Statement of Findings Regarding the Approval of the Sacramento Valley – Red Bluff Subbasin 2024 Groundwater Sustainability Plan

California Department of Water Resources (DWR) | February 27th, 2025

Statement of Findings Regarding the Approval of the San Joaquin Valley – Turlock Subbasin 2024 Groundwater Sustainability Plan

California Department of Water Resources (DWR) | February 27th, 2025

Statement of Findings Regarding the Determination of Inadequate Status of the San Joaquin Valley – Pleasant Valley Subbasin 2024 Groundwater Sustainability Plan

California Department of Water Resources (DWR) | February 27th, 2025

Surface Water-Groundwater Interaction Report, Ventura River Habitat Conservation Plan, Ventura River, California

County of Ventura | February 12th, 2001

ENTRIX, Inc. was contracted by the Cooperating Agencies to perform an analysis of surface water and groundwater hydrology in the Ventura River basin as part of th

ENTRIX, Inc. was contracted by the Cooperating Agencies to perform an analysis of surface water and groundwater hydrology in the Ventura River basin as part of the Habitat Conservation Plan (HCP) for the Ventura River in Ventura County, California. The Cooperating Agencies consist of the County of Ventura, the Ventura County Flood Control District (VCFCD), the City of San Buenaventura, the Casitas Municipal Water District (Casitas), the Meiners Oaks County Water District (MOCWD), the Ojai Valley Sanitary District (OVSD), the Ojai Basin Groundwater Management Agency, the Southern California Water Company (SCWC), the Ventura County Water Agency, and the City of Ojai. These agencies all operate and maintain facilities that may affect sensitive biological resources along the Ventura River. To comply with the Endangered Species Act (ESA), the agencies are developing a HCP in consultation with the National Marine Fisheries Service (NMFS) and U.S. Fish and Wildlife Service (USFWS) to serve as the basis for an Incidental Take Permit. The objectives of the surface water-groundwater interaction evaluation, outlined in The Ventura River Habitat Conservation Plan Technical Approach dated March 30, 2000, are to develop an improved understanding of the hydrologic system dynamics and determine the likelihood of groundwater pumping impacts on surface flows, based on available empirical data. The scope of work involved collecting and evaluating available surface flow and groundwater data and prior analyses of the surface and groundwater system. The focus of the evaluation was on the river reaches where the Cooperating Agencies can affect flow. The availability of concurrent surface flow and groundwater data determined the study period(s) and specific reaches analyzed. The study is focused on the Upper Ventura River and San Antonio Creek basins, and a brief discussion is also included for the Ojai Valley groundwater basin. The data reviewed as part of the evaluation included seasonal changes in groundwater levels and groundwater storage, groundwater flow relationships, and estimated contributions from groundwater to surface water.

Wetland Management Strategy to Reduce Mercury in Water and Bioaccumulation in Fish

Society of Environmental Toxicology and Chemistry (SETAC) | July 25th, 2019

Wetland environments provide numerous ecosystem services but also facilitate methylmercury (MeHg) production and bioaccumulation. We developed a wetland‐management tech

Wetland environments provide numerous ecosystem services but also facilitate methylmercury (MeHg) production and bioaccumulation. We developed a wetland‐management technique to reduce MeHg concentrations in wetland fish and water. We physically modified seasonal wetlands by constructing open‐ and deep‐water treatment cells at the downstream end of seasonal wetlands to promote naturally occurring MeHg‐removal processes. We assessed the effectiveness of reducing mercury (Hg) concentrations in surface water and western mosquitofish that were caged at specific locations within 4 control and 4 treatment wetlands. Methylmercury concentrations in wetland water were successfully decreased within treatment cells during only the third year of study; however, treatment cells were not effective for reducing total Hg concentrations. Furthermore, treatment cells were not effective for reducing total Hg concentrations in wetland fish. Mercury concentrations in fish were not correlated with total Hg concentrations in filtered, particulate, or whole water; and the slope of the correlation with water MeHg concentrations differed between months. Fish total Hg concentrations were weakly correlated with water MeHg concentrations in April when fish were introduced into cages but were not correlated in May when fish were retrieved from cages. Fish total Hg concentrations were greater in treatment wetlands than in control wetlands the year after the treatment wetlands’ construction but declined by the second year. During the third year, fish total Hg concentrations increased in both control and treatment wetlands after an unexpected regional flooding event. Overall, we found limited support for the use of open‐ and deep‐water treatment cells at the downstream end of wetlands to reduce MeHg concentrations in water but not fish. We suggest that additional evaluation over a longer period of time is necessary.