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Long-term climate and competition explain forest mortality patterns under extreme drought

Ecology Letters (Wiley) | December 20th, 2016

Summary

Rising temperatures are amplifying drought‐induced stress and mortality in forests globally. It remains uncertain, however, whether tree mortality across drought‐stri

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Long-term groundwater depletion in the United States

National Groundwater Association (NGWA) | December 15th, 2014

Summary

The volume of groundwater stored in the subsurface in the United States decreased by almost 1000 km3 during 1900–2008. The aquifer systems with the three largest volu

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Long-term Monitoring of Pollutants in Fish and Mussels Documents Major Improvements and Persistent Problems

California State Water Resources Control Board (SWRCB) | December 1st, 2007

Summary

Of the 390 sites sampled between 1998 and 2003, 32 percent fell into the “low” contamination category. These sites were scattered throughout the state, with

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Long-Term Operations of the Central Valley Project and State Water Project Draft Environmental Impact Statement

U.S. Bureau of Reclamation (USBR) | July 26th, 2024

Summary

The Bureau of Reclamation (Reclamation) prepared this Environmental Impact Statement (EIS) for the 2021 Endangered Species Act Reinitiation of Section 7 Consultation on t

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Long-term variation in concentrations and mass loads in a semi-arid watershed influenced by historic mercury mining and urban pollutant sources

Science of the Total Environment (Elsevier) | December 15th, 2017

Summary

Urban watersheds are significantly anthropogenically-altered landscapes. Most previous studies cover relatively short periods, without addressing concentrations, loads, a

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Longitudinal metatranscriptomic sequencing of Southern California wastewater representing 16 million people from August 2020–21 reveals widespread transcription of antibiotic resistance genes

Water Research (Elsevier) | November 22nd, 2022

Summary

Municipal wastewater provides a representative sample of human fecal waste across a catchment area and contains a wide diversity of microbes. Sequencing wastewater sample

Municipal wastewater provides a representative sample of human fecal waste across a catchment area and contains a wide diversity of microbes. Sequencing wastewater samples provides information about human-associated and medically important microbial populations, and may be useful to assay disease prevalence and antimicrobial resistance (AMR). Here, we present a study in which we used untargeted metatranscriptomic sequencing on RNA extracted from 275 sewage influent samples obtained from eight wastewater treatment plants (WTPs) representing approximately 16 million people in Southern California between August 2020 – August 2021. We characterized bacterial and viral transcripts, assessed metabolic pathway activity, and identified over 2,000 AMR genes/variants across all samples. Because we did not deplete ribosomal RNA, we have a unique window into AMR carried as ribosomal mutants. We show that AMR diversity varied between WTPs (as measured through PERMANOVA, P < 0.001) and that the relative abundance of many individual AMR genes/variants increased over time (as measured with MaAsLin2, Padj < 0.05). Similarly, we detected transcripts mapping to human pathogenic bacteria and viruses suggesting RNA sequencing is a powerful tool for wastewater-based epidemiology and that there are geographical signatures to microbial transcription. We captured the transcription of gene pathways common to bacterial cell processes, including central carbon metabolism, nucleotide synthesis/salvage, and amino acid biosynthesis. We also posit that due to the ubiquity of many viruses and bacteria in wastewater, new biological targets for microbial water quality assessment can be developed. To the best of our knowledge, our study provides the most complete longitudinal metatranscriptomic analysis of a large population's wastewater to date and demonstrates our ability to monitor the presence and activity of microbes in complex samples. By sequencing RNA, we can track the relative abundance of expressed AMR genes/variants and metabolic pathways, increasing our understanding of AMR activity across large human populations and sewer sheds.

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Los Angeles Basin Stormwater Conservation Study: Plan of Study

U.S. Bureau of Reclamation (USBR) | February 28th, 2013

Summary

Imported water supplies to Los Angeles County, California, are uncertain due to periodic droughts in northern California and the Colorado River Basin, court decisions r

Imported water supplies to Los Angeles County, California, are uncertain due to periodic droughts in northern California and the Colorado River Basin, court decisions related to endangered species in the Bay Delta, and potential allocations of Colorado River water. Changing demographics, climate variability, and the competing interest for available water present additional long-term risks to the stability and reliability of imported water. Accordingly, various Los Angeles area agencies with water management authority, such as the Los Angeles County Flood Control District (LACFCD), are actively pursuing a strategy aimed at achieving water independence by developing local water resources such as stormwater. The LACFCD is the primary agency for conducting groundwater replenishment operations in Los Angeles County. In typical years, the LACFCD infiltrates more than 270,000 acre-feet of captured stormwater, imported water, and recycled water into the various groundwater basins in Los Angeles County. In wetter years, that number can exceed 700,000 acre-feet and, in drier years, may be little more than 150,000 acre-feet. LACFCD partnered with the U.S. Department of the Interior, Bureau of Reclamation’s (Reclamation) Southern California Area Office to study long-term flood control and water conservation impacts from projected population and climate conditions. The Los Angeles Basin Stormwater Conservation Study (Basin Study) will recommend potential changes to the operation of stormwater capture systems, modifications to existing facilities, and development of new facilities that could help resolve future flood control and water supply issues. The Los Angeles River, San Gabriel River, Ballona Creek, South Santa Monica Bay, North Santa Monica Bay, and Dominguez Channel/Los Angeles Harbor watersheds (Watersheds) are the focus of this Basin Study (figure 1). This study incorporates the entire watershed boundaries, including where they extend outside Los Angeles County. The Watersheds share attributes such as overlapping municipal and water agency boundaries, an interconnected flood control system, and a common planning purpose with major ongoing planning efforts like the Greater Los Angeles County Integrated Regional Water Management Plan (IRWMP), Gateway IRWMP and the Metropolitan Water District Integrated Resources Plan. Related links: Los Angeles Basin Study Summary Report Task 2: Water Supply and Demand Analysis Click here for Reclamation's index of inter-related LA Basin Study reports and appendices.

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Los Angeles Basin Stormwater Conservation Study: Task 2 Water Supply & Water Demand Projections

U.S. Bureau of Reclamation (USBR) | December 1st, 2014

Summary

The Los Angeles County Flood Control District (LACFCD) partnered with the U.S. Department of the Interior, Bureau of Reclamation (Reclamation) to collaborate on t

The Los Angeles County Flood Control District (LACFCD) partnered with the U.S. Department of the Interior, Bureau of Reclamation (Reclamation) to collaborate on the Los Angeles Basin Stormwater Conservation Study (LA Basin Study). The purpose of the LA Basin Study is to study long-term water conservation and flood control impacts from projected climate conditions and population changes in the Los Angeles Basin. The LA Basin Study will recommend potential changes to the operation of stormwater capture systems, modifications to existing facilities, and development of new facilities that could help resolve future water supply and flood control issues. The recommendations will be developed through identifying alternatives and conducting trade-off analyses. For Task 2 of the LA Basin Study, Water Supply and Water Demand Projections, existing and projected water supplies and demands were characterized for the LA Basin Study Area (Study Area) out to 2095, with consideration of projected climate change effects. It is important to note that this Task 2 report inventories projected available supplies (i.e., potential supplies), and does not make assumptions for the volume of each supply source that will actually be used to meet projected demands, nor the facilities necessary to access and serve those supplies. This determination would require more in-depth integrated supply and demand planning to predict and analyze the multitude of factors that influence water supply and use decisions such as policy, cost, environmental factors, reliability, etc. This Task 2 report is intended to provide a supply and demand basis for understanding the potential need and benefit of additional stormwater capture systems that could be implemented across the region by the LACFCD and its partners. Given that stormwater is a local and relatively inexpensive source of supply, it must be a critical and substantial part of the LA Basin water supply portfolio that could help meet demands through 2095 and beyond.

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Los Angeles Basin Stormwater Conservation Study: Task 3.1 Climate Change and Hydrologic Projections Appendices

U.S. Bureau of Reclamation (USBR) | October 1st, 2013

Summary

Reclamation’s Technical Service Center (TSC) performed Task 3.1 of the LA Basin Study—to develop and evaluate projected future climate conditions related to precipita

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Los Angeles Basin Stormwater Conservation Study: Task 3.2 Hydrologic Modeling Report

U.S. Bureau of Reclamation (USBR) | December 3rd, 2013

Summary

The Los Angeles County Flood Control District (LACFCD) partnered with the U.S. Department of the Interior, Bureau of Reclamation (Reclamation) to collaborate on t

The Los Angeles County Flood Control District (LACFCD) partnered with the U.S. Department of the Interior, Bureau of Reclamation (Reclamation) to collaborate on the Los Angeles Basin Stormwater Conservation Study (LA Basin Study). The purpose of the LA Basin Study is to investigate long-range water conservation and flood control impacts caused by projected changes in climate conditions and population in the Los Angeles region. The LA Basin Study will recommend potential modifications or changes in the operation of the existing stormwater capture systems, and the development of new facilities that could help resolve future water supply and flood control issues. These recommendations will be developed by identifying alternatives and conducting trade-off analyses. For Task 3, Downscaled Climate Change and Hydrologic Modeling of the LA Basin Study, Reclamation developed downscaled climate change projections, while LACFCD applied these projections to generate the future hydrology. LACFCD utilized the Watershed Management Modeling System (WMMS) to perform the hydrologic modeling for the LA Basin Study. This report summarizes the data, methods, and results of the historic and future hydrologic modeling. The purpose of Task 3.2, Hydrologic Modeling is to simulate hydrology with respect to climate change for the Los Angeles River, San Gabriel River, Ballona Creek, South Santa Monica Bay, North Santa Monica Bay, Malibu Creek, and Dominguez Channel/Los Angeles Harbor watersheds (Basin Study Watersheds). This study incorporates the entire watershed boundaries, including where they extend outside of Los Angeles County. The following sub-tasks were identified to achieve this objective: Historic Hydrologic Modeling (Water Year 1987 through 2000) Determine baseline scenario modeling assumptions Prepare WMMS to simulate baseline scenario Perform WMMS baseline simulations Analyze and summarize WMMS results Projected Hydrologic Modeling (Water Year 2012 through 2095) Determine future scenario modeling assumptions Prepare WMMS to simulate future scenarios Perform WMMS simulations Analyze and summarize WMMS results

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Page : 283

Long-term climate and competition explain forest mortality patterns under extreme drought

Long-term groundwater depletion in the United States

Long-term Monitoring of Pollutants in Fish and Mussels Documents Major Improvements and Persistent Problems

Long-Term Operations of the Central Valley Project and State Water Project Draft Environmental Impact Statement

Long-term variation in concentrations and mass loads in a semi-arid watershed influenced by historic mercury mining and urban pollutant sources

Longitudinal metatranscriptomic sequencing of Southern California wastewater representing 16 million people from August 2020–21 reveals widespread transcription of antibiotic resistance genes

Los Angeles Basin Stormwater Conservation Study: Plan of Study

Los Angeles Basin Stormwater Conservation Study: Task 2 Water Supply & Water Demand Projections

Los Angeles Basin Stormwater Conservation Study: Task 3.1 Climate Change and Hydrologic Projections Appendices

Los Angeles Basin Stormwater Conservation Study: Task 3.2 Hydrologic Modeling Report

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