Using Watershed Science to Build Consensus and Maximize Benefits of L.A. County’s Safe Clean Water Program

Accelerate Resilience LA (ARLA) | January 31st, 2022

To meet its diverse goals, SCWP scoring criteria, processes, and guidelines were initially developed to incentivize projects that simultaneously address water, environmen

To meet its diverse goals, SCWP scoring criteria, processes, and guidelines were initially developed to incentivize projects that simultaneously address water, environmental, MS4 compliance, and social issues. However, the first two SCWP funding cycles of Stormwater Investment Plans (SIP) featured extensive committee debate and public comments concerning the balance of these goals. This public debate illuminated the need for an assessment of the extent to which SCWP guidance, criteria, structure, and processes are successfully driving meaningful progress toward the fourteen SCWP Goals.

Value of SWAMP's Statewide Monitoring Programs

California State Water Resources Control Board (SWRCB) | October 1st, 2011

One of the key features of probability-based surveys such as the Surface Water Ambient Monitoring Program’s (SWAMP) Perennial Streams Assessment (PSA) is thei

One of the key features of probability-based surveys such as the Surface Water Ambient Monitoring Program’s (SWAMP) Perennial Streams Assessment (PSA) is their lack of bias in the selection of sample sites. In the case of the PSA, each sampling location represents a known fraction of California’s stream network. This allows the State to produce statistically sound and cost-effective estimates of the condition of California’s perennial stream network.

Variable coastal hypoxia exposure and drivers across the southern California Current

Nature Portfolio (Springer Nature) | May 25th, 2021

Declining oxygen is one of the most drastic changes in the ocean, and this trend is expected to worsen under future climate change scenarios. Spatial variability in disso

Declining oxygen is one of the most drastic changes in the ocean, and this trend is expected to worsen under future climate change scenarios. Spatial variability in dissolved oxygen dynamics and hypoxia exposures can drive differences in vulnerabilities of coastal ecosystems and resources, but documentation of variability at regional scales is rare in open-coast systems. Using a regional collaborative network of dissolved oxygen and temperature sensors maintained by scientists and fishing cooperatives from California, USA, and Baja California, Mexico, we characterize spatial and temporal variability in dissolved oxygen and seawater temperature dynamics in kelp forest ecosystems across 13° of latitude in the productive California Current upwelling system. We find distinct latitudinal patterns of hypoxia exposure and evidence for upwelling and respiration as regional drivers of oxygen dynamics, as well as more localized effects. This regional and small-scale spatial variability in dissolved oxygen dynamics supports the use of adaptive management at local scales, and highlights the value of collaborative, large-scale coastal monitoring networks for informing effective adaptation strategies for coastal communities and fisheries in a changing climate.

Variations on a method for evaluating decadal-scale changes in the groundwater quality of two GAMA coastal study units 2004–14, California GAMA Priority Basin Project

U.S. Geological Survey (USGS) | August 8th, 2018

Decadal changes in groundwater quality in two study units on the north-central California coast were evaluated by the Priority Basin Project (PBP) of the Groundwater Ambi

Decadal changes in groundwater quality in two study units on the north-central California coast were evaluated by the Priority Basin Project (PBP) of the Groundwater Ambient Monitoring and Assessment (GAMA) Program. Groundwater samples collected from wells during 2004–05 were compared on a pair-wise basis to samples collected from the same wells during 2014. The data set consisted of paired-samples from 50 public supply wells in 2 GAMA-PBP study units (25 wells each in the North San Francisco Bay and the Monterey Bay and Salinas Valley Basins), with analytical results for 160 water-quality constituents. Statistical analysis was done on grouped results for the 59 constituents that were detected in at least 10 percent of the samples during either sampling period to evaluate decadal-scale change by a step-trend analysis. The data for both of the sampling periods were processed three different ways, resulting in three variations of the paired results to be submitted for statistical analyses. The first evaluation method variation processed data only to facilitate comparison of data when one or both of the results was a non-detection. The second and third variations applied the additional requirement that differences between initial and decadal-sample results exceed a defined threshold to prevent small differences from supporting the conclusion of a step trend. One method for setting the difference threshold between initial-sampling and resampling results is based on criteria used by the GAMA-PBP to determine whether or not replicate results are acceptable. The other difference-threshold-setting method uses a calculated confidence interval around each result based on demonstrated analytical variability for the constituents during each sampling period. Finally, constituents for which decadal-scale changes were statistically significant were identified using the Wilcoxon-Pratt signed-rank test on each of the three evaluation method variations. Step trends were identified by at least 1 of the 3 method variations for 33 constituents. After considering other factors, however, such as water-quality context and the results of quality-control samples, it was concluded that decadal changes were meaningful for 14 constituents in at least 1 of the 2 study units. Constituents for which step trends indicated meaningful increases were dissolved oxygen, total nitrogen, nitrate, orthophosphate, calcium, chloride, sulfate, iron, and lithium. Constituents for which step trends indicated meaningful decreases were temperature, arsenic, lead, the isotopic ratio of carbon-13, and tritium.

Volatile organic compounds in groundwater used for public supply across the United States: Occurrence, explanatory factors, and human-health context

Science of the Total Environment (Elsevier) | March 11th, 2022

This systematic assessment of occurrence for 85 volatile organic compounds (VOCs) in raw (untreated) groundwater used for public supply across the United States (U.S.), w

This systematic assessment of occurrence for 85 volatile organic compounds (VOCs) in raw (untreated) groundwater used for public supply across the United States (U.S.), which includes 43 compounds not previously monitored by national studies, relates VOC occurrence to explanatory factors and assesses VOC detections in a human-health context. Samples were collected in 2013 through 2019 from 1537 public-supply wells in aquifers representing 78% of the volume pumped for public drinking-water supply. Laboratory detection limits for VOCs generally were less than 0.1 μg/L. Detections were reported for 36% of the sampled principal-aquifer area (38% of sampled wells) and were most common in wells in shallow, unconfined aquifers in urban areas that produce high proportions of modern-age and oxic groundwater. The disinfection by-product trichloromethane (chloroform) was the most commonly detected VOC associated primarily with anthropogenic sources (24% of the sampled area, 25% of sampled wells), followed by the gasoline oxygenate methyl tert-butyl ether (8.4% of area, 11% of wells). Carbon disulfide (12% of area, 14% of wells) was examined separately because of likely substantial contributions from natural sources. Newly monitored VOCs were each detected in

Volatile Organic Compounds in the Nation’s Ground Water and Drinking Water Supply Wells

U.S. Geological Survey (USGS) | August 29th, 2014

This national assessment of 55 volatile organic compounds (VOCs) in ground water gives emphasis to the occurrence of VOCs in aquifers that are used as an important supply

This national assessment of 55 volatile organic compounds (VOCs) in ground water gives emphasis to the occurrence of VOCs in aquifers that are used as an important supply of drinking water. In contrast to the monitoring of VOC contamination of ground water at point-source release sites, such as landfills and leaking underground storage tanks (LUSTs), our investigations of aquifers are designed as large-scale resource assessments that provide a general characterization of water-quality conditions. Nearly all of the aquifers included in this assessment have been identified as regionally extensive aquifers or aquifer systems.(2)  The assessment of ground water (Chapter 3) included analyses of about 3,500 water samples collected during 1985–2001 from various types of wells, representing almost 100 different aquifer studies. This is the first national assessment of the occurrence of a large number of VOCs with different uses, and the assessment addresses key questions about VOCs in aquifers. The assessment also provides a foundation for subsequent decadal assessments of the U.S. Geological Survey (USGS) National Water-Quality Assessment (NAWQA) Program to ascertain long-term trends of VOC occurrence in these aquifers.

Vulnerability Assessments in Support of the Climate Ready Estuaries Program: A Novel Approach Using Expert Judgment, Volume I

U.S. Environmental Protection Agency (EPA) | January 1st, 2012

The San Francisco Bay estuary is highly vulnerable to climate - related changes including increased water temperatures, changes in precipitation and winds, and sea leve

The San Francisco Bay estuary is highly vulnerable to climate - related changes including increased water temperatures, changes in precipitation and winds, and sea level rise. Impacts such as increased inundation of coastal wetlands, changes in water availability and quality, and altered patterns of sedimentation and erosion are increasingly interacting with other human stressors such as extractive water uses and land use changes. Thus it is essential that estuary managers become ‘climate-ready’ by: assessing the vulnerability of natural resources to climate change; considering strategic choices among adaptation strategies in the near term; and engaging in longer term planning based on a range of plausible scenarios of future change. In an era of shrinking budgets coupled with increasingly complex decision-making needs—often taking place in a context of uncertainty and incomplete information— managing natural resources in the face of climate change will be challenging. There is a need for assessment methods that take advantage of existing scientific expertise to help identify robust adaptation strategies, weigh difficult trade-offs, and justify strong action, all in a timely and efficient manner. The purpose of this project was to carry out a pilot vulnerability assessment for the San Francisco Estuary Partnership’s (SFEP) natural resources using expert judgment, the results of which could be linked to adaptation planning. To this aim, EPA’s Office of Research and Development collaborated with SFEP and the San Francisco Bay Conservation and Development Commission on a novel expert elicitation exercise for ‘rapid’ vulnerability assessment. A trial exercise was carried out during a two-day workshop in which two groups of seven experts each focused on two key ecosystem processes: sediment retention in salt marshes and community interactions of shorebirds with their predators and prey (see Figure ES - 1). The exercise, which was based on formal expert elicitation techniques but tailored specifically for qualitative analysis of ecosystem processes, was designed to glean expert information on the sensitivities of ecosystem process components under future climate scenarios . This was followed by group discussions of the implications of the results for management in light of climate change, as well as feedback on the exercise itself.  

Wastewater Infrastructure: Overview, Funding, and Legislative Developments

Congressional Research Service (CRS) | September 22nd, 2017

The collection and treatment of wastewater remains among the most important public health interventions in human history and has contributed to a significant decrease in

The collection and treatment of wastewater remains among the most important public health interventions in human history and has contributed to a significant decrease in waterborne diseases during the past century. Nevertheless, waste discharges from municipal sewage treatment plants into rivers and streams, lakes, and estuaries and coastal waters remain a significant source of water quality problems throughout the country. The Clean Water Act (CWA) establishes performance levels to be attained by municipal sewage treatment plants in order to prevent the discharge of harmful wastes into surface waters. The act also provides financial assistance so that communities can construct treatment facilities and related equipment to comply with the law. Although approximately $95 billion in CWA assistance has been provided since 1972, funding needs for wastewater infrastructure remain high. According to the most recent estimate by the Environmental Protection Agency and the states, the nation’s wastewater treatment facilities will need $271 billion over the next 20 years to meet the CWA’s water quality objectives. Meeting the nation’s wastewater infrastructure needs efficiently and effectively is likely to remain an issue of considerable interest to policymakers. The CWA authorizes the principal federal program to support wastewater treatment plant construction and related eligible activities. Congress established the CWA Title II construction grants program in 1972, significantly enhancing what had previously been a modest grant program. Federal funds were provided through annual appropriations under a state-by-state allocation formula contained in the act. States used their allotments to make grants to cities to build or upgrade categories of wastewater treatment projects including treatment plants, related interceptor sewers, correction of infiltration/inflow of sewer lines, and sewer rehabilitation. In 1987, Congress amended the CWA and created the State Water Pollution Control Revolving Fund (SRF) program. This program represented a major shift in how the nation finances wastewater treatment needs. In contrast to the Title II construction grants program, which provided grants directly to localities, SRFs are loan programs. States use their SRFs to provide several types of loan assistance to communities, including project construction loans made at or below market interest rates, refinancing of local debt obligations, providing loan guarantees, and purchasing insurance. In 2014, Congress revised the SRF program by providing additional loan subsidies (including forgiveness of principal and negative interest loans) in certain instances. The law identifies a number of types of projects as eligible for SRF assistance, including wastewater treatment plant construction, stormwater treatment and management, energy-efficiency improvements at treatment works, reuse and recycling of wastewater or stormwater, and security improvements at treatment works. In both FY2016 and FY2017, Congress provided $1.394 billion for the clean water SRF program. President Trump’s FY2018 budget proposal requests the same amount as provided for the previous two fiscal years. Although appropriation levels have remained consistent in recent years (in nominal dollars), policymakers have continued to propose changes to the funding program. Issues debated in connection with these proposals include extending SRF assistance to help states and cities meet the estimated funding needs, modifying the program to assist small and economically disadvantaged communities, and enhancing the SRF program to address a number of water quality priorities beyond traditional treatment plant construction—particularly the management of wet weather pollutant runoff from numerous sources, which is the leading cause of stream and lake impairment nationally.

Wastewater Reuse for Agriculture: Development of a Regional Water Reuse Decision-Support Model (RWRM) for Cost-Effective Irrigation Sources

American Chemical Society (ACS) | August 8th, 2016

Water scarcity has become a critical problem in many semiarid and arid regions. The single largest water use in such regions is for crop irrigation, which typically relie

Water scarcity has become a critical problem in many semiarid and arid regions. The single largest water use in such regions is for crop irrigation, which typically relies on groundwater and surface water sources. With increasing stress on these traditional water sources, it is important to consider alternative irrigation sources for areas with limited freshwater resources. One potential irrigation water resource is treated wastewater for agricultural fields located near urban centers. In addition, treated wastewater can contribute an appreciable amount of necessary nutrients for plants. The suitability of reclaimed water for specific applications depends on water quality and usage requirements. The main factors that determine the suitability of recycled water for agricultural irrigation are salinity, heavy metals, and pathogens, which cause adverse effects on human, plants, and soils. In this paper, we develop a regional water reuse decision-support model (RWRM) using the general algebraic modeling system to analyze the cost-effectiveness of alternative treatment trains to generate irrigation water from reclaimed wastewater, with the irrigation water designed to meet crop requirements as well as California’s wastewater reuse regulations (Title 22). Using a cost-minimization framework, least-cost solutions consisting of treatment processes and their intensities (blending ratios) are identified to produce alternative irrigation sources for citrus and turfgrass. Our analysis illustrates the benefits of employing an optimization framework and flexible treatment design to identify cost-effective blending opportunities that may produce high-quality irrigation water for a wide range of end uses.

Wastewater surveillance for public health

American Association for the Advancement of Science (AAAS) | January 5th, 2023