South Coast

Consumption Change Detection for Urban Planning: Monitoring and Segmenting Water Customers During Drought

American Geophysical Union (AGU) | March 11th, 2020

Demand management is a powerful way for water utilities to address the challenges of population growth and climate change. Although active conservation efforts have been

Demand management is a powerful way for water utilities to address the challenges of population growth and climate change. Although active conservation efforts have been studied extensively, recent evidence suggests households respond to many external events beyond a utility's control, including political responses to extreme climatic episodes and corresponding mass media coverage. Despite their importance, these external factors are difficult to analyze in a controlled setting, and few tools exist to evaluate their influence on customers. Here, we present a consumption change detection (CCD) method that offers new insights into how climate‐related mass media and policy events affect conservation by pinpointing the timing and magnitude of customer‐level water use shifts. We use CCD to monitor and segment the responses of residential water customers to policy and media events in Costa Mesa, California, during the severe 2012–2016 drought. Our results show consumption reductions among 75% of customers. Of these, 80% reduced water use before mandatory restrictions were imposed, coincident with intensifying state policy responses and spikes in media coverage that affected all customer types during 2014. Analysis of standardized drought consumption trajectories indicates that 16% of conserving customers increased consumption in 2015–2016. Conservation and rebound were both more likely among affluent and educated customers, suggesting that CCD can identify engaged and informed water savers who make suitable targets for water‐efficient retrofit incentive schemes. This study demonstrates CCD's potential as a novel demand analysis tool in an interconnected world where external social, political, and climatic stressors can exert an important influence on customer behavior.

Contributions of Climate Change and ENSO Variability to Future Precipitation Extremes Over California

American Geophysical Union (AGU) | June 14th, 2023

Counties Wresting Control: Local Responses to California's Statewide Water Market

University of Denver Water Law Review (UDWLR) | January 1st, 2003

Critical Review: Regulatory Incentives and Impediments for onsite Graywater Reuse in the United States

Water Environment Research | July 11th, 2013

Graywater is a potential water source for reducing water demand. Accordingly, a review was undertaken of graywater reuse regulations and guidelines within the 50 United

Graywater is a potential water source for reducing water demand. Accordingly, a review was undertaken of graywater reuse regulations and guidelines within the 50 United States. Major issues considered included acceptability for graywater segregation as a separate wastewater stream, allowable graywater storage, onsite treatment requirements, and permitted graywater use applications. Existing regulations and plumbing codes in the different states suggest that there are impediments to overcome but also potential incentives for graywater reuse. It is encouraging that regulations in 29 states promote safe graywater reuse, but there are also inconsistencies between plumbing codes and other regulations within and among the 50 states. Impediments to graywater reuse include disallowances of graywater segregation or collection, and restriction of graywater reuse to mostly subsurface irrigation with limited indoor use permission. Ease on restrictions and guidelines to promote development of low-cost and proven treatment technologies are needed to promote graywater reuse.

Dam effects on bedload transport on the upper Santa Ana River, California, and implications for native fish habitat

River Research and Applications (Wiley) | May 23rd, 2019

Dams disrupt the flow of water and sediment and thus have the potential to affect the downstream geomorphic characteristics of a river. Though there are some well‐known

Dams disrupt the flow of water and sediment and thus have the potential to affect the downstream geomorphic characteristics of a river. Though there are some well‐known and common geomorphic responses to dams, such as bed armouring, the response downstream from any particular dam is dependent on local conditions. Herein, we investigate the response of the upper Santa Ana River in southern California, USA, to the construction of a large dam at the transition from mountains to valley, using calculations of bedload transport capacity on the mainstem below the dam and for major tributaries. Approximate sediment budgets were constructed for downstream reaches to estimate deposition and erosion rates for sand, gravel, and cobble particle sizes. Our results indicate that the classical response of bed armouring and erosion is likely limited to a short reach immediately below the dam. Farther downstream, though transport capacity is reduced by flow regulation by the dam, the channel reaches are likely to remain depositional but with reduced deposition rates. Persistent deposition, as opposed to erosion, is the result of the replenishment of flow and sediment supply by large downstream tributaries. In addition, the calculations indicate that the composition of the bed is unlikely to change substantially in downstream reaches. A Monte Carlo approach was employed to estimate the uncertainty in the sediment budget predictions. The impacts of the dam on the geomorphic character of the river downstream could have implications for native fish that rely on coarse substrate that supports their food base.

Dams within Jurisdiction of the State of California

California Department of Water Resources (DWR) | October 31st, 2023

Data from Exploratory Sampling of Groundwater in Selected Oil and Gas Areas of Coastal Los Angeles County and Kern and Kings Counties in Southern San Joaquin Valley, 2014–15

U.S. Geological Survey (USGS) | December 9th, 2016

Exploratory sampling of groundwater in coastal Los Angeles County and Kern and Kings Counties of the southern San Joaquin Valley was done by the U.S. Geological Survey fr

Exploratory sampling of groundwater in coastal Los Angeles County and Kern and Kings Counties of the southern San Joaquin Valley was done by the U.S. Geological Survey from September 2014 through January 2015 as part of the California State Water Resources Control Board’s Water Quality in Areas of Oil and Gas Production Regional Groundwater Monitoring Program. The Regional Groundwater Monitoring Program was established in response to the California Senate Bill 4 of 2013 mandating that the California State Water Resources Control Board design and implement a groundwater-monitoring program to assess potential effects of well-stimulation treatments on groundwater resources in California. The U.S. Geological Survey is in cooperation with the California State Water Resources Control Board to collaboratively implement the Regional Groundwater Monitoring Program through the California Oil, Gas, and Groundwater Project. Many researchers have documented the utility of different suites of chemical tracers for evaluating the effects of oil and gas development on groundwater quality. The purpose of this exploratory sampling effort was to determine whether tracers reported in the literature could be used effectively in California. This reconnaissance effort was not designed to assess the effects of oil and gas on groundwater quality in the sampled areas. A suite of water-quality indicators and geochemical tracers were sampled at groundwater sites in selected areas that have extensive oil and gas development. Groundwater samples were collected from a total of 51 wells, including 37 monitoring wells at 17 multiple-well monitoring sites in coastal Los Angeles County and 5 monitoring wells and 9 water-production wells in southern San Joaquin Valley, primarily in Kern and Kings Counties. Groundwater samples were analyzed for field water-quality indicators; organic constituents, including volatile and semi-volatile organic compounds and dissolved organic carbon indicators; naturally present inorganic constituents, including trace elements, nutrients, major and minor ions, and iron species; naturally present stable and radioactive isotopes; dissolved noble gases; dissolved standard and hydrocarbon gases, ?13C of methane, ethane, and ?2H of methane. In total, 249 constituents and water-quality indicators were measured. Four types of quality-control samples (blanks, replicates, matrix spikes, and surrogates spiked in environmental and blank samples) were collected at approximately 10 percent of the wells. The quality-control data were used to determine whether the groundwater-sample data were of sufficient quality for the measured analytes to be used as potential indicators of oil and gas effects. The data from the 51 groundwater samples and from the quality-control samples are presented in this report.

DDT Residues in Pacific Sea Birds: a Persistent Insecticide in Marine Food Chains

Nature Portfolio (Springer Nature) | November 1st, 1967

THE accumulation and biological concentration of DDT and its metabolites*within food chains of terrestrial, freshwater and estuarine ecosystems have been well doc

THE accumulation and biological concentration of DDT and its metabolites*within food chains of terrestrial, freshwater and estuarine ecosystems have been well documented. Significant residue concentrations have occasionally been reported in marine organisms, but these have usually been attributed to local sources of contamination4. The present study, which is based on analyses of collections of birds, fish and invertebrates from Pacific Ocean localities, indicates that DDT is also a component of marine ecosystems and that pelagic species may accumulate high concentrations of DDT residues. The results of the work with fish will be published elsewhere.

Debris flow occurrence under changing climate and wildfire regimes: A southern California perspective

Geomorphology (Elsevier) | December 2nd, 2022

In southern California, wildfire incidents are increasing in frequency and magnitude. There is a great deal of research predicting the impact of climate change on large s

In southern California, wildfire incidents are increasing in frequency and magnitude. There is a great deal of research predicting the impact of climate change on large scale fire regimes. These impacts, now the new normal, include increases in future fire incidents and burn severities. Yet predictive studies on how ecosystems respond to changing fire regimes are lacking. Identifying trends in post-fire erosion patterns, such as post-fire debris flows, is critical for increasing human resiliency and adaptation to changing weather patterns and eventual long-term climate change. The relative historical abundance of post-fire debris flows in southern California presents this concern: will worsening wildfire regimes result in more post-fire debris flows? Our research addresses this concern by utilizing a descriptive approach to analyze post-fire debris flows in southern California from 2001 to 2018 to elucidate possible trends. We found that 84 % of debris flows originate from watersheds with soils burnt at moderate soil burn severity. We found that debris flow occurrence is more reliant on the percent coverage of a soil burn severity classification than its areal extent. Further, larger fires also tended to produce more debris flows and most (73 %) debris flow watersheds occurred in predominantly bedrock areas. Our research suggests that the number of post-fire runoff-generated debris flows in the region will increase if fires continue to increase in size, occur on slopes of at least 20°, burn south-facing watersheds with bedrock of igneous or sedimentary origin to at least a moderate severity, and peak rainfall intensity return intervals do not change. These findings highlight the interconnectivity between natural erosive processes, wildfires, humans, and climate change.

Decline of the world's saline lakes

Nature Portfolio (Springer Nature) | October 23rd, 2017

Many of the world's saline lakes are shrinking at alarming rates, reducing waterbird habitat and economic benefits while threatening human health. Saline lakes are long-t

Many of the world's saline lakes are shrinking at alarming rates, reducing waterbird habitat and economic benefits while threatening human health. Saline lakes are long-term basin-wide integrators of climatic conditions that shrink and grow with natural climatic variation. In contrast, water withdrawals for human use exert a sustained reduction in lake inflows and levels. Quantifying the relative contributions of natural variability and human impacts to lake inflows is needed to preserve these lakes. With a credible water balance, causes of lake decline from water diversions or climate variability can be identified and the inflow needed to maintain lake health can be defined. Without a water balance, natural variability can be an excuse for inaction. Here we describe the decline of several of the world's large saline lakes and use a water balance for Great Salt Lake (USA) to demonstrate that consumptive water use rather than long-term climate change has greatly reduced its size. The inflow needed to maintain bird habitat, support lake-related industries and prevent dust storms that threaten human health and agriculture can be identified and provides the information to evaluate the difficult tradeoffs between direct benefits of consumptive water use and ecosystem services provided by saline lakes.