Evaluating groundwater quality influences from oil field operations and other anthropogenic activities in an urban setting, Santa Fe Springs, California

Science of the Total Environment (Elsevier) | June 22nd, 2026

Groundwater quality is often affected by anthropogenic activities in urban settings. This study examines groundwater quality in and around the Santa Fe Springs Oil Field

Groundwater quality is often affected by anthropogenic activities in urban settings. This study examines groundwater quality in and around the Santa Fe Springs Oil Field in Los Angeles County, California, where oil and gas production commonly intersects with high density industrial, commercial and residential land uses. Utilizing a combination of new and historical data, we evaluated potential pathways that would allow for oil field formation fluids to migrate into groundwater and whether mixing may have occurred based on the distribution of groundwater and oil field formation fluid tracers in samples. Samples were analyzed for a wide array of constituents including volatile organic compounds, light hydrocarbons, major ions, and various isotopic compositions. Despite evidence of oil field infrastructure providing potential pathways of migration via uncemented annular spaces, casing breaches and historical disposal of oil field formation water in surface ponds, the distribution and occurrence of stable isotopes of water, chloride, boron, and total dissolved solids do not indicate mixing of oil field formation water and groundwater. However, methane isotopic signatures and the presence of heavier alkanes suggest gas from oil-bearing formations have migrated from depth via oil field well infrastructure. Volatile organic compound detections were mainly from manufactured compounds unrelated to oil and gas production, with a relatively limited number of petroleum hydrocarbons also detected. Volatile organic compounds were generally found in wells tapping shallow, modern aged groundwater, indicating anthropogenic activities occurring at or near land surface as the source. Study results suggest that while oil field infrastructure provides migration pathways for oil field formation fluids to be introduced into groundwater, urban land uses not related to oil and gas production are the primary drivers of groundwater quality degradation.

Evaluating historical changes in a mussel bed community in northern California

Nature Portfolio (Springer Nature) | January 14th, 2025

Evaluating Micrometeorological Estimates of Groundwater Discharge from Great Basin Desert Playas

National Groundwater Association (NGWA) | March 6th, 2018

Groundwater availability studies in the arid southwestern United States traditionally have assumed that groundwater discharge by evapotranspiration (ETg) from desert play

Groundwater availability studies in the arid southwestern United States traditionally have assumed that groundwater discharge by evapotranspiration (ETg) from desert playas is a significant component of the groundwater budget. However, desert playa ETg rates are poorly constrained by Bowen ratio energy budget (BREB) and eddy‐covariance (EC) micrometeorological measurement approaches. Best attempts by previous studies to constrain ETg from desert playas have resulted in ETg rates that are within the measurement error of micrometeorological approaches. This study uses numerical models to further constrain desert playa ETg rates that are within the measurement error of BREB and EC approaches, and to evaluate the effect of hydraulic properties and salinity‐based groundwater density contrasts on desert playa ETg rates. Numerical models simulated ETg rates from desert playas in Death Valley, California and Dixie Valley, Nevada. Results indicate that actual ETg rates from desert playas are significantly below the uncertainty thresholds of BREB‐ and EC‐based micrometeorological measurements. Discharge from desert playas likely contributes less than 2% of total groundwater discharge from Dixie and Death Valleys, which suggests discharge from desert playas also is negligible in other basins. Simulation results also show that ETg from desert playas primarily is limited by differences in hydraulic properties between alluvial fan and playa sediments and, to a lesser extent, by salinity‐based groundwater density contrasts.

Evaluating the Accuracy of Reclamation’s 24-Month Study Lake Powell Projections

Utah State University | February 18th, 2022

The bias for inflow predictions will likely be reduced now that the reference period includes a more recent, and somewhat drier, span of time, but projections of future i

The bias for inflow predictions will likely be reduced now that the reference period includes a more recent, and somewhat drier, span of time, but projections of future inflows are likely to remain biased, because the hydrology of the 1991-2020 reference period was still wetter than the current Millennium Drought.

Evaluating the Effects of Turf-Replacement Programs in Los Angeles County

University of California, Los Angeles (UCLA) | August 4th, 2017

In 2014, the Metropolitan Water District of Southern California (MWD) undertook an unprecedented investment to incentive turf replacement throughout Southern California i

In 2014, the Metropolitan Water District of Southern California (MWD) undertook an unprecedented investment to incentive turf replacement throughout Southern California in response to the state’s serious drought. MWD devoted $350 million to the program, resulting in more than 46,000 rebate payments to remove 165 million square feet of turf. The funding boost served as a tremendous natural experiment to better understand the effects turf replacement programs. As part of an evaluation of this program, UCLA and the University of Utah examined socio-economic and demographic characteristics of program participation and assessed changes in vegetation and landscapes of front yards resulting from turf replacement. We examined address-level records of 24,921 participants who applied for turf replacement rebates between February 2014 and April 2016 in Los Angeles (LA) County. We analyzed the socioeconomic and spatial determinants of program participation. Further, we used Google Earth Street View to characterize the landscapes and plants resulting from turf replacement based on a set of randomly selected participating properties. We ascertained the types of turf replacements that were installed and developed a classification system for landscape design types.

Evaluating the environmental impact of cleaning the North Pacific Garbage Patch

Nature Portfolio (Springer Nature) | May 27th, 2025

Evaluating the hidden costs of drinking water treatment technologies

Nature Portfolio (Springer Nature) | April 3rd, 2023

Drinking water treatment technologies are largely evaluated on the basis of metrics such as contaminant removal efficiency, capital costs and health impacts. However, the

Drinking water treatment technologies are largely evaluated on the basis of metrics such as contaminant removal efficiency, capital costs and health impacts. However, the potential for safe water technologies to lead to positive health outcomes depends greatly on user satisfaction, consistent and sustained operation, and financial viability. In this Perspective, we argue for the importance for engineering, public health and economics researchers to assess the ‘hidden’ costs of drinking water treatment technologies, including affordability, labour burden, user acceptance, and the (often) gendered nature of these. Neglecting these factors results in an underestimation of the full costs of drinking water treatment technologies and an overestimation of the potential for treatment options that require substantial behaviour change and time to succeed. Here we present a set of user-centric evaluation criteria for water service providers, practitioners, governments and other stakeholders to consider when deciding which drinking water treatment technologies to implement, scale up or take to market.

Evaluating the hydrologic effects of the 2021–2022 Scott and Shasta irrigation curtailments using remote sensing and streamflow gages

Klamath Tribal Water Quality Consortium | September 11th, 2023

Key Points • Satellite remote sensing data indicated that curtailment orders in 2022 reduced consumptive water use (evapotranspiration, ETa) on agricultural lands i

Key Points • Satellite remote sensing data indicated that curtailment orders in 2022 reduced consumptive water use (evapotranspiration, ETa) on agricultural lands in Shasta Valley, but not Scott Valley. • Streamflow gage data indicate that flows in the Shasta River and some Scott River tributaries (Shackleford and French creeks) were substantially higher in summer 2022 than 2020 or 2021, but similar increases did not occur in the mainstem Scott River. • A likely major reason for the lack of Scott River flow increases was that groundwater use was allowed to continue under Local Cooperative Solutions (LCS) agreements in which water users agreed to reduce pumping by 30% from a prior year baseline. Despite abundant worldwide evidence that reducing consumptive use (i.e., evapotranspiration) is key to increasing environmental water, all LCS cropping and irrigation practices were given equal weight toward the 30% reduction, regardless of the effects on consumptive use. Pumping was not measured and compliance was primarily self-reported, with limited independent verification.

Evaluation and Refinement of Chlorophyll-a Algorithms for High-Biomass Blooms in San Francisco Bay

Remote Sensing (MDPI) | March 21st, 2024

Evaluation and Synthesis of the Yolo Bypass Fish Monitoring Program

U.S. Geological Survey (USGS) | August 18th, 2026

The Yolo Bypass is the largest functional remnant floodplain of the Sacramento River, providing benefits to aquatic taxa of the San Francisco Bay and Sacram

The Yolo Bypass is the largest functional remnant floodplain of the Sacramento River, providing benefits to aquatic taxa of the San Francisco Bay and Sacramento–San Joaquin Delta (hereafter, Bay-Delta). Because of the Yolo Bypass’s vital role in flood control and its ecological effects, the California Department of Water Resources started the Yolo Bypass Fish Monitoring Program (YBFMP) to monitor the aquatic ecology of the floodplain. Here, we present a scientific evaluation of the monitoring program to assess the efficacy and efficiency of the program in meeting its objective of collecting biological data to understand the ecological role the Yolo Bypass plays in the larger Bay-Delta. We used a multivariate assessment of floodplain flow to classify flood events (no flood, intense, early, late) and water years (low, average, high). To assess efficacy, we used a null hypothesis approach to determine if the YBFMP could distinguish variability in measured constituents (water quality and nutrient concentrations; phytoplankton, zooplankton, drift invertebrates, and fish communities; and densities of Chinook salmon [Oncorhynchus tshawytscha], Sacramento splittail [Pogonichthys macrolepidotus], and prickly sculpin [Cottus asper]) across different flood regime classifications. To assess efficiency, we used a data subsampling approach to quantify the amount of data needed to reach similar conclusions to analyses that used the entire dataset. Regarding efficacy, we concluded that the YBFMP is generally effective at identifying variability across various spatial and temporal scales (including flood regimes). Regarding efficiency, we concluded that reduced sampling effort would likely result in similar conclusions, enabling program managers to identify sites or periods that do not provide data essential to meeting program objectives. Our evaluation of the YBFMP indicated where data variability might limit mechanistic inference (particularly for phytoplankton and zooplankton), thus indicating that a series of targeted studies may be a prerequisite for further analysis. This evaluation has also identified areas where existing sampling may not be providing additional informational value, allowing for reallocation of effort to address management concerns.