Colorado River

Selected trace-elements in alluvium and rocks, western Mojave Desert, southern California

Journal of Geochemical Exploration (Elsevier) | September 3rd, 2018

Concentrations of twenty-seven elements, including naturally-occurring water-quality contaminants arsenic, chromium, and uranium, were measured in 217 samples of alluviu

Concentrations of twenty-seven elements, including naturally-occurring water-quality contaminants arsenic, chromium, and uranium, were measured in 217 samples of alluvium and rock from the western Mojave Desert, southern California, using portable (pXRF) and laboratory (LXRF) X-ray fluorescence. Comparison of measurements with NIST-traceable standards was good, although pXRF overestimated iron compared to LXRF. Results suggest pXRF survey data are sufficiently accurate to assess regional geochemical differences in geologic-source terrains. Principal component analysis showed rubidium and potassium were associated with alluvium eroded from felsic terrain, while iron, copper, chromium, and to a lesser extent titanium, manganese, and nickel were associated with alluvium eroded from mafic terrain. Zinc, vanadium, and arsenic were associated with alluvium eroded from hydrothermal terrain. Elemental assemblages associated with different source terrains were traced spatially to identify the source and composition of alluvium composing aquifers pumped for water supply. Changes in geologic source terrain to the Mojave River, associated with movement along the San Andreas Fault over the past one to five million years, reduced the mafic fraction and increased the felsic fraction of alluvium deposited to the regionally important floodplain aquifer along the Mojave River—lowering chromium concentrations in alluvium through geologic time. Comparison of pXRF and sequential extraction data from 40samples showed arsenic and uranium were more abundant on the surfaces of mineral grains, while chromium and vanadium remained mostly within unweathered mineral grains—suggesting arsenic and uranium may be more readily mobilized into groundwater with changes in pH, redox, or ionic strength than chromium or vanadium.

Selenium Hazards in the Salton Sea Environment— Summary of Current Knowledge to Inform Future Wetland Management

U.S. Geological Survey (USGS) | July 20th, 2023

Quaternary marine and continental shales in the western United States are sources of selenium that can be loaded into the aquatic environment through mining, agricultural

Quaternary marine and continental shales in the western United States are sources of selenium that can be loaded into the aquatic environment through mining, agricultural, and energy production processes. The mobilization of selenium from shales through agricultural irrigation has been recognized since the 1930s; however, discovery of deformities in birds and other wildlife using agricultural habitats during the 1980s spurred studies to determine the extent and effects of the contamination. Through these early studies, researchers determined that biota in the Salton Sea drainage basin was at risk from legacy selenium contamination in the Colorado River watershed.

Senate Bill No. 1157

State of California | September 28th, 2022

Senate Bill No. 389, Chapter 486, An act to amend Section 1051 of the Water Code, relating to water

State of California Office of Legislative Counsel | October 8th, 2023

Click here for analysis by Legal Planet.

Click here for analysis by Legal Planet.

Sensitivity of Mountain Hydroclimate Simulations in Variable-Resolution CESM to Microphysics and Horizontal Resolution

American Geophysical Union (AGU) | July 31st, 2018

Serum concentrations of PFASs and exposure-related behaviors in African American and non-Hispanic white women

Journal of Exposure Science & Environmental Epidemiology (Springer) | January 8th, 2019

Per- and polyfluoroalkyl substances (PFASs) are used in a wide range of consumer products for their water- and grease-resistant properties, but few studies have e

Per- and polyfluoroalkyl substances (PFASs) are used in a wide range of consumer products for their water- and grease-resistant properties, but few studies have explored this exposure route. We used multiple regression to investigate associations between six self-reported behaviors hypothesized to influence PFAS exposure and serum concentrations of six PFAS chemicals in 178 middle-aged women enrolled in the Child Health and Development Studies, about half of whom are African American. Blood samples were collected in 2010–2013, and participants were interviewed about behavior in 2015–2016. Results showed that African American women had lower levels of perfluorooctanoic acid (PFOA) and perfluorohexanesulfonic acid (PFHxS) compared with non-Hispanic white women. In African Americans, but not others, frequent consumption of prepared food in coated cardboard containers was associated with higher levels of four PFASs. Flossing with Oral-B Glide, having stain-resistant carpet or furniture, and living in a city served by a PFAS-contaminated water supply were also associated with higher levels of some PFASs. Product testing using particle-induced γ-ray emission (PIGE) spectroscopy confirmed that Oral-B Glide and competitor flosses contained detectable fluorine. Despite the delay between blood collection and interview, these results strengthen the evidence for exposure to PFASs from food packaging and implicate exposure from polytetrafluoroethylene (PTFE)-based dental floss for the first time.

SGMA Alternative Groundwater Sustainability Plan – Bridge Document for the Indio Subbasin

Coachella Valley Water District (CVWD) | December 15th, 2016

Decline in the Coachella Valley’s groundwater table was first noted in the 1910s. Concerned that their artesian wells were drying, local residents and farmers formed th

Decline in the Coachella Valley’s groundwater table was first noted in the 1910s. Concerned that their artesian wells were drying, local residents and farmers formed the Coachella Valley Water District (CVWD) in 1918. CVWD took steps to secure water supplies from the Colorado River that led to the completion of the Coachella Branch of the All-American Canal in 1949. CVWD and Desert Water Agency (DWA) contracted with the State of California for water from the State Water Project (SWP) in the early 1960s with the first deliveries in 1973. At that time, CVWD and DWA implemented groundwater replenishment programs and collected replenishment assessment from groundwater producers. However, continued growth in the Valley resulted in groundwater level declines and overdraft. Twenty years before the adoption of SGMA, CVWD began development of the initial Water Management Plan in 1994 after recognizing the need to sustainably manage the Coachella Valley Groundwater Basin. CVWD adopted the Coachella Valley Water Management Plan in 2002 (2002 WMP) to eliminate groundwater overdraft in the Basin. The 2002 WMP was updated in 2010 (2010 WMP Update) and adopted in 2012. This plan covers the Indio Subbasin of the Coachella Valley Groundwater Basin. CVWD, along with DWA and Mission Springs Water District also prepared the Mission Creek-Garnet Hill Water Management Plan (MCGH WMP) that covers the Mission Creek Subbasin and the Garnet Hill Subarea of the Indio Subbasin. As of 2016, plan implementation is showing positive results with stabilizing water levels throughout much of the Valley. Continued implementation is expected to eliminate water level declines by about 2025.

SGMA Alternative Groundwater Sustainability Plan Bridge Document for the Indio Subbasin

Coachella Valley Water District (CVWD) | December 29th, 2016

SGMA Alternative Groundwater Sustainability Plan Bridge Document for the Mission Creek Subbasin

Coachella Valley Water District (CVWD) | December 29th, 2016

Sharpening of cold-season storms over the western United States

Nature Portfolio (Springer Nature) | January 19th, 2023

Winter storms are responsible for billion-dollar economic losses in the western United States. Because storm structures are not well resolved by global climate models, it

Winter storms are responsible for billion-dollar economic losses in the western United States. Because storm structures are not well resolved by global climate models, it is not well established how single events and their structures change with warming. Here we use regional storm-resolving simulations to investigate climate change impact on western US winter storms. Under a high-emissions scenario, precipitation volume from the top 20% of winter storms is projected to increase by up to 40% across the region by mid-century. The average increase in precipitation volume (31%) is contributed by 22% from increasing area coverage and 19% from increasing storm intensity, while a robust storm sharpening with larger increase in storm centre precipitation compared with increase in storm area reduces precipitation volume by 10%. Ignoring storm sharpening could result in overestimation of the changes in design storms currently used in infrastructure planning in the region.