological condition of streams within the watershed based on a statistically based random sample design and the California Rapid Assessment Method for streams (CRAM).

This report describes the updates to the vernal pool habitat map, the development of the ambient baseline ecological condition survey of vernal pool systems within the Central Valley, and the development and results of the habitat development curve. A fictional project example shows how CRAM and the vernal pool complex CDFs and HDCs can help project proponents and the regulatory agencies think critically about project designs (using CRAM Attributes and Metrics as a standard measure), evaluate project conditions within a regional landscape context, and monitor project performance over time to ensure that project goals are met.

Funding for this report was provided through an agreement with the U.S. Environmental Protection Agency (USEPA).  This report does not necessarily reflect the views and policies of USEPA nor does the mention of trade names or commercial products within this report constitute endorsement or recommendation for use.

This report describes baseline information about the amount and distribution of aquatic resources, and evaluates the overall ecological conditions of streams using the California Rapid Assessment Method (CRAM), for the West Valley watershed in Santa Clara County; consisting of Sunnyvale East and West Channels, Calabazas Creek, San Tomas Aquino and Saratoga creeks, and many smaller tributaries.

This report demonstrates a possible watershed-based approach to evaluating mitigation sites using the California Rapid Assessment Method (CRAM). The Santa Clara Valley Water District (Valley Water) is leading the Llagas Creek Flood Control Project in the upper Pajaro River watershed, Santa Clara County, CA. Mitigation for the Project involves enhancing riverine wetlands on-site (within the flood control channel) and restoring riverine wetlands and enhancing depressional wetlands at Lake Silveira, in the Llagas Creek watershed. Valley Water is incorporating CRAM into its planning and assessment of mitigation efforts and Valley Water's Priority D.5 Project's Pajaro River Watershed ambient stream condition survey (2015) provided the watershed context for evaluating project conditions against the general ecological conditions of streams within the watershed - employing CRAM. This WRAMP demonstration compared pre-project ecological condition assessments (employing CRAM) from the project's impact and mitigation sites to ambient watershed conditions and estimated the amount of ecological lift expected in the future as a result of the planned mitigation and restoration efforts.

Municipal wastewater effluent has been proposed as one pathway for microplastics to enter the aquatic environment. Here we present a broad study of municipal wastewater treatment plant effluent as a pathway for microplastic pollution to enter receiving waters. A total of 90 samples were analyzed from 17 different facilities across the United States. Averaging all facilities and sampling dates, 0.05 ± 0.024 microparticles were found per liter of effluent. Though a small value on a per liter basis, even minor municipal wastewater treatment facilities process millions of liters of wastewater each day, yielding daily discharges that ranged from ∼50,000 up to nearly 15 million particles. Averaging across the 17 facilities tested, our results indicate that wastewater treatment facilities are releasing over 4 million microparticles per facility per day. Fibers and fragments were found to be the most common type of particle within the effluent; however, some fibers may be derived from non-plastic sources. Considerable inter- and intra-facility variation in discharge concentrations, as well as the relative proportions of particle types, was observed. Statistical analysis suggested facilities serving larger populations discharged more particles. Results did not suggest tertiary filtration treatments were an effective means of reducing discharge. Assuming that fragments and pellets found in the effluent arise from the 'microbeads' found in many cosmetics and personal care products, it is estimated that between 3 and 23 billion (with an average of 13 billion) of these microplastic particles are being released into US waterways every day via municipal wastewater. This estimate can be used to evaluate the contribution of microbeads to microplastic pollution relative to other sources (e.g., plastic litter and debris) and pathways (e.g., stormwater) of discharge.

The response of shallow groundwater to sea-level rise is a relatively new field of study. For low-lying coastal communities, sea-level rise adaptation efforts must consider the potential for groundwater rise to avoid maladaptation. The need to better understand this slow and chronic threat was identified as a critical data gap in the San Francisco Bay Area’s (Bay Area’s) adaptation efforts during the Bay Area Groundwater and Sea-Level Rise Workshop in 2019.

Pathways Climate Institute LLC (Pathways) and the San Francisco Estuary Institute (SFEI) gathered and analyzed multiple data sets and collaborated with city and county partners to analyze and map the existing “highest annual” shallow groundwater table and its likely response to future sea-level rise. This effort covers four counties (Alameda, Marin, San Francisco, San Mateo) and was funded by the Bay Area Council’s California Resilience Challenge. The study focused on the San Francisco Bay side of each county and does not include the Pacific coastline of Marin, San Francisco, nor San Mateo Counties. An advisory committee composed of city and county representatives provided essential support by gathering data and reviewing depth-to-groundwater maps. Additional academic and agency advisors participated in project team meetings and informed project direction. This effort produced the following publicly available data and online tools to support adaptation efforts:

• Existing and future condition depth to groundwater GIS data available for download (geodatabase format).
• A StoryMap providing background information and graphical representations of the processes and impacts of groundwater rise.
• Web maps showing: (1) existing depth to groundwater; and (2) a comparison of the extent of emergent groundwater to the extent of coastal flooding under various sea-level-rise scenarios.

Stormwater agencies in the San Francisco Bay Area are identifying watershed areas that are polluted with PCBs in order to prioritize management efforts to reduce impairment in the Bay caused by PCBs carried in stormwater. Water sampling during storms has been used to characterize PCB concentrations but management prioritization based on the comparison of concentrations between watersheds is made difficult due to variations in flow and sediment erosion between storms and in relation to varying land use. In addition, identifying PCB source areas within priority watersheds has proven complex and costly. To address these challenges, the San Francisco Bay Regional Monitoring Program (RMP) has developed two new interpretive methods based on storm-event PCB yields (PCBs mass per unit area per unit time) and fingerprints of Aroclors (commercial PCB mixtures) that make existing data more useful for decision-making. 

The objectives of this study were to: 

• Apply the yield method to the regional stormwater dataset and provide new rankings, 
• Estimate the presence of Aroclors in samples where congener data are available
• Evaluate data weaknesses and recommend watersheds to resample, and
• Classify watersheds into high, medium, and low categories for potential management.

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.