Support for Sediment Bioaccumulation Evaluation: Toxicity Reference Values for San Francisco Bay

San Francisco Estuary Institute (SFEI) | December 3rd, 2018

This special study of the Regional Monitoring Program for Water Quality in San Francisco Bay was conducted to support the Dredged Material Management Office (DMMO) proces

This special study of the Regional Monitoring Program for Water Quality in San Francisco Bay was conducted to support the Dredged Material Management Office (DMMO) process of evaluating results from bioaccumulation testing performed for routine dredging projects. The goal was to use the current DMMO methodology for selecting Toxicity Reference Values (TRVs) from the US Army Corps of Engineers Environmental Residue-Effects Database (ERED), in order to develop a standard list of TRVs for San Francisco Bay. TRVs are used as a conservative screening tool to efficiently evaluate whether observed invertebrate test organism body burdens could indicate adverse ecological effects on benthic organisms in situ. Currently, there are no published standard TRVs for the Bay, and TRV selection is presently performed on a case-by-case basis during the evaluation of bioaccumulation testing results submitted by individual dredgers. A standard list would promote consistent application of the methodology and improve the efficiency of dredging project evaluations. 

Surveillance and Monitoring Program (SAMP) Revised Final Report

Central Valley Salinity Alternatives for Long-Term Sustainability (CV-SALTS) | December 1st, 2016

Among other things, the State Recycled Water Policy (SRWP) requires that development of the Salt and Nitrate Management Plan (SNMP) include the following element (S

Among other things, the State Recycled Water Policy (SRWP) requires that development of the Salt and Nitrate Management Plan (SNMP) include the following element (SRWP Section 6.b.3 (a)): “A basin/sub‐basin wide monitoring plan that includes an appropriate network of monitoring locations. The scale of the basin/subbasin monitoring plan is dependent upon the sitespecific conditions and shall be adequate to provide a reasonable, cost‐effective means of determining whether the concentrations of salt, nutrients, and other constituents of concern as identified in the salt and nutrient plans are consistent with applicable water quality objectives.” Furthermore, “Salts, nutrients, and the constituents identified in paragraph 6(b)(1)(f) shall be monitored. The frequency of monitoring shall be determined in the salt/nutrient management plan and approved by the Regional Water Board pursuant to paragraph 6(b)(2).” This report describes the CV‐SALTS Surveillance and Monitoring Program (SAMP), which was developed to meet the monitoring requirements of the SRWP.

Suspect Screening and Chemical Profile Analysis of Storm-Water Runoff Following 2017 Wildfires in Northern California

Society of Environmental Toxicology and Chemistry (SETAC) | May 5th, 2022

The combustion of structures and household materials as well as firefighting during wildfires lead to releases of potentially hazardous chemicals directly into the landsc

The combustion of structures and household materials as well as firefighting during wildfires lead to releases of potentially hazardous chemicals directly into the landscape. Subsequent storm-water runoff events can transport wildfire-related contaminants to downstream receiving waters, where they may pose water quality concerns. To evaluate the environmental hazards of northern California fires on the types of contaminants in storm water discharging to San Francisco Bay and the coastal marine environment, we analyzed storm water collected after the northern California wildfires (October 2017) using a nontargeted analytical (NTA) approach. Liquid chromatography quadrupole time-of-flight mass spectrometric analysis was completed on storm-water samples (n = 20) collected from Napa County (impacted by the Atlas and Nuns fires), the city of Santa Rosa, and Sonoma County (Nuns and Tubbs fires) during storm events that occurred in November 2017 and January 2018. The NTA approach enabled us to establish profiles of contaminants based on peak intensities and chemical categories found in the storm-water samples and to prioritize significant chemicals within these profiles possibly attributed to the wildfire. The results demonstrated the presence of a wide range of contaminants in the storm water, including surfactants, per- and polyfluoroalkyl substances, and chemicals from consumer and personal care products. Homologs of polyethylene glycol were found to be the major contributor to the contaminants, followed by other widely used surfactants. Nonylphenol ethoxylates, typically used as surfactants, were detected and were much higher in samples collected after Storm Event 1 relative to Storm Event 2. The present study provides a comprehensive approach for examining wildfire-impacted storm-water contamination of related contaminants, of which we found many with potential ecological risk.

Suspended Sediment Flux in the San Francisco Estuary: Part I—Changes in the Vertical Distribution of Suspended Sediment and Bias in Estuarine Sediment Flux Measurements

Estuaries and Coasts (Springer) | April 22nd, 2020

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 S

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.

Sustainability of irrigated agriculture in the San Joaquin Valley, California

National Academy of Sciences (NAS) | October 25th, 2005

The sustainability of irrigated agriculture in many arid and semiarid areas of the world is at risk because of a combination of several interrelated factors, including

The sustainability of irrigated agriculture in many arid and semiarid areas of the world is at risk because of a combination of several interrelated factors, including lack of fresh water, lack of drainage, the presence of high water tables, and salinization of soil and groundwater resources. Nowhere in the United States are these issues more apparent than in the San Joaquin Valley of California. A solid understanding of salinization processes at regional spatial and decadal time scales is required to evaluate the sustainability of irrigated agriculture. A hydro-salinity model was developed to integrate subsurface hydrology with reactive salt transport for a 1,400-km2 study area in the San Joaquin Valley. The model was used to reconstruct historical changes in salt storage by irrigated agriculture over the past 60 years. We show that patterns in soil and groundwater salinity were caused by spatial variations in soil hydrology, the change from local groundwater to snowmelt water as the main irrigation water supply, and by occasional droughts. Gypsum dissolution was a critical component of the regional salt balance. Although results show that the total salt input and output were about equal for the past 20 years, the model also predicts salinization of the deeper aquifers, thereby questioning the sustainability of irrigated agriculture.

Sustainable Cotton Project

San Francisco Estuary Institute (SFEI) | November 19th, 2009

Contamination from pesticide application to row crops is a major water quality issue in California. Cotton receives three to five times greater application of pesticide p

Contamination from pesticide application to row crops is a major water quality issue in California. Cotton receives three to five times greater application of pesticide per acre than other row crops (USGS 2008). This Project included outreach, education, and technical support for growers to test alternatives to synthetic pesticides and inorganic fertilizers. In addition, water quality monitoring of cotton field runoff in the Central Valley of California was conducted during the 2007 and 2008 growing seasons. The goal of the study was to evaluate differences in pesticide and nutrient loads to receiving water bodies comparing biological and conventional growing practices. The types and concentrations of pesticides in the sampled tail water were similar for biologically and conventionally grown cotton. Average pesticide concentrations in water and estimated loads for diuron, glyphosate, chlorpyrifos, and prometryn were not statistically significantly different with BMP implementations at the biological sites due to sample size limitations. However, there was a trend toward lower pesticide concentrations for diuron and prometryn at the biological sites. Concentrations for most nutrient forms and loads were also generally similar within the two site types when compared to flow passing the site at the point of sampling. Nitrate and nitrite loads, however, were reduced at the biological fields by more than 70% compared to the conventional sites. Additionally, limited bioassessment samples showed slightly greater numbers of individuals and numbers of species collected at the biological sites.

Sustainable L.A. Grand Challenge Environmental Report Card for Los Angeles County: Water 2019

University of California, Los Angeles (UCLA) | October 22nd, 2019

The Sustainable LA Grand Challenge (SLA GC) Environmental Report Card (ERC) for Los Angeles County (L.A. County) is the only comprehensive environmental report card for

The Sustainable LA Grand Challenge (SLA GC) Environmental Report Card (ERC) for Los Angeles County (L.A. County) is the only comprehensive environmental report card for a megacity in the world. This 2019 ERC on Water provides an in-depth look at the region’s efforts in moving toward a more resilient local water supply, which requires maximizing high quality local water supplies, improving water conveyance and treatment infrastructure, reducing water consumption, and implementing innovative technology and policy solutions. Twenty indicators were assessed across eight categories. Many of these indicators are new areas of assessment for the ERC and will provide a more comprehensive picture of current conditions compared to the 2015 ERC that last assessed L.A. County’s water. Grades were assigned in each category based on compliance with environmental laws or numeric standards where applicable, on our best professional judgment, and on historical improvements and context. This year’s grades range from D/ Incomplete to B+, and although there has been great progress in some areas, others still require significant improvement to raise the county’s C+ average.

Sutter Bypass East Levee Project Initial Study/Proposed Mitigated Negative Declaration

California Department of Water Resources (DWR) | July 10th, 2025

Sycamore Alluvial Woodland Planting Guide

San Francisco Estuary Institute (SFEI) | August 1st, 2018

This memo builds on recent field-based studies which examined the relative distribution, health, and regeneration patterns of two major stands of sycamore alluvial woodla

This memo builds on recent field-based studies which examined the relative distribution, health, and regeneration patterns of two major stands of sycamore alluvial woodland (SAW) in Santa Clara County. Given that the acquisition, restoration, and improved management of SAW is mandated as part of the Santa Clara Valley Habitat Plan (VHP), it is increasingly critical to understand how, when, and where sycamores establish, which is critical for successful restoration design and planting success. This memo is meant to summarize recent studies on habitat requirements of the SAW habitat type, and present a planting plan and monitoring framework for restoring SAW habitat at two sites in Santa Clara County. As the science and restoration of SAW is an ongoing topic of interest, we also suggest possible subsequent studies needed to further sycamore restoration goals. 

Sycamore Alluvial Woodland: Habitat Mapping and Regeneration Study

San Francisco Estuary Institute (SFEI) | February 1st, 2017

This study investigates the relative distribution, health, and regeneration patterns of two major stands of sycamore alluvial woodland (SAW), representing managed and nat

This study investigates the relative distribution, health, and regeneration patterns of two major stands of sycamore alluvial woodland (SAW), representing managed and natural settings. Using an array of ecological and geomorphic field analyses, we discuss site characteristics favorable to SAW health and regeneration, make recommendations for restoration and management, and identify next steps. Findings from this study will contribute to the acquisition, restoration, and improved management of SAW as part of the Santa Clara Valley Habitat Plan (VHP).