Tehachapi Reclaimed Water Project

City of Tehachapi | September 24th, 2024

As part of the proposed project, the City would change the location of application of the secondary treated effluent produced at the Tehachapi WWTP from the agricultural

As part of the proposed project, the City would change the location of application of the secondary treated effluent produced at the Tehachapi WWTP from the agricultural fields near the Tehachapi Municipal Airport to a new location south of the Borrow Pit. Overall WWTP effluent production and WWTP throughput capacity would remain unchanged as would the time of year of application (from April to October).

Temporal changes in the vertical distribution of flow and chloride in deep wells

National Groundwater Association (NGWA) | July 4th, 2005

The combination of flowmeter and depth‐dependent water‐quality data was used to evaluate the quantity and source of high‐chloride water yielded from different depth

The combination of flowmeter and depth‐dependent water‐quality data was used to evaluate the quantity and source of high‐chloride water yielded from different depths to eight production wells in the Pleasant Valley area of southern California. The wells were screened from 117 to 437 m below land surface, and in most cases, flow from the aquifer into the wells was not uniformly distributed throughout the well screen. Wells having as little as 6 m of screen in the overlying upper aquifer system yielded as much as 50% of their water from the upper system during drought periods, while the deeper parts of the well screens yielded 15% or less of the total yield of the wells. Mixing of water within wells during pumping degraded higher‐quality water with poorer‐quality water from deeper depths, and in some cases with poorer‐quality water from the overlying upper aquifer system. Changes in the mixture of water within a well, resulting from changes in the distribution of flow into the well, changed the quality of water from the surface discharge of wells over time. The combination of flowmeter and depth‐dependent water quality data yielded information about sources of high‐chloride water to wells that was not available on the basis of samples collected from nearby observation wells. Changing well design to eliminate small quantities of poor‐quality water from deeper parts of the well may improve the quality of water from some wells without greatly reducing well yield.

Temporal concentrations of Quaternary ammonium compounds in wastewater treatment effluents during the COVID-19 pandemic, 2020–2021

Elsevier | November 19th, 2024

Temporal variability in irrigated land and climate influences on salinity loading across the Upper Colorado River Basin, 1986-2017

Environmental Research Letters (IOP) | January 19th, 2024

Term 91: Stored Water Bypass Requirements

California State Water Resources Control Board (SWRCB) | April 8th, 2012

Pursuant to numerous Board decisions (D-1485, D-1641, Order 2001-05), the Projects are required to release stored water to meet water quality standards in the Delta (incl

Pursuant to numerous Board decisions (D-1485, D-1641, Order 2001-05), the Projects are required to release stored water to meet water quality standards in the Delta (including flow and salinity standards) where natural flows are insufficient. The obligation was originally placed on the Projects as an interim measure pending future studies of how the obligation to meet water quality standards would be shared with other appropriators. In return for resolving Project protests on subsequent applications to appropriate water, Term 91 was developed and made a condition to permits issued after 1965. Term 91 prohibits diversions by these Permittees when natural and abandoned flows to the Delta are insufficient to meet the water quality standards and the Projects are supplementing such flows with previously stored water to meet the standards. The purpose of this report is to explore the enhanced use and more vigorous enforcement of diversion curtailments as a means to achieve flow standards. This subject matter is relevant to the Delta even through the Projects are under a present and legal obligation to meet existing flows standards.

The Anatomy of a Drought in the Upper San Francisco Estuary: Water Quality and Lower-Trophic Responses to Multi-Year Droughts Over a Long-Term Record (1975-2021)

University of California, Davis (UC Davis) | December 23rd, 2024

The California Stream Condition Index

California State Water Resources Control Board (SWRCB) | December 1st, 2015

The California Stream Conditon Index (CSCI) is a biological scoring tool that helps aquatc resource managers translate complex data about benthic macroinver

The California Stream Conditon Index (CSCI) is a biological scoring tool that helps aquatc resource managers translate complex data about benthic macroinvertebrates found living in a stream into an overall measure of stream health. The CSCI score indicates whether, and to what degree, the ecology of a stream is altered from a healthy state. Direct measures of ecosystem health like the CSCI are preferable to those based on chemical or physical measurements for many management questons. Living organisms integrate the efects of multple stressors, such as sedimentaton, nutrient enrichment and riparian disturbance, over both space and tme.

The California Stream Condition Index (CSCI): A New Statewide Biological Scoring Tool for Assessing the Health of Freshwater Streams

California State Water Resources Control Board (SWRCB) | September 1st, 2015

California’s dramatic environmental diversity supports a broad array of natural stream types throughout the state. Bioassessment of freshwater stream and rivers is esp

California’s dramatic environmental diversity supports a broad array of natural stream types throughout the state. Bioassessment of freshwater stream and rivers is especially challenging in such a region because the reference condition, or the benchmark of biological condition expected when human disturbance in the environment is absent or minimal, varies greatly among natural stream types. Previous indices used by monitoring programs were developed on a regional basis to help partition the state’s environmental diversity, but statewide assessments were confounded by different criteria used in different regions. The CSCI, which translates complex data about individual benthic macroinvertebrates (BMIs) found living in a stream into an overall measure of stream health, was developed specifically to address some of the shortcomings of earlier indices. First, the CSCI was developed with a much larger, more representative data set that makes it applicable statewide and that covers the broad range of environmental variability among natural stream types. Second, the CSCI sets biological benchmarks for a site based on its site-specific environmental setting. Finally, the CSC combines two separate types of indices, each of which provides unique information about the biological condition of a stream: a multi-metric index (MMI) that measures ecological structure and function, and an observed-to-expected (O/E) index that measures taxonomic completeness. Together they provide multiple lines of evidence about the condition of a stream, providing greater confidence in results than a single index.

The California Stream Condition Index (CSCI): A New Statewide Biological Scoring Tool for Assessing the Health of Freshwater Streams

California State Water Resources Control Board (SWRCB) | October 19th, 2015

California’s dramatic environmental diversity supports a broad array of natural stream types throughout the state. Bioassessment of freshwater stream and rivers is espe

California’s dramatic environmental diversity supports a broad array of natural stream types throughout the state. Bioassessment of freshwater stream and rivers is especially challenging in such a region because the reference condition, or the benchmark of biological condition expected when human disturbance in the environment is absent or minimal, varies greatly among natural stream types. Previous indices used by monitoring programs were developed on a regional basis to help partition the state’s environmental diversity, but statewide assessments were confounded by different criteria used in different regions. The CSCI, which translates complex data about individual benthic macroinvertebrates (BMIs) found living in a stream into an overall measure of stream health, was developed specifically to address some of the shortcomings of earlier indices. First, the CSCI was developed with a much larger, more representative data set that makes it applicable statewide and that covers the broad range of environmental variability among natural stream types. Second, the CSCI sets biological benchmarks for a site based on its site-specific environmental setting. Finally, the CSCI combines two separate types of indices, each of which provides unique information about the biological condition of a stream: a multi-metric index (MMI) that measures ecological structure and function, and an observed-to-expected (O/E) index that measures taxonomic completeness.  Together they provide multiple lines of evidence about the condition of a stream, providing greater confidence in results than a single index.

The Collapse of Pelagic Fishes in the Upper San Francisco Estuary: El Colapso de los Peces Pelagicos en La Cabecera Del Estuario San Francisco

American Fisheries Society (AFS) | January 9th, 2007

Although the pelagic fish community of the upper San Francisco Estuary historically has shown substantial variability, a recent collapse has captured the attention of res

Although the pelagic fish community of the upper San Francisco Estuary historically has shown substantial variability, a recent collapse has captured the attention of resource managers, scientists, legislators, and the general public. The ecological and management consequences of the decline are most serious for delta smelt (Hypomesus transpacificus), a threatened species whose narrow range overlaps with large water diversions that supply water to over 25 million people. The decline occurred despite recent moderate hydrology, which typically results in at least modest recruitment, and investments of hundreds of millions of dollars in habitat restoration and environmental water allocations to support native fishes. In response to the pelagic fish collapse, an ambitious multi-agency research team has been working since 2005 to evaluate the causes of the decline, which likely include a combination of factors: stock-recruitment effects, a decline in habitat quality, increased mortality rates, and reduced food availability due to invasive species.