Monitoring for Acidification Threats in West Coast Estuaries: A San Francisco Bay Case Study

San Francisco Estuary Institute (SFEI) | June 6th, 2017

The estuaries of the U.S. Pacific Coast are diverse and productive ecosystems of high ecological, cultural, and economic value. They have many stakeholders, are managed t

The estuaries of the U.S. Pacific Coast are diverse and productive ecosystems of high ecological, cultural, and economic value. They have many stakeholders, are managed to meet many different, often competing, objectives, and contend with environmental stressors from a variety of sources. Ocean acidification (OA) is one stressor expected to have widespread impacts on the Pacific coastal ecosystems. Recently, the West Coast Ocean Acidification & Hypoxia Science Panel recommended improved monitoring to assess biological impacts in the coastal ocean and estuaries. However, the current status and impacts of ocean acidification on West Coast estuaries are largely unknown. A workshop in October 2016 brought together scientists from throughout the West Coast of the United States, leading researchers on San Francisco Bay, the region’s largest estuary, and representatives from a variety of management agencies. The main objectives of the Workshop were to assess whether acidification is of concern in the Bay and to identify its potential impacts to beneficial uses, cost-effective monitoring strategies, and potential management actions. Although the Bay was the case study, the aim was to develop general guidance that could be applied to West Coast estuaries.

Monitoring Special Study (MSS) Salinity Point Source and Ion Sampling CY 2022–2023

California Department of Water Resources (DWR) | August 15th, 2022

The interior southern Delta region of the San Francisco Estuary (SFE) has relatively higher seasonal-based salinity compared to other interior freshwater regions. Some of

The interior southern Delta region of the San Francisco Estuary (SFE) has relatively higher seasonal-based salinity compared to other interior freshwater regions. Some of this degradation in water quality in the interior southern Delta likely originates in upstream salt loading from agriculture drainage in the San Joaquin River prior to reaching the channels of Old River and Grant Line Canal. However, there is also measurable increases in salt loading within the channel networks of Old River at Head (OH1) east to lower Old River near Mountain House Creek (ORM) and the interconnected sloughs of Paradise and Sugar Cut in the region of Doughty Cut (Figure 1) (in-Delta agriculture drainage), as well as other naturally occurring (i.e., groundwater) sources and other non-point and point sources. The California Department of Water Resources (DWR) and U.S. Bureau of Reclamation (Reclamation), under the State Water Resources Control Board’s (State Water Board) Water Right Decision 1641 (D-1641), are assigned partial responsibility for meeting interior southern Delta water quality objectives each year at multiple compliance stations that measure specific conductance (EC) data continuously at 15-minute intervals.

Monitoring Well Destruction, Replacement, and New Installations at Various Locations Soquel, Capitola, and Aptos, CA

Soquel Creek Water District | June 14th, 2012

A total of six new monitoring wells and seven replacement monitoring wells were drilled and constructed, and 13 monitoring well destroyed between February 7 and April 26,

A total of six new monitoring wells and seven replacement monitoring wells were drilled and constructed, and 13 monitoring well destroyed between February 7 and April 26, 2012 for the Soquel Creek Water District (District). This work took place at six different locations in the Soquel-Aptos area. The work was accomplished in order to meet the basin management objectives of the Soquel-Aptos Groundwater Management Plan (Soquel Creek Water District and Central Water District, 2007) and recommendations made in the Water Year 2010 Annual Report and Review (HydroMetrics WRI, 2011). A summary of the work performed and monitoring well construction details at each of the six locations are provided below. 

Movement and Age of Ground Water in the Western Part of the Mojave Desert, Southern California, USA

U.S. Geological Survey (USGS) | July 15th, 2004

Tritium and carbon-14 data in water from wells in the Mojave River and the Morongo groundwater basins in the western part of the Mojave Desert show recent recharge focuse

Tritium and carbon-14 data in water from wells in the Mojave River and the Morongo groundwater basins in the western part of the Mojave Desert show recent recharge focused in the floodplain aquifer along the Mojave River. Older ground water was present in parts of the regional aquifer that surround and underlie the floodplain aquifer. Movement of water between the floodplain and the regional aquifers occurs near on the upgradient side of faults as water from the regional aquifer discharges to the floodplain aquifer and on the downgradient side of the faults where water from the floodplain aquifer recharges the regional aquifer. On the basis of carbon-14 ages, corrected for mineralogic reactions with aquifer materials, water from some wells was recharged more than 20,000 years ago. Geochemical data show ground-water recharge has gradually decreased as the climate changed since that time.

Moving Toward a Multi-Benefit Approach for Water Management

Pacific Institute | April 11th, 2019

There is broad recognition that adapting to climate change, coupled with the need to address aging infrastructure, population growth, and degraded ecosystems, will re

There is broad recognition that adapting to climate change, coupled with the need to address aging infrastructure, population growth, and degraded ecosystems, will require rethinking programs and policies and investing in our natural and built water systems. There are a variety of strategies for addressing water challenges, from watershed restoration and efficiency improvements to vegetated swales and green roofs. Because water is deeply linked with economic, environmental, and community wellbeing, many of these strategies can also provide other benefits, such as reducing energy use and greenhouse gas emissions, providing wildlife habitat, and enhancing community livability.

MSS Salinity Point Source and Ion Sampling to the Monitoring Special Study Plan CY 2022–2023 Work Plan Monitoring Plan

California Department of Water Resources (DWR) | August 16th, 2023

The interior southern Delta region of the San Francisco Estuary (SFE) has relatively higher seasonal-based salinity compared to other interior freshwater regions. Some of

The interior southern Delta region of the San Francisco Estuary (SFE) has relatively higher seasonal-based salinity compared to other interior freshwater regions. Some of this degradation in water quality in the interior southern Delta likely originates in upstream salt loading from agriculture drainage in the San Joaquin River prior to reaching the channels of Old River and Grant Line Canal. However, there is also measurable increases in salt loading within the channel networks of Old River at Head (OH1) east to lower Old River near Mountain House Creek (ORM) and the interconnected sloughs of Paradise and Sugar Cut in the region of Doughty Cut (in-Delta agriculture drainage), as well as other naturally occurring (i.e., groundwater) sources and other non-point and point sources. The California Department of Water Resources (DWR) and U.S. Bureau of Reclamation (Reclamation), under the State Water Resources Control Board’s (State Water Board) Water Right Decision 1641 (D-1641), are assigned partial responsibility for meeting interior southern Delta water quality objectives each year at multiple compliance stations that measure specific conductance (EC) data continuously at 15-minute intervals.

Multi-box mass balance model of PFOA and PFOS in different regions of San Francisco Bay

Chemosphere (Elsevier) | August 3rd, 2020

We present a model to predict the long-term distribution and concentrations of perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) in estuaries comprisi

We present a model to predict the long-term distribution and concentrations of perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) in estuaries comprising multiple intercommunicated sub-embayments. To that end, a mass balance model including rate constants and time-varying water inputs was designed to calculate levels of these compounds in water and sediment for every sub-embayment. Subsequently, outflows and tidal water exchanges were used to interconnect the different regions of the estuary. To calculate plausible risks to population, outputs of the model were used as inputs in a previously designed model to simulate concentrations of PFOA and PFOS in a sport fish species (Cymatogaster aggregata). The performance of the model was evaluated by applying it to the specific case of San Francisco Bay, (California, USA), using 2009 sediment and water sampled concentrations of PFOA and PFOS in North, Central and South regions. Concentrations of these compounds in the Bay displayed exponential decreasing trends, but with different shapes depending on region, compound, and compartment assessed. Nearly stable PFOA concentrations were reached after 50 years, while PFOS needed close to 500 years to stabilize in sediment and fish. Afterwards, concentrations stabilize between 4 and 23 pg/g in sediment, between 0.02 and 44 pg/L in water, and between 7 and 104 pg/g wet weight in fish, depending on compound and region. South Bay had the greatest final concentrations of pollutants, regardless of compartment. Fish consumption is safe for most scenarios, but due to model uncertainty, limitations in monthly intake could be established for North and South Bay catches.

Multi-region assessment of chemical mixture exposures and predicted cumulative effects in USA wadeable urban/agriculture-gradient streams

Science of the Total Environment (Elsevier) | February 4th, 2021

Chemical-contaminant mixtures are widely reported in large stream reaches in urban/agriculture-developed watersheds, but mixture compositions and aggregate biolog

Chemical-contaminant mixtures are widely reported in large stream reaches in urban/agriculture-developed watersheds, but mixture compositions and aggregate biological effects are less well understood in corresponding smaller headwaters, which comprise most of stream length, riparian connectivity, and spatial biodiversity. During 2014–2017, the U.S. Geological Survey (USGS) measured 389 unique organic analytes (pharmaceutical, pesticide, organic wastewater indicators) in 305 headwater streams within four contiguous United States (US) regions. Potential aquatic biological effects were evaluated for estimated maximum and median exposure conditions using multiple lines of evidence, including occurrence/concentrations of designed-bioactive pesticides and pharmaceuticals and cumulative risk screening based on vertebrate-centric ToxCast™ exposure-response data and on invertebrate and nonvascular plant aquatic life benchmarks. Mixed-contaminant exposures were ubiquitous and varied, with 78% (304) of analytes detected at least once and cumulative maximum concentrations up to more than 156,000 ng/L. Designed bioactives represented 83% of detected analytes. Contaminant summary metrics correlated strong-positive (rho (ρ): 0.569–0.719) to multiple watershed-development metrics, only weak-positive to point-source discharges (ρ: 0.225–353), and moderate- to strong-negative with multiple instream invertebrate metrics (ρ: −0.373 to −0.652). Risk screening indicated common exposures with high probability of vertebrate-centric molecular effects and of acute toxicity to invertebrates, respectively. The results confirm exposures to broad and diverse contaminant mixtures and provide convincing multiple lines of evidence that chemical contaminants contribute substantially to adverse multi-stressor effects in headwater-stream communities.

Multiple lines of evidence point to pesticides as stressors affecting invertebrate communities in small streams in five United States regions

Science of the Total Environment (Elsevier) | January 24th, 2024

Multiple lines of evidence point to pesticides as stressors affecting invertebrate communities in small streams in five United States regions

Science of the Total Environment (Elsevier) | February 2nd, 2024