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.

Assessment of the Economic Impacts of California's Drought on Urban Areas

Rand Corporation (Rand) | September 6th, 1993

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

Associations between PFAS in public water system drinking water and serum among Southern California adults

Nature Portfolio (Springer Nature) | October 30th, 2025

The CARE (California Regional Exposure) biomonitoring study measured PFAS in serum of Southern and Eastern California adults between 2018 and 2020. Participant addresses

The CARE (California Regional Exposure) biomonitoring study measured PFAS in serum of Southern and Eastern California adults between 2018 and 2020. Participant addresses were geocoded and geographically assigned to public water systems (PWS). Between 2019 and 2022, the California State Water Resources Control Board issued investigative PFAS monitoring orders to potentially impacted PWS, focusing primarily on source wells. PFAS detections above the required reporting limit (4 ng/L for PFAS included in the final analysis) were used to assess associations with serum PFAS levels.

Assumptions and Estimates for California Water Plan Update 2018

California Department of Water Resources (DWR) | April 13th, 2017

The California Water Plan (Water Plan) is the State government’s strategic plan for sustainably managing and developing water resources statewide for current and future

The California Water Plan (Water Plan) is the State government’s strategic plan for sustainably managing and developing water resources statewide for current and future generations. The Water Plan development process provides a planning framework for elected officials, agencies, tribes, water and resource managers, businesses, academia, stakeholders, and the public to collaborate on findings and recommendations and make informed decisions regarding California’s water future. The goal for each update of the Water Plan is to receive broad input and support from Californians, meet California Water Code (Water Code) requirements, guide State investments, and advance integrated water management and regional sustainability.  This draft report and the related data posted online comprise the Draft Assumptions and Estimates Report (Draft A&E Report) for California Water Plan Update 2018 (Update 2018). The Draft A&E Report presents key assumptions and estimates, data and data sources, and companion plans that will be considered for the preparation of Update 2018. The report increases the transparency of the Water Plan process by disclosing the data, tools, methods, and references used to prepare Update 2018. This report meets Water Code requirements, which stipulate that the California Department of Water Resources (DWR) must publish the Water Plan’s assumptions and estimates one year prior to the plan’s publication, as well as provide an opportunity for public review and comment. Water code requirements for the Draft A&E Report are presented below.  The Draft A&E Report also describes the approach DWR is taking to improve the analytical tools and data being used to develop Update 2018. DWR will continue to update Draft A&E Report content online during the remainder of the Update 2018 development process. A draft glossary for Update 2018 is included as part of this report, and the final version of that glossary will be published as a component of Update 2018. The final data and data sources will be included in the Update 2018 reference and technical information. 

Assumptions and Estimates for California Water Plan Update 2023 (Draft)

California Department of Water Resources (DWR) | October 14th, 2022

The draft Assumptions and Estimates for California Water Plan Update 2023 (draft A&E Report) describes key assumptions and estimates, data and data sources; improvements

The draft Assumptions and Estimates for California Water Plan Update 2023 (draft A&E Report) describes key assumptions and estimates, data and data sources; improvements to analytical tools, methods, and approaches; and the supporting documents and companion State plans being used to prepare California Water Plan Update 2023 (Update 2023), State government’s strategic plan for managing and developing water resources for sustainability and resilience. The draft A&E Report cites the statutory requirements for the California Water Plan (Water Plan), key legislative and policy drivers, assumptions, and estimates related to water data portfolios, future scenarios, water accounting, watershed resilience planning, and equity in water resource management. Also discussed are resource management strategies, the alignment of integrated watershed programs and plans, and integration and alignment of State plans.

Asymmetric emergence of low-to-no snow in the midlatitudes of the American Cordillera

Nature Portfolio (Springer Nature) | November 14th, 2022

Societies and ecosystems within and downstream of mountains rely on seasonal snowmelt to satisfy their water demands. Anthropogenic climate change has reduced mountain sn

Societies and ecosystems within and downstream of mountains rely on seasonal snowmelt to satisfy their water demands. Anthropogenic climate change has reduced mountain snowpacks worldwide, altering snowmelt magnitude and timing. Here the global warming level leading to widespread and persistent mountain snowpack decline, termed low-to-no snow, is estimated for the world’s most latitudinally contiguous mountain range, the American Cordillera. We show that a combination of dynamical, thermodynamical and hypsometric factors results in an asymmetric emergence of low-to-no-snow conditions within the midlatitudes of the American Cordillera. Low-to-no-snow emergence occurs approximately 20 years earlier in the southern hemisphere, at a third of the local warming level, and coincides with runoff efficiency declines (8% average) in both dry and wet years. The prevention of a low-to-no-snow future in either hemisphere requires the level of global warming to be held to, at most, +2.5 °C.

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.

Atlantic-Pacific influence on western U.S. hydroclimate and water resources

Nature Portfolio (Springer Nature) | September 11th, 2023