Assessment of the condition of San Francisco Bay Area depressional wetlands

California State Water Resources Control Board (SWRCB) | March 23rd, 2017

Depressional wetlands are the most abundant, yet most threatened wetland type in California. Despite their relatively ubiquitous nature, they are poorly characterized, an

Depressional wetlands are the most abundant, yet most threatened wetland type in California. Despite their relatively ubiquitous nature, they are poorly characterized, and unlike streams, they are not subject to any systematic ambient monitoring and assessment in California. Consequently, decisions regarding protection, restoration, and management, such as issuance of Section 401 water quality certifications or prioritization of projects for wetland restoration grant funding, are usually made without the benefit of any regional context of condition, knowledge of predominant stressors, or rigorous documentation of reference conditions. The goals of this study were to apply tools for ambient monitoring of depressional wetlands in the San Francisco Bay region to accomplish the following: 1) To evaluate the regional condition of depressional wetlands in this portion of northern California, and 2) To evaluate the relationship between condition and stress by sampling both local stressors (intensity of direct wetland use, water chemistry, and sediment chemistry) and landscape stressors (adjacent land use, flow diversions, and road density). Once achieved, these goals should establish the foundation for developing a robust ambient depressional wetland monitoring program. This study included perennial (have surface water year round) and seasonal (lack surface water for part of the year) depressional wetlands as defined by Brinson (1993) located within the boundaries of the San Francisco Bay Regional Water Quality Control Board. Depressional wetlands in this study includes both natural water bodies such as sag ponds and small lakes, as well as created wetlands such as abandoned or active stock ponds, aesthetic ponds, and irrigation/treatment ponds. Wetlands were not considered for this study if they were concrete lined, marine influenced, wastewater treatment ponds, livestock wastewater ponds, riverine (i.e., dominated by riverine hydrology), dry, or vernal pools. It is likely that a majority of wetlands sampled in this study would be considered waters of the State of California; the field teams did not perform a regulatory-based delineation of a wetland as part of this study. Thirty wetlands in the San Francisco Bay area were sampled during the spring of 2014, including both perennial and seasonal wetlands. The proportion of wetlands in the region considered “likely intact” (scores in the upper 50th percentile of the range found at reference sites) varied by indicator.

Assessment of the condition of Southern California depressional wetlands

California State Water Resources Control Board (SWRCB) | April 18th, 2016

Application of Macroinvertebrate, Diatom and Overall Condition Indices for Assessing Southern California Depressional Wetlands Depressional wetlands are the most abund

Application of Macroinvertebrate, Diatom and Overall Condition Indices for Assessing Southern California Depressional Wetlands Depressional wetlands are the most abundant, yet most threatened wetland type in California. Despite their relatively ubiquitous nature, they are poorly characterized, and unlike streams, they are not subject to any systematic monitoring and assessment. Consequently, decisions regarding protection, restoration, and management are usually made without the benefit of any regional context of condition, knowledge of predominant stressors, or rigorous documentation of reference conditions. Ambient monitoring of depressional wetlands can be a critical tool to inform management decisions. However, before such a program can be implemented, biological assessment tools must be evaluated, validated, and modified (if necessary). Once these steps are completed, preliminary assessments can begin to provide answers to critical questions regarding wetland condition and key stressors. The goals of this study were 1) to adapt three readily available bioassessment tools for assessing depressional wetland condition in southern California. This included a statewide rapid assessment method that had been calibrated and validated for depressional wetlands (CRAM) but had no prior use in a regional assessment program, a macroinvertebrate index developed for depressional wetlands from a different geography (northern California), and a benthic diatom index which had been developed for a different habitat type (wadeable streams). 2) To evaluate the regional condition of depressional wetlands in southern California using the adapted tools. 3) To evaluate the relationship between condition and stress by sampling both local stressors (intensity of direct wetland use, water chemistry and sediment toxicity) and landscape stressors (adjacent land use, flow diversions, road density). Once achieved, these goals should establish the foundation for developing a robust and ongoing depressional wetland ambient monitoring program. This study included perennial or seasonal depressional wetlands as defined by Brinson (1993) located within the boundaries of the Los Angeles, Santa Ana, and San Diego Regional Water Quality Control Boards. Wetlands were not considered for this study if they were concrete-lined, marine-influenced, treatment ponds, livestock wastewater ponds, riverine (i.e. dominated by riverine hydrology), dry (i.e. not seasonal), or on-military bases (due to access issues). Vernal pools were also excluded; while these are considered a subclass of depressional wetlands, they represent a distinct wetland habitat that is typically evaluated with specific methods. Furthermore, given their rarity and ecological sensitivity they are often assessed through focused studies.

Associations between per-and polyfluoroalkyl substances (PFAS) and county-level cancer incidence between 2016 and 2021 and incident cancer burden attributable to PFAS in drinking water in the United States

Nature Portfolio (Springer Nature) | January 9th, 2025

At Risk: Public Supply Well Vulnerability Under California’s Sustainable Groundwater Management Act

Pacific Institute | June 1st, 2021

At the Great Salt Lake, record salinity and low water imperils millions of birds

American Association for the Advancement of Science (AAAS) | September 9th, 2022

Utah’s Great Salt Lake is smaller and saltier than at any time in recorded history. In July, the U.S. Geological Survey (USGS) reported that the world’s third-largest

Utah’s Great Salt Lake is smaller and saltier than at any time in recorded history. In July, the U.S. Geological Survey (USGS) reported that the world’s third-largest saline lake had dropped to the lowest level ever documented. And last week researchers measured the highest salt concentrations ever seen in the lake’s southern arm, a key bird habitat. Salinity has climbed to 18%, exceeding a threshold at which essential microorganisms begin to die. The trends, driven by drought and water diversion, have scientists warning that a critical feeding ground for millions of migrating birds is at risk of collapse. “We’re into uncharted waters,” says biochemist Bonnie Baxter of Westminster College, who has been documenting the lake’s alarming changes. “One week the birds are gone from a spot we usually see them. The next week we see dead flies along the shore. And each week we have to walk further to reach the water.” After years of inaction, the prospect of a dying lake, plus the risk of harmful dust blowing from the dry lakebed, is galvanizing policymakers to find ways to restore water to the shrinking lake.

Atmospheric rivers impact California's coastal water quality via extreme precipitation

Science of the Total Environment (Elsevier) | June 25th, 2019

Precipitation in California is projected to become more volatile: less frequent but more extreme as global warming pushes midlatitude frontal cyclones further poleward wh

Precipitation in California is projected to become more volatile: less frequent but more extreme as global warming pushes midlatitude frontal cyclones further poleward while bolstering the atmospheric rivers (ARs), which tend to produce the region's extreme rainfall. Pollutant accumulation and delivery to coastal waters can be expected to increase, as lengthening dry spells will be increasingly punctuated by more extreme precipitation events. Coastal pollution exposes human populations to high levels of fecal bacteria and associated pathogens, which can cause a variety of health impacts. Consequently, studying the impact of atmospheric rivers as the mechanism generating pulses of water pollution in coastal areas is relevant for public health and in the context of climate change. We aimed to quantify the links between precipitation events and water quality in order to explore meteorological causes as first steps toward effective early warning systems for the benefit of population health in California and beyond. We used historical gridded daily precipitation and weekly multiple fecal bacteria indicators at ~500 monitoring locations in California's coastal waters to identify weekly associations between precipitation and water quality during 2003–09 using canonical correlation analysis to account for the nested/clustered nature of longitudinal data. We then quantified, using a recently published catalog of atmospheric rivers, the proportion of coastal pollution events attributable to ARs. Association between precipitation and fecal bacteria was strongest in Southern California. Over two-thirds of coastal water pollution spikes exceeding one standard deviation were associated with ARs. This work highlights the importance of skillful AR landfall predictions in reducing vulnerability to extreme weather improving resilience of human populations in a varying and changing climate. Quantifying the impacts of ARs on waterborne diseases is important for planning effective preventive strategies for public health.

Authority and Effectiveness of the State Water Resources Control Board

Delta Vision Blue Ribbon Task Force (Delta Vision) | July 1st, 2008

This report addresses issues related to the effectiveness of the California State Water Resources Control Board (“State Board” or “Board”) in carrying out its rol

This report addresses issues related to the effectiveness of the California State Water Resources Control Board (“State Board” or “Board”) in carrying out its roles and responsibilities, with particular reference to the Sacramento-San Joaquin San Francisco Bay-Delta (“Delta”). Section 1 presents an overview and evaluation of the authority and responsibility of the State Board. Section 2 describes actions of the State Board over many years in connection with the Delta, and in summary form, the Mono Lake basin and the Yuba River. Based on the preceding sections, Section 3 evaluates the effectiveness of the Board with particular reference to the Delta and sets forth some observations related to the Board’s authority and effectiveness.

Averting disaster: Action now for the Salton Sea

Little Hoover Commission | September 1st, 2015

The Salton Sea is shrinking. Currently the state’s largest inland body of water, as it dries up, the Sea poses a substantial threat to public health and the environment

The Salton Sea is shrinking. Currently the state’s largest inland body of water, as it dries up, the Sea poses a substantial threat to public health and the environment. Left unaddressed, desert winds will lift dust from thousands of acres of newly-revealed lakebed and blow it into population centers, agricultural areas and world-class resort economies. This impending crisis is long in the making, a policy paralysis driven by years of government process without implementing a fix. There are clear, understandable and specific mitigation steps that should be taken immediately. The decisions California leaders make in the near future about this remote desert lake will determine whether this dismal scenario will be averted. The Commission urges the Natural Resources Agency to begin implementing shovel-ready projects and the Governor and Legislature to immediately begin planning and funding the next phase of Salton Sea projects while developing a long-term restoration plan. ... When California signed the QSA, it agreed to mitigate the impacts on the Salton Sea caused by the water transfers. The state clarified its intent to restore the sea through the QSA’s implementing legislation. Experts testified it would be tens of billions of dollars cheaper to mitigate the impacts of a shrinking sea up front than to deal with the adverse impacts of inaction. Fulfilling California’s commitment to the Salton Sea is an element of maintaining the terms of the QSA, which provides water security to many Californians. Continued inaction, and the consequent public health and environmental impacts, could undermine political support for the QSA. Further, in the larger picture, California’s fulfillment of its commitments is critical to its ability to negotiate future difficult agreements. ...    

Base of fresh ground water (approximately 3,000 micromhos) in the San Joaquin Valley, California

U.S. Geological Survey (USGS) | June 30th, 1971

Widespread pumping of groundwater in the San Joaquin Valley began about 1900, and since 1940 pumpage has increased at an accelerated rate. In response to the heavy withdr

Widespread pumping of groundwater in the San Joaquin Valley began about 1900, and since 1940 pumpage has increased at an accelerated rate. In response to the heavy withdrawal of groundwater, water levels have declined rapidly beneath extensive areas of the valley. Consequently, it becomes necessary to delineate the base of fresh groundwater so that changes in thickness of the fresh-water zone can be monitored, and limited depths of water wells can be determined. In turn, those data will be useful in determining favorable areas for groundwater storage, and areas and depths for waste-water disposal wells. Because other agencies and the U.S. Geological Survey have collected a vast amount of well log and other data, most of the information in this report was assembled from existing files. However, for areas where data were scanty, a few hundred additional electrical logs were collected to supplement the available information.

Base of fresh water, groundwater salinity, and well distribution across California

National Academy of Sciences (NAS) | December 9th, 2020

The depth at which groundwaters transition from fresh to more saline—the “base of fresh water”—is frequently used to determine the stringency and types of measure

The depth at which groundwaters transition from fresh to more saline—the “base of fresh water”—is frequently used to determine the stringency and types of measures put in place to manage groundwater and protect it from contamination. Therefore, it is important to understand salinity distributions and compare defined bases of fresh water with salinity distributions and groundwater well depths. Here we analyze two distinct datasets: 1) a large set of total dissolved solids concentration (TDS) measurements (n = 216,754) and 2) groundwater well locations and depths (n = 399,454) across California. We find that 19 to 56% of the groundwater TDS measurements made at depths deeper than defined bases of fresh water pump fresh groundwater (TDS < 2,000 mg/L). Because fresh groundwater is found at depths deeper than the base of fresh water, current policies informed by base of fresh water assessments may not be managing and protecting large volumes of deep fresh groundwater. Furthermore, we find that nearly 4% of existing groundwater wells penetrate defined bases of fresh water, and nearly 16% of wells overlie it by no more than 100 m, evidencing widespread encroachment on the base of fresh water by groundwater users. Consequently, our analysis suggests that groundwater sustainability in California may be poorly safeguarded in some places and that the base-of-fresh-water concept needs to be reconsidered as a means to define and manage groundwater.