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Inter- and intra-ethnic variation in water intake, contact, and source estimates among Tucson residents: Implications for exposure analysis

Journal of Exposure Science & Environmental Epidemiology (Springer) | January 7th, 2002

Summary

Water-related exposures among Hispanics, particularly among Mexican Americans, are relatively unknown. Exposure and risk assessment is further complicated by the

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Inter-population differences in salinity tolerance of adult wild Sacramento splittail: osmoregulatory and metabolic responses to salinity

Conservation Physiology (Society of Experimental Biology) | December 10th, 2020

Summary

The Sacramento splittail (Pogonichthys macrolepidotus) is composed of two genetically distinct populations endemic to the San Francisco Estuary (SFE). The allop

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Interactions between snow cover and evaporation lead to higher sensitivity of streamflow to temperature

Nature Portfolio (Springer Nature) | December 4th, 2020

Summary

Estimates of potential evaporation often neglect the effects of snow cover on evaporation process. Here, we present a definition of potential evaporation that explicitly

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Interim instream flow criteria for the protection of fishery resources in the Scott River watershed, Siskiyou County

California Department of Fish and Wildlife (CDFW) | February 6th, 2017

Summary

This document describes the methods and results of an analysis using historical flow data and regional regression relationships to develop interim instream flow criteria

This document describes the methods and results of an analysis using historical flow data and regional regression relationships to develop interim instream flow criteria suitable for anadromous fish in the Scott River watershed in Siskiyou County. The Scott River watershed provides aquatic habitat for four species of anadromous fish; Chinook Salmon (Oncorhynchus tshawytscha), Coho Salmon (O. kisutch), steelhead trout (O. mykiss), and Pacific Lamprey (Lampetra tridentata). Specifically, the Scott River is one of the most important Coho Salmon spawning and rearing tributaries in the Klamath River watershed. Instream flow requirements can be generated from flow standard setting techniques or from the results of site specific studies. The interim instream flow criteria presented for the Scott River were developed using flow standard setting techniques. Stream flow standards derived from standard setting techniques are designed to identify the environmental resource in need of flow protection, identify biologically significant criterion that can be used to measure potential flow related impacts, and specify the amount of flow required to protect the resource. Most individual standards evaluate only one or more, but not all the criterion needed to fully evaluate the flow needs of an aquatic species. This limitation can lead to prescribing a single minimum threshold or “flat-line” affect (Poff et al. 1997). The seasonal and inter-annual variability in the hydrograph must be maintained to protect stream ecology and provide an ecosystem based standard (Annear 2004). To account for the seasonal and the inter-annual hydrologic variability of the Scott River, the Department applied a detailed hydrologic analysis along with application of three standard setting methods to evaluate the life history flow needs of salmonids in the Scott River near Fort Jones. Adult fish passage was estimated using the equation developed by R2 Resources (R2 2008) for the State Water Resources Control Board’s (SWRCB) North Coast Instream Flow Policy (SWRCB 2014), spawning and juvenile rearing were evaluated using the Hatfield and Bruce regional equations (Hatfield and Bruce 2000), and the results were adjusted monthly based on estimates of unimpaired hydrology using Tessmann’s adaptation (Tessmann 1980) of the Tennant or Montana Method (Tennant 1975).

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Interpretation of Hydrostratigraphy and Water Quality from AEM Data Collected in the Northern Salinas Valley, CA

Marina Coast Water District | March 15th, 2018

Summary

Groundwater management, in the Monterey area of California, requires an accurate understanding of the hydrostratigraphy of the coastal aquifer system, as well as an unde

Groundwater management, in the Monterey area of California, requires an accurate understanding of the hydrostratigraphy of the coastal aquifer system, as well as an understanding of the groundwater quality variability within that system. The hydraulic properties of, and connectivity between, the individual units in the aquifer system determine potential routes for the movement of groundwater within and between aquifers. An understanding of the distribution of water quality within the aquifer system and an understanding of the hydrostratigraphy of the system are needed to evaluate the current state of groundwater resources, and to assess the potential impact of any proposed activity on the groundwater resources in the area. The focus of this study is the Northern Salinas Valley. Figure 1 shows the specific region of interest outlined in pink. The orange contour shows the extent of saltwater intrusion into the uppermost aquifers in this area, as determined from well data by the Monterey County Water Resources Agency as the regions where groundwater contains concentrations of chloride greater than 500 mg/L. But there is some question as to whether this contour accurately captures the extent of saltwater intrusion into these aquifers. The detection of water with anomalously low concentrations of total dissolved solids in five newly constructed monitoring well clusters suggests the presence of isolated lenses of fresher groundwater in the Dune Sand Aquifer and Perched Dune Sand Aquifer (outlined in light blue) and in the 180-Foot Aquifer (outlined in dark blue) (Hopkins Groundwater Consultants, 2016). The locations of seven wells from the Monterey Peninsula Water Supply Project (MPWSP) are also shown in Figure 1 as red diamonds, and wells owned by the Marina Coast Water District (MCWD) are shown as green circles. The two groundwater subbasins in the region of interest—the Monterey Subbasin and the 180/400 Aquifer Subbasin—are outlined in purple and blue, respectively. The objective of this study was to use the geophysical method, airborne electromagnetics (AEM), to evaluate the current understanding of the hydrostratigraphy in this area and to interpret the distribution of groundwater quality indicated by available well data. To evaluate the understanding of the hydrostratigraphy, a hydrostratigraphic model of the region of interest was first built using existing data, and was then updated with the information supplied by the AEM data. This approach was followed for two separate initial models. The first initial model was based on the North Marina Groundwater Model (NMGWM), developed by Geoscience Support Services as part of the MPWSP. The second initial model was built in-house using lithology data and hydrostratigraphic interpretations from a variety of previously published reports. Our interpretation of the distribution of groundwater quality in the region is based on statistical relationships built between water quality samples and borehole geophysical data collected in the wells shown in Figure 1.

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Investing In Clean Agriculture: How California Can Strengthen Agriculture, Reduce Pollution And Save Money

Pacific Institute | February 8th, 2005

Summary

Global competition, suburban encroachment, tighter regulations, and rising input costs are making farming in California more difficult and, in some cases, less profitable

Global competition, suburban encroachment, tighter regulations, and rising input costs are making farming in California more difficult and, in some cases, less profitable. At the same time, pesticide pollution from farming is causing significant harm to California’s surface and groundwater, air quality, and human health. But there is a way to reduce pesticide use, protect the environment, and help farmers stay competitive according to a new report, Investing In Clean Agriculture: How California Can Strengthen Agriculture, Reduce Pollution And Save Money, published today by the Pacific Institute. “Business as usual isn’t working for our state,” declared Dr. Gary H. Wolff, author of the report and Principal Economist and Engineer with the Pacific Institute of Oakland, California. “Our plan will reduce pesticide use, protect public health, preserve the environment, and help California’s farmers stay competitive in a rapidly changing economy. We think this will be a win for consumers, a win for taxpayers, and a win for agriculture.” A US Geological Survey study of groundwater wells in the San Joaquin-Tulare Basin found at least one pesticide in 59 of 100 samples. But current efforts to reduce pesticide pollution are caught up in the courts. The rebate approach creates a voluntary incentive to reduce pesticide use while leaving it up to farmers to figure out the best way forward. “The Pacific Institute’s innovative proposal will reward farmers who are willing to learn about farming practices that protect water quality,” noted Leland Swenson of the Community Alliance With Family Farmers. “It is a voluntary and incentive-based way for farmers to respond to water quality regulations and keep pesticides out of drinking water.” The report describes how farmers can be rewarded for learning voluntarily about sustainable agricultural practices. A modest increase in the statewide “mill” fee, now levied on pesticides, is returned to farmers who take a short course on sustainable agriculture techniques and storm runoff management. This helps farmers stay competitive while reducing pesticide use – which will protect human health, preserve the environment, and eventually save taxpayers money by reducing medical costs. “Everybody wins if we can reduce our dependence on pesticides,” said Jonathan Kaplan of NRDC. “As the head of California’s Department of Pesticide Regulation just stated, ‘Integrated Pest Management is good for our economy as well as our environment’.” Investing In Clean Agriculture: How California Can Strengthen Agriculture, Reduce Pollution And Save Money estimates that the voluntary program and fee increase could bring $60 million per year into the agricultural sector while also bringing the most cutting edge research on sustainable farming techniques to those in the field.

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Is there an urban pesticide signature? Urban streams in five U.S. regions share common dissolved-phase pesticides but differ in predicted aquatic toxicity

Science of the Total Environment (Elsevier) | June 15th, 2021

Summary

Pesticides occur in urban streams globally, but the relation of occurrence to urbanization can be obscured by regional differences. In studies of five regions of the Unit

Pesticides occur in urban streams globally, but the relation of occurrence to urbanization can be obscured by regional differences. In studies of five regions of the United States, we investigated the effect of region and urbanization on the occurrence and potential toxicity of dissolved pesticide mixtures. We analyzed 225 pesticide compounds in weekly discrete water samples collected during 6–12 weeks from 271 wadable streams; development in these basins ranged from undeveloped to highly urbanized. Sixteen pesticides were consistently detected in 16 urban centers across the five regions—we propose that these pesticides comprise a suite of urban signature pesticides (USP) that are all common in small U.S. urban streams. These USPs accounted for the majority of summed maximum pesticide concentrations at urban sites within each urban center. USP concentrations, mixture complexity, and potential toxicity increased with the degree of urbanization in the basin. Basin urbanization explained the most variability in multivariate distance-based models of pesticide profiles, with region always secondary in importance. The USPs accounted for 83% of pesticides in the 20 most frequently occurring 2-compound unique mixtures at urban sites, with carbendazim+prometon the most common. Although USPs were consistently detected in all regions, detection frequencies and concentrations varied by region, conferring differences in potential aquatic toxicity. Potential toxicity was highest for invertebrates (benchmarks exceeded in 51% of urban streams), due most often to the neonicotinoid insecticideimidacloprid and secondarily to organophosphate insecticides and fipronil. Benchmarks were rarely exceeded in urban streams for plants (at 3% of sites) or fish (<1%). We propose that the USPs identified here would make logical core (nonexclusive) constituents for monitoring dissolved pesticides in U.S. urban streams, and that unique mixtures containing imidacloprid, fipronil, and carbendazim are priority candidates for mixtures toxicity testing.

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Joint Report to the Legislature on the Department of Fish and Wildlife and State Water Resources Control Board pilot project to address the Environmental Impacts of Cannabis Cultivation (Watershed Enforcement Team)

California State Water Resources Control Board (SWRCB) | March 16th, 2015

Summary

This report is in response to the 2014-2015 Supplemental Report for item 3600-001-0001-Department of Fish and Wildlife (Department or CDFW), which provides the following

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Kern County Subbasin Staff Review of 2025 Draft of Groundwater Sustainability Plans

California State Water Resources Control Board (SWRCB) | September 5th, 2025

Summary

The Kern County Subbasin (subbasin or basin) is a critically overdrafted subbasin in the southern portion of the San Joaquin Valley with an area of about 1.78 million acr

The Kern County Subbasin (subbasin or basin) is a critically overdrafted subbasin in the southern portion of the San Joaquin Valley with an area of about 1.78 million acres. The subbasin is currently managed by 20 GSAs. DWR determined the subbasin’s 2022 GSPs were inadequate and referred the subbasin to the State Water Board in March 2023, which initiated the state intervention process. The subbasin GSAs submitted their revised, adopted GSPs to the Board in December 2024, and Board staff determined that these updated GSPs did not resolve all the deficiencies identified by staff in the previous GSPs. On February 20, 2025, the State Water Board held a hearing to determine whether to designate the subbasin as probationary. In recognition of the substantial progress the subbasin made, the Board continued the hearing to September 17, 2025, giving the GSAs additional time to resolve the remaining deficiencies and directing the GSAs to submit revised draft GSPs to the Board by June 20, 2025 for review. On June 20, 2025, the GSAs submitted seven amended draft GSPs to the Board (2025 Draft GSPs). Board staff reviewed the 2025 Draft GSPs and conclude that the GSAs substantially, though not completely, address the deficiencies identified in the previous GSPs. Staff recommends returning the subbasin to DWR for review of the updated GSPs pursuant to Water Code section 10733.4 if the GSAs resolve three of the remaining issues: (1) providing an adequate mitigation program for drinking water wells impacted by any constituent for which a minimum threshold is established in the GSPs, including 1,2,3-TCP, where groundwater management activities cause concentrations to exceed those minimum thresholds; (2) providing an adequate mitigation program for state small water system wells (or domestic wells with more than four service connections) impacted by groundwater management activities; and (3) eliminating the Kern Non-Districted Land Authority GSA Joint Exercise of Powers Agreement May 2026 sunset provision, which would result in unmanaged areas of the subbasin that are a potential basis for state intervention.

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Lahar Hazard Zones for Eruption-Generated Lahars in the Lassen Volcanic Center, California

U.S. Geological Survey (USGS) | September 25th, 2012

Summary

Lahars, Indonesian for volcanic mudflows or debris-flows, are a rapidly flowing mixture of rock debris and water that originates on the slopes of a volcano. Lahar generat

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Page : 54

Inter- and intra-ethnic variation in water intake, contact, and source estimates among Tucson residents: Implications for exposure analysis

Inter-population differences in salinity tolerance of adult wild Sacramento splittail: osmoregulatory and metabolic responses to salinity

Interactions between snow cover and evaporation lead to higher sensitivity of streamflow to temperature

Interim instream flow criteria for the protection of fishery resources in the Scott River watershed, Siskiyou County

Interpretation of Hydrostratigraphy and Water Quality from AEM Data Collected in the Northern Salinas Valley, CA

Investing In Clean Agriculture: How California Can Strengthen Agriculture, Reduce Pollution And Save Money

Is there an urban pesticide signature? Urban streams in five U.S. regions share common dissolved-phase pesticides but differ in predicted aquatic toxicity

Joint Report to the Legislature on the Department of Fish and Wildlife and State Water Resources Control Board pilot project to address the Environmental Impacts of Cannabis Cultivation (Watershed Enforcement Team)

Kern County Subbasin Staff Review of 2025 Draft of Groundwater Sustainability Plans

Lahar Hazard Zones for Eruption-Generated Lahars in the Lassen Volcanic Center, California

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