Occurrence of natural and anthropogenic hexavalent chromium (Cr VI) in groundwater near a mapped plume, Hinkley, CA

U.S. Geological Survey (USGS) | March 22nd, 2018

This report describes (1) work done between January 2015 and May 2017 as part of the U.S. Geological Survey (USGS) hexavalent chromium, Cr(VI), background study and (2) t

This report describes (1) work done between January 2015 and May 2017 as part of the U.S. Geological Survey (USGS) hexavalent chromium, Cr(VI), background study and (2) the summative-scale approach to be used to estimate the extent of anthropogenic (man-made) Cr(VI) and background Cr(VI) concentrations near the Pacific Gas and Electric Company (PG&E) natural gas compressor station in Hinkley, California. Most of the field work for the study was completed by May 2017. The summative-scale approach and calculation of Cr(VI) background were not well-defined at the time the USGS proposal for the background Cr(VI) study was prepared but have since been refined as a result of data collected as part of this study. The proposed summative scale consists of multiple items, formulated as questions to be answered at each sampled well. Questions that compose the summative scale were developed to address geologic, hydrologic, and geochemical constraints on Cr(VI) within the study area. Each question requires a binary (yes or no) answer. A score of 1 will be assigned for an answer that represents data consistent with anthropogenic Cr(VI); a score of –1 will be assigned for an answer that represents data inconsistent with anthropogenic Cr(VI). The areal extent of anthropogenic Cr(VI) estimated from the summative-scale analyses will be compared with the areal extent of anthropogenic Cr(VI) estimated on the basis of numerical groundwater flow model results, along with particle-tracking analyses. On the basis of these combined results, background Cr(VI) values will be estimated for “Mojave-type” deposits, and other deposits, in different parts of the study area outside the summative-scale mapped extent of anthropogenic Cr(VI). 

Occurrence of water and thermogenic gas from oil-bearing formations in groundwater near the Orcutt Oil Field, California, USA

Journal of Hydrology: Regional Studies (Elsevier) | April 11th, 2022

Study region: Santa Barbara County, California, USA. Study focus: To analyze a wide array of newly collected chemical, isotopic, dissolved gas, and age dating tracers

Study region: Santa Barbara County, California, USA. Study focus: To analyze a wide array of newly collected chemical, isotopic, dissolved gas, and age dating tracers in conjunction with historical data from groundwater and oil wells to determine if water and/or thermogenic gas from oil-bearing formations have mixed with groundwater in the Orcutt Oil Field and surrounding area. New hydrological insights for the region: Three of 15 groundwater samples had compositions indicating potential mixing with water and/or thermogenic gas from oil-bearing formations. Relevant indicators included salinity tracers (TDS, Cl, Br), NH3, DOC, enriched δ13C-DIC, δ2H- CH4, δ13C-CH4, and δ13C-C2H6 values, and trace amounts of C3-C5 gas. The potential sources/ pathways for oil-bearing formation water and/or thermogenic gas in groundwater overlying and adjacent to the Orcutt Oil Field include: (1) upward movement from formations developed for oil production due to: (a) natural migration; or (b) anthropogenic activity such as injection and/or movement along wellbores; and (2) oil and gas shows in overlying non-producing oil-bearing formations. Groundwater age tracers, elevated 4He concentrations, and isotopic compositions of noble gases indicated legacy produced water ponds were not a source. This phase of the study relied on samples and data from existing infrastructure. Additional data on potential end-member compositions from new and existing wells and assessments of potential vertical head gradients and pathways between oil and groundwater zones may yield additional insight.

Ocean acidification impairs olfactory discrimination and homing ability of a marine fish

National Academy of Sciences (NAS) | February 2nd, 2009

The persistence of most coastal marine species depends on larvae finding suitable adult habitat at the end of an offshore dispersive stage that can last weeks or

The persistence of most coastal marine species depends on larvae finding suitable adult habitat at the end of an offshore dispersive stage that can last weeks or months. We tested the effects that ocean acidification from elevated levels of atmospheric carbon dioxide (CO2) could have on the ability of larvae to detect olfactory cues from adult habitats. Larval clownfish reared in control sea- water (pH 8.15) discriminated between a range of cues that could help them locate reef habitat and suitable settlement sites. This discriminatory ability was disrupted when larvae were reared in conditions simulating CO2-induced ocean acidification. Larvae be- came strongly attracted to olfactory stimuli they normally avoided when reared at levels of ocean pH that could occur ca. 2100 (pH 7.8) and they no longer responded to any olfactory cues when reared at pH levels (pH 7.6) that might be attained later next century on a business-as-usual carbon-dioxide emissions trajectory. If acidifi- cation continues unabated, the impairment of sensory ability will reduce population sustainability of many marine species, with potentially profound consequences for marine diversity.

Ocean Climate Indicators: A Monitoring Inventory and Plan for Tracking Climate Change in the North-central California Coast and Ocean Region

Gulf of the Farallones National Marine Sanctuary Advisory Council | August 14th, 2014

The impacts of climate change, defined as increasing atmospheric and oceanic carbon dioxide and associated increases in average global temperature and oceanic a

The impacts of climate change, defined as increasing atmospheric and oceanic carbon dioxide and associated increases in average global temperature and oceanic acidity, have been observed both globally and on regional scales, such as in the North-central California coast and ocean, a region that extends from Point Arena to Point Año Nuevo and includes the Pacific coastline of the San Francisco Bay Area. Because of the high economic and ecological value of the region’s marine environment, the Gulf of the Farallones National Marine Sanctuary (GFNMS) and other agencies and organizations have recognized the need to evaluate and plan for climate change impacts.

Ocean, Harbor and Bay Water Quality Report 2019-2020

Orange County Health Care Agency (OCHCA) | April 30th, 2021

The 2019–2020 Ocean, Harbor and Bay Water Quality Report provides updated data on sewage spills and their impacts resulting in ocean water closures and provid

The 2019–2020 Ocean, Harbor and Bay Water Quality Report provides updated data on sewage spills and their impacts resulting in ocean water closures and provides an analysis of bacteriological water quality data collected at Orange County’s (OC) ocean, harbor and bay waters.

Ocean, Harbor and Bay Water Quality Report 2023 – 2024

Orange County Health Care Agency (OCHCA) | May 30th, 2025

The 2023-2024 Ocean, Harbor and Bay Water Quality Report provides updated data on sewage spills, the spill impacts resulting in ocean water closures and an analysis of ba

The 2023-2024 Ocean, Harbor and Bay Water Quality Report provides updated data on sewage spills, the spill impacts resulting in ocean water closures and an analysis of bacteriological water quality data collected at Orange County’s (OC) ocean, harbor and bay waters.

Oil, Food, and Water: Challenges and Opportunities for California Agriculture

Pacific Institute | December 1st, 2015

A new comprehensive study by the Pacific Institute  sheds light on the risks posed when oil and gas exploration and production operate alongside agriculture. “There

A new comprehensive study by the Pacific Institute  sheds light on the risks posed when oil and gas exploration and production operate alongside agriculture. “There is growing concern about competition for land and water, and the impacts of soil and water contamination on the food supply and health and safety of farmworkers and consumers,” said Matthew Heberger, the study’s lead author. The disposal of oil and gas wastewater, which contains harmful chemicals, is a particular concern for agriculture. Disposal in unlined percolation pits poses a significant risk of contaminating groundwater resources that may, in turn, be used by agriculture. While this practice has been banned in several states, it is still widely used in California’s Central Valley, one of the nation’s most important agricultural regions. There are also serious deficiencies in the way California regulates the underground injection of wastes – current practices are not sufficiently protective of freshwater aquifers that may be used as drinking water or to irrigate crops and water livestock.

Ojai Basin Groundwater Management Agency Groundwater Management Plan – 2018 Update

Ojai Basin Groundwater Management Agency | August 30th, 2018

In September, 2014, Governor Jerry Brown signed into law a package of three bills (AB 1739, SB 1168, and SB 1319) known as the Sustainable Groundwater Management Act (“

In September, 2014, Governor Jerry Brown signed into law a package of three bills (AB 1739, SB 1168, and SB 1319) known as the Sustainable Groundwater Management Act (“SGMA”). SGMA provides a framework for sustainable management of groundwater supplies by local authorities, with a limited role for state intervention only if necessary to protect the resource.  The Act requires the formation of local groundwater sustainability agencies that must assess conditions in their local water basins and adopt locally-based management plans. SGMA provides local agencies with the tools and authority to require registration of groundwater wells, measure and manage extractions, require reports and assess fees, and request revisions of basin boundaries, including establishing new subbasins.  High- and medium-priority basins, as defined by the State of California Department of Water Resources (“DWR”), must adopt groundwater sustainability plans within five to seven years, depending on whether the basin is in critical overdraft. Statewide groundwater basins are prioritized based on eight criteria: (1) overlying population, (2) projected growth of overlying population, (3) public supply wells, (4) total water wells, (5) overlying irrigated acreage, (6) reliance on groundwater as the primary source of water (7) impacts on the groundwater, including overdraft, subsidence, saline intrusion, and other water quality degradation, and (8) any other information determined to be relevant by the DWR.  Consistent with its Enabling Legislation, the Ojai Basin Groundwater Management Agency (“OBGMA” or “Agency”) has worked to preserve the quantity and quality of groundwater in the Ojai Valley Groundwater Basin (“Ojai Basin”) for sustainable long-term use since the agency’s establishment in 1991. (The Agency’s Enabling Legislation, SB 534, approved by the Governor October 8, 1991, is also referred to herein as the “OBGMA Act.”) These management efforts have resulted in the protection and maintenance of the long-term water supply for the common benefit of all water users in the Basin. As a result, the Ojai Basin has operated within its “sustainable yield” for the past several decades with no evidence of “undesirable results.”  Per OBGMA Resolution No. 2014-4, adopted by its Board of Directors on December 4, 2014 (copy included as Appendix A), OBGMA is designated as the Groundwater Sustainability Agency (“GSA”) for the Ojai Groundwater Basin. In addition, SGMA identifies OBGMA as an “exclusive local agency” within its statutory boundaries for purposes of implementing the requirements of the Act. (Water Code § 10723(c)(1).) Since OBGMA, in compliance with its Enabling Legislation, already performs many of the planning and management tasks required by SGMA, and sustainable conditions have persisted in the Basin for more than a 10-year period. OBGMA determined it would comply with SGMA by making the Alternative Demonstration of groundwater sustainability authorized by Water Code § 10733.6(b)(3).  To comply with SGMA, OBGMA issued its December 23, 2016 “Report Supporting Alternative Demonstration Made Pursuant to Water Code 10733.6(b)(3). The report contained a physical description of the Basin, including groundwater levels, groundwater quality, information on groundwater-surface water interaction, data on historical and projected water demands and supplies, monitoring and management provisions. The report demonstrated how the Ojai Basin has operated within its “sustainable yield” for the past several decades with no evidence of “undesirable results.”  In sum, OBGMA’s management of the Basin pursuant to its Enabling Legislation has allowed the Agency to make the Alternative Demonstration authorized by SGMA. This 2018 Update to the Agency’s Groundwater Management Plan, undertaken in compliance with its Enabling Legislation, is part of the Agency’s ongoing efforts to preserve the long-term quantity and quality of groundwater in the Ojai Basin for the common benefit all users in the Basin. 

Opportunities to Accelerate Nature-Based Solutions: A Roadmap for Climate Progress, Thriving Nature, Equity, and Prosperity

White House Domestic Climate Policy Office | November 30th, 2022

Opportunities to protect drinking water sources and advance watershed goals through the Clean Water Act

U.S. Environmental Protection Agency (EPA) | November 10th, 2014

We live in times of both declining public agency resources and increasing complexity of environmental and public health problems, like the increasing occurrence, intensit

We live in times of both declining public agency resources and increasing complexity of environmental and public health problems, like the increasing occurrence, intensity, and duration of harmful algal blooms and precursors to disinfection by-products in drinking water. These and other problems are compounded by population growth, climate extremes, and excess water in some places as well as insufficient water in others. Complex times demand creative and thoughtful approaches to challenges. It is critical that we find innovative solutions that leverage expertise, resources, efficiencies, and authorities to achieve our Nation’s water quality and source water protection goals. As part of a State-U.S. Environmental Protection Agency (EPA) collaboration initiative, a workgroup was formed to identify opportunities to coordinate among clean water and drinking water programs. This workgroup recognizes that many difficult issues cross program boundaries, and thus a coordinated approach has the potential to make greater headway nationally. In developing the product that follows, the workgroup also drew on the experiences of states and EPA practitioners managing these programs. This Toolkit is a result of state and EPA collaboration. It could not have been developed without the time, effort and dedication of those who contributed to it and particularly the expertise of the state and EPA regional participants who are implementing the practices in this report. This initiative and Toolkit invite a more holistic and coordinated planning and funding approach between the clean water and drinking water programs, and with other public and private partners at the federal, state, and local levels, including water and wastewater utilities. The opportunities outlined in this Toolkit do not reflect all possible environmental authorities that may work together to protect drinking water; it is beyond the scope of this document to acknowledge all threats to, and challenges involved in, protecting drinking water. Instead, the suggestions below describe the fundamental steps toward protective actions that may catalyze broader collaboration among a diversity of programs and entities. It is important to note that this Toolkit does not impose legally binding requirements on EPA, states, tribes, or the regulated community, nor does it confer legal rights or impose legal obligations on any member of the public. This Toolkit does not constitute a regulation, nor does it change or substitute for any Clean Water Act or Safe Drinking Water Act1 provision or EPA regulations. Rather, this Toolkit is designed to support discussion, institutional change, and advance water quality goals and the protection of drinking water sources of public water systems (PWSs)2, also known as source water protection.